Patent Application
20140213834
This disclosure relates to ultra high viscosity, synthetic polyalphaolefin fluids useful as lubricating oil base stocks or co-base stocks, lubricating oils derived therefrom, and processes for preparing same.
Lubricants in commercial use today are prepared from a variety of natural and synthetic base stocks admixed with various additive packages and solvents depending upon their intended application. The base stocks typically include mineral oils, polyalphaolefins (PAO), gas-to-liquid base oils (GTL), silicone oils, phosphate esters, diesters, polyol esters, and the like.
A major trend for industrial engine oils is an overall improvement in quality as higher quality base stocks become more readily available. Typically the highest quality industrial products are formulated with base stocks such as PAOs or GTL stocks.
Conventional PAOs are produced using promoted BF3 or AlCl3 catalysts and are commercially available. Conventional high viscosity PAOs are produced using activated chromium on silica gel catalysts and are commercially available. However, these PAOs have broad molecular weight distribution that results in low shear stability of the product.
Conventional very high viscosity PAO is produced using activated chromium on silica gel catalyst. However, these PAO fluids have broad molecular weight distribution that results in low shear stability of the product. Also, the fluid is produced using a process with low productivity. There are other commercially available fluids, e.g., such as Lucant 600 cSt produced by Mitsui Chemicals. However, these products have low viscosity index (VI) and high pour points.
High viscosity PAOs made with metallocenes have not found wide applicability in the marketplace, particularly the lubricant marketplace, due to inefficient process, cost and property deficits. The instant disclosure address such and other needs by providing new PAOs having excellent property combinations and an improved process to produce them.
High viscosity index polyalphaolefins prepared by polymerization of alphaolefins using reduced metal oxide catalysts (e.g., chromium) are described in U.S. Pat. Nos. 4,827,064; 4,827,073; 4,990,771; 5,012,020; and 5,264,642. These high viscosity index polyalphaolefins are characterized by having a high viscosity index of 130 and above, a branch ratio of less than 0.19, a weight average molecular weight of between 300 and 45,000, a number average molecular weight of between 300 and 18,000. However, the molecular weight distribution of these fluids are generally >2, that results in low shear stability fluids.
One problem facing producers of high viscosity index polyalphaolefins is that of reducing the unsaturation of the as-polymerized carbon chains of the PAO products, which can be quantified by bromine number (ASTM D1159). A PAO fluid cannot be satisfactorily used as a lubricant base stock if its bromine number exceeds 3. The unsaturation indicated by higher bromine number can result in poor high temperature stability of the PAO molecules. Accordingly, it is typical to hydrogenate these as-polymerized PAO products in order to reduce the level of unsaturation in the molecules, so as to render them suitable for use as lubricant base stocks. WO 2007/011462 discloses post-polymerization hydrogenation in order to produce a polyalphaolefin having a bromine number of less than 2.
There is an unmet need in the art to optimize the polymerization reaction process for producing PAOs, so as to avoid the need for expensive, post-polymerization hydrogen finishing, such that the as-polymerized product is suitable for use as a lubricant base stock. Also, there is a need to improve catalyst productivity, so that the cost for the total catalyst system can be reduced and the catalyst system removal can be simplified. This improved productivity can improve the overall process economics.
Further, there is a need for ‘ultra’ high viscosity (300-900 cSt at 100° C.) fluids for industrial lubes. There is a need for very high viscosity products (300-900 cSt at 100° C.) with very high VI, low pour points (unlike Lucant 600 type product) and fluids with narrow molecular weight distribution and high shear stability (unlike SpectraSyn Ultra 300 product).
The present disclosure also provides many additional advantages, which shall become apparent as described below.
This disclosure relates in part to a composition related to the synthesis of specific synthetic fluids with specific physical properties. The specific fluid is a fluid that can be used as synthetic base stock or co-base stock for lubes, especially for industrial lubes. The fluid has following physical properties. The fluid has ‘ultra’ high viscosity (Kv100 300-900 cSt) with high viscosity index (VI) (>250), low pour points (PP) (<−25° C.), narrow molecular weight distribution (<2.0) as synthesized, low residual unsaturation (Bromine Number <2.0) as synthesized, low glass transition temperature Tg (<−60° C.), no crystallization peak as measured by differential scanning calorimetry and high thermal stability. Moreover, the fluid is produced using a process with very high productivity (>50,000 g lube/g of catalyst).
In accordance with this disclosure, ‘ultra’ high viscosity fluids with very high VI and very low pour points can be prepared. These fluids also have superior shear stability, superior oxidative stability and superiors low temperature properties. Furthermore, the ‘ultra’ high viscosity PAOs have low bromine number (low residual double bonds or unsaturation) and no crystalline peak but only low glass-transition temperature peak as measured by differential scanning calorimetry (DSC).
This disclosure further relates in part to a polyalphaolefin (PAO) fluid comprising a polymer of one or more C8 to C12 alphaolefin monomers. The PAO has:
The PAO further has:
This disclosure yet further relates in part to a process for producing a polyalphaolefin (PAO). The process comprises: contacting in a reactor a feed stream comprising at least one alphaolefin monomer having 8 to 12 carbon atoms with a catalyst system comprising a precatalyst compound and a non-coordinating anion activator, and optionally an alkyl-aluminum compound, under polymerization conditions, optionally in the presence of hydrogen, and the alphaolefin monomer having 8 to 12 carbon atoms is present at 10 volume % or more, based upon the total volume of the catalyst, monomers, and any diluents or solvents present, in the reactor; and obtaining the PAO; wherein the precatalyst compound is represented by the formula
wherein:
M is a group 4 metal;
L1 is a unsubstituted fluorenyl, unsubstituted heterocyclopentapentalenyl, unsubstituted heterofluorenyl, substituted fluorenyl, substituted heterocyclopentapentalenyl, or substituted heterofluorenyl ligand with pseudo symmetric substituents, each substituent group being, independently, a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl, and optionally two or more adjacent substituents may join to form a substituted or unsubstituted, saturated, partially unsaturated or aromatic, cyclic or polycyclic substituent;
L2 is a cyclopentadienyl ring or a substituted cyclopentadienyl ring with pseudo symmetric substituents in the 2 and 5 positions of the ring, each substituent group being, independently, a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl;
G is a bridging group; and
each X is independently halogen, alkoxide, aryloxide, amide, phosphide, hydride radicals, hydrocarbyl radicals, substituted hydrocarbyl radicals, halocarbyl radicals, substituted halocarbyl radicals, silylcarbyl radicals, substituted silylcarbyl radicals, germylcarbyl radicals, or substituted germylcarbyl radicals; or both X are joined and bound to the metal atom to form a metallacycle ring containing from 3 to 20 carbon atoms; or both together can be an olefin, diolefin or aryne ligand; or both X can also be joined to form a anionic chelating ligand.
The polyalphaolefin fluids of this disclosure have very high viscosity (300-900 cSt at 100° C.) with very high VI, low pour points (unlike Lucant 600 type products) and fluids with narrow molecular weight distribution and high shear stability (unlike SpectraSyn Ultra 300 products). The ‘ultra’ high viscosity fluids also have superior shear stability, superior oxidative stability and superior low temperature properties. Furthermore, the ‘ultra’ high viscosity PAOs have low bromine number (low residual double bonds or unsaturation) and no crystalline peak but only low glass-transition temperature peak as measured by differential scanning calorimetry (DSC).
Further objects, features and advantages of the present disclosure will be understood by reference to the following drawings and detailed description.
All numerical values within the detailed description and the claims herein are modified by “about” or “approximately” the indicated value, and take into account experimental error and variations that would be expected by a person having ordinary skill in the art. Unless otherwise stated all pressures in psi are psig and all molecular weights are g/mol.
For purposes of this disclosure and the claims thereto, a polymer is referred to as comprising homopolymers and copolymers, where copolymers include any polymer having two or more chemically distinct monomers.
For the purposes of this disclosure and the claims thereto the term “polyalphaolefin,” “polyalphaolefin,” or “PAO” includes homopolymers and copolymers of C3 or greater alphaolefin monomers.
For the purposes of this disclosure and the claims thereto the active species in a catalytic cycle may comprise the neutral or ionic forms of the catalyst.
The term “catalyst system” is defined to mean a catalyst precursor/activator pair, such as a metallocene/activator pair, optionally with co-activator. When “catalyst system” is used to describe such a pair before activation, it means the unactivated catalyst (precatalyst) together with an activator and, optionally, a co-activator (such as a trialkylaluminum compound). When it is used to describe such a pair after activation, it means the activated transition metal catalyst including the charge-balancing moiety if the activated catalyst carries a charge. Additionally, the catalyst system may optionally comprise a co-activator.
“Catalyst precursor” is also often referred to as precatalyst, catalyst, precursor, metallocene, transition metal compound, precatalyst compound, unactivated catalyst, or transition metal complex. These words are used interchangeably. Activator and catalyst are also used interchangeably. A scavenger is a compound that is typically added to facilitate polymerization by scavenging impurities. Some scavengers may also act as activators and may be referred to as co-activators. A co-activator which is not a scavenger may also be used in conjunction with an activator in order to form an active catalyst with a transition metal compound. In some embodiments, a co-activator can be pre-mixed with the transition metal compound to form an alkylated transition metal compound, also referred to as an alkylated catalyst compound or alkylated metallocene. Co-activators are often aluminum alkyls, also referred to as alkyl-aluminums, alkylaluminum compounds, alkylaluminums, or alkylaluminum compounds.
For purposes of this disclosure and the claims thereto non-coordinating anion (NCA) is defined to mean an anion which either does not coordinate to the catalyst metal cation or that coordinates only weakly to the metal cation. An NCA coordinates weakly enough that a neutral Lewis base, such as an olefinically or acetylenically unsaturated monomer, can displace it from the catalyst center. Any metal or metalloid that can form a compatible, weakly coordinating complex with the catalyst metal cation may be used or contained in the non-coordinating anion. Suitable metals include, but are not limited to, aluminum, gold, and platinum. Suitable metalloids include, but are not limited to, boron, aluminum, phosphorus, and silicon. A subclass of non-coordinating anions comprises stoichiometric activators, which can be either neutral or ionic. The terms ionic activator, stoichiometric ionic activator, discrete ionic activator, non-coordinating anion activator, and NCA activator can be used interchangeably. Likewise, the terms neutral stoichiometric activator and Lewis acid activator can be used interchangeably.
For purposes of this disclosure and the claims thereto, a designated fraction of the product obtained as a PAO may be referred to as ‘lube’, ‘lube fluid’ or ‘lube fraction’.
The polyalphaolefins (PAOs) of this disclosure comprise one or more C8 to C12 monomers. The PAOs have a viscosity (Kv100) from 300 to 900 cSt at 100° C.; a viscosity index (VI) greater than 250; a pour points (PP) less than −25° C.; a molecular weight distribution (Mw/Mn) less than 2.0 as synthesized; a residual unsaturation (Bromine Number) less than 2.0; and a glass transition temperature Tg less than −60° C. The PAOs further have no crystallization peak as measured by differential scanning calorimetry; and high thermal stability.
The PAOs produced in accordance with the process of this disclosure possess high viscosity, low pour points and superior shear stability, oxidative stability and low temperature properties. Furthermore, the ‘ultra’ high viscosity PAOs of this disclosure have low bromine number (low residual double bonds or unsaturation) and no crystalline peak but only low glass-transition temperature peak as measured by differential scanning calorimetry (DSC).
The polyolefin products have an “ultra” high viscosity (Kv100) from 300 to 900 cSt at 100° C., preferably from 350 to 850 cSt at 100° C., and more preferably from 400 to 800 cSt at 100° C. The polyolefin products have a viscosity index (VI) greater than 250, preferably greater than 275, and more preferably greater than 300. As used herein, viscosity (Kv100) is determined by ASTM D 445-01, and viscosity index (VI) is determined by ASTM D 2270-93 (1998).
In another embodiment according to the present disclosure, any PAO described herein may have a kinematic viscosity (Kv) at 100° C. in any of the following ranges: from 100 to 1,000 cSt, from 250 to 950 cSt, from 300 cSt to 900 cSt, from 400 cSt to 800 cSt, wherein all values are measured by ASTM D445-01.
The PAOs of this disclosure have a high viscosity index and a Kv100 of 300 cSt or more, alternatively 350 cSt or more, alternatively 400 cSt or more, up to 900 cSt, with a VI of 250 or more, alternatively 270 or more, alternatively 300 or more. Usually base stock VI is a function of fluid viscosity. Usually, the higher the VI, the better it is for lube application. Base stock VI also depends on feed composition. Fluids made from single 1-octene, 1-nonene, 1-decene, or 1-dodecene have excellent VI and good low pour point. Fluids made from two or more olefins selected from C8 to C12 alphaolefins generally have excellent high VI and superior low pour points if the average carbon chain length of feed LAOs is kept within 8 to 12 carbons. A relatively much lower average chain length in the feed (much below 6 carbons) of the mixed LAO would result in lower VI. Too high of a average chain length in the feed (much above 12 carbons) of the mixed LAO would result in very high pour point, around room temperature.
In another embodiment according to the present disclosure, any polyalphaolefin described herein has a viscosity index (VI) of 200 or more, or 260 or more, or 270 or more; alternatively, from 250 to 450, alternatively from 260 to 400, alternatively from 270 to 300, alternatively the viscosity index is at least 250, alternatively at least 260, alternatively at least 270. Viscosity index is determined according to ASTM Method D2270-93 [1998].
The viscosity-temperature relationship of lubricating oil is one of the critical criteria which must be considered when selecting a lubricant for a particular application. Viscosity Index (VI) is an empirical, unitless number which indicates the rate of change in the viscosity of an oil within a given temperature range and is related to kinematic viscosities measured at 40° C. and 100° C. (typically using ASTM Method D 445). Fluids exhibiting a relatively large change in viscosity with temperature are said to have a low viscosity index. The low VI oil, for example, will thin out at elevated temperatures faster than the high VI oil. Usually, the high VI oil is more desirable because it has higher viscosity at higher temperature, which translates into better or thicker lubrication film and better protection of the contacting machine elements. As the oil operating temperature decreases, the viscosity of the high VI oil will not increase as much as the viscosity of low VI oil. This is advantageous because the excessive high viscosity of the low VI oil will decrease the efficiency of the operating machine. Thus high VI oil has performance advantages in both high and low temperature operation.
The polyolefin products produced in accordance with the process of this disclosure have low pour points (PP) less than −25° C., preferably less than −30° C., and more preferably less than −35° C. As used herein, pour point is determined by ASTM D97.
In an embodiment of this disclosure, any PAO described herein may have a pour point of less than −25° C. (as measured by ASTM D97), preferably less than −35° C., preferably less than −45° C., preferably less than −55° C., preferably less than −65° C., and preferably between −25° C. and −75° C.
The polyolefin products produced in accordance with the process of this disclosure have a narrow molecular weight distribution (Mw/Mn) less than 2.0, preferably less than 1.95, and more preferably less than 1.9 as synthesized. As used herein, molecular weight distribution (Mw/Mn) is determined by GPC using a column for medium to low molecular weight polymers, tetrahydrofuran as solvent and polystyrene as calibration standard.
The polyalphaolefins of this disclosure have a Mw of 100,000 g/mol or less, or between 2000 and 80,000 g/mol, or between 2500 and 60,000 g/mol, or between 2800 and 50,000 g/mol, or between 3360 and 40,000 g/mol. Preferred Mw's include those from 840 to 55,100 g/mol, or from 900 to 45,000 g/mol, or 1000 to 40,000 g/mol, or 2,000 to 37,500 g/mol. Alternatively preferred Mw's include 2240 to 67900 g/mol and 2240 to 37200 g/mol.
The polyalphaolefins of this disclosure preferably have an Mn of 50,000 g/mol or less, or 40,000 g/mol or less, or between 2000 and 40,000 g/mol, or between 2500 and 30,000 g/mol, preferably between 5000 and 20,000 g/mol. Preferred Mn ranges include those from 2800 to 10,000 g/mol or from 2800 to 8,000 g/mol. Alternatively preferred Mn ranges are from 2000 to 20,900 g/mol, or 2800 to 20,000 g/mol, or 2000 to 17000 g/mol, or 2000 to 12000 g/mol, or 2800 to 29000 g/mol, or 2800 to 17000 g/mol, or 2000 to 5000 g/mol.
The Mw and Mn are measured by GPC using a column for medium to low molecular weight polymers, tetrahydrofuran as solvent and polystyrene as calibration standard, correlated with the fluid viscosity according to a power equation.
In another embodiment, the PAOs described herein have a narrow molecular weight distribution of greater than 1 and less than 2, alternatively less than 1.95, alternatively less than 1.90, alternatively less than 1.85. The Mn and Mw are measured by gel permeation chromatography (GPC) using a column for medium to low molecular weight polymers, tetrahydrofuran as solvent and narrow molecular weight distribution polystyrene as calibration standard, correlated with the fluid viscosity according to a power equation. The MWD of PAO is a function of fluid viscosity. Alternatively any of the polyalphaolefins described herein preferably have an Mw/Mn of between 1 and 2.0, alternatively between 1 and 1.95, depending on fluid viscosity.
The polyolefin products produced in accordance with the process of this disclosure have low residual unsaturation (Bromine Number) less than 2.0, preferably less than 1.75, and more preferably less than 1.5, as synthesized As used herein, Bromine Number is determined by ASTM D1159.
The polyalphaolefins of this disclosure comprise polymers of one or more C8 to C12 alphaolefins having an as-polymerized Bromine number of less than 2, preferably between 0.2 to 1.6. The ‘as-polymerized’ Bromine number is the Bromine number of the material exiting the polymerization reactor and before contact with a hydrogenation catalyst. When a polymer is synthesized from 1-decene with any pre-hydrogenation, each polymer will contain one unsaturated double bond. In this completely un-hydrogenated polyalphaolefin, the lube product Bromine number can be predicted by the following equation: Bromine number=56.158×(100° C. Kv in cSt)(−0.50939). When un-expected hydrogenation occurs, the product Bromine number will be significantly less than this amount.
The Bromine numbers of the PAOs of this disclosure usually are less than the calculated Bromine number of 56.158×(100° C. Kv in cSt)(−0.50939). In a preferred embodiment, the Bromine number of the PAOs of this disclosure are at least 10% lower than the calculated Bromine number (56.158×(100° C. Kv in cSt)(−0.50939), preferably at least 25% lower, preferably at least 50% lower. It is preferable to have a Bromine number of less than 2 or more preferably less than 1.5. Lower Bromine number indicates higher degree of saturation, which is usually indicative of higher oxidative stability and high quality of base stock. Bromine number is measured by ASTM D 1159.
In another embodiment, any of the polyalphaolefins produced herein preferably have a Bromine number of 1.8 or less as measured by ASTM D1159, preferably 1.7 or less, preferably 1.6 or less, preferably 1.5 or less, preferably 1.4 or less, preferably 1.3 or less, preferably 1.2 or less, preferably 1.1 or less, preferably 1.0 or less, preferably 0.5 or less, preferably 0.1 or less.
The polyolefin products produced in accordance with the process of this disclosure have low glass transition temperature Tg less than −60° C., preferably less than −70° C., and more preferably less than −80° C. As used herein, glass transition temperature Tg is determined by differential scanning calorimetry (DSC). The polyolefin products produced in accordance with the process of this disclosure have no crystallization peak as measured by differential scanning calorimetry and high thermal stability.
The polyolefin products produced in accordance with the process of this disclosure can be produced at very high productivity greater than 50,000 g lube/g of catalyst, preferably greater than 60,000 g lube/g of catalyst, and more preferably greater than 70,000 g lube/g of catalyst. Alternatively, the productivity of the process described herein is typically greater than 50 kg of PAO per gram of transition metal compound, alternatively greater than 200 kg of PAO per gram of transition metal compound, alternatively greater than 250 kg of transition metal compound, alternatively greater than 500 kg/g of transition metal compound, alternatively greater than 1000 g/g of transition metal compound, and/or greater than 10 kg of PAO per gram of activator, alternatively greater than 50 kg/g of activator, alternatively greater than 100 kg/g of activator, alternatively greater than 500 kg/g of activator.
The PAOs of this disclosure can comprise a single alphaolefin monomer type, or may comprise two or more different alphaolefin monomers. In one embodiment, this disclosure relates to PAOs comprising a molar amount of C8 to C12 alphaolefin monomers selected from the group consisting of 55 mol % or more, 60 mol % or more, 65 mol % or more, 70 mol % or more, 75 mol % or more, 80 mol % or more, 85 mol % or more, 90 mol % or more, 95 mol % or more, 100 mol %, all based on the total moles of monomers present in the polyalphaolefin, as measured by 13C NMR. When two or more alphaolefin monomers are present, it is sometimes desirable to add propylene, or butene (typically 1-butene) olefins into the feed. Use of these smaller olefins in the feed offers the advantage of lower feed cost and/or more abundant feed source. When adding C3 or 1-C4 olefins as one of the feed components, it is important to maintain the total average carbon chain length of the feed LAO (linear alphaolefin) between 8 to 12 carbons.
In one or more embodiments, the PAOs comprise polymers of one or more alphaolefins (also known as 1-olefins) with carbon numbers of C8 to C12. Preferably, at least one of the alphaolefins is a linear alphaolefin (LAO); more preferably, all the alphaolefins are LAOS. Suitable LAOs include 1-octene, 1-nonene, 1-decene, 1-undecene, and 1-dodecene, and blends thereof.
In one or more embodiments, the PAO comprises polymers of two or more C8 to C12 LAOs to make ‘copolymer’ or ‘terpolymer’ or higher-order copolymer combinations. Other embodiments involve polymerization of a mixture of LAOs selected from C8 to C12 LAOs with even carbon numbers, preferably a mixture of two or three LAOs selected from 1-octene, 1-decene, and 1-dodecene.
In one or more embodiments, the PAO comprises polymers of a single alphaolefin species having a total carbon count of 8 to 12. In other embodiments, the PAO comprises polymers of mixed (i.e., two or more) alphaolefin species, wherein each alphaolefin species has a carbon number of 8 to 12. In other embodiments, the PAO comprises polymers of mixed alphaolefin species wherein the molar-average carbon number (“CLAO”) is 8 to 12 or 9 to 11.
In another embodiment according to the present disclosure, any polyalphaolefin described herein may have a kinematic viscosity at 100° C. from 300 to 900 cSt and a flash point of 150° C. or more, preferably 200° C. or more (as measured by ASTM D56).
In another embodiment according to the present disclosure, any polyalphaolefin described herein may have a density of 0.75 to 0.96 g/cm3, preferably 0.80 to 0.94 g/cm3, alternatively from 0.76 to 0.855 g/cm3.
The high viscosity PAOs of this disclosure are desirable for use as lubricating oil base stocks and also blend stocks with API Groups I to V or gas-to-liquid (GTL) derived lube base stocks for use in industrial and automotive engine or gear oil, especially certain high Kv100 grades of 300 to 900 cSt which are especially desirable for use as lubricating oil base stocks or blend stocks with Groups I to V or GTL-derived lube base stocks for use in industrial and automotive engine or gear oil.
These higher viscosity PAOs can be used as lubricating oil base stocks and also superior blend stocks. They can be blend stocks with any of the API Group I to V and GTL fluids to give the optimum viscometrics, solvency, high and low temperature lubricity, etc. The PAOs can be further blended with proper additives, including antioxidants, antiwear additives, friction modifiers, dispersants, detergents, corrosion inhibitors, defoamants, extreme pressure additives, seal swell additives, and optionally viscosity modifiers, etc. Description of typical additives can be found in the book “Lubricant Additives: Chemistry and Applications,” L. R. Rudnick, ed. Marcel Dekker Inc., New York, 2001.
The viscosity loss by mechanical shear down of a lubricant or lubricant base stock can be measured by several methods, including Tapered Roller Bearing (TRB) test according to CEC L-45-T-93 procedure, Orbahn (ASTM D3945) or Sonic Shear Tests (ASTM D2603). The TRB test is believed to correlate better to the actual field shear stability performance of viscous fluids than the other shear tests and in event of conflict between the test data, the TRB test shall be used. In one embodiment, the POAs produced herein have a 100° C. Kv loss (Tapered Roller Bearing (TRB) test according to CEC L-45-T-93 procedure) of 30% or less, alternatively 22% or less, alternatively 20% or less.
One embodiment of the present disclosure discloses an improved process to produce poly-alphaolefins. This improved process employs transition metal catalysts together with one or more activators (such as a non-coordinating anion). One aspect of the processes described herein also includes an optional treatment of the feed olefins to remove catalyst poisons, such as peroxides, oxygen, sulfur, nitrogen-containing organic compounds, and or acetylenic compounds. This treatment is believed to increase catalyst productivity, typically more than 5 fold, preferably more than 10 fold.
In an embodiment, this disclosure relates to a process for producing polyalphaolefins. The process comprises contacting in a reactor a feed stream comprising at least one alphaolefin monomer having 8 to 12 carbon atoms with a catalyst system comprising a precatalyst compound and a non-coordinating anion activator, and optionally an alkyl-aluminum compound, under polymerization conditions, optionally in the presence of hydrogen. The alphaolefin monomer having 8 to 12 carbon atoms is present at 10 volume % or more, based upon the total volume of the catalyst, monomers, and any diluents or solvents present, in the reactor.
Alternatively, in any process described herein hydrogen, if present, is present in the reactor at 1000 ppm or less by weight, or 750 ppm or less, or 500 ppm or less, or 250 ppm or less, or 100 ppm or less, or 50 ppm or less, or 25 ppm or less, or 10 ppm or less, or 5 ppm or less. Alternatively, in any process described herein hydrogen, if present, is present in the feed at 1000 ppm or less by weight, or 750 ppm or less, or 500 ppm or less, or 250 ppm or less, or 100 ppm or less, or 50 ppm or less, or 25 ppm or less, or 10 ppm or less, or 5 ppm or less.
Unless otherwise stated all pressures in psi are psig.
Polyalphaolefins comprise a class of hydrocarbons manufactured by the catalytic polymerization to low molecular weight products of linear alphaolefins (LAOs) typically ranging from 1-octene to 1-dodecene, with 1-decene as the most common and often preferred material. Such fluids are described, for example, in U.S. Pat. No. 6,824,671 and patents referenced therein. Polyalphaolefins produced by conventional Friedel-Crafts catalysts, however are usually characterized by having extra relatively short branches, such as methyl and ethyl short side chains, even though the feed olefins do not contain these short branches. This is thought to be because Friedel-Crafts catalysts partially isomerize the starting alphaolefins and the intermediates formed during the polymerization process. The presence of short chain branches typically is less desirable for superior lubricant properties, including VI and volatility.
In another embodiment, this disclosure relates to a process to produce a polyalphaolefin comprising contacting at least one alphaolefin monomer having 8 to 12 carbon atoms with a precatalyst compound and an activator under polymerization conditions. Hydrogen, if present, is present at a partial pressure of 200 psi (1379 kPa) or less, based upon the total pressure of the reactor, or alternatively 150 psi (1034 kPa) or less, or 100 psi (690 kPa) or less, or 50 psi (345 kPa) or less, or 25 psi (173 kPa) or less, or 10 psi (69 kPa) or less. Alternatively if the hydrogen is present in the reactor, it is present in amounts of 1000 ppm or less by weight, or 750 ppm or less, or 500 ppm or less, or 250 ppm or less, or 100 ppm or less, or 50 ppm or less, or 25 ppm or less, or 10 ppm or less, or 5 ppm or less. The alphaolefin monomer having 8 to 12 carbon atoms is present at 10 volume % or more based upon the total volume of the catalyst/activator/co-activator solutions, monomers, and any diluents or solvents present in the reaction. The process further comprises obtaining a polyalphaolefin with Bromine number of less than 4, alternatively less than 3, alternatively less than 2, alternatively less than 1 for the as-polymerized PAO, optionally hydrogenating the PAO and obtaining a PAO comprising at least 50 mole % of a C8 to C12 alphaolefin monomer. The polyalphaolefin has a kinematic viscosity at 100° C. of 300 to 900 cSt.
In yet another embodiment, this disclosure relates to a process to produce a polyalphaolefin comprising contacting a feed stream comprising at least one alphaolefin monomer having 8 to 12 carbon atoms with a metallocene catalyst compound and a non-coordinating anion activator and optionally an alkyl-aluminum compound, under polymerization conditions. The alphaolefin monomer having 8 to 12 carbon atoms is present at 10 volume % or more based upon the total volume of the catalyst/activator/co-activator solution, monomers, and any diluents or solvents present in the reactor. The feed alphaolefin, diluent or solvent stream comprises less than 300 ppm of heteroatom containing compounds. The process further comprises obtaining a polyalphaolefin comprising at least 50 mole % of a C6 to C12 alphaolefin monomer where the polyalphaolefin has a kinematic viscosity at 100° C. of 300 to 900 cSt. If hydrogen is present, it is present in the reactor at 1000 ppm or less by weight, alternatively 750 ppm or less, alternatively 500 ppm or less, alternatively 250 ppm or less, alternatively 100 ppm or less, alternatively 50 ppm or less, alternatively 25 ppm or less, alternatively 10 ppm or less, alternatively 5 ppm or less.
In a further embodiment, this disclosure relates to a process to produce a polyalphaolefin comprising contacting a feed stream comprising at least one alphaolefin monomer having 8 to 12 carbon atoms with a metallocene catalyst compound and a non-coordinating anion activator, and optionally an alkyl-aluminum compound, under polymerization conditions. The alphaolefin monomer having 2 to 24 carbon atoms is present at 10 volume % or more based upon the total volume of the catalyst/activator/co-activator solution, monomers, and any diluents or solvents present in the reactor. The feed alphaolefin, diluent or solvent stream comprise less than 300 ppm of heteroatom containing compounds. The process also comprises obtaining a polyalphaolefin comprising at least 50 mole % of a C8 to C12 alphaolefin monomer where the polyalphaolefin has a kinematic viscosity at 100° C. of 300 to 900 cSt.
The above processes of this disclosure can also involve isolating the lube fraction polymers (also referred to as ‘lube’, ‘lube fluid’ or ‘lube fraction’) and using these polymers as lubricant base stock after distillation when the polymer has Bromine number less than 2, alternatively less than 1.9; or alternatively, if the Bromine number is significantly higher than 2 or 3 or 4, then contacting this lube fraction with hydrogen under typical hydrogenation conditions with hydrogenation catalyst to give fluid with Bromine number below 2.
The synthetic fluids of this disclosure are prepared using catalyst. The preferred catalyst includes homogeneous single site catalyst. Especially useful catalyst includes metallocene catalyst with activators. The preferred metallocene catalyst includes diphenylmethylidene(cyclopentadienyl)(9-fluorenyl) zirconium dichloride activated with non-coordinating anion, N,N-dimethylanilinium tetra(perfluorophenyl) borate in the presence of suitable amount of hydrogen. In accordance with this disclosure, the fluid produced using diphenylmethylidene(cyclopentadienyl)(9-fluorenyl) zirconium dichloride metallocene catalyst activated with N,N-dimethylanilinium tetra(perfluorophenyl) borate has high activity (>50,000 g lube/g of Zr based catalyst) and fluid has superior low temperature properties when used as a base stock by itself or when used as a blending component with other base stocks.
This process of this disclosure produces compositions related to synthesis of specific synthetic fluids with specific physical properties. The specific fluid is fluid that can be used as synthetic base stock or co-base stock for lubes, especially industrial lubes. The fluid has following physical properties. The fluid has ‘ultra’ high viscosity (Kv100 300-900 cSt) with high viscosity index (VI) (>250), low pour points (PP) (<−25° C.), narrow molecular weight distribution (<2.0) as synthesized, low residual unsaturation (Bromine Number <2.0) as synthesized, low glass transition temperature Tg (<−60° C.), no crystallization peak as measured by differential scanning calorimetry and stability. Moreover, in accordance with the process of this disclosure, the fluid is produced with very high productivity (>50,000 g lube/g of catalyst).
For purposes of this disclosure, transition metal compounds have symmetry elements and belong to symmetry groups. These elements and groups are well established and can be referenced from Chemical Applications of Group Theory (2nd Edition) by F. Albert Cotton, Wiley-Interscience, 1971. Compounds with Cs symmetry possess a mirror plane.
Compounds with pseudo-Cs symmetry are similar with the exception that the bridging group, the labile ligands, and distant substituents of similar size on the cyclopentadienyl ligand or fluorenyl ligand are not included in determining the symmetry of the compound. These compounds, while not truly Cs-symmetric, are considered to have Cs-symmetric active sites for olefin polymerization. Therefore, a compound, for example having a MeEtSi or MePhSi bridging ligand, is considered to have a pseudo Cs-plane of symmetry given the appropriate remaining ligand structure. Likewise, a compound, for example having one Me and one Cl labile ligand, is considered to have a pseudo Cs-plane of symmetry given the appropriate remaining ligand structure.
Compounds with pseudo-Cs symmetry can also have unlike substituents on the non-labile ligands (i.e. cyclopentadienyl or fluorenyl ligands) if the substituents are distant from the active site. Substituents of this type, referred to as pseudo symmetric substituents, are typically adjacent to the bridging group and do not substantially differ in size from one another. Typically the size difference of these substituents is within 2 non-hydrogen atoms of each other. Thus a cyclopentadienyl substituted at the 2 and the 5 positions with methyl and ethyl, respectively, or a fluorenyl substituted at the 1 and the 8 positions with hexyl and octyl, respectively, would be considered to have pseudo-Cs symmetry.
Illustrative catalyst compounds useful in the process of this disclosure are disclosed, for example, in U.S. Patent Application Publication No. 2011/0160502, which is incorporated herein in its entirety.
In an embodiment of the disclosure, catalysts capable of making the inventive PAO structure(s) comprise metallocene compounds (pre-catalysts) represented by the formula (1) having Cs symmetry or pseudo-Cs symmetry:
wherein M is the metal center, and is a group 4 metal preferably titanium, zirconium or hafnium, most preferably zirconium or hafnium;
L1 is a unsubstituted fluorenyl, heterocyclopentapentalenyl, or heterofluorenyl, or a substituted fluorenyl, heterocyclopentapentalenyl, or heterofluorenyl ligand with pseudo symmetric substituents, each substituent group being, independently, a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl, and optionally two or more adjacent substituents may join to form a substituted or unsubstituted, saturated, partially unsaturated or aromatic, cyclic or polycyclic substituent;
L2 is a cyclopentadienyl ring or a substituted cyclopentadienyl ring with pseudo symmetric substituents in the 2 and 5 positions of the ring, each substituent group being, independently, a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl;
G is a bridging group;
X are independently, hydride radicals, hydrocarbyl radicals, substituted hydrocarbyl radicals, halocarbyl radicals, substituted halocarbyl radicals, silylcarbyl radicals, substituted silylcarbyl radicals, germylcarbyl radicals, or substituted germylcarbyl radicals; or both X are joined and bound to the metal atom to form a metallacycle ring containing from 3 to 20 carbon atoms; or both together can be an olefin, diolefin or aryne ligand; both X may, independently, be a halogen, alkoxide, aryloxide, amide, phosphide or other univalent anionic ligand or both X can also be joined to form a anionic chelating ligand.
In formula (1), L1 is preferably fluorenyl or substituted fluorenyl, more preferably fluorenyl, 2,7-dimethylfluorenyl, 2,7-diethylfluorenyl, 2,7-dipropylfluorenyl, 2,7-dibutylfluorenyl, 2,7-diphenylfluorenyl, 2,7-dichlorofluorenyl, 2,7-dibromofluorenyl, 3,6-dimethylfluorenyl, 3,6-diethylfluorenyl, 3,6-dipropylfluorenyl, 3,6-dibutylfluorenyl, 3,6-diphenylfluorenyl, 3,6-dichlorofluorenyl, 3,6-dibromofluorenyl or 1,1,4,4,7,7,10,10-octamethyl-octahydrodibenzofluorenyl, more preferably fluorenyl, 2,7-dimethylfluorenyl, 2,7-diethylfluorenyl, 2,7-dipropylfluorenyl, 2,7-dibutylfluorenyl, 3,6-dimethylfluorenyl, 3,6-diethylfluorenyl, 3,6-dipropylfluorenyl, 3,6-dibutylfluorenyl, or 1,1,4,4,7,7,10,10-octamethyl-octahydrodibenzofluorenyl, most preferably 2,7-di-tert-butylfluorenyl or fluorenyl; L2 is preferably cyclopentadienyl; G is preferably methylene, dimethylmethylene, diphenylmethylene, dimethylsilylene, diphenylsilylene, di(4-triethylsilylphenyl)silylene, ethylene, more preferably diphenylmethylene, diphenylsilylene, dimethylsilylene and ethylene; and most preferably diphenylmethylene; X is preferably hydrocarbyl or halo, more preferably methyl, benzyl, fluoro or chloro, most preferably methyl or chloro; M is preferably zirconium or hafnium, most preferably zirconium.
In a preferred embodiment of the disclosure, a subset of the metallocene compounds (pre-catalysts) represented by formula (1) having Cs or pseudo-Cs symmetry are represented by formula (2):
wherein M, G and X are defined as in formula (1);
each Ra and Rb are selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl, germylcarbyl or polar radicals, and optionally two or more adjacent substituents may join to form a substituted or unsubstituted, saturated, partially unsaturated or aromatic, cyclic or polycyclic substituent, with the proviso that each Ra is the same and each Rb is the same and allow the compound to be Cs-symmetric or pseudo Cs-symmetric;
each Rc is a pseudo symmetric substituent with respect to the other and is selected from hydrogen or a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl radicals;
each Rd is a pseudo symmetric substituent with respect to the other and is selected from hydrogen or a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl radicals.
In some embodiments of the disclosure of formula (2), each Rd, Ra and Rc are preferably hydrogen; and each Rb is preferably a hydrogen, hydrocarbyl, halogen, silylcarbyl, or polar radical; more preferably, hydrogen, methyl, ethyl, propyl, butyl, phenyl, mesityl, fluoro, chloro, bromo, dimethylamido, diethylamido or methoxy; even more preferably hydrogen or butyl; still more preferably hydrogen or tert-butyl; and most preferably hydrogen.
In other embodiments of the disclosure of formula (2), each Rd, Rb and Rc are preferably hydrogen, and each Ra is preferably a hydrogen, hydrocarbyl, halogen, or silylcarbyl; more preferably, hydrogen, methyl, ethyl, propyl, butyl, fluoro, chloro, or bromo; even more preferably hydrogen or butyl; still more preferably hydrogen or tert-butyl; and most preferably hydrogen.
Still, in other embodiments of the disclosure of formula (2), each Rd and Rc are preferably hydrogen, and each Ra and Rb are joined together to form a fused partially saturated six-membered carbon ring, each such fused ring preferably substituted with four methyl substituents. Such preferred ligand structure is illustrated in formula (3):
Still in other embodiments of the disclosure of formula (2) Rc and Rd are preferably hydrogen; each Ra and Rb are chosen from hydrogen, bromine, chlorine, methyl, ethyl, propyl, butyl or phenyl, more preferably Ra is hydrogen and Rb is chosen from hydrogen, methyl, ethyl, propyl, or butyl, or Rb is hydrogen and Ra is chosen from hydrogen, methyl, ethyl, propyl, or butyl, even more preferably Ra is hydrogen and Rb is tert-butyl or hydrogen; G is preferably methylene, dimethylmethylene, diphenylmethylene, dimethylsilylene, diphenylsilylene, di(4-triethylsilylphenyl)silylene, ethylene, more preferably diphenylmethylene, diphenylsilylene, and dimethylsilylene; and most preferably diphenylmethylene; X is preferably hydrocarbyl or halo, more preferably methyl, benzyl, floro or chloro, most preferably methyl or chloro; M is preferably zirconium or hafnium, most preferably zirconium.
Preferred but non-limiting examples of pre-catalysts represented by formula (1) include: diphenylmethylene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride, methylene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride, dimethylmethylene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride, dimethylsilylene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride, diphenylsilylene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride, ethylene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(9-fluorenyl)zirconium dimethyl, methylene(cyclopentadienyl)(9-fluorenyl)zirconium dimethyl, dimethylmethylene(cyclopentadienyl)(9-fluorenyl)zirconium dimethyl, dimethylsilylene(cyclopentadienyl)(9-fluorenyl)zirconium dimethyl, diphenylsilylene(cyclopentadienyl)(9-fluorenyl)zirconium dimethyl, and ethylene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride. The most preferred pre-catalysts represented by formula (1) are diphenylmethylene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride and diphenylmethylene(cyclopentadienyl)(9-fluorenyl)zirconium dimethyl.
The catalyst precursors, when activated by a commonly known activator form active catalysts for the polymerization of olefins. Lewis acid activators include triphenylboron, tris-perfluorophenylboron, tris-perfluorophenylaluminum and the like, but exclude the class of activators referred to as alumoxanes. Ionic activators include dimethylanilinium tetrakisperfluorophenylborate, triphenylcarbonium tetrakisperfluorophenylborate, dimethylanilinium tetrakisperfluorophenylaluminate, and the like. Collectively, Lewis acid activators and ionic activators are referred to as discrete activators since they can be readily characterized, whereas alumoxanes are not well characterized. Likewise, Lewis acid activators and ionic activators are referred to as stoichiometric activators since relatively low molar ratios of activator to transition metal compound are needed as compared to alumoxanes activators that require large excesses.
A co-activator is a compound capable of alkylating the transition metal complex, such that when used in combination with a discrete activator, an active catalyst is formed. Co-activators include alumoxanes such as methylalumoxane, modified alumoxanes such as modified methylalumoxane, and aluminum alkyls such trimethylaluminum, tri-isobutylaluminum, triethylaluminum, and tri-isopropylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, tri-n-decylaluminum or tri-n-dodecylaluminum. Co-activators are typically used in combination with Lewis acid activators and ionic activators when the pre-catalyst is not a dihydrocarbyl or dihydride complex. Sometimes co-activators are also used as scavengers to deactivate impurities in feed or reactors. Sometimes co-activators are also used as chain transfer or chain shuttling agents.
Particularly preferred co-activators include alkylaluminum compounds represented by the formula: R3Al, where each R is, independently, a C1 to C18 alkyl group, preferably each R is, independently, selected from the group consisting of methyl, ethyl, n-propyl, iso-propyl, iso-butyl, n-butyl, t-butyl, n-pentyl, iso-pentyl, neopentyl, n-hexyl, iso-hexyl, n-heptyl, iso-heptyl, n-octyl, iso-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecy, n-hexadecyl, n-heptadecyl, n-octadecyl, and their iso-analogs.
In the process, hydrogen is a useful chain transfer agent in the reaction. In a preferred embodiment, alternative chain transfer agents (CTA's) can be used in the processes described herein, reducing the need for hydrogen wherein hydrogen is absent or used in limited amounts. Preferred alternative chain transfer agents include diethylzinc, and trialkylaluminums such as triisobutylaluminum, tri-n-octylaluminum, triethylaluminum and the like, or mixtures thereof. Alternative CTA's are often used at transition metal compound to CTA molar ratios of from 1:1 to 1:100, preferably from 1:4 to 1:50, more preferably from 1:10 to 1:33. The molar ratio of alternative CTA to transition metal compound is preferably less than 100:1 more preferably less than 50:1, and most preferably less than 35:1.
It is within the scope of this disclosure to use neutral or ionic activators such as tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate, trisperfluorophenylboron, trisperfluoronaphthylboron, polyhalogenated heteroborane anions (WO 98/43983), boric acid (U.S. Pat. No. 5,942,459) or combinations thereof.
Stoichiometric activators (at times used in combination with a co-activator) may be used in the practice of this disclosure. Preferably, discrete ionic activators such as [Me2PhNH][B(C6F5)4], [Ph3C][B(C6F5)4], [Me2PhNH][B(C6H3-3,5-(CF3)2)4], [Ph3C][B(C6H3-3,5-(CF3)2)4], [NH4][B(C6H5)4] or Lewis acidic activators such as B(C6F5)3 or B(C6H5)3 can be used, where Ph is phenyl and Me is methyl.
Examples of neutral stoichiometric activators include tri-substituted boron, tellurium, aluminum, gallium and indium or mixtures thereof. The three substituent groups are each independently selected from alkyls, alkenyls, halogen, substituted alkyls, aryls, arylhalides, alkoxy and halides. Preferably, the three groups are independently selected from halogen, mono or multicyclic (including halosubstituted) aryls, alkyls, and alkenyl compounds and mixtures thereof, preferred are alkenyl groups having 1 to 20 carbon atoms, alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms and aryl groups having 3 to 20 carbon atoms (including substituted aryls). More preferably, the three groups are alkyls having 1 to 4 carbon groups, phenyl, naphthyl or mixtures thereof. Even more preferably, the three groups are halogenated, preferably fluorinated, aryl groups. Most preferably, the neutral stoichiometric activator is trisperfluorophenyl boron or trisperfluoronaphthyl boron.
Ionic stoichiometric activator compounds may contain an active proton, or some other cation associated with, but not coordinated to or only loosely coordinated to, the remaining ion of the ionizing compound. Such compounds and the like are described in European publications EP-A-0 570 982, EP-A-0 520 732, EP-A-0 495 375, EP-B1-0 500 944, EP-A-0 277 003 and EP-A-0 277 004, and U.S. Pat. Nos. 5,153,157, 5,198.401, 5,066,741, 5,206,197, 5,241,025, 5,384,299 and 5,502,124 and U.S. patent application Ser. No. 08/285,380, filed Aug. 3, 1994, all of which are herein fully incorporated by reference.
Ionic catalysts can be prepared by reacting a transition metal compound with an activator, such as B(C6F6)3, which upon reaction with the hydrolyzable ligand (X′) of the transition metal compound forms an anion, such as ([B(C6F5)3(X′)]−), which stabilizes the cationic transition metal species generated by the reaction. The catalysts can be, and preferably are, prepared with activator components which are ionic compounds or compositions. However preparation of activators utilizing neutral compounds is also contemplated by this disclosure.
Compounds useful as an activator component in the preparation of the ionic catalyst systems used in the process of this disclosure comprise a cation, which is preferably a Bronsted acid capable of donating a proton, and a compatible non-coordinating anion which anion is relatively large (bulky), capable of stabilizing the active catalyst species which is formed when the two compounds are combined and said anion will be sufficiently labile to be displaced by olefinic diolefinic and acetylenically unsaturated substrates or other neutral Lewis bases such as ethers, nitriles and the like. Two classes of compatible non-coordinating anions have been disclosed in EPA 277,003 and EPA 277,004 published 1988: 1) anionic coordination complexes comprising a plurality of lipophilic radicals covalently coordinated to and shielding a central charge-bearing metal or metalloid core, and 2) anions comprising a plurality of boron atoms such as carboranes, metallacarboranes and boranes.
In a preferred embodiment, the ionic stoichiometric activators include a cation and an anion component, and may be represented by the following formula: (L**-H)d+(Ad−) wherein L** is an neutral Lewis base; H is hydrogen; (L**-H)+ is a Bronsted acid, and Ad− is a non-coordinating anion having the charge d−, and d is an integer from 1 to 3.
The cation component, (L**-H)d+ may include Bronsted acids such as protons or protonated Lewis bases or reducible Lewis acids capable of protonating or abstracting a moiety, such as an alkyl or aryl, from the precatalyst after alkylation.
The activating cation (L**-H)d+ may be a Bronsted acid, capable of donating a proton to the alkylated transition metal catalytic precursor resulting in a transition metal cation, including ammoniums, oxoniums, phosphoniums, silyliums, and mixtures thereof, preferably ammoniums of methylamine, aniline, dimethylamine, diethylamine, N-methylaniline, diphenylamine, trimethylamine, triethylamine, N,N-dimethylaniline, methyldiphenylamine, pyridine, p-bromo N,N-dimethylaniline, p-nitro-N,N-dimethylaniline, phosphoniums from triethylphosphine, triphenylphosphine, and diphenylphosphine, oxomiuns from ethers such as dimethyl ether, diethyl ether, tetrahydrofuran and dioxane, sulfoniums from thioethers, such as diethyl thioethers and tetrahydrothiophene, and mixtures thereof. The activating cation (L**-H)d+ may also be a moiety such as silver, tropylium, carbeniums, ferroceniums and mixtures, preferably carboniums and ferroceniums; most preferably triphenyl carbonium. The anion component Ad− include those having the formula [Mk+Qn]d− wherein k is an integer from 1 to 3; n is an integer from 2-6; n−k=d; M is an element selected from group 13 of the Periodic Table of the Elements, preferably boron or aluminum, and Q is independently a hydride, bridged or unbridged dialkylamido, halide, alkoxide, aryloxide, hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, and halosubstituted-hydrocarbyl radicals, said Q having up to 20 carbon atoms with the proviso that in not more than one occurrence is Q a halide. Preferably, each Q is a fluorinated hydrocarbyl group having 1 to 20 carbon atoms, more preferably each Q is a fluorinated aryl group, and most preferably each Q is a pentafluoryl aryl group. Examples of suitable Ad− also include diboron compounds as disclosed in U.S. Pat. No. 5,447,895, which is fully incorporated herein by reference.
Illustrative, but not limiting examples of boron compounds which may be used as a non-coordinating anion activator in combination with a co-activator in the preparation of the improved catalysts of this disclosure are tri-substituted ammonium salts such as: trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, tri(tert-butyl)ammonium tetraphenylborate, N,N-dimethylanilinium tetraphenylborate, N,N-diethylanilinium tetraphenylborate, N,N-dimethyl-(2,4,6-trimethylanilinium)tetraphenylborate, trimethylammonium tetrakis(pentafluorophenyl)borate, triethylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(pentafluorophenyl)borate, tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate, tri(sec-butyl)ammonium tetrakis(pentafluorophenyl)borate, N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, N,N-diethylanilinium tetrakis(pentafluorophenyl)borate, N,N-dimethyl-(2,4,6-trimethylanilinium)tetrakis(pentafluorophenyl)borate, trimethylammonium tetrakis-(2,3,4,6-tetrafluorophenyl)borate, triethylammonium tetrakis-(2,3,4,6-tetrafluorophenyl)borate, tripropylammonium tetrakis-(2,3,4,6-tetrafluorophenyl)borate, tri(n-butyl)ammonium tetrakis-(2,3,4,6-tetrafluorophenyl)borate, dimethyl(tert-butyl)ammonium tetrakis-(2,3,4,6-tetrafluorophenyl)borate, N,N-dimethylanilinium tetrakis-(2,3,4,6-tetrafluorophenyl)borate, N,N-diethylanilinium tetrakis-(2,3,4,6-tetrafluorophenyl)borate, N,N-dimethyl-(2,4,6-trimethylanilinium)tetrakis-(2,3,4,6-tetrafluorophenyl)borate, trimethylammonium tetrakis(perfluoronaphthyl)borate, triethylammonium tetrakis(perfluoronaphthyl)borate, tripropylammonium tetrakis(perfluoronaphthyl)borate, tri(n-butyl)ammonium tetrakis(perfluoronaphthyl)borate, tri(tert-butyl)ammonium tetrakis(perfluoronaphthyl)borate, N,N-dimethylanilinium tetrakis(perfluoronaphthyl)borate, N,N-diethylanilinium tetrakis(perfluoronaphthyl)borate, N,N-dimethyl-(2,4,6-trimethylanilinium)tetrakis(perfluoronaphthyl)borate, trimethylammonium tetrakis(perfluorobiphenyl)borate, triethylammonium tetrakis(perfluorobiphenyl)borate, tripropylammonium tetrakis(perfluorobiphenyl)borate, tri(n-butyl)ammonium tetrakis(perfluorobiphenyl)borate, tri(tert-butyl)ammonium tetrakis(perfluorobiphenyl)borate, N,N-dimethylanilinium tetrakis(perfluorobiphenyl)borate, N,N-diethylanilinium tetrakis(perfluorobiphenyl)borate, N,N-dimethyl-(2,4,6-trimethylanilinium)tetrakis(perfluorobiphenyl)borate, trimethylammonium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, triethylammonium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, tripropylammonium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, tri(n-butyl)ammonium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, tri(tert-butyl)ammonium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, N,N-dimethylanilinium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, N,N-diethylanilinium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, N,N-dimethyl-(2,4,6-trimethylanilinium)tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, and diallyl ammonium salts such as: di-(iso-propyl)ammonium tetrakis(pentafluorophenyl)borate, and dicyclohexylammonium tetrakis(pentafluorophenyl)borate; and other salts such as tri(o-tolyl)phosphonium tetrakis(pentafluorophenyl)borate, tri(2,6-dimethylphenyl)phosphonium tetrakis(pentafluorophenyl)borate, tropillium tetraphenylborate, triphenylcarbenium tetraphenylborate, triphenylphosphonium tetraphenylborate, triethylsilylium tetraphenylborate, benzene(diazonium)tetraphenylborate, tropillium tetrakis(pentafluorophenyl)borate, triphenylcarbenium tetrakis(pentafluorophenyl)borate, triphenylphosphonium tetrakis(pentafluorophenyl)borate, triethylsilylium tetrakis(pentafluorophenyl)borate, benzene(diazonium)tetrakis(pentafluorophenyl)borate, tropillium tetrakis-(2,3,4,6-tetrafluorophenyl)borate, triphenylcarbenium tetrakis-(2,3,4,6-tetrafluorophenyl)borate, triphenylphosphonium tetrakis-(2,3,4,6-tetrafluorophenyl)borate, triethylsilylium tetrakis-(2,3,4,6-tetrafluorophenyl)borate, benzene(diazonium)tetrakis-(2,3,4,6-tetrafluorophenyl)borate, tropillium tetrakis(perfluoronaphthyl)borate, triphenylcarbenium tetrakis(perfluoronaphthyl)borate, triphenylphosphonium tetrakis(perfluoronaphthyl)borate, triethylsilylium tetrakis(perfluoronaphthyl)borate, benzene(diazonium)tetrakis(perfluoronaphthyl)borate, tropillium tetrakis(perfluorobiphenyl)borate, triphenylcarbenium tetrakis(perfluorobiphenyl)borate, triphenylphosphonium tetrakis(perfluorobiphenyl)borate, triethylsilylium tetrakis(perfluorobiphenyl)borate, benzene(diazonium)tetrakis(perfluorobiphenyl)borate, tropillium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, triphenylcarbenium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, triphenylphosphonium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, triethylsilylium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, and benzene(diazonium)tetrakis(3,5-bis(trifluoromethyl)phenyl)borate.
Most preferably, the non-coordinating anion activator, (L**-H)d+(Ad−), is N,N-dimethylanilinium tetrakis(perfluorophenyl)borate, N,N-dimethylanilinium tetrakis(perfluoronaphthyl)borate, N,N-dimethylanilinium tetrakis(perfluorobiphenyl)borate, N,N-dimethylanilinium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, triphenylcarbenium tetrakis(perfluoronaphthyl)borate, triphenylcarbenium tetrakis(perfluorobiphenyl)borate, triphenylcarbenium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, or triphenylcarbenium tetra(perfluorophenyl)borate.
The catalyst precursors can also be activated with cocatalysts or activators that comprise non-coordinating anions containing metalloid-free cyclopentadienide ions. These are described in U.S. Patent Publication 2002/0058765 A1, published on 16 May 2002, and for the instant disclosure, require the addition of a co-activator to the catalyst pre-cursor. “Compatible” non-coordinating anions are those which are not degraded to neutrality when the initially formed complex decomposes. Further, the anion will not transfer an anionic substituent or fragment to the cation so as to cause it to form a neutral transition metal compound and a neutral by-product from the anion. Preferred non-coordinating anions useful in accordance with this disclosure are those that are compatible, stabilize the transition metal complex cation in the sense of balancing its ionic charge at +1, yet retain sufficient liability to permit displacement by an ethylenically or acetylenically unsaturated monomer during polymerization. These types of cocatalysts are sometimes used with scavengers such as but not limited to tri-iso-butylaluminum, tri-n-octylaluminum, tri-n-hexylaluminum, triethylaluminum or trimethylaluminum.
Disclosure processes also can employ cocatalyst compounds or activator compounds that are initially neutral Lewis acids but form a cationic metal complex and a non-coordinating anion, or a zwitterionic complex upon reaction with the alkylated transition metal compounds. The alkylated metallocene compound is formed from the reaction of the catalyst pre-cursor and the co-activator. For example, tris(pentafluorophenyl)boron or aluminum act to abstract a hydrocarbyl ligand to yield an disclosure cationic transition metal complex and stabilizing non-coordinating anion, see EP-A-0 427 697 and EP-A-0 520 732 for illustrations of analogous group-4 metallocene compounds. Also, see the methods and compounds of EP-A-0 495 375. For formation of zwitterionic complexes using analogous group 4 compounds, see U.S. Pat. Nos. 5,624,878; 5,486,632; and 5,527,929.
Additional neutral Lewis-acids are known in the art and are suitable for abstracting formal anionic ligands. See in particular the review article by E. Y.-X. Chen and T. J. Marks, “Cocatalysts for Metal-Catalyzed Olefin Polymerization: Activators, Activation Processes, and Structure-Activity Relationships”, Chem. Rev., 100, 1391-1434 (2000).
When the cations of non-coordinating anion activators are Bronsted acids such as protons or protonated Lewis bases (excluding water), or reducible Lewis acids such as ferrocenium or silver cations, or alkali or alkaline earth metal cations such as those of sodium, magnesium or lithium, the catalyst-precursor-to-activator molar ratio may be any ratio. Combinations of the described activator compounds may also be used for activation.
When an ionic or neutral stoichiometric activator (such as an NCA) is used, the catalyst-precursor-to-activator molar ratio is from 1:10 to 1:1; 1:10 to 10:1; 1:10 to 2:1; 1:10 to 3:1; 1:10 to 5:1; 1:2 to 1.2:1; 1:2 to 10:1; 1:2 to 2:1; 1:2 to 3:1; 1:2 to 5:1; 1:3 to 1.2:1; 1:3 to 10:1; 1:3 to 2:1; 1:3 to 3:1; 1:3 to 5:1; 1:5 to 1:1; 1:5 to 10:1; 1:5 to 2:1; 1:5 to 3:1; 1:5 to 5:1; 1:1 to 1:1.2. The catalyst-precursor-to-co-activator molar ratio is from 1:500 to 1:1, 1:100 to 100:1; 1:75 to 75:1; 1:50 to 50:1; 1:25 to 25:1; 1:15 to 15:1; 1:10 to 10:1; 1:5 to 5:1, 1:2 to 2:1; 1:100 to 1:1; 1:75 to 1:1; 1:50 to 1:1; 1:25 to 1:1; 1:15 to 1:1; 1:10 to 1:1; 1:5 to 1:1; 1:2 to 1:1; 1:10 to 2:1.
In some embodiments preferred activators and activator/co-activator combinations include dimethylanilinium tetrakis(pentafluorophenyl)borate or tris(pentafluorophenyl)boron, or mixtures of trialkyl aluminum with dimethylanilinium tetrakis(pentafluorophenyl)borate or tris(pentafluorophenyl)boron. In some embodiments, scavenging compounds are used with stoichiometric activators. Typical aluminum or boron alkyl components useful as scavengers are represented by the general formula RxJ′Z′2 where J′ is aluminum or boron, Rx is as previously defined above, and each Z′ is independently Rx or a different univalent anionic ligand such as halogen (Cl, Br, I), alkoxide (ORx) and the like. Most preferred aluminum alkyls include triethylaluminum, diethylaluminum chloride, tri-iso-butylaluminum, tri-n-octylaluminum, tri-n-hexylaluminum, trimethylaluminum and the like. Preferred boron alkyls include triethylboron. Scavenging compounds may also be alumoxanes and modified alumoxanes including methylalumoxane and modified methylalumoxane.
Supported catalysts and or supported catalyst systems may be used to prepare PAOs of this disclosure. To prepare uniform supported catalysts, the catalyst precursor preferably dissolves in the chosen solvent. The term “uniform supported catalyst” means that the catalyst precursor, the activator, and or the activated catalyst approach uniform distribution upon the support's accessible surface area, including the interior pore surfaces of porous supports. Some embodiments of supported catalysts prefer uniform supported catalysts; other embodiments show no such preference.
Useful supported catalyst systems may be prepared by any method effective to support other coordination catalyst systems, effective meaning that the catalyst so prepared can be used for polymerizing olefins in a heterogenous process. The catalyst precursor, activator, co-activator (if needed), suitable solvent, and support may be added in any order or simultaneously.
By one method, the activator (with or without co-activator), dissolved in an appropriate solvent such as toluene, may be stirred with the support material for 1 minute to 10 hours to prepare the supported catalyst. The total solution volume (of the catalyst solution, the activator solution or both) may be greater than the pore volume of the support, but some embodiments limit the total solution volume below that needed to form a gel or slurry (90% to 400%, preferably 100-200%, of the pore volume). The mixture is optionally heated from 30-200° C. during this time. The catalyst precursor may be added to this mixture as a solid, if a suitable solvent is employed in the previous step, or as a solution. Alternatively, the mixture can be filtered, and the resulting solid mixed with a catalyst precursor solution. Similarly, the mixture may be vacuum dried and mixed with a catalyst precursor solution. The resulting catalyst mixture is then stirred for 1 minute to 10 hours, and the supported catalyst is either filtered from the solution and vacuum dried or subjected to evaporation to remove the solvent.
Alternatively, the catalyst precursor and activator (and optional co-activator) may be combined in solvent to form a solution. The support is then added to the solution, and the resulting mixture is stirred for 1 minute to 10 hours. The total activator/catalyst-precursor solution volume may be greater than the pore volume of the support, but some embodiments limit the total solution volume below that needed to form a gel or slurry (90% to 400%, preferably 100-200% of the pore volume). After stirring, the residual solvent is removed under vacuum, typically at ambient temperature and over 10-16 hours; however, greater or lesser times and temperatures may be used.
The catalyst precursor may also be supported absent the activator; in this case, the activator (and co-activator if needed) is added to the liquid phase of a slurry process. For example, a solution of catalyst precursor may be mixed with a support material for a period of 1 minute to 10 hours. The resulting precatalyst mixture may be filtered from the solution and dried under vacuum or treated with evaporation to remove the solvent. The total catalyst-precursor-solution volume may be greater than the support's pore volume, but some embodiments limit the total solution volume below that needed to form a gel or slurry (90% to 400%, preferably 100-200% of the pore volume).
Additionally, two or more different catalyst precursors may be placed on the same support using any of the support methods disclosed above. Likewise, two or more activators or an activator and a co-activator, may be placed on the same support.
Suitable solid particle supports are typically comprised of polymeric or refractory oxide materials, each being preferably porous. Any support material that has an average particle size greater than 10 μm is suitable for use in this disclosure. Various embodiments select a porous support material, such as for example, talc, inorganic oxides, inorganic chlorides, for example magnesium chloride and resinous support materials such as polystyrene polyolefin or polymeric compounds or any other organic support material and the like. Some embodiments select inorganic oxide materials as the support material including group-2, -3, -4, -5, -13, or -14 metal or metalloid oxides. Some embodiments select the catalyst support materials to include silica, alumina, silica-alumina, and their mixtures. Other inorganic oxides may serve either alone or in combination with the silica, alumina, or silica-alumina. These are magnesia, titania, zirconia, and the like. Lewis acidic materials such as montmorillonite and similar clays may also serve as a support. In this case, the support can optionally double as an activator component. But additional activator may also be used. In some cases, a special family of solid support commonly known as MCM-41 can also be used. MCM-41 is a new class of unique crystalline support and can be prepared with tunable pore size and tunable acidity when modified with a second component. A detailed description of this class of materials and their modification can be found in U.S. Pat. No. 5,264,203.
The support material may be pretreated by any number of methods. For example, inorganic oxides may be calcined, chemically treated with dehydroxylating agents such as aluminum alkyls and the like, or both.
As stated above, polymeric carriers will also be suitable in accordance with the disclosure, see for example the descriptions in WO 95/15815 and U.S. Pat. No. 5,427,991. The methods disclosed may be used with the catalyst compounds, activators or catalyst systems of this disclosure to adsorb or absorb them on the polymeric supports, particularly if made up of porous particles, or may be chemically bound through functional groups bound to or in the polymer chains.
Useful catalyst carriers typically have a surface area of from 10-700 m2/g, and or a pore volume of 0.1-4.0 cc/g and or an average particle size of 10-500 μm. Some embodiments select a surface area of 50-500 m2/g, and or a pore volume of 0.5-3.5 cc/g, and or an average particle size of 20-200 μm. Other embodiments select a surface area of 100-400 m2/g, and or a pore volume of 0.8-3.0 cc/g, and or an average particle size of 30-100 μm. Useful carriers typically have a pore size of 10-1000 Angstroms, alternatively 50-500 Angstroms, or 75-350 Angstroms.
The precatalyst and or the precatalyst/activator combinations are generally deposited on the support at a loading level of 10-100 micromoles of catalyst precursor per gram of solid support; alternatively 20-80 micromoles of catalyst precursor per gram of solid support; or 40-60 micromoles of catalyst precursor per gram of support. But greater or lesser values may be used provided that the total amount of solid catalyst precursor does not exceed the support's pore volume.
The precatalyst and or the precatalyst/activator combinations can be supported for gas-phase, bulk, or slurry polymerization, or otherwise as needed. Numerous support methods are known for catalysts in the olefin polymerization art, particularly alumoxane-activated catalysts; all are suitable for use herein. See, for example, U.S. Pat. Nos. 5,057,475 and 5,227,440. An example of supported ionic catalysts appears in WO 94/03056. U.S. Pat. No. 5,643,847 and WO 96/04319A which describe a particularly effective method. Both polymers and inorganic oxides may serve as supports, see U.S. Pat. Nos. 5,422,325, 5,427,991, 5,498,582 and 5,466,649, and international publications WO 93/11172 and WO 94/07928.
In another preferred embodiment, the precatalyst and or activator (with or without a support) are combined with an alkylaluminum compound, preferably a trialkylaluminum compound, prior to entering the reactor. Preferably the alkylaluminum compound is represented by the formula: R3Al, where each R is independently a C1 to C20 alkyl group; preferably the R groups are independently selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, n-butyl, pentyl, isopentyl, n-pentyl, hexyl, isohexyl, n-hexyl, heptyl, octyl, isooctyl, n-octyl, nonyl, isononyl, n-nonyl, decyl, isodecyl, n-decyl, undecyl, isoundecyl, n-undecyl, dodecyl, isododecyl, and n-dodecyl, preferably isobutyl, n-octyl, n-hexyl, and n-dodecyl. Preferably the alkylaluminum compound is selected from tri-isobutyl aluminum, tri n-octyl aluminum, tri-n-hexyl aluminum, and tri-n-dodecyl aluminum.
The catalyst compounds described herein are used to polymerize any unsaturated monomer or monomers. Such monomers include C8 to C12 olefins. In some embodiments monomers include linear, branched or cyclic alphaolefins, such as C8 to C12 linear alphaolefins. Particular olefin monomers may be one or more of 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, and mixtures thereof.
In one embodiment, the process described herein may be used to produce homopolymer (for the purposes of this disclosure and the claims thereto, a homopolymer may comprise two, three, four, or more different monomer units). Polymers produced herein include polymers of any of the above monomers. In an embodiment the polymer is a homopolymer of any C8 to C12 alphaolefin. Preferably the polymer is a homopolymer of 1-octene, 1-nonene, 1-decene, 1-undecene, or 1-dodecene.
The alphaolefins used to make PAOs of this disclosure include, but are not limited to, C8 to C12 alphaolefins, such as 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, being preferred. Useful PAOs are made from C8 to C12 alphaolefins.
In another embodiment, the PAO comprises two or more monomers, or may comprise three or more monomers, or may comprise four or more monomers, or may comprise five or more monomers. For example, a C8 and C10 mixture, a C8 and C12 mixture, a C8, C10, C12-linear alphaolefin mixture can be used as a feed.
The alphaolefins used herein can be produced directly from ethylene growth process as practiced by several commercial production processes, or they can be produced from Fischer-Tropsch hydrocarbon synthesis from CO/H2 syngas, or from metathesis of internal olefins with ethylene, or from cracking of petroleum or Fischer-Tropsch synthetic wax at high temperature, or any other alphaolefin synthesis routes. A preferred feed for this disclosure is preferably at least 80 weight % alphaolefin (preferably linear alphaolefin), preferably at least 90 weight % alphaolefin (preferably linear alphaolefin), more preferably 100% alphaolefin (preferably linear alphaolefin). However, alphaolefin mixtures can also be used as feeds in this disclosure, especially if the other components are internal-olefins, branched olefins, paraffins, cyclic paraffins, aromatics (such as toluene and or xylenes). These components have diluent effects and are believed to not have a substantial detrimental effect on the polymerization of alphaolefins. In other words, the process described herein can selectively convert alphaolefins in a mixture and leave the other components unreacted. This is particularly useful when ethylene is not present in the mixture. This technology can be used to separate out alphaolefins from a mixture by selectively reacting them with polymerization catalyst systems completely eliminating the need to separate alphaolefins from the remainder of the components in a mixed feedstream. This is economically advantageous, for example, in a process utilizing Fisher-Tropsch synthesis olefin product streams containing alphaolefins, internal-olefins and branched olefins. Such a mixture can be fed to the polymerization technology as described herein and to selectively react away the alphaolefin. No separate step to isolate the alphaolefin is needed. Another example of the utility of this process involves-alphaolefins produced by the metathesis of internal olefins with ethylene, which may contain some internal olefins. This mixed olefin base stock feed can be reacted as is in the polymerization process of the present disclosure, which selectively converts the alphaolefins into lube products. Thus one can use the alphaolefin for the base stock synthesis without having to separate the alphaolefin from internal olefin. This can bring a significant improvement in process economics.
In an embodiment, the PAOs produced herein may contain monomers having branches at least 2, preferably at least 3 carbons away from the alpha-unsaturation, such 4-methyl-1-decene, 4-ethyl-1-decene, etc. These olefins may be present in the linear alphaolefins from the manufacturing process or they can be added deliberately. The copolymers of slightly branched alphaolefins with completely linear alphaolefins have improved low temperature properties.
In an embodiment, any of the PAOs described herein may comprise at least 50 mole % C8 to C12 alphaolefins and from 0.5 to 20 mole % ethylene. Preferably any of the PAOs described herein may comprise at least 60 mole % monomers having 8 to 12 carbon atoms (preferably at least 70 mole %, preferably at least 80 mole %, preferably at least 85 mole %, preferably at least 90 mole %, preferably at least 95 mole %) and from 0.5 to 20 mole % ethylene (preferably from 1 to 15 mole %, preferably from 2 to 10 mole %, preferably form 2 to 5 mole %).
In an embodiment, the present disclosure is directed to an improved process for polymerization of alphaolefins, the process comprising contacting one or more C8 to C12 alphaolefins with
(A) a pre-catalyst as previously described above and represented by any of formulae (1), (2) or (3) having Cs or pseudo-Cs symmetry;
(B) non-coordinating anion activator,
(C) a trialkylaluminum, such as tri-isobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, tri-n-decylaluminum, tri-n-dodecylaluminum,
(D) optionally in the absence of hydrogen or in the presence of a limited amount of hydrogen, and in the absence of an alkylalumoxane, under reaction temperature and pressure conditions sufficient to polymerize said alphaolefins. In another embodiment, the non-coordinating anion activator comprises N,N-dimethylanilinium tetra(perfluorophenyl)borate. In a further embodiment, the Cs or pseudo-Cs symmetric catalyst is represented by formula (1), (2) or (3). In another embodiment, the catalyst comprises diphenylmethylidene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride (also called diphenylmethylene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride.
The reaction temperature is from 30° C. to 200° C., preferably 50 to 160° C., more preferably 60 to 150° C., more preferably 70 to 140° C. and the hydrogen partial pressure in the reactor is from 5 psig to 300 psig, preferably 10 to 200 psi, preferably 20 to 200 psi, preferably 25 to 150 psi. The total reactor pressure can be from 10 psi to 1000 psi by having some inert gas, such as nitrogen or argon, in the reactor, or by having the partial pressure from the feed olefins. The preferred total reactor pressure can be from 10 psi to 800 psi, preferably from 15 psi to 500 psi, from 15 psi to 300 psi or from 15 psi to 200 psi.
The mole ratio of metallocene catalyst to non-coordinating anion activator is from 5 to 0.2. An alternative ratio is from 2 to 0.5, or from 1.5 to 0.7, or from 1.2 to 0.8 or from 1.1 to 0.9. The metallocene concentration is selected to be less than 1 mg per gram of olefin feed, or less than 0.1 mg per gram of olefin feed, or less than 50 microgram per gram of olefin feed, or less than 30 microgram per gram of olefin feed, or less than 20 microgram per gram of olefin feed, or less than 10 microgram per gram of olefin feed, or less than 5 microgram per gram of olefin feed, or less than 2 microgram per gram of olefin feed. Sometimes, a slightly higher amount of catalyst may be used so that the reaction is completed in a selected time, or to compensate for potential poisons that may be present in the reactor. In general, the goal is to keep the catalyst concentration at an optimum level to maintain good conversion within reasonable time and avoid shutting down the reactor due to poison.
In the polymerization process, a co-activator is optionally used. The co-activator converts the halides or salts of the metallocenes into metal alkyls. The co-activator to metallocene ratio can range from 2 to 200, or from 4 to 100 or from 4 to 20. The co-activator in the disclosed embodiments may be tri-isobutylaluminum, tri-n-octylaluminum, or tri-n-hexylaluminum.
A scavenger, usually a tri-alkylaluminum compound or other reactive chemical, may be added to scavenge all impurity in feed or solvent system. The scavenger can be the same or different from the co-activator. The molar ratio of the aluminum compound to metallocene compound can be ranged from 4 to 1000, preferably from 10 to 500, preferably from 20 to 500, preferably from 50 to 300, preferably from 75 to 300, preferably from 100 to 300, more preferably from 150 to 200. The large amount of the right scavenger significantly improves catalyst productivity.
Many polymerization processes and reactor types used for metallocene-catalyzed polymerizations such as solution, slurry, and bulk polymerization processed can be used in this disclosure. In some embodiments, if a solid or supported catalyst is used, a slurry or continuous fixed bed or plug flow process is suitable. In a preferred embodiment, the monomers are contacted with the metallocene compound and the activator in the solution phase, bulk phase, or slurry phase, preferably in a continuous stirred tank reactor, continuous tubular reactor, or a batch reactor. The monomer(s), metallocene, and activator are contacted for a residence time of 1 second to 100 hours, or 30 seconds to 50 hours, or 2 minutes to 6 hours, or 1 minute to 4 hours. In another embodiment, solvent or diluent is present in the reactor and is preferably selected from the group consisting of butanes, pentanes, hexanes, heptanes, octanes, nonanes, decanes, undecanes, dodecanes, tridecanes, tetradecanes, pentadecanes, hexadecanes, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, isopropylbenzene, and n-butylbenzene; preferably toluene and or xylenes and or ethylbenzene, normal paraffins (such as Norpar solvents available for ExxonMobil Chemical Company, Houston, Tex.), or isoparaffin solvents (such as Isopar solvents available for ExxonMobil Chemical Company, Houston, Tex.). These solvents or diluents are usually pre-treated in same manners as the feed olefins.
Typically, in the processes of this disclosure, one or more transition metal compounds, one or more activators, and one or more monomers are contacted to produce polymer. These catalysts may be supported and as such will be particularly useful in the known slurry, solution, or bulk operating modes conducted in single, series, or parallel reactors. If the catalyst, activator or co-activator is a soluble compound, the reaction can be carried out in a solution mode. Even if one of the components is not completely soluble in the reaction medium or in the feed solution, either at the beginning of the reaction or during or at the later stages of the reaction, a solution or slurry type operation is still applicable. In any instance, the catalyst components, dissolved or suspended insolvents, such as toluene or other conveniently available aromatic solvents, or in aliphatic solvent, or in the feed alphaolefin stream, are fed into the reactor under inert atmosphere (usually nitrogen or argon blanketed atmosphere) to allow the polymerization to take place.
The polymerization can be run in a batch mode, where all the components are added into a reactor and allowed to react to a pre-designed degree of conversion, either to partial conversion or full conversion. Subsequently, the catalyst is deactivated by any possible means, such as exposure to air or water, or by addition of alcohols or solvents containing deactivating agents. The polymerization can also be carried out in a semi-continuous operation, where feeds and catalyst system components are continuously and simultaneously added to the reactor so as to maintain a constant ratio of catalyst system components to feed olefin(s). When all feeds and catalyst components are added, the reaction is allowed to proceed to a pre-determined stage. The reaction is then discontinued by catalyst deactivation in the same manner as described for batch operation. The polymerization can also be carried out in a continuous operation, where feeds and catalyst system components are continuously and simultaneously added to the reactor so to maintain a constant ratio of catalyst system and feed olefins. The reaction product is continuously withdrawn from the reactor, as in a typical continuous stirred tank reactor (CSTR) operation. The residence times of the reactants are controlled by a pre-determined degree of conversion. The withdrawn product is then typically quenched in the separate reactor in a similar manner as other operation.
In a preferred embodiment, any of the processes to prepare PAOs described herein are continuous processes. Preferably the continuous process comprises the steps of a) continuously introducing a feed stream comprising at least 10 mole % of the one or more C8 to C12 alphaolefins into a reactor, b) continuously introducing the metallocene compound, co-activator, and the activator into the reactor, and c) continuously withdrawing the polyalphaolefin from the reactor. In another embodiment, the continuous process comprises the step of maintaining a partial pressure of hydrogen in the reactor of 200 psi (1379 kPa) or less, based upon the total pressure of the reactor, or 150 psi (1034 kPa) or less, or 100 psi (690 kPa) or less, or 50 psi (345 kPa) or less, or 25 psi (173 kPa) or less, or 10 psi (69 kPa) or less. Alternatively the hydrogen, if present, is present in the reactor at 1000 ppm or less by weight, or 750 ppm or less, or 500 ppm or less, or 250 ppm or less, or 100 ppm or less, or 50 ppm or less, or 25 ppm or less, or 10 ppm or less, or 5 ppm or less. Alternatively the hydrogen, if present, is present in the feed at 1000 ppm or less by weight, or 750 ppm or less, or 500 ppm or less, or 250 ppm or less, or 100 ppm or less, or 50 ppm or less, or 25 ppm or less, or 10 ppm or less, or 5 ppm or less.
Reactors range in size from 2 ml and up, with commercial production reactors having a volume of at least one liter. A production facility may have one single reactor or several reactors arranged in series or in parallel or in both to maximize productivity, product properties and general process efficiency. The reactors and associated equipments are usually pre-treated to ensure proper reaction rates and catalyst performance. The reaction is usually conducted under inert atmosphere, where the catalyst system and feed components will not be in contact with any catalyst deactivator or poison which is usually polar oxygen, nitrogen, sulfur or acetylenic compounds.
One or more reactors in series or in parallel may be used in the present disclosure. The transition metal compound, activator and when required, co-activator, may be delivered as a solution or slurry in a solvent or in the alphaolefin feed stream, either separately to the reactor, activated in-line just prior to the reactor, or preactivated and pumped as an activated solution or slurry to the reactor. Polymerizations are carried out in either single reactor operation, in which monomer, or several monomers, catalyst/activator/co-activator, optional scavenger, and optional modifiers are added continuously to a single reactor or in series reactor operation, in which the above components are added to each of two or more reactors connected in series. The catalyst components can be added to the first reactor in the series. The catalyst component may also be added to both reactors, with one component being added to first reaction and another component to other reactors. In one preferred embodiment, the precatalyst is activated in the reactor in the presence of olefin. In another embodiment, the precatalyst such as the dichloride form of the metallocenes is pre-treated with alkylalumum reagents, especially, triisobutylaluminum, tri-n-hexylaluminum and/or tri-n-octylaluminum, followed by charging into the reactor containing other catalyst component and the feed olefins, or followed by pre-activation with the other catalyst component to give the fully activated catalyst, which is then fed into the reactor containing feed olefins. In another alternative, the pre-catalyst metallocene is mixed with the activator and/or the co-activator and this activated catalyst is then charged into reactor, together with feed olefin stream containing some scavenger or co-activator. In another alternative, the whole or part of the co-activator is pre-mixed with the feed olefins and charged into the reactor at the same time as the other catalyst solution containing metallocene and activators and/or co-activator.
In some embodiments, a small amount of poison scavenger, such as trialkylaluminum (trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum) or methylalumoxane is added to the feed olefin stream to further improve catalyst activity. In a preferred embodiment, the monomers are contacted with an alkylaluminum compound, preferably a trialkylaluminum compound, prior to being introduced into the reactor. In another preferred embodiment, the metallocene and or activator are combined with an alkylaluminum compound, preferably a trialkylaluminum compound, prior to entering the reactor. Preferably the alkylaluminum compound is represented by the formula: R3Al, where each R is independently a C1 to C20 alkyl group, preferably the R groups are independently selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, n-butyl, pentyl, isopentyl, n-pentyl, hexyl, isohexyl, n-hexyl, heptyl, octyl, isocotyl, n-octyl, nonyl, isononyl, n-nonyl, decyl, isodecyl, n-cecyl, undecyl, isoundecyl, n-undecyl, dodecyl, isododecyl, and n-dodecyl, preferably isobutyl, n-octyl, n-hexyl, and n-dodecyl. Preferably the alkylaluminum compound is selected from tri-isobutylaluminum, tri-n-octylaluminum, tri-n-hexylaluminum, and tri-n-dodecylaluminum.
In one embodiment of any of the process described herein, the feed olefins and or solvents are treated to remove catalyst poisons, such as peroxides, oxygen or nitrogen-containing organic compounds or acetylenic compounds. The treatment of the linear alphaolefin with an activated 13× molecular sieve and a de-oxygenation catalyst, i.e., a reduced copper catalyst, increased catalyst productivity more than 10-fold. Alternatively, the feed olefins and or solvents are treated with an activated molecular sieve, such as 3 A, 4 A, 8 A or 13× molecular sieve, and/or in combination with an activated alumina or an activated de-oxygenated catalyst. Such treatment will increase catalyst productivity 2- to 10-fold or more. The improved process also includes special treatment of the feed olefins to remove catalyst poisons, such as peroxides, oxygen, sulfur or nitrogen-containing organic compounds or other trace impurities. This treatment can increase catalyst productivity substantially (typically more than 10-fold). Preferably the feed olefins are contacted with a molecular sieve, activated alumina, silica gel, oxygen removing catalyst, and or purifying clays to reduce the heteroatom-containing compounds in the feed, preferably below 50 ppm, preferably below 10 ppm.
The catalyst compositions can be used individually or can be mixed with other known polymerization catalysts to prepare polymer blends. Monomer and catalyst selection allows polymer blend preparation under conditions analogous to those using individual catalysts. Polymers having increased molecular weight distribution are available from polymers made with mixed catalyst systems and can thus be achieved. Mixed catalyst can comprise two or more catalyst precursors and or two or more activators.
Generally, when using metallocene catalysts, after pre-treatment of feed olefins, solvents, diluents and after precautions to keep the catalyst component stream(s) and reactor free of impurities, the reaction should proceed well. In some embodiments, when using metallocene catalysts, particularly when they are immobilized on a support, the complete catalyst system will additionally comprise one or more scavenging compounds. Here, the term scavenging compound means a compound that removes polar impurities from the reaction environment. These impurities adversely affect catalyst activity and stability. Typically, purifying steps are usually used before introducing reaction components to a reaction vessel. But such steps will rarely allow polymerization without using some scavenging compounds. Normally, the polymerization process will still use at least small amounts of scavenging compounds.
Typically, the scavenging compound will be an organometallic compound such as the group 13 organometallic compounds of U.S. Pat. Nos. 5,153,157, 5,241,025 and WO-A-91/09882, WO-A-94/03506, WO-A-93/14132, and WO 95/07941. Exemplary compounds include previously disclosed trialkylaluminums. Scavenging compounds having bulky or C6-C20 linear hydrocarbyl substituents connected to the metal or metalloid center usually minimize adverse interaction with the active catalyst. Examples include triethylaluminum, but more preferably, bulky compounds such as tri-iso-butyl aluminum, tri-iso-prenyl aluminum, and long-chain linear alkyl-substituted aluminum compounds, such as tri-n-hexyl aluminum, tri-n-octyl aluminum, or tri-n-dodecyl aluminum. Alumoxanes also may be added in scavenging quantities with other activators, e.g., methylalumoxane, [Me2HNPh]+[B(pfp)4]− or B(pfp)3, where pfp is perfluorophenyl (C6F5), Me is methyl and Ph is phenyl.
In a preferred embodiment, ethylene is present in the feed at 10 mole % or less, preferably 0.5 to 8 mole %, preferably 0.5 to 5 mole %, preferably from 1 to 3 mole %.
The PAOs described herein can also be produced in homogeneous solution processes. Generally this involves polymerization in a continuous reactor in which the polymer formed and the starting monomer and catalyst materials supplied, are agitated to reduce or avoid concentration or temperature gradients. Temperature control in the reactor is generally obtained by balancing the heat of polymerization and with reactor cooling by reactor jackets or cooling coils or a cooled side-stream of reactant to cool the contents of the reactor, auto refrigeration, pre-chilled feeds, vaporization of liquid medium (diluent, monomers or solvent) or combinations of the above. Adiabatic reactors with pre-chilled feeds may also be used. The reactor temperature depends on the catalyst used and the product desired. Higher temperatures tend to give lower molecular weights and lower temperatures tend to give higher molecular weights, however this is not a hard and fast rule.
In order to produce fluids with narrow molecular distribution, such as to promote the highest possible shear stability, it is useful to control the reaction temperature to obtain minimum of temperature fluctuation in the reactor or over the course of the reaction time. If multiple reactors are used in series or in parallel, it is useful to keep the temperature constant in a pre-determined value to minimize any broadening of molecular weight distribution. In order to produce fluids with broad molecular weight distribution, one can adjust the reaction temperature swing or fluctuation, or as in series operation, the second reactor temperature is preferably higher than the first reactor temperature. In parallel reactor operation, the temperatures of the two reactors are independent. One can also use two types of metallocene catalyst.
The reaction time or reactor residence time is usually dependent on the type of catalyst used, the amount of catalyst used, and the desired conversion level. Different metallocenes have different activities. Usually, a higher degree of alkyl substitution on the cyclopentadienyl ring, or bridging, improves catalyst productivity. Catalysts such as diphenylmethylidene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride, isopropyl idene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride, diphenylsilylene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride, dimethylsilylene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride, and ethylene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride, and mixtures thereof are particularly useful herein.
The amount of catalyst components used may be determinative for reaction efficiency. High amount of catalyst loading may give high conversion at short reaction time. However, high amount of catalyst usage makes the production process uneconomical and it may be difficult to manage the reaction heat or to control the reaction temperature. Therefore, for the disclosed disclosure, it is useful to choose a catalyst with maximum catalyst productivity to minimize the amount of precatalyst and the amount of activator needed. When the catalyst system is a metallocene plus a Lewis acid or an ionic activator with a NCA component, the metallocene used is typically in the range of 0.01 microgram to 500 micrograms of metallocene component/gram of alphaolefin feed. Usually the preferred range is from 0.1 microgram to 100 microgram of metallocene component per gram of alphaolefin feed. Furthermore, the molar ratio of the NCA activator to metallocene is in the range from 0.1 to 10, preferably 0.5 to 5, preferably 0.5 to 3. If a co-activator of alkylaluminum compound is used, the molar ratio of the Al to metallocene is in the range from 1 to 1000, alternatively 2 to 500, alternatively 4 to 400, alternatively 4 to 200, alternatively 4 to 50.
Typically one prefers to have the highest possible conversion (close to 100%) of feed alphaolefin in shortest possible reaction time. However, in CSTR operation, sometimes it is beneficial to run the reaction at an optimum conversion, which is slightly less than 100% conversion. There are also occasions, when partial conversion is more desirable when the narrowest possible molecular weight distribution of the product is desirable because partial conversion can avoid a molecular weight distribution broadening effect. If the reaction is conducted to less than 100% conversion of the alphaolefin, the unreacted starting material after separation from other product and solvents/diluents can be recycled to increase the total process efficiency.
When a solid supported catalyst is used, a slurry polymerization process generally operates in the similar temperature, pressure and residence time range as described previously. In a slurry polymerization, a suspension of solid catalyst, promoters, monomer and comonomers are added. The suspension including diluent is intermittently or continuously removed from the reactor. The catalyst is then separated from the product by filtration, centrifuge or settlement. The fluid is then distilled to remove solvent, any unreacted components and light product. A portion or all of the solvent and unreacted component or light components can be recycled for reuse.
If the catalyst used is a solution catalyst (i.e. not supported), when the reaction is complete (such as in a batch mode), or when the product is withdrawn from the reactor (such as in a CSTR), the product may still contain soluble, suspended or mixed catalyst components. These components are preferably deactivated or removed. Any of the usual catalyst deactivation methods or aqueous wash methods can be used to remove the catalyst component. Typically, the reaction is deactivated by addition of stoichiometric amount or excess of air, moisture, alcohol, isopropanol, etc. The mixture is then washed with dilute sodium hydroxide or with water to remove catalyst components. The residual organic layer is then subjected to distillation to remove solvent, which can be recycled for reuse. The distillation can further remove any light reaction product from C18 and less. These light components can be used as diluent for further reaction. Or they can be used as olefinic raw material for other chemical synthesis, as these light olefin product have vinylidene unsaturation, most suitable for further functionalization to convert in high performance fluids. Or these light olefin products can be hydrogenated to be used as high quality paraffinic solvents.
Alternatively, a different catalyst removal method is used. After the polymerization reaction is deactivated by the addition of stoichiometric amount of excess air, moisture, alcohol, isopropanol, etc., a small amount of solid sorbent, such as Celite, silica gel, alumina gel, natural clay, synthetic clay, modified clay, diatomaceous earth, activated charcoal, silica gel, alumina, aluminosilicate, zeolites, molecular sieves, cellulose material, metal oxides or metal salts, such as calcium oxides, magnesium oxides, titanium oxides, zirconium oxides, aluminum oxides, activated or treated in appropriate manners. The solid sorbent can absorb most of the catalyst components. After slurry for appropriate amount of time, the solid sorbent can be removed by filtration. The liquid product can then be subjected to similar distillation as described earlier to isolate desirable products.
In another embodiment, any of polyalphaolefins produced herein is hydrogenated. In particular the polyalphaolefin is preferably treated to reduce heteroatom containing compounds to less than 600 ppm, and then contacted with hydrogen and a hydrogenation catalyst to produce a polyalphaolefin having a Bromine number less than 1.8. In a preferred embodiment, the treated polyalphaolefin comprises 100 ppm of heteroatom containing compounds or less, preferably 10 ppm of heteroatom containing compounds or less. (A heteroatom containing compound is a compound containing at least one atom other than carbon and hydrogen). Preferably the hydrogenation catalyst is selected from the group consisting of supported group 7, 8, 9, and 10 metals, preferably the hydrogenation catalyst selected from the group consisting of one or more of Ni, Pd, Pt, Co, Rh, Fe, Ru, Os, Cr, Mo, and W, supported on silica, alumina, clay, titania, zirconia, or mixed metal oxide supports. A preferred hydrogenation catalyst is nickel supported on Kieselguhr, or platinum or palladium supported on alumina, or cobalt-molydenum supported on alumina. Usually, a high nickel content catalyst, such as 60% Ni on Kieselguhr catalyst is used, or a supported catalyst with high amount of Co—Mo loading. Alternatively, the hydrogenation catalyst is nickel supported on Kieselguhr, silica, alumina, clay or silica-alumina.
In one embodiment the polyalphaolefin is contacted with hydrogen and a hydrogenation catalyst at a temperature from 25 to 350° C., preferably 100 to 300° C. In another embodiment the polyalphaolefin is contacted with hydrogen and a hydrogenation catalyst for a time period from 5 minutes to 100 hours, preferably from 5 minutes to 24 hours. In another embodiment the polyalphaolefin is contacted with hydrogen and a hydrogenation catalyst at a hydrogen pressure of from 25 psi to 2500 psi, preferably from 100 to 2000 psi. For further information on hydrogenation of PAOs see U.S. Pat. No. 5,573,657 and “Lubricant Base Oil Hydrogen Refining Processes” (page 119 to 152 of Lubricant Base Oil and Wax Processing, by Avilino Sequeira, Jr., Marcel Dekker, Inc., NY, 1994).
This hydrogenation process can be accomplished in a slurry reactor in a batch operation or in a continuous stirred tank reactor (CSTR), where the catalyst in 0.001 wt % to 20 wt % of the PAO feed or preferably 0.01 to 10 wt %, hydrogen and the polyalphaolefins are continuously added to the reactor to allow for certain residence time, usually 5 minutes to 10 hours to allow complete hydrogenation of the unsaturated olefins. The amount of catalyst added is usually very small just to compensate for the catalyst deactivation. The catalyst and hydrogenated PAO are continuously withdrawn from the reactor. The product mixture was then filtered, centrifuged or settled to remove the solid hydrogenation catalyst. The catalyst can be regenerated and reused. The hydrogenated PAO can be used as is or further distilled or fractionated to the right component if necessary. In some cases, when the hydrogenation catalyst show no catalyst deactivation over long term operation, the stir tank hydrogenation process can be carried out in a manner where a fixed amount of catalyst is maintained in the reactor, usually 0.1 wt % to 10 wt % of the total reactant, and only hydrogen and PAO feed are continuously added at certain feed rate and only hydrogenated PAO was withdrawn from the reactor.
The hydrogenation process can also be accomplished by a fixed bed process, in which the solid catalyst is packed inside a tubular reactor and heated to reactor temperature. Hydrogen and PAO feed can be fed through the reactor simultaneously from the top or bottom or countercurrently to maximize the contact between hydrogen, PAO and catalyst and to allow best heat management. The feed rate of the PAO and hydrogen are adjusted to give proper residence to allow complete hydrogenation of the unsaturated olefins in the feed. The hydrogenated PAO fluid can be used as is or further distilled or fractionated to give the right component, if necessary. Usually, the finished hydrocarbon PAO fluids have Bromine number less than 2.
The poly-alphaolefins of this disclosure, when used alone or blended with other fluid, have unique lubrication properties.
In another embodiment, a novel lubricant of the present disclosure comprises the PAOs produced in this disclosure as the base stock, or together with one or more other base stocks, including Group I to Group V base stocks with viscosity range from 1.5 to 100 cSt at 100° C. to formulate suitable viscosity grades. In addition, additives of one or more of: thickeners, VI improvers, antioxidants, anti-wear additives, detergent/dispersant/inhibitor (DDI) packages, and/or anti-rust additives may be added. In a preferred embodiment the PAOs produced herein are combined with one or more of dispersants, detergents, friction modifiers, traction improving additives, demulsifiers, defoamants, chromophores (dyes), and/or haze inhibitors. These fully formulated lubricants can be used preferably in industrial oils, and also in automotive crank case oil (engine oil), grease, or gas turbine engine oil. These are examples of additives used in finished lubricant formulations. Additional information on the use of PAOs in the formulations of full synthetic, semi-synthetic or part synthetic lubricant or functional fluids can be found in “Synthetic Lubricants and High-Performance Functional Fluids,” 2nd Ed. L. Rudnick, ed. Marcel Dekker, Inc., N.Y. (1999). Additional information on additives used in product formulation can be found in “Lubricants and Lubrications,” T. Mang and W. Dresel, eds., Wiley-VCH GmbH. Weinheim 2001.
The PAOs produced in this disclosure can be used preferably in the formulation of industrial lubricants, and also in the formulation of automotive engine lubricants, greases, hydraulic lubricants, etc. with improved viscometrics, superior low temperature properties, leading to improved fuel economy or energy efficiency, or significantly improved wear protection and cleanliness. For example, the PAO can be used in industrial lubricant formulation to improve VI, alone or used together with other traditional VI improver (OCP (olefin-copolymer) or polymethacrylates). In the engine oil formulations, the other suitable base stocks used in the blend include API Groups I to V, low viscosity fluids, in proper portions. In addition, additives are added to the formulation. Typical additives include anti-oxidants, anti-wear agents, dispersants, detergents, extreme-pressure additives, corrosion inhibitors, defoamant agents, etc. Examples of automotive engine lubricant formulations and additives can be found in U.S. Pat. No. 6,713,438.
The PAOs disclosed in this disclosure preferably can be used as a base stock or co-base stock in industrial lubricant formulations. In industrial lube formulations, 1 to 99 wt % or 1 to 90 wt %, or 50 to 99 wt %, or 55 to 90 wt %, or 5 wt % to 45 wt %, or 5 to 60 wt %, or 5 to 45 wt % or 20% to 60% of one, or more than one, viscosity grade of the PAO in this disclosure can be blended with one or more of the API Group I to V base stocks to give the base oil for the industrial lube formulation. Often, one or multiple of these other base stocks are chosen to blend with PAOs to obtain the optimized viscometrics and the performance. Further, preferred embodiments relate to the viscosity index of the base stocks usable as blending components in this disclosure, where in some instances the viscosity index is preferably 250 or greater, more preferably 260 or greater, and even more preferably 270 or greater.
In addition to these PAOs described above, in a preferred embodiment a second class of fluids, selected to be different from the fluids discussed above, and preferably having a higher polarity is also added to the formulation. The polarity of a fluid may be determined by one of ordinary skill in the art, such as by aniline points as measured by ASTM D611 method. Usually fluids with higher polarity will have lower aniline points. Fluids with lower polarity will have higher aniline points. Most polar fluids will have aniline points of less than 100° C. In preferred embodiments, such fluids are selected from the API Group V base stocks. Examples of these Group V fluids include alkylbenzenes (such as those described in U.S. Pat. Nos. 6,429,345, 4,658,072), and alkylnaphthalenes (e.g., U.S. Pat. Nos. 4,604,491, and 5,602,086). Other alkylated aromatics are described in “Synthetic Lubricants and High Performance Functional Fluids”, M. M Wu, Chapter 7, (L. R. Rudnick and R. L. Shubkin, eds.), Marcel Dekker, NY, 1999.
The viscosity grade of the final product is adjusted by suitable blending of base stock components of differing viscosities. In many conventional industrial lubricant formulations, thickeners are used to increase viscosity. One particular advantage of the present disclosure is that thickeners are not necessary and in preferred embodiments no thickeners are used. PAO fluids of different viscosity grades are most suitably used to achieve wide finished viscosity grades with significant performance advantages. Usually, differing amounts of the various base stock components (primary hydrocarbon base stocks, secondary base stock and any additional base stock components) of different viscosities, may be suitably blended together to obtain a base stock blend with a viscosity appropriate for blending with the other components of the finished lubricant. This may be determined by one of ordinary skill in the art in possession of the present disclosure without undue experimentation. The viscosity grades for the final product are preferably in the range of ISO 2 to ISO 1000 or even higher for industrial gear lubricant applications, for example, up to ISO 46,000. For the lower viscosity grades, typically from ISO 2 to ISO 13,100, the viscosity of the combined base stocks will be slightly higher than that of the finished product, typically from ISO 2 to ISO 220 but in the more viscous grades up to ISO 46,000, the additives will frequently decrease the viscosity of the base stock blend to a slightly lower value. With an ISO 680 grade lubricant, for example, the base stock blend might be 780-800 cSt (at 40° C.) depending on the nature and concentration(s) of the additives.
In addition to base stocks, many additives are used in industrial lubricant formulation. Examples of these additives include antioxidants, anti-wear additives, extreme pressure additives, dispersants, detergents, corrosion inhibitors, defoamants, etc.
Shear stability is important for many industrial oil operations. Higher shear stability means the oil does not lose its viscosity at high shear. Such shear-stable oil can offer better protection under more severe operation conditions. The oil compositions described in this disclosure have superior shear stability for industrial oil applications. The formulated oil containing PAOs usually have excellent viscometrics, high VI, all these contributing to the energy efficiency for the lubricants.
Similarly, the PAOs can be used in automotive gear oil formulation, in grease and hydraulic oil formulations.
In the above detailed description, the specific embodiments of this disclosure have been described in connection with its preferred embodiments. However, to the extent that the above description is specific to a particular embodiment or a particular use of this disclosure, this is intended to be illustrative only and merely provides a concise description of the exemplary embodiments. Accordingly, the disclosure is not limited to the specific embodiments described above, but rather, the disclosure includes all alternatives, modifications, and equivalents falling within the true scope of the appended claims. Various modifications and variations of this disclosure will be obvious to a worker skilled in the art and it is to be understood that such modifications and variations are to be included within the purview of this application and the spirit and scope of the claims.
The following examples are for purposes of illustration only and are non-limiting examples.
The 1-decene used for all of the experiments was purified by mixing 1 liter of untreated raw material with 20 grams of activated 13× molecular sieve (which was activated by calcining at 200° C. for at least four hours under a stream of purging dry nitrogen gas), and 10 grams of Oxi-Clear catalyst (purchased from Altech Associates, Inc of Deerfield, Ill. 60115) for at least two days inside a glove box under a dry, inert atmosphere of nitrogen. The molecular sieve and de-oxygenation catalyst were then removed by filtration in the glove box to provide purified 1-decene. Alternatively, the feeds were purified by passing through a bed of activated 13× molecular sieve alone under nitrogen atmosphere.
The polymerization reaction was carried out under nitrogen (N2) inert atmosphere or argon inert atmosphere. All solutions were prepared using purified toluene as solvent. In the examples, the following abbreviations are used:
Metallocene A=diphenylmethylidene(cyclopentadienyl)(9-fluorenyl) zirconium dichloride (BSC453)
Activator D=N,N-dimethylanilinium tetra(perfluorophenyl) borate;
TIBA=tri-isobutylaluminum.
A solution of 100 grams of purified 1-decene, 2.641 grams of a TIBA stock solution (1 mg TIBA/g solution) and 0.9188 grams of Metallocene A stock solution (1 mg Metallocene A/g solution) was charged into a clean 600 ml autoclave equipped with an agitator, at room temperature. The reactor was then pressurized with 30 psig hydrogen. The mixture was then heated to 130° C. with stirring. A second solution containing 20 g toluene solvent and 1.292 grams of Activator D stock solution (1 mg Activator D/g solution) was added and the reaction temperature was maintained at 130° C. overnight, then cooled down to room temperature, and any reactor pressure was vented. The liquid product was diluted with 50 ml toluene, stirred with 5 grams activated alumina for half an hour and filtered to remove solids. The lube product was then isolated by removing the light ends (toluene and unreacted 1-decene) with a rotary evaporator and high boiling C20 dimer at 180° C. under high vacuum (1 mm) for two hours to isolate the lube product.
Examples 2-7 were conducted in a similar manner to Example 1, except that reaction temperatures and hydrogen pressures were varied to demonstrate that lubes with wide viscosity ranges were obtained using this method. The results and properties are summarized in Table 1 below.
Example 8 is a high viscosity 300 cSt PAO produced using activated chromium on silica gel catalyst and is commercially available from ExxonMobil Chemicals Synthetic technology as SpectraSyn Ultra product. Example 9 is commercially available Lucant 600 from Mitsui Chemicals.
The results set forth in Table 1 indicate several advantages for products of this disclosure over either PAO300 or Lucant 600 product.
The viscosity-temperature relationship of lubricating oil is one of the critical criteria which must be considered when selecting a lubricant for a particular application. Viscosity Index (VI) is an empirical, unit less number which indicates the rate of change in the viscosity of an oil within a given temperature range and is related to kinematic viscosities measured at 40° C. and 100° C. (typically using ASTM Method D 445). Fluids exhibiting a relatively large change in viscosity with temperature are said to have a low viscosity index. The low VI oil, for example, will thin out at elevated temperatures faster than the high VI oil. Usually, the high VI oil is more desirable because it has higher viscosity at higher temperature, which translates into better or thicker lubrication film and better protection of the contacting machine elements. As the oil operating temperature decreases, the viscosity of the high VI oil will not increase as much as the viscosity of low VI oil. This is advantageous because the excessive high viscosity of the low VI oil will decrease the efficiency of the operating machine. Thus high VI oil has performance advantages in both high and low temperature operation.
1. A polyalphaolefin (PAO) fluid comprising a polymer of one or more C8 to C12 alphaolefin monomers, said PAO having:
2. The polyalphaolefin (PAO) fluid of clause 1, wherein said PAO further has:
3. The polyalphaolefin (PAO) fluid of clauses 1 and 2 wherein the PAO has a kinematic viscosity at 100° C. of 400 to 800 cSt, an as-synthesized Mw/Mn of 1.9 or less, and an as-synthesized Bromine number of less than 1.9.
4. The polyalphaolefin (PAO) fluid of clauses 1-3 wherein the monomers are alphaolefins selected from the group consisting of octene, nonene, decene, undecene and dodecene.
5. A process for producing a polyalphaolefin (PAO) comprising:
contacting in a reactor a feed stream comprising at least one alphaolefin monomer having 8 to 12 carbon atoms with a catalyst system comprising a precatalyst compound and a non-coordinating anion activator, and optionally an alkyl-aluminum compound, under polymerization conditions, optionally in the presence of hydrogen, and the alphaolefin monomer having 8 to 12 carbon atoms is present at 10 volume % or more, based upon the total volume of the catalyst, monomers, and any diluents or solvents present, in the reactor; and
obtaining the PAO;
wherein the precatalyst compound is represented by the formula
wherein:
M is a group 4 metal;
L1 is a unsubstituted fluorenyl, unsubstituted heterocyclopentapentalenyl, unsubstituted heterofluorenyl, substituted fluorenyl, substituted heterocyclopentapentalenyl, or substituted heterofluorenyl ligand with pseudo symmetric substituents, each substituent group being, independently, a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl, and optionally two or more adjacent substituents may join to form a substituted or unsubstituted, saturated, partially unsaturated or aromatic, cyclic or polycyclic substituent;
L2 is a cyclopentadienyl ring or a substituted cyclopentadienyl ring with pseudo symmetric substituents in the 2 and 5 positions of the ring, each substituent group being, independently, a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl;
G is a bridging group; and
6. The process of clause 5 wherein the precatalyst compound is represented by the formula
wherein each Ra and Rb are selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl, germylcarbyl or polar radicals, and optionally two or more adjacent substituents may join to form a substituted or unsubstituted, saturated, partially unsaturated or aromatic, cyclic or polycyclic substituent, with the proviso that each Ra is the same and each Rb is the same and allow the compound to be Cs-symmetric or pseudo Cs-symmetric; each Rc is a pseudo symmetric substituent with respect to the other and is selected from hydrogen or a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl radicals; each Rd is a pseudo symmetric substituent with respect to the other and is selected from hydrogen or a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl radicals.
7. The process of clauses 5 and 6 wherein the PAO has the following characteristics:
8. The process of clause 7 wherein said PAO further has:
9. The process of clauses 5-8 further comprising: 1) optionally treating the PAO to reduce heteroatom containing compounds to less than 600 ppm; and/or 2) optionally separating the PAO from solvents or diluents; and/or 3) contacting the PAO with hydrogen, and a hydrogenation catalyst; and/or 4) obtaining a PAO having a Bromine Number less than 1.8.
10. The process of clauses 5-9 wherein the activator comprises one or more of N,N-dimethylanilinium tetra(pentafluorophenyl)borate, N,N-dialkylphenylanilinium tetra(pentafluorophenyl)borate where the alkyl is a C1 to C18 alkyl group, trityl tetra(pentafluorophenyl)borate, tris(pentafluorophenyl)boron, tri-alkylammonium tetra(pentafluorophenyl)borate where the alkyl is a C1 to C18 alkyl group, tetra-alkylammonium tetra(pentafluorophenyl)borate where the alkyl is a C1 to C18 alkyl group.
11. The process of clauses 5-10 wherein an alkylaluminum compound is present and the alkylaluminum compound is represented by the formula: R3Al, where each R is, independently, selected from the group consisting of methyl, ethyl, n-propyl, iso-propyl, iso-butyl, n-butyl, t-butyl, n-pentyl, iso-pentyl, neopentyl, n-hexyl, iso-hexyl, n-heptyl, iso-heptyl, n-octyl, iso-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecy, n-hexadecyl, n-heptadecyl, n-octadecyl, and their iso-analogs.
12. The process of clauses 5-11 wherein the metallocene comprises diphenylmethylidene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride.
13. The process of clauses 5-12 wherein the one or more alphaolefin monomers are contacted with the metallocene compound and the activator in a reactor and the reactor is a continuous stirred tank reactor, a continuous tabular reactor, or a batch reactor.
14. The process of clauses 5-13 wherein the productivity is greater than 50 kg/g of metallocene compound or is greater than 10 kg/g of activator.
15. A lubricant comprising (i) a base stock comprising the PAO of clauses 1-4, or (ii) a conventional base stock and a co-base stock, wherein the co-base stock comprises the PAO of clauses 1-4.
All patents and patent applications, test procedures (such as ASTM methods, UL methods, and the like), and other documents cited herein are fully incorporated by reference to the extent such disclosure is not inconsistent with this disclosure and for all jurisdictions in which such incorporation is permitted.
When numerical lower limits and numerical upper limits are listed herein, ranges from any lower limit to any upper limit are contemplated. While the illustrative embodiments of the disclosure have been described with particularity, it will be understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the spirit and scope of the disclosure. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the examples and descriptions set forth herein but rather that the claims be construed as encompassing all the features of patentable novelty which reside in the present disclosure, including all features which would be treated as equivalents thereof by those skilled in the art to which the disclosure pertains.
The present disclosure has been described above with reference to numerous embodiments and specific examples. Many variations will suggest themselves to those skilled in this art in light of the above detailed description. All such obvious variations are within the full intended scope of the appended claims.
