Patent Application
20220010232
The invention is directed to the reaction product of an alkali or alkaline earth salt of an acidic organic compound, a boron compound and an amine component. It is also directed to a lubricant composition comprising this reaction product, a method for its production and its uses.
One of the primary functions of lubricants is to decrease friction. Frequently, however, lubricating oils need additional properties to be used effectively. For example, lubricants used in large diesel engines, such as, for example, marine diesel engines, are often subjected to operating conditions requiring special considerations.
The marine oils used in low-speed two-stroke crosshead engines are of two types. On the one hand, cylinder oils ensuring the lubrication of the cylinder-piston assembly and, on the other hand, system oils ensuring the lubrication of all the moving parts apart from the cylinder-piston assembly. Within the cylinder-piston assembly, the combustion residues containing acid gases are in contact with the lubricating oil.
The acid gases are formed from the combustion of the fuel oils; these are in particular sulphur oxides (SO2, SO3), which are then hydrolyzed on contact with the moisture present in the combustion gases and/or in the oil. This hydrolysis generates sulphurous (HSO3) or sulphuric (H2SO4) acid.
To protect the surface of piston liners and avoid excessive corrosive wear, these acids must be neutralized, which is generally done by reaction with the basic sites included in the lubricant.
An oil's neutralization capacity is measured by its BN or Base Number, characterized by its basicity. It is measured according to standard ASTM D-2896 and is expressed as an equivalent in milligrams of potash per gram of oil (also called “mg of KOH/g” or “BN point”). The BN is a standard criterion making it possible to adjust the basicity of the cylinder oils to the sulphur content of the fuel oil used, in order to be able to neutralize all of the sulphur contained in the fuel, and capable of being converted to sulphuric acid by combustion and hydrolysis.
Thus, the higher the sulphur content of a fuel oil, the higher the BN of a marine oil needs to be. This is why marine oils with a BN varying from 5 to 140 mg KOH/g are found on the market. This basicity is provided by detergents that are neutral and/or overbased by insoluble metallic salts, in particular metallic carbonates. The detergents, mainly of anionic type, are for example metallic soaps of salicylate, phenate, sulphonate, carboxylate type etc. which form micelles where the particles of insoluble metallic salts are maintained in suspension. The usual neutral detergents intrinsically have a BN typically less than 150 mg KOH per gram of detergent and the usual overbased detergents intrinsically have a BN in a standard fashion comprised between 150 and 700 mg KOH per gram of detergent. Their percentage by mass in the lubricant is fixed as a function of the desired BN level.
Environmental concerns have led, in certain areas and in particular coastal areas, to requirements relating to the limitation of the level of sulphur in the fuel oils used on ships. Thus, the regulation MARPOL Annex 6 (Regulations for the Prevention of Air Pollution from Ships) issued by the IMO (International Maritime Organization) entered into force in May 2005. It sets a global cap of 4.5% w/w on the sulphur content of heavy fuel oils as well as creating sulphur oxide emission control areas, called SECAs (Sulphur Emission Control Areas). Ships entering these areas must use fuel oils with a maximum sulphur content of 1.5% w/w or any other alternative treatment intended to limit the SOx emissions in order to comply with the specified values. The notation w/w denotes the percentage by weight of a compound relative to the total weight of fuel oil or lubricating composition in which it is included.
More recently the MEPC (Marine Environment Protection Committee) met in April 2008 and approved proposed amendments to the regulation MARPOL Annex 6. These proposals are summarized in the table below. They present a scenario in which the restrictions on the maximum sulphur content become more severe with a worldwide maximum content reduced from 4.5% w/w to 3.5% w/w as from 2012. The SECAs (Sulphur Emission Control Areas) will become ECAs (Emission Control Areas) with an additional reduction in the maximum permissible sulphur content from 1.5% w/w to 1.0% w/w as from 2010 and the addition of new limits relating to contents of NOx and particles.
Ships sailing trans-continental routes already use different heavy fuel oil depending on local environmental constraints, allowing them to optimize their operating costs. This situation will continue irrespective of the final level of the maximum permissible sulphur content of fuel oils. Thus the majority of container ships currently under construction provide for the utilization of bunker tanks, for a “high sea” fuel oil with a high sulphur content on the one hand and for a ‘SECA’ fuel oil with a sulphur content less than or equal to 0.1% w/w on the other hand. Switching between these two categories of fuel oil can require adaptation of the engine's operating conditions, in particular the utilization of appropriate cylinder lubricants.
Currently, in the presence of fuel oil with a high sulphur content (3.5% w/w and less), marine lubricants having a BN of the order of 70 or less are used. In the presence of a fuel oil with a low sulphur content (0.1% w/w), marine lubricants having a BN of the order of 40 or less are used. In these two cases, a sufficient neutralizing capacity is achieved as the necessary concentration in basic sites provided by the neutral and/or the overbased detergents of the marine lubricant is reached, but it is necessary to change lubricant at each change of type of fuel oil.
Moreover, each of these lubricants has limits of use resulting from the following observations: the use of a high BN cylinder lubricant in the presence of a fuel oil with a low sulphur content (0.1 w/w) and at a fixed lubrication level, creates a significant excess of basic sites (high BN) and a risk of destabilization of the micelles of unused overbased detergent, which contain insoluble metallic salts. This destabilization results in the formation of deposits of insoluble metallic salts (for example calcium carbonate), mainly on the piston crown, and can eventually lead to a risk of excessive wear of the liner-polishing type. Further, the use of a low BN cylinder lubricant is not sufficient in term of total neutralization capacity in the presence of a fuel oil with a high sulphur content and thus can cause an important risk of corrosion.
Therefore, the optimization of the cylinder lubrication of a low-speed two-stroke engine then requires the selection of the lubricant with the BN adapted to the fuel oil and to the operating conditions of the engine. This optimization reduces the flexibility of operation of the engine and requires a significant degree of technical expertise on the part of the crew in defining the conditions under which the switching from one type of lubricant to the other must be carried out.
Actually, the operating conditions of marine engine and notably of two-stroke marine engine, are increasingly stringent standards. Accordingly, the lubricant being directly in contact with the engine, and notably with the hot section of the engine as for example the segment-piston-pump assembly, shall ensure a resistance to an elevated temperature and thus, reduce or prevent the formation of deposits in the hot section of the engine but also shall ensure a good neutralization towards the sulfuric acid generated during the combustion of fuel.
There is a need for a marine detergent, which is able to be used in presence of high-sulphur fuels and also low-sulphur fuels and having a good neutralization capacity of sulfuric acid while maintaining a good thermal resistance and thus a lower risk of deposits formation in the hot section of the engine.
There is also a need for marine lubricants having a BN, notably having a BN inferior or equal to BN 70, able to be used in presence of high-sulphur fuels and also low-sulphur fuels and having a good neutralization of sulfuric acid while maintaining a good thermal resistance and thus a lower risk of deposits formation in the hot section of the engine.
It would also be desirable to have a lubricant for marine engines, including for a two-stroke marine engine, displaying no or few risk of viscosity increase over time, and particularly during its use.
An object of the present invention is to provide a lubricant additive overcoming all or part of the aforementioned drawbacks. Another object of the present invention is to provide a lubricant additive whose formulation within lubricant compositions is easy to implement.
Another object of the present invention is to provide a lubricant composition overcoming all or part of the aforementioned drawbacks.
Another object of the present invention is to provide a lubricant composition whose formulation is easy to implement.
Another object of the present invention is to provide a method for lubricating a marine engine, and especially for lubricating a two-stroke marine engine used with both low-sulphur fuel and high-sulphur fuel.
Another object of the present invention is to provide a method for lubricating a marine engine, and especially for a two-stroke marine engine used with very low-sulphur fuel.
Another object of the present invention is to provide a method for reducing the formation of deposits in the hot section of a marine engine, notably of a two-stroke marine engine.
Document US 2015/0299606 discloses a metal-free detergent and antioxidant additive that can be used in a lubricating oil comprising the reaction product of an acidic organic compound, a boron compound, a polyamine such as polyethylene imine, and optionally an alkoxylated amine and/or an alkoxylated amide.
US 2005/172543 discloses a composition comprising the reaction product of an acidic organic compound, a boron compound and a basic organic compound and its use as a detergent additive for lubricants and hydrocarbon fuels.
EP 3 072 951 discloses a detergent composition for use in lubricating oil compositions, said detergent comprising:
US 2016/0281014 discloses a lubricating oil detergent composition comprising an overbased calcium sulfonate and a low ash detergent, which is metal free and comprises the reaction product of an acidic organic compound such as an alkylated salicylic acid, a boron compound and an amine component.
Document US 2017/313955 discloses a marine engine lubricating composition comprising at least one lubricant base oil and at least one fatty amine of formula R1R2N—(CH2)3—[NH(CH2)3]n—NH2 wherein R1 and R2 represents a saturated, linear or branched alkyl group comprising at least 14 carbon atoms, and n represents 0, 1 or 2.
EP 1 783 134, EP 2 316 823 and EP 2 322 591 disclose the preparation of middle to high TBN detergent-dispersant additives for lubricating oil applications for internal combustion engines. These additives consist in alkali and/or alkaline earth metal alkyl hydroxybenzoate, optionally overbased.
WO 2017/021426 A1 discloses the use of one or more fatty amines soluble in a lubricant composition for preventing and/or reducing the metal losses of the parts of a marine engine.
None of these documents discloses the reaction product of an alkali or alkaline earth metal salt of an acidic organic compound, a boron compound and an amine component as defined here-under.
Additives combining an alkylated salicylic acid, a boron compound and an amine component provide satisfactory resistance to corrosion and wear. However, for some of those compounds, increasing the amount of additive in the lubricating oil increases oil viscosity while neutralization occurs, thus degrading the lubricating efficacy. Other compounds have proven satisfactory with regards to the control of oil viscosity increase but are less satisfactory with regards to detergency performance. Other compounds have also proven satisfactory with regards to the performance of detergency but are less satisfactory with regards to oil viscosity increase while neutralisation occurs.
Thus, there is a need for a lubricant additive that will simultaneously provide effective corrosion and wear resistance, that will provide satisfactory rheology while in use, in order to enhance lubricating efficacy, and that will provide high detergency performance, thus avoiding the formation of deposits.
The reaction products of the present invention advantageously provide improved detergency and oxidation stability. Furthermore, the reaction products provide excellent detergency and cleanliness to a lubricating oil and do not degrade the oil rheology under use. They provide excellent corrosion and wear resistance.
The invention concerns the reaction product of at least:
wherein,
in formula (I) at least one of n and z are superior or equal to 1,
in formula (II) n is superior or equal to 1.
The invention is also directed to a lubricant composition comprising such a reaction product and a base oil.
The invention is also directed to the use of the product or the lubricant composition, for lubricating two-stroke marine engines and four-stroke marine engines, more preferably two-stroke marine engine.
According to a favourite embodiment, the alkali and/or alkaline earth metal hydrocarbyl-substituted hydroxybenzoate compound is selected from mono-alk(en)yl substituted salicylate salts, di-alk(en)yl substituted salicylate salts, carboxylate functionalized calixarenes salts, notably salicylate calixarenes salts, and mixtures thereof.
According to a more favourite embodiment, the alkali and/or alkaline earth metal hydroxybenzoate compound, optionally substituted by a hydrocarbyl group, is chosen from alkali and/or alkaline earth metal salts of compounds of formula (III):
wherein:
X represents a hydrocarbyl with 1 to 50 carbon atoms, and X can comprise one or more heteroatoms,
a is an integer, a represents 0, 1 or 2.
According to a favourite variant, in formula (III), a represents 1 or 2.
According to another variant, in formula (III), a represents 0.
According to an even more favourite embodiment, the alkali and/or alkaline earth metal hydroxybenzoate compound, optionally substituted by a hydrocarbyl group, is chosen from alkali and/or alkaline earth metal salts of compounds of formula (IIIA):
According to a favourite variant, in formula (IIIA), a represents 1 or 2.
According to another variant, in formula (IIIA), a represents 0.
According to a favourite embodiment, the boron compound is selected from: boric acid, boric acid complexes, boric oxide, a trialkyl borate in which the alkyl groups comprise independently from 1 to 4 carbon atoms, a C1-C12 alkyl boronic acid, a C1-C12 dialkyl boric acid, a C6-C12 aryl boric acid, a C6-C12 diaryl boric acid, a C7-C12 aralkyl boric acid, a C7-C12 diaralkyl boric acid, or products deriving from these by substitution of an alkyl group by one or more alkoxy unit, advantageously, the boron compound is boric acid.
According to a favourite embodiment, the polyalkylamine composition comprises at least 4% w/w, at least 5% w/w, at least 6% w/w, at least 7% w/w, or at least 7.5% w/w of branched compounds of formula (I) or (II), with regards to the total weight of polyalkylamine compounds (I) and (II) in the composition, branched compound signifying that:
in formula (I) at least one of n or z are superior or equal to 1,
in formula (II) n is superior or equal to 1.
According to a favourite variant, the polyalkylamine composition comprises at least 5% by weight, with regards to the total weight of compounds (I) and (II), of products of formulae (I) and (II) with a linear structure, linear meaning n is 0 in formulae (I) and (II) and z is 0 in formula (I).
According to another favourite variant, the polyalkylamine composition further comprises derivatives of polyalkylamines of formula (I) or (II), said derivatives are alkoxylates which are optionally methylated.
According to a favourite embodiment, the polyalkylamine composition further comprises derivatives of polyalkylamines of formula (I) or (II), said derivatives are methylated.
The term “consists essentially of” followed by one or more characteristics, means that may be included in the process or the material of the invention, besides explicitly listed components or steps, components or steps that do not materially affect the properties and characteristics of the invention.
The expression “comprised between X and Y” includes boundaries, unless explicitly stated otherwise. This expression means that the target range includes the X and Y values, and all values from X to Y.
“Alkyl” means a saturated hydrocarbon chain, that can be linear, branched or cyclic.
“Alkenyl” means a hydrocarbon chain, that can be linear, branched or cyclic and comprises at least one unsaturation, preferably a carbon-carbon double bond.
“Aryl” means an aromatic hydrocarbon functional group. This functional group can be monocyclic or polycyclic. As examples of an aryl group one can mention: phenyl, naphtalen, anthracen, phenanthren and tetracen.
“Aralkyl” means an aromatic hydrocarbon functional group, preferably monocyclic, that comprises an alkyl chain substituent.
“Hydrocarbyl” means a compound or fragment of a compound selected from: an alkyl, an alkenyl, an aryl, an aralkyl. Where indicated, some hydrocarbyl groups include heteroatoms.
“overbased” refers to a class of metal salts or complexes. These materials have also been referred to as “basic”, “superbased”, “hyperbased”, “complexes”, “metal complexes”, “high-metal containing salts”, and the like. Overbased products are metal salts or complexes characterized by a metal content in excess of that which would be present according to the stoichiometry of the metal and the particular acidic organic compound reacted with the metal, for example a carboxylic acid.
The term “Total Base Number” or “TBN” refers to the equivalent number of milligrams of KOH needed to neutralize 1 gram of a product. Therefore, a high TBN reflects strongly overbased products and, as a result, a higher base reserve for neutralizing acids. The TBN of a product can be determined according to ASTM Standard No. D2896 or equivalent procedure.
The Alkali or Alkaline Earth Metal Hydroxybenzoate
The alkali and/or alkaline earth metal hydroxybenzoate compounds, optionally substituted by a hydrocarbyl group, are alkali and/or alkaline earth metal salts of molecules that comprise at least one benzoate fragment, and the aromatic ring bears at least one hydroxyl function and possibly one alkyl, alkenyl, aryl or aralkyl substituent. When present, the hydrocarbyl substituent and the hydroxy function can be in ortho, meta or para position with regards to the carboxylate function and with regards to each other. The hydrocarbyl substituent can comprise from 1 to 50 carbon atoms.
The alkali and/or alkaline earth metal hydroxybenzoate compounds include salicylate (hydroxy-2-benzoate) salts, hydroxy-3-benzoate salts, hydroxy-4-benzoate salts, preferably salicylate salts.
The alkali and/or alkaline earth metal hydrocarbyl-substituted hydroxybenzoate compounds include, non limitatively, mono-alk(en)yl substituted salicylate salts, di-alk(en)yl substituted salicylate salts, carboxylate functionalized calixarenes salts, notably salicylate calixarenes, and mixtures thereof.
A calixarene is a macrocycle consisting of several phenolic units which can be para-substituted and connected by a methylene bridge. This cyclic oligomer comprises a sequence of 4 to 16 phenols forming a ring and connected by methylene bridges —(CH2)— or similar bridges.
According to one variant, the alkali and/or alkaline earth metal hydroxybenzoate compounds are chosen from alkali metal salts.
Preferably, the alkali metal is lithium, sodium or potassium, more preferably potassium.
According to a second variant, the alkali and/or alkaline earth metal hydroxybenzoate compounds are chosen from alkaline earth metal salts.
Preferably, the alkaline earth metal is calcium, barium, magnesium or strontium, more preferably calcium.
According to a first embodiment, the alkali and/or alkaline earth metal hydroxybenzoate compounds, optionally substituted by a hydrocarbyl group, are chosen from alkali and/or alkaline earth metal salts of compounds of formula (III) below:
wherein:
X represents a hydrocarbyl with 1 to 50 carbon atoms, and X can comprise one or more heteroatoms,
a is an integer, a represents 0, 1 or 2.
According to a first variant a=0.
According to another variant a=1 or 2.
When a=2, the two hydrocarbyl groups can be identical or different.
Advantageously a=1.
Hydrocarbyl groups in formula (III) means alkyl, alkenyl, aryl and aralkyl groups, possibly comprising one or more heteroatoms.
Hydrocarbyl groups in formula (III) may be linear, branched or cyclic.
Heteroatoms in X can be selected from O, N, S. For example, they can be present as one or more of: an —OH, —NH2, or —SH substituent, or an —O—, —NH—, —N═ or —S— bridge.
Preferably, X does not comprise heteroatoms.
Preferably, X is selected from alkyl and alkenyl groups.
Advantageously, X represents an alkyl or an alkenyl with 1 to 50 carbon atoms.
Preferably, X is selected from linear and branched alkyl and alkenyl groups.
Even more advantageously, X represents a linear alkyl with 1 to 50 carbon atoms.
Preferably X comprises from 12 to 40 carbon atoms, even more preferably X comprises from 18 to 30 carbon atoms.
Advantageously, in formula (III), —OH and —COOH are in the ortho position on the phenyl ring, and the molecule of formula (III) is salicylic acid or a salicylic acid derivative of formula (IIIA):
wherein X and a have the same definition as in formula (III) and the favourite variants of these parameters are the same as in formula (III).
Sodium salicylate is commercially available (CAS number: 54-21-7).
Alkali metal alkylhydroxybenzoate compounds may notably be prepared by neutralizing at least one alkylphenol with an alkali metal base to obtain an alkali metal alkylphenate and then carboxylating the alkali metal alkylphenate with carbon dioxide.
Alkaline earth metal alkylhydroxybenzoate compounds can then be obtained by acidifying the alkali metal alkylhydroxybenzoate to form the alkylhydroxybenzoic acid and further reacting the alkylhydroxybenzoic acid with a molar excess of an alkaline earth metal base.
Methods for the preparation of alkaline and/or alkali earth metal alkylhydroxybenzoate compounds are notably disclosed in EP 2 316 823.
According to a variant, in the reaction with the boron compound and the amine component, the alkali and/or alkaline earth metal hydroxybenzoate compound, optionally substituted by a hydrocarbyl group, can be used as a mixture with an alkylphenol.
According to this variant, the mixture can comprise up to 50% mol of alkylphenol, based on the total number of moles of the mixture of alkylphenol and alkali and/or alkaline earth metal hydroxybenzoate compounds. Such mixtures and their preparation are disclosed in, for example, EP 1 783 134 and EP 2 316 823.
The Boron Compound
The boron compound is selected from boric acid, hydrocarbyl boronic acids, boric esters and hydrocarbyl boronic esters, boric oxide, boric acid complexes.
The boron compound can, for example, be selected from: boric acid, boric oxide, boric acid complexes, a trialkyl borate in which the alkyl groups comprise independently from 1 to 4 carbon atoms, a C1-C12 alkyl boronic acid, a C1-C12 dialkyl boric acid, a C6-C12 aryl boric acid, a C6-C12 diaryl boric acid, a C7-C12 aralkyl boric acid, a C7-C12 diaralkyl boric acid, or products deriving from these by substitution of an alkyl group by one or more alkoxy unit.
Alkyl groups and alkoxy groups can be linear, branched or cyclic.
Boric acid complexes are complexes with a molecule comprising one or more alcohol functionality.
Advantageously, the boron compound is boric acid.
The Amine Component
The amine component is a mixture or composition comprising one or more di-fatty-alkyl(ene) polyalkylamine (designated “polyalkylamine”) of formulae (I) or (II):
wherein,
or derivatives thereof,
whereby said polyalkylamine mixture or composition comprises at least 3% by weight of branched compounds of formula (I) or (II), with regards to the total weight of polyalkylamine compounds (I) and (II) in the composition, branched compound signifying that:
in formula (I) at least one of n and z are superior or equal to 1,
in formula (II) n is superior or equal to 1.
In an embodiment, the polyalkylamine mixtures or compositions comprise at least 4% by weight (% w/w) with regards to the total weight of compounds of formula (I) or (II), suitably at least 5% w/w, suitably at least 6% w/w, suitably more than 7% w/w, suitably more than 7.5% w/w, suitably more than 10% w/w, suitably more than 20% w/w of branched compounds whereof at least one of n or z is superior or equal to 1. For the products of formula (I) this means that at least one of n or z must be superior or equal to 1. For the products of formula (II) this means that n must be superior or equal to 1.
It is noted that whenever n, o, p, or z is 0, then the hydrogen represented at the extremity of the chain is covalently bound to the corresponding secondary nitrogen.
Preferably the amine mixture or composition comprises di-fatty-alkyl(ene) polyalkylamine compounds of formula (I) or (II) wherein n, o, p, and z, when not 0, are 1 or 2, more preferably n, o, p, and z, when not 0, are 1.
According to one favorite embodiment, the amine mixture or composition consists essentially of di-fatty-alkyl(ene) polyalkylamine compounds of formula (I) or (II) wherein n, o, p, and z, are independently 0, 1 or 2, more preferably n, o, p, and z, are independently 0 or 1.
According to another favorite embodiment, the amine mixture or composition consists essentially of di-fatty-alkyl(ene) polyalkylamine compounds of formula (I) or (II) and their derivatives, wherein n, o, p, and z, are independently 0, 1 or 2, more preferably n, o, p, and z, are independently 0 or 1.
Derivatives of compounds (I) and (II) are described here-under.
Each R is, independent of the other R, preferably selected from linear and branched alkyl groups and alkenyl groups. Even more preferably each R is, independent of the other R, selected from linear alkyl groups and linear alkenyl groups.
Each R is, independent of the other R, preferably selected from alkyl groups and alkenyl groups comprising from 4 to 30 atoms of carbon, even more preferably from 8 to 22 carbon atoms preferably with 14 to 18 carbon atoms, more preferably with 16 to 18 carbon atoms, which is linear or branched.
According to a favourite variant, each R is, independent of the other R, selected from linear alkyl groups and linear alkenyl groups with 14 to 22 carbon atoms, preferably with 14 to 18 carbon atoms, more preferably with 16 to 18 carbon atoms.
Although the groups R can be different, they are, in one embodiment, the same, since such materials are more economically produced. Irrespective of whether they are the same or not, R groups are, independently, preferably derived from chemical feedstock or from a natural source, such as from natural oils and fats. Particularly if a natural source is used, it means that each R may be a mixture of alkyl and alkenyl radicals with varied chain lengths. Suitably R groups are derived from animal and vegetal oils and fats, such as from tallow oil, colza oil, sunflower oil, soya oil, flax oil, olive oil, palm oil, castor oil, wood oil, corn oil, squash oil, grapeseed oil, jojoba oil, sesame oil, walnut oil, hazelnut oil, almond oil, shea oil, macadamia oil, cotton oil, alfalfa oil, rye oil, safflower oil, peanut oil, coconut oil and copra oil, and mixtures thereof.
Preferably R groups are derived from tallow oil, coconut oil and palm oil. Preferably the R groups represent an aliphatic group obtained from tallow oil, and the corresponding mixture of fatty-alkyl(ene) polyamines are formed.
R groups are derived from animal and vegetal oils and fats means that R groups correspond to the mixture of aliphatic chains obtained by reduction of the fatty acids obtained from animal and vegetal oils and fats.
According to some variant, it may be beneficial to use hydrogenated R groups. However, for certain feedstocks, even after hydrogenization, an appreciable amount of unsaturated bonds may remain. Suitably a fully hydrogenated tallow group is used as the R group, and the corresponding mixture of di-fatty-alkyl(ene) polyalkyl amines are formed. Alternatively, the R group of the raw material is unsaturated whereby the unsaturated R group may be wholly or partially hydrogenated during the process to make the claimed di-fatty-alkyl(ene) polyalkylamines being a mixture of di-fatty-alkyl polyalkylene amines and di-fatty-alkylene polyalkylene amines.
Alternatively, the R groups of the raw material are unsaturated. Also, compounds of formula (I) and (II) wherein one of R is fully saturated and one of R is unsaturated are amine products that can be used according to the invention.
Therefore, as used herein, “di-fatty-alkyl(ene) polyalkylamines” refers to di-fatty-alkyl polyalkylamines, di-fatty-alkylene polyalkylamines, fatty-alkyl fatty-alkylene polyalkylamines, and mixtures thereof.
Derivatives of the di-fatty-alkyl(ene) polyalkylamines compositions of the invention include products wherein one or more of the NH moieties of the dialkyl polyalkylamines of the invention are methylated, alkoxylated, or both. Such products were found to have desirable solubility, particularly in lubricating oils. Alkoxylated derivatives are suitably butoxylated, propoxylated and/or ethoxylated. If two or more different alkoxylation agents are used, they can be used in any sequence, e.g. EO-PO-EO, and the various alkoxy units can be of blocky nature and/or be present in a random fashion. Suitably a primary —NH2 group is alkoxylated with one or more alkylene oxides in a conventional way to form a —NH-AO—H group, wherein AO stands for one or more alkylene-oxy units. The resulting —NH-AO—H group can be further alkoxylated to form —N(AO—H)2 groups. Especially when large amounts of alkylene oxide (i.e. when more than 8 AO molecules per polyalkylamine molecule) are used, typically also one or more of the secondary amine functions, if present, are alkoxylated.
In an embodiment, all primary and secondary amine functions of the di alkyl polyamine are alkoxylated. In another embodiment, the di-fatty-alkyl(ene) polyalkylamines are derivatized by methylating one or more of the N—H functions in a conventional way, for example by reaction with formic acid and formaldehyde. In another embodiment, one or more of the O—H functions of an alkoxylated di-fatty-alkyl(ene) polyalkylamines is methylated in a conventional way.
The compositions comprising mixtures of polyalkylamines of the formula (I) are preferred. However, since compositions comprising mixtures of polyalkylamines of the formula (II) can be more economical to make, under specific circumstances, compositions comprising mixtures of polyalkylamines of the formula (II) may be preferred. If suitable, compositions comprising mixtures of polyalkylamines of the formulae (I) and (II) are used.
The branched polyalkylamines can be produced using any conventional process steps that are conducted in such order and way that the disclosed mixtures are obtained.
A suitable way to produce them is described in the experimental section of WO2017/148816, starting from a diamine and involving two or more cycles, for economic reasons preferably two, each cycle including a cyanoethylation step and a hydrogenation step. Hereinafter this process is named the two-step process. However, in an alternative process, one equivalent of a di-alkyl(ene)-diamine is reacted in one step with two or more equivalents of acrylonitrile, followed by hydrogenation. In that case, optional further cycles involving a cyanoethylation and a hydrogenation step can be performed. Such a one-step process can be beneficial since it requires less reaction steps.
For increased branching in the two-cycle process, an acidic catalyst is used, such as HCl or acetic acid. Also increasing the reaction temperature during cyanoethylation will result in increased branching in this process. In an embodiment of a multicycle process, the temperature of a later cyanoethylation step is higher than the temperature in an earlier cyanoethylation step, to get a product with the desired branching. In an embodiment, more than 1 mole of acrylonitrile is used per mole of the starting polyamine, which was also found to increase the branching of the resulting product to the desired level.
The temperature in each cyanoethylation step is suitably selected in the range from 70 to 125° C. In an embodiment the reaction is conducted, for economic reasons, at a temperature up to 80, 85, 90, 95, or 100° C.
For maintaining a homogeneous reaction mixture, a solvent is suitably used. Suitable solvents include C1-4 alcohols and C2-4 diols. Ethanol may be a solvent of choice for ease of handling. Surprisingly the C1-4 alcohols and C2-4 diols were found not to be mere solvents. They turned out to also have co-catalytic activity in the cyanoethylation step.
The amount of solvent to be used can vary over a wide range. For economic purposes, the amount is typically kept at a minimum. The amount of solvent, particularly in a cyanoethylation step, is suitably less than 50, 40, 30, or 25% by weight of the liquid reaction mixture. The amount of solvent, particularly in a cyanoethylation step, is suitably more than 0.1, 0.5, 1, 5, or 10% by weight of the liquid reaction mixture.
Amines as above-defined can be prepared by the protocols disclosed WO2017/148816. They are commercially available from Akzo, especially under commercial reference Tetrameen® 2HBT.
Reaction Product
The reaction of the alkali or alkaline earth metal hydroxybenzoate compound, optionally substituted by a hydrocarbyl, the boron compound, and the amine component can be effected in any suitable manner.
For example, the reaction can be conducted by first combining the alkali or alkaline earth metal hydroxybenzoate compound (optionally hydrocarbyl substituted) and the boron compound in the desired ratio and in the presence of a suitable solvent.
Suitable solvents are for example naphtha and polar solvents such as water and an alcohol, like for example: methanol, ethanol, propanol, butanol.
Advantageously, the reaction is conducted with a molar ratio of hydrocarbyl-substituted hydroxybenzoic acid compound:boron compound of from about 15:1 to about 1:5, preferably from 5:1 to 1:2, more preferably from 4:1 to 1:1. A most preferred ratio is about 2:1.
After a sufficient time, the boron compound dissolves. Then, the amine component is added slowly to the mixture to effect neutralization and formation of the desired reaction product.
Advantageously, the amine component is added in amounts such that the molar ratio of hydrocarbyl-substituted hydroxybenzoic acid compound:amine component is from about 15:1 to about 1:5, preferably from 5:1 to 1:2, more preferably from 4:1 to 1:1. A most preferred ratio is about 2:1.
Advantageously, the amine component is added in amounts such that the molar ratio of boron compound:amine component is from about 10:1 to 1:10, preferably from 5:1 to 1:5, even more preferably from 2:1 to 1:2. A most preferred ratio is about 1:1.
The reaction can advantageously be conducted by maintaining the reaction medium at a temperature of from about 20° C. to about 100° C., for example from about 50° C. to about 75° C., generally for a time period ranging from about 0.5 to 5 hours, more preferably from 1 to 4 hours.
After the reaction is completed, the solvent may be evaporated from the reaction medium, preferably, it is evaporated by distillation under vacuum. Alternately, the solvent may remain in mixture with the reaction products which are used as such.
A diluting oil can be added as needed to control viscosity, particularly during removal of solvents by distillation.
The product resulting from this reaction will contain a complex mixture of compounds. The reaction product mixture need not be separated to isolate one or more specific components. Accordingly, the reaction product mixture can be employed as is in the lubrication oil composition of the present invention.
The reaction can be achieved with other reactants in addition to the alkali or alkaline earth metal hydroxybenzoate compound (optionally hydrocarbyl substituted), the boron compound, and the amine component.
However, according to the invention, preferably the reaction product results from the reaction of a mixture of reactants (not including the solvent(s)) that consists essentially of at least one alkali or alkaline earth metal hydroxybenzoate compound (optionally hydrocarbyl substituted), at least one boron compound, and at least one amine component.
Even more preferably, the reaction product results from the reaction of a mixture of reactants (not including the solvent(s)) that consists of at least one alkali or alkaline earth metal hydroxybenzoate compound (optionally hydrocarbyl substituted), at least one boron compound, and at least one amine component.
According to a second preferred embodiment, the reaction product results from the reaction of a mixture of reactants (not including the solvent(s)) that consists essentially of at least one boron compound, at least one amine component, and a mixture comprising the alkali and/or alkaline earth metal hydroxybenzoate compound, optionally substituted by a hydrocarbyl group, and an alkylphenol.
Even more preferably, according to this second preferred embodiment, the reaction product results from the reaction of a mixture of reactants (not including the solvent(s)) that consists of at least one boron compound, at least one amine component, and a mixture comprising the alkali and/or alkaline earth metal hydroxybenzoate compound, optionally substituted by a hydrocarbyl group, and an alkylphenol.
According to this second preferred embodiment, the mixture can comprise up to 50% mol of alkylphenol, based on the total number of moles of the mixture of alkylphenol and alkali and/or alkaline earth metal hydroxybenzoate compounds.
Lubricant Composition
The invention is also directed to the use of the reaction products that have been above-disclosed as additives in lubricating oil (or lubricant) compositions. It is also directed to the lubricant compositions comprising such additives.
Advantageously, the lubricant composition comprises:
the percentages being defined by weight of component as compared to the total weight of the composition.
Even more advantageously, the lubricant composition comprises:
the percentages being defined by weight of component as compared to the total weight of the composition.
Base Oils
Generally, the lubricating oil compositions according to the invention comprise as a first component an oil of lubricating viscosity, also called “base oils”. The base oil for use herein can be any presently known or later-discovered oil of lubricating viscosity used in formulating lubricating oil compositions for any of the following applications, e.g., engine oils, marine cylinder oils, functional fluids such as hydraulic oils, gear oils, transmission fluids, like for example automatic transmission fluids, turbine lubricants, trunk piston engine oils, compressor lubricants, metal-working lubricants, and other lubricating oil and grease compositions.
Advantageously, the lubricant compositions according to the invention are marine engine lubricating oil compositions, preferably they are 2-stroke marine engine lubricating oil compositions.
Generally, the oils also called “base oils” used for formulating lubricant compositions according to the present invention may be oils of mineral, synthetic or plant origin as well as their mixtures. The mineral or synthetic oils generally used in the application belong to one of the classes defined in the API classification as summarized below:
These mineral oils of Group 1 may be obtained by distillation of selected naphthenic or paraffinic crude oils followed by purification of these distillates by methods such as solvent extraction, solvent or catalytic dewaxing, hydrotreating or hydrogenation.
The oils of Groups 2 and 3 are obtained by more severe purification methods, for example a combination of hydrotreating, hydrocracking, hydrogenation and catalytic dewaxing. Examples of synthetic bases of Groups 4 and 5 include poly-alpha olefins, polybutenes, polyisobutenes, alkylbenzenes.
These base oils may be used alone or as a mixture. A mineral oil may be combined with a synthetic oil.
The lubricant compositions of the invention have a viscosity grade of SAE-20, SAE-30, SAE-40, SAE-50 or SAE-60 according to the SAEJ300 classification.
Grade 20 oils have a kinematic viscosity at 100° C. of between 5.6 and 9.3 mm2/s.
Grade 30 oils have a kinematic viscosity at 100° C. of between 9.3 and 12.5 mm2/s.
Grade 40 oils have a kinematic viscosity at 100° C. of between 12.5 and 16.3 mm2/s.
Grade 50 oils have a kinematic viscosity at 100° C. of between 16.3 and 21.9 mm2/s.
Grade 60 oils have a kinematic viscosity at 100° C. of between 21.9 and 26.1 mm2/s.
Preferably, the lubricant composition according to the first aspect and the second aspect is a cylinder lubricant.
The cylinder oils for two-stroke diesel marine engines have a viscosimetric grade SAE-40 to SAE-60, generally preferentially SAE-50 equivalent to a kinematic viscosity at 100° C. comprised between 16.3 and 21.9 mm2/s. Typically, a conventional formulation of cylinder lubricant for two-stroke marine diesel engines is of grade SAE 40 to SAE 60, preferentially SAE 50 (according to the SAE J300 classification) and comprises at least 50% by weight of a lubricating base oil of mineral and/or synthetic origin, adapted to the use in a marine engine, for example of the API Group 1 class. Their viscosity index (VI) is comprised between 80 and 120; their sulfur content is greater than 0.03% and their saturated substance content is less than 90%.
The system oils for two-stroke diesel marine engines have a viscosimetric grade SAE-20 to SAE-40, generally preferentially SAE-30 equivalent to a kinematic viscosity at 100° C. comprised between 9.3 and 12.5 mm2/s.
These viscosities may be obtained by mixing additives and base oils for example containing mineral bases of Group 1 such as Neutral Solvent (for example 150 NS, 500 NS or 600 NS) bases and brightstock. Any other combination of mineral, synthetic bases or bases of plant origin, having, as a mixture with the additives, a viscosity compatible with the chosen SAE grade, may be used.
The quantity of base oil in the lubricant composition of the invention is from 30% to 90% by weight relative to the total weight of the lubricant composition, preferably from 40% to 90%, more preferably from 50% to 90%.
In one embodiment of the invention, the lubricant composition has a Base Number (BN) determined according to the standard ASTM D-2896 of at most 50, preferably at most 40, advantageously at most 30 milligrams of potassium hydroxide per gram of the lubricating composition, in particular ranging from 10 to 40, preferably from 15 to 40 milligrams of potassium hydroxide per gram of the lubricant composition.
In another embodiment of the invention, the lubricant composition has a BN determined according to the standard ASTM D-2896 of at least 50, preferably at least 60, more preferably at least 70, advantageously from 70 to 100.
Additives:
It is optionally possible to substitute the above-described base oils in full or in part by one or more thickening additives whose role is to increase both the hot and cold viscosity of the composition, or by additives improving the viscosity index (VI).
The lubricant composition of the invention may comprise at least one optional additive, chosen in particular from among those frequently used by persons skilled in the art.
In one embodiment, the lubricant composition further comprises an optional additive chosen amongst a neutral detergent, an overbased detergent, an anti-wear additive, an oil soluble fatty amine, a polymer, a dispersing additive, an anti-foaming additive or a mixture thereof. Detergents are typically anionic compounds containing a long lipophilic hydrocarbon chain and a hydrophilic head, wherein the associated cation is typically a metal cation of an alkali metal or alkaline earth metal. The detergents are preferably selected from alkali metal salts or alkaline earth metal (particularly preferably calcium, magnesium, sodium or barium) salts of carboxylic acids, sulphonates, salicylates, naphthenates, as well as the salts of phenates. These metal salts may contain the metal in an approximately stoichiometric amount relative to the anion group(s) of the detergent. In this case, one refers to non-overbased or “neutral” detergents, although they also contribute to a certain basicity. These “neutral” detergents typically have a BN measured according to ASTM D2896, of less than 150 mg KOH/g, or less than 100 mg KOH/g, or less than 80 mg KOH/g of detergent. This type of so-called neutral detergent may contribute in part to the BN of lubricating compositions. For example, neutral detergents are used such as carboxylates, sulphonates, salicylates, phenates, naphthenates of the alkali and alkaline earth metals, for example calcium, sodium, magnesium, barium. When the metal is in excess (amount greater than the stoichiometric amount relative to the anion groups(s) of the detergent), then these are so-called overbased detergents. Their BN is high, higher than 150 mg KOH/g of detergent, typically from 200 to 700 mg KOH/g of detergent, preferably from 250 to 450 mg KOH/g of detergent. The metal in excess providing the character of an overbased detergent is in the form of insoluble metal salts in oil, for example carbonate, hydroxide, oxalate, acetate, glutamate, preferably carbonate. In one overbased detergent, the metals of these insoluble salts may be the same as, or different from, those of the oil soluble detergents. They are preferably selected from calcium, magnesium, sodium or barium. The overbased detergents are thus in the form of micelles composed of insoluble metal salts that are maintained in suspension in the lubricating composition by the detergents in the form of soluble metal salts in the oil. These micelles may contain one or more types of insoluble metal salts, stabilised by one or more types of detergent. The overbased detergents comprising a single type of detergent-soluble metal salt are generally named according to the nature of the hydrophobic chain of the latter detergent. Thus, they will be called a phenate, salicylate, sulphonate, naphthenate type when the detergent is respectively a phenate, salicylate, sulphonate or naphthenate. The overbased detergents are called mixed type if the micelles comprise several types of detergents, which are different from one another by the nature of their hydrophobic chain. The overbased detergent and the neutral detergent may be selected from carboxylates, sulphonates, salicylates, naphthenates, phenates and mixed detergents combining at least two of these types of detergents. The overbased detergent and the neutral detergent include compounds based on metals selected from calcium, magnesium, sodium or barium, preferably calcium or magnesium. The overbased detergent may be overbased by metal insoluble salts selected from the group of carbonates of alkali and alkaline earth metals, preferably calcium carbonate. The lubricating composition may comprise at least one overbased detergent and at least a neutral detergent as defined above.
Polymers are typically polymers having a low molecular weight of from 2000 to 50 000 dalton (Mn). The polymers are selected amongst PIB (of from 2000 Dalton), polyacrylates or polymethacrylates (of from 30 000 Dalton), olefin copolymers, olefin and alpha-olefin copolymers, EPDM, polybutenes, poly alpha-olefin having a high molecular weight (viscosity 100° C.>150), hydrogenated or non-hydrogenated styrene-olefin copolymers.
Anti-wear additives protect the surfaces from friction by forming a protective film adsorbed on these surfaces. The most commonly used is zinc dithiophosphate or DTPZn. Also in this category, there are various phosphorus, sulphur, nitrogen, chlorine and boron compounds. There are a wide variety of anti-wear additives, but the most widely used category is that of the sulphur phospho additives such as metal alkylthiophosphates, especially zinc alkylthiophosphates, more specifically, zinc dialkyl dithiophosphates or DTPZn. The preferred compounds are those of the formula Zn((SP(S)(OR1)(OR2))2, wherein R1 and R2 are alkyl groups, preferably having 1 to 18 carbon atoms. The DTPZn is typically present at levels of about 0.1 to 2% by weight relative to the total weight of the lubricating composition. The amine phosphates, polysulphides, including sulphurised olefins, are also widely used anti-wear additives. One also optionally finds nitrogen and sulphur type anti-wear and extreme pressure additives in lubricating compositions, such as, for example, metal dithiocarbamates, particularly molybdenum dithiocarbamate. Glycerol esters are also anti-wear additives. Mention may be made of mono-, di- and trioleates, monopalmitates and monomyristates. In one embodiment, the content of anti-wear additives ranges from 0.01 to 6%, preferably from 0.1 to 4% by weight relative to the total weight of the lubricating composition.
Dispersants are well known additives used in the formulation of lubricating compositions, in particular for application in the marine field. Their primary role is to maintain in suspension the particles that are initially present or appear in the lubricant during its use in the engine. They prevent their agglomeration by playing on steric hindrance. They may also have a synergistic effect on neutralisation. Dispersants used as lubricant additives typically contain a polar group, associated with a relatively long hydrocarbon chain, generally containing 50 to 400 carbon atoms. The polar group typically contains at least one nitrogen, oxygen, or phosphorus element. Compounds derived from succinic acid are particularly useful as dispersants in lubricating additives. Also used are, in particular, succinimides obtained by condensation of succinic anhydrides and amines, succinic esters obtained by condensation of succinic anhydrides and alcohols or polyols. These compounds can then be treated with various compounds including sulphur, oxygen, formaldehyde, carboxylic acids and boron-containing compounds or zinc in order to produce, for example, borated succinimides or zinc-blocked succinimides. Mannich bases, obtained by polycondensation of phenols substituted with alkyl groups, formaldehyde and primary or secondary amines, are also compounds that are used as dispersants in lubricants. In one embodiment of the invention, the dispersant content may be greater than or equal to 0.1%, preferably 0.5 to 2%, advantageously from 1 to 1.5% by weight relative to the total weight of the lubricating composition. It is possible to use a dispersant from the PIB succinimide family, e.g. boronated or zinc-blocked.
Other optional additives may be chosen from defoamers, for example, polar polymers such as polydimethylsiloxanes, polyacrylates. They may also be chosen from antioxidant and/or anti-rust additives, for example organometallic detergents or thiadiazoles. These additives are known to persons skilled in the art. These additives are generally present in a weight content of 0.1 to 5% based on the total weight of the lubricating composition.
In one embodiment, the lubricant composition according to the invention may further comprise an oil soluble fatty amine.
The fatty amine is of a general formula (VI):
R′1—[(NR′2)—R′3]n—NR′4R′5, (VI)
wherein,
Preferably, the fatty amine is of general formula (VI), wherein:
In one embodiment, the fatty amine of general formula (VI) represents of from 0.5 to 10%, preferably of from 0.5 to 8% by weight with respect to the total weight of the lubricant composition.
The optional additives such as defined above contained in the lubricant compositions of the present invention can be incorporated in the lubricant composition as separate additives, in particular through separate addition thereof in the base oils. However, they may also be integrated in a concentrate of additives for marine lubricant compositions.
Method for Producing a Marine Lubricant
The present disclosure provides a method for producing a marine lubricant as above-disclosed comprising the step of mixing the base oil with the reaction product of at least an alkali or alkaline earth metal hydroxybenzoate compound (optionally hydrocarbyl substituted), a boron compound, and an amine component as above-defined.
Use for Lubricating Engines
The application also relates to the use of a reaction product of at least an alkali or alkaline earth metal hydroxybenzoate compound (optionally hydrocarbyl substituted), a boron compound, and an amine component as above-defined for lubricating engines, preferably marine engines. Specifically, the invention is directed to the use of a reaction product of at least an alkali or alkaline earth metal hydroxybenzoate compound (optionally hydrocarbyl substituted), a boron compound, and an amine component as above-defined for lubricating two-stroke marine engines and four-stroke marine engines, more preferably two-stroke marine engine.
In particular, the reaction product of at least an alkali or alkaline earth metal hydroxybenzoate compound (optionally hydrocarbyl substituted), a boron compound, and an amine component as above-defined is suitable for use in a lubricant composition, as cylinder oil or system oil, for lubricating 2-stroke engines and four-stroke marine engines, more preferably 2-stroke engines.
The application also relates to a method for lubricating a two-stroke marine engines and four-stroke marine engines, more preferably two-stroke marine engine said method comprising application to said marine engine of the marine lubricant as above-disclosed. In particular, the lubricant is applied to the cylinder wall, typically by a pulse lubricating system or by spraying the lubricant onto the piston's rings pack through an injector for lubricating 2-stroke engines. It has been observed that applying to the cylinder wall the lubricant composition according to the invention provides increased protection against corrosion, improved engine cleanliness.
| Number | Date | Country | Kind |
|---|---|---|---|
| 18306475.7 | Nov 2018 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2019/080569 | 11/7/2019 | WO | 00 |
