Process for alkoxylation of esters and products produced therefrom

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for producing alkoxylated esters and, more particularly, to a process for producing such esters having a narrow homolog distribution of the alkoxylated ester.
2. Description of the Prior Art
Alkoxylated esters, e.g. alkoxylated esters of fatty acids, are well known and find use in surfactant and other applications. Such esters can be prepared by various techniques well known in the art. For example, German reference DE 3914131 describes the alkoxylation of fatty acid esters using calcined hydrotalcites as catalysts. It is also well known to prepare such alkoxylated fatty acid esters using sodium hydroxide/alcohol and sodium methoxide catalysts. The use of catalysts such as sodium hydroxide and sodium methoxide results in the production of alkoxylated esters having a broad homolog distribution of the alkoxylated product. Additionally, the reaction times using these catalysts is slow and conversions are low. Although the use of hydrotalcite, as discussed in the above referenced German patent publication, is claimed to produce the alkoxylated fatty acid ester in high yield with a narrow homolog distribution, the distribution of the end product cannot be considered truly "peaked", i.e. with the desired narrow distribution of homologs.
U.S. Pat. No. 4,820,673 discloses a calcium based catalyst for use in the alkoxylation of organic compounds having at least one active hydrogen to provide end products having a narrow distribution of the alkoxylation species.
U.S. Pat. No. 4,835,321 discloses another type of calcium based catalyst for the alkoxylation of alcohols to provide alkoxylated alcohols having a narrow distribution of the alkoxylation species.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an improved process for producing alkoxylated methyl esters of fatty acids.
Another object of the present invention is to provide a process for producing alkoxylated methyl esters of fatty acids wherein the product has a narrow distribution of the alkoxylation species.
Still a further object of the present invention is to provide a process for the production of alkoxylated methyl esters of fatty acids which requires a relatively small amount of catalyst, has a relatively short reaction time and exhibits a high level of conversion of starting material.
The above and other objects of the present invention will become apparent from the drawings, the description given herein and the appended claims.
According to the process of the present invention, alkoxylated esters having the formula: ##STR1## wherein m is from 2 to 4, p is from about 1 to about 50, and R is an organic radical containing from about 1 to about 30 carbon atoms are prepared. In the process, an alkylene oxide containing from 2 to 4 carbon atoms is reacted with a compound having the formula: ##STR2## The reaction is conducted at a temperature of from about 80.degree. to about 200.degree. C. and at a pressure which can range from sub-ambient up to about 100 psi or higher. A catalytically effective amount of a calcium catalyst is employed in the reaction. The catalyst is select from the group consisting of (1) Calcium Catalyst A formed by reacting a reactant mixture comprising an alkoxylated alcohol mixture containing compounds having the general formula:
R.sub.1 --O--(C.sub.m H.sub.2m O).sub.p H (III)
wherein R.sub.1 is an organic radical containing from about 1 to about 30 carbon atoms, a calcium containing compound which is at least partially dispersible in said alkoxylated alcohol mixture, an inorganic acid, and a metal alkoxide selected from compounds having the formulas: ##STR3## wherein R.sub.2, R.sub.3, R.sub.4 and R.sub.5 is each a hydrocarbon radical containing from about 1 to about 30 carbon atoms, said calcium containing compound and said alkoxylated alcohol mixture being mixed prior to addition of said metal alkoxide, said reactant mixture being heated to a temperature and for a time sufficient to effect at least a partial exchange reaction between the alkoxide groups of said metal alkoxide and said hydroxyl groups of said alkoxylated alcohol (2) Calcium Catalyst B formed by solubilizing, at least partially, a calcium containing compound with an activator having the formula:
Z.sub.a --X--Q--Y--Z'.sub.b (V)
wherein X and Y are the same or different electronegative, hetero-atoms selected from the group consisting of oxygen, nitrogen, sulfur and phosphorus; a and b are the same or different integers satisfying the valency requirements of X and Y; Q is an organic radical which is electropositive or essentially neutral relative as to X and/or Y; Z and Z' are the same or different and are either hydrogen or an organic radical which does not prevent said solubilizing, and mixtures of Calcium Catalyst A and Calcium Catalyst B.

BRIEF DESCRIPTION OF THE DRAWING
The simple FIGURE shows a comparison of alkoxylate methyl esters using the process of the present invention with prior art processes.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
Alkoxylated esters which are produced according to the process of the present invention have the formula: ##STR4## wherein m is from 2 to 4, p is from about 1 to about 50, and R is an organic radical containing from about 1 to about 30 carbon atoms. Especially preferred are esters wherein R is from about 6 to about 30, hereinafter defined as "fatty acid esters", m is 2 and p is from about 4 to about 20. Although R is preferably a hydrocarbon radical, especially a linear or branched chain alkyl group, R can also be alkenyl, aryl, alkylaryl or alicyclic in nature. R can also contain hetero atoms such as oxygen, sulfur, nitrogen, etc. For example, R can contain ether linkages, ketonic structures, various sulfur containing groups, etc. It is only necessary that R be free of groups containing active hydrogen atoms which would readily alkoxylate or in some other manner deleteriously affect alkoxylation of the ester. Preferably, R will be a branched or straight chain hydrocarbon radical, i.e. an alkyl group, straight chain or linear hydrocarbon radicals being particularly preferred for most surfactant applications.
As noted, the alkoxylated esters produced by the process of the present invention can vary widely in structure and, accordingly, a wide variety of starting, non-alkoxylated esters can be employed. In general, the starting ester will have the formula: ##STR5## wherein R has the same connotation stated above with respect to Formula I. Non-limiting examples of suitable esters than can be used as starting materials include the methyl ester of acids such as acetic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, lauric acid, mystic acid, palmitic acid, stearic acid, oleic acid, eicosanoic acid, tricosanoic acid, etc. Thus, the starting ester can be of a type such that (a) the organic radical R contains a relatively few number of carbon atoms, e.g. 3 to 5 or (b) the organic radical R contains a relatively large number of carbon atoms, e.g. 8 to 30. The starting material esters may be obtained synthetically or, more conveniently and generally more economically, from natural sources. It is well known that methyl esters can be made from many triglycerides which are widely distributed in nature in a variety of animal and vegetable products. For example, the ester starting material can be derived from materials such as whale oil, beeswax, carnauba wax, animal fat, etc. Other suitable esters can be derived from vegetable sources such as palm oil, coconut oil, olive oil, cottonseed oil, soybean oil, peanut oil, etc. When obtaining the starting material esters from natural sources, this can be conveniently done by methanolysis followed by stripping or distilation techniques well known to those skilled in the art. It will also be understood that in such cases, a blend of starting material esters is commonly obtained. For example, whereas a stripped methyl coconate will contain mainly C.sub.12 and C.sub.14 methyl esters (following methanolysis), an unstripped blend, in addition to such esters also contains appreciable amounts of C.sub.8 and C.sub.10 methyl esters (following methanolysis). In practice, the starting material esters will usually be blends of esters which have been obtained from natural or synthetic sources. Especially preferred ester starting materials are those esters in which R is a linear or branched chain alkyl group containing from about 6 to about 30 carbon atoms, more particularly from about 6 to about 20 carbon atoms.
The starting material esters are reacted with an alkylene oxide containing from 2 to 4 carbon atoms. Thus, alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, tetramethylene oxide, can be used. It will be understood that mixtures of such alkylene oxides, e.g. mixtures of ethylene oxide and propylene oxide can be employed. Thus, it will be appreciated that the alkoxylated ester can contain an oxyalkylene chain which is heteric in nature (when a single alkylene oxide is used), block in nature (when two or more alkylene oxides are employed) or random in nature (when two or more alkylene oxides are employed). In general, the amount of alkylene oxide used will be such as to provide an alkylene oxide content of from about 10 to about 70 percent-by-weight of the alkoxylated ester. It will be appreciated that the amount of the alkylene oxide employed can be varied over wide limits to tailor the end products for desired purposes. For example, in certain applications it is more desirable that the average number of alkoxy groups per ester molecule be a relatively low number, e.g. from about 2 to about 4, whereas in other applications it is desirable that the number of alkoxy groups be greater, e.g. from about 6 to about 10.
The catalysts used in the process of the present invention are calcium based catalysts, i.e. derived from calcium compounds. The two types of calcium catalysts used in the process of the present invention, identified as Calcium Catalyst A and Calcium Catalyst B, can be prepared by methods well known in the art. Calcium Catalyst A can be produced by the process disclosed in U.S. Pat. No. 4,775,653, incorporated herein by reference for all purposes. Calcium Catalyst B can be prepared by the method disclosed in U.S. Pat. No. 4,820,673, incorporated herein by reference for all purposes.
Since the method of preparing Calcium Catalyst A is clearly taught in U.S. Pat. No. 4,775,653, it need not be discussed in detail herein. However, in general, Calcium Catalyst A is prepared by forming a catalyst pre-mix by admixing and reacting an alkoxylated alcohol mixture containing an alkoxylated alcohol having the general formula:
R.sub.1 --O--(C.sub.m H.sub.2m O).sub.p H III
wherein R.sub.1 is an organic radical containing from about 1 to about 30 carbon atoms, a calcium-containing compound which is at least partially dispersible in the alkoxylated alcohol mixture, an inorganic acid and a metal alkoxide selected from compounds having the formula: ##STR6## wherein R.sub.2, R.sub.3, R.sub.4 and R.sub.5 is each a hydrocarbon radical containing from about 1 to about 30, preferably from about 8 to about 14, carbon atoms, the calcium-containing compound and the alkoxylated alcohol mixture being mixed prior to addition of the metal alkoxide and heating the catalyst pre-mix to a temperature and for a time sufficient to effect at least a partial exchange reaction between the alkoxide groups of the metal alkoxide and the hydroxyl groups of the alkoxylated alcohol. While the use of titanium alkoxides is not disclosed in U.S. Pat. No. 4,775,653, in preparing Calcium Catalyst A, the titanium alkoxide is merely substituted for the aluminum alkoxide or, if desired, a mixture of the aluminum alkoxide and titanium alkoxide can be employed.
In a similar vein, since the preparation of Calcium Catalyst B is clearly taught in U.S. Pat. No. 4,820,673, it is unnecessary to provide a detailed description of its preparation herein. However, in general, Calcium Catalyst B is formed by solubilizing, at least partially, a calcium-containing compound with an activator having the formula:
Z.sub.a --X--Q--Y--Z'.sub.b V
wherein X and Y are the same or different electronegative, hetero-atoms selected from the group consisting of oxygen, nitrogen, sulfur and phosphorus, a and b are the same or different integers satisfying the valency requirements of X and Y, Q is an organic radical which is electropositive or essentially neutral relative as to X and/or Y, and Z and Z' are the same or different and are either hydrogen or an organic radical which does not prevent said solubilizing. In addition to using either Calcium Catalyst A or Calcium Catalyst B, mixtures of Calcium Catalyst A and Calcium Catalyst B can be employed.
While both calcium catalysts give peaked alkoxylated esters according to the process of the present invention, the use of Calcium Catalyst A is especially preferred since it provides for a much more efficient process to alkoxylate the esters. In particular, Calcium Catalyst A is superior to Calcium Catalyst B with respect to reaction time.
Although as disclosed in U.S. Pat. Nos. 4,775,653 and 4,820,673, Calcium Catalyst A and Calcium Catalyst B, respectively, can be used to alkoxylate compounds having an active hydrogen, e.g. an alcohol, to provide a highly peaked end product, it was unexpected that the calcium-based catalysts would effectively, especially in the case of Calcium Catalyst A, alkoxylate esters which do not possess an active hydrogen.
The alkoxylated esters of the present invention are prepared by reacting a suitable ester starting material, a suitable alkylene oxide(s) in the presence of a catalytically effective amount of Calcium Catalyst A or Calcium Catalyst B. In the case of Calcium Catalyst A, the amount of catalyst employed will generally be from about 0.1 to about 20 weight percent based upon the total reaction mixture. For example, if the weight of the reaction mixture, including all alkylene oxide, is 300 g, typically from about 0.3 g to about 60 g of Calcium Catalyst A would be employed in the reaction. In the case of Calcium Catalyst B, and since Calcium Catalyst B is a less efficient catalytic species, the amount of Calcium Catalyst B employed will range from about 3 to about 90 percent of the total reaction mixture.
The process of the present invention can be conducted over a wide range of temperature and pressure conditions. For example, the reaction can be conducted at temperatures ranging from about 80.degree. C. or lower to about 200.degree. C. and higher. Pressures can range from sub ambient up to about 100 psi, pressures of from about 10 to about 60 psi being preferred.
Typically, the process can be conducted by charging a suitable reaction vessel, e.g. an autoclave, with the ester starting material in the desired amount. In this regard, the amount of ester starting material chosen will be determined by the desired weight percent of the alkylene oxide in the final alkoxylated ester product. The mixture is then heated to the desired elevated temperature under nitrogen or some other suitable inert gas. The reactor is then placed under vacuum to produce a nitrogen sparge in the reactor to remove water, if present. The catalyst is then injected into the reaction mixture and the temperature raised to the desired reaction temperature, the reaction mixture being maintained under a nitrogen blanket. When the desired reaction temperature is reached, the reactor is evacuated and the chosen alkylene oxide, e.g. ethylene oxide, introduced at the appropriate pressure. As the alkylene oxide reacts, additional amounts are added, the temperature being maintained substantially constant throughout the reaction.
The alkoxylated methyl esters produced by the process of the present invention find utility as detergents, surfactants and the like.
Certain of the alkoxylated esters of the present invention, as distinguished from prior art alkoxylated esters, are markedly "peaked" providing new compositions. The unique, peaked alkoxylated esters of the present invention are characterized by a distribution such that, when the most prevalent alkoxylated species has greater than about 5 oxyalkylene groups per ester linkage, the portion of the product mixture having 3 or more oxyalkylene groups per ester linkage than the most prevalent alkoxylation species is less than 50 percent-by-weight of the mixture. Similarly, in this case the alkoxylation species having fewer oxyalkylene groups per ester linkage by 3 or more oxyalkylene groups than the most prevalent alkoxylation species is usually relatively minor, e.g. less than about 25 percent-by-weight, more often less than about 15 percent-by-weight of the product mixture. Thus, there is produced an alkoxylated ester composition having the formula: ##STR7## wherein m is from 2 to 4, p is from about 6 to about 9 and R is an organic radical containing from about 1 to about 30 carbon atoms, the alkoxylated ester composition comprising a mixture having a molecular weight distribution such that the portion of the mixture having 3 or more oxyalkylene groups per ester linkage than the most prevalent alkoxylation species is less than 50 percent-by-weight of the mixture and the portion of the mixture having fewer oxyalkylene groups per ester linkage by 3 or more oxyalkylene groups than the most prevalent oxyalkylene species is less than about 25 percent-by-weight, more often less than about 15 percent-by-weight.
In the process of the present invention, particularly employing Calcium Catalyst A, it is possible to produce alkoxylated esters that exhibit peaking at two different levels of alkoxylation, i.e. one can not only obtain, as shown in DE 3914131, a relatively narrow homolog distribution of the alkoxylated ester wherein the product has an average of from about 1 to about 5 oxyalkylene groups per ester linkage; it is also possible, as noted above, to obtain a markedly narrow homolog distribution of the alkoxylated ester wherein the product has an average of from about 6 to about 9 oxyalkylene groups per ester linkage. In the latter case it is found that the composition of the present invention exhibits unexpected peaking in the sense that products made by prior art processes using catalysts such as NaOH, NaOMe or hydrotalcite exhibit very little to slight peaking in the range of oxyalkylene groups per ester linkage. By adjusting conditions, e.g. concentration of reactants, one can peak the alkoxylated ester around virtually any desired homolog.
To more fully illustrate the present invention, the following non-limiting example is presented.
EXAMPLE
A series of experiments were conducted to demonstrate the preparation of alkoxylated methyl esters using the process of the present invention as well as prior art processes for comparative purposes to show that the process of the present invention is much more efficient in requiring less catalyst, or exhibiting shorter reaction times or higher conversion rates or in resulting in an alkoxylated methyl ester which shows significantly greater peaking than that obtained by prior art processes and catalysts.
PROCEDURE 1
Typical Preparation of Ethoxylated Ester Using NaOMe Catalyst
A stainless steel autoclave is charged with the requisite amount of the starting material ester as determined by the desired weight percent ethylene oxide in the final product and the desired amount of NaOMe. For example, in a typical preparation, if the total final reaction mixture is 300 g, 1.0 g of NaOMe, i.e. 0.3 weight percent based on the total final weight of reaction mixture, is used. The mixture is heated under nitrogen to 110.degree. C. at which time a vacuum is applied to produce a nitrogen sparge of 5 psig in the reactor. The reaction mixture is sufficiently dry after 20 minutes of sparging. Fifteen grams of n-dodecanol or an alcohol ethoxylate (5% based on the weight of the reaction mixture) is injected. The temperature is subsequently raised to 175.degree. C. with nitrogen blanketing the reaction mixture. At 175.degree. C., the reactor is evacuated and ethylene oxide (EO) introduced to approximately 50 psig. Subsequent amounts of ethylene oxide are introduced into the reactor when the pressure drops as a result of ethoxylation. Temperature is maintained at or near 175.degree. C. throughout the reaction. The catalyst is destroyed upon completion of the reaction by injection of the requisite amount of glacial acetic acid after cooling to approximately 80.degree. C.
PROCEDURE 2
Typical Preparation of Ethoxylated Ester Using NaOH Catalyst
The procedure employed using the NaOMe catalyst is employed with the exception that 50 percent-by-weight aqueous sodium hydroxide is employed as a catalyst.
PROCEDURE 3
Typical Preparation of Ethoxylated Ester Using Calcined Hydrocalcite as the Catalyst
The process used in this example corresponds to that disclosed in Example 2 of German Reference DE 3914131, incorporated herein by reference for all purposes.
PROCEDURE 4
Typical Preparation of Ethoxylated Ester Using Calcium Catalyst B
The procedure employed was essentially the same as Procedure 1 with the exception that Calcium Catalyst B prepared as per the teachings of Run No. 21 of Example 1 of U.S. Pat. No. 4,820,673 was used and the catalyst was added to the starting material ester after drying. Additionally, no dodecanol or alcohol ethoxylate was employed and the catalyst was not destroyed using glacial acetic acid. In preparing Calcium Catalyst B, a three neck flask equipped with mechanical stirrer, nitrogen purge and a condenser for vacuum distillation was employed. Nine grams of CaO and 840 grams of MEEG (monoethyl ether of ethylene glycol) were introduced into the flask. The mixture was heated to 135.degree.-140.degree. C. with removal of water and some MEEG over a period of about 5 hours. ALFOL.RTM. 1214 GC alcohol, 890 g, (trademark of a blend of 30% w/w 12 carbon and 70% w/w 14 carbon alcohols marketed by Vista Chemical Company) was then introduced and the reaction mixture cooled to 75.degree. C. Concentrated H.sub.2 SO.sub.4, 3.05 g, was added. Distillation of MEEG followed upon heating to 175.degree.- 180.degree. C. The majority of the MEEG was removed at this stage. Some loss of alcohol was compensated by the addition of 300 g more of ALFOL.RTM. 1214 GC alcohol. The residual MEEG was removed from the reaction mixture at 225.degree. C. and about 180 mm Hg. Final GC traces of the reaction mixture showed no MEEG present. Enough ALFOL.RTM. 12 (trademark of n-dodecanol marketed by Vista Chemical Company) was subsequently added to the catalyst to reestablish the C.sub.12 to C.sub.14 alcohol ratios observed in ALFOL.RTM. 1214 GC alcohol. The Calcium Catalyst B employed had a Ca:SO.sub.4 ratio of 5.2:1 derived from calcium oxide and sulfuric acid. The catalyst contained 0.096 g of calcium, i.e. 0.96 percent-by-weight calcium, corresponding to 10.0 g of catalyst for reaction.
PROCEDURE 5
Typical Preparation of Ethoxylated Ester Using Calcium Catalyst A
The procedure employed was the same as Procedure 4 with the exception that Calcium Catalyst A prepared substantially as per the teachings of U.S. Pat. No. 4,775,653 was employed and there was no addition of n-dodecanol or alcohol ethoxylate. Additionally, it was not necessary to destroy the catalyst by the addition of glacial acetic acid. To prepare Calcium Catalyst A, in general a mixture of 125 g ALFONIC.RTM. 1012-40.sup.1 alcohol ethoxylate, 2 g 2-ethyl hexanoic acid, and 10.9 g Ca(OH).sub.2 was stirred in a stainless steel autoclave under a nitrogen atmosphere while concentrated H.sub.2 SO.sub.4 (2 g) was added over a period of 10 minutes. Stirring was continued after H.sub.2 SO.sub.4 addition for about 5 hours. The mixture was subsequently heated to 150.degree. C. and sparged for 15 minutes with nitrogen to remove water. Upon cooling to about 125.degree. C., 17.5 g of aluminum trialkoxide in which the alkoxide groups have an average chain length of 10 carbon atoms (mixed 2-30 carbon chain length) and containing about 6 percent-by-weight of aluminum was added, the mixture being maintained under nitrogen. The temperature was then raised to 190.degree. C. at which time stripping of a portion of the alcohol from the aluminum alkoxide took place using a nitrogen sparge. Heating at 190.degree. C. for an additional 0.5 hour followed by cooling under nitrogen to ambient temperature provided the active catalyst. The Calcium Catalyst A employed had a Ca:SO.sub.4 :Al ratio of 5:1:1 derived from calcium hydroxide, sulfuric acid and aluminum. The combined amount of Ca and Al in the catalyst was 0.054 g, i.e. the catalyst contained 3 percent-by-weight calcium and 0.6 percent-by-weight aluminum.
.sup.1 Mixture of 52.8 percent-by-weight C.sub.10 alcohol and 4.2 percent-by-weight C.sub.12 alcohol with 40 percent-by-weight ethylene oxide marketed by Vista Chemical Company.
Table 1 below shows the data obtained on a series of ethoxylated methyl esters made according to the process of the present invention using Procedure 5, i.e. employing Calcium Catalyst A as compared with a run using Procedure 1 (NaOMe catalyst). In Table 1 and the other Tables, the "Target" refers to the desired weight percent ethoxylates. Also, in all cases "final reaction mixture" means the combined weight of the starting material ester and the alkylene (ethylene) oxide.
TABLE 1__________________________________________________________________________METHYL ESTER ETHOXYLATES: DATA FOR CALCIUMCATALYST A.sup.a (CCA) AND NaOMeExpt. Me EO % w/w.sub.b Cat. Run TimeNo. Ester Target Calc. Obsd..sup.c Catalyst g min.__________________________________________________________________________1 myristate 60 61.2 61.5 CCA 3.0.sup.a 91.sup.d2 myristate 60 60.2 CCA 6.0.sup.a 55.sup.e3 myristate 60 60.0 CCA 3.0.sup.a 60.sup.f4 myristate 60 59.5 CCA 9.0.sup.a 485 coconate.sup.g 55 53.3 61.0 CCA 1.5.sup.h 1156 coconate.sup.g 60 60.5 64.1 CCA 3.0.sup.a 1467 coconate.sup.g 65 63.4 71.3 CCA 1.5.sup.h 1068 coconate.sup.g 70 68.9 73.9 CCA 1.5.sup.h 1059 coconate.sup.i 55 54.7 59.1 CCA 1.5.sup.h 5910 coconate.sup.i 60 60.5 63.5 CCA 3.0.sup.a 8411 coconate.sup.i 65 64.4 68.8 CCA 1.5.sup.h 5712 coconate.sup.i 70 70.5 75.5 CCA 1.5.sup.h 7013 myristate.sup.j 60 60.9 61.4 CCA 3.0.sup.a 8414 laurate 30 28.8 33.0 CCA 1.5.sup.h 4415 laurate 30 29.3 27.6 NaOMe.sup.k 0.75.sup.h 101__________________________________________________________________________ .sup.a For each experiment, the total final reaction mixture weight was 300 g and the reaction temperature was 175.degree. C., unless specified otherwise. .sup.b Calculated from weight of final reaction mixture. .sup.c These values obtained by nuclear magnetic resonance spectroscopy. .sup.d 8.4 ppm dioxane in final reaction mixture. .sup.e 7.1 ppm dioxane in final reaction mixture. .sup.f 115.degree. C. reaction temperature; the only products were polyethylene glycol and recovered starting material. .sup.g Unstripped methyl coconate, mainly C.sub.12 and C.sub.14 methyl esters with some C.sub.8 and C.sub.10 methyl esters. .sup.h For this experiment, the total final reaction mixture weight was 150 g. .sup.i Stripped methyl coconate, mainly C.sub.12 and C.sub.14 methyl esters. .sup.j Repeat of Experiment No. 1. .sup.k Crystalline solid.
As can be seen from the data in Table 1, the use of Calcium Catalyst A is markedly better in terms of catalyst used than the use of a conventional sodium methoxide catalyst. For example, in comparing Experiments Nos. 14 and 15, the combined weight of calcium and aluminum in Calcium Catalyst A used in Experiment No. 14 is 0.054 g, whereas the amount of sodium employed in Experiment No. 15 is 0.32 g. Note also that for the same target amount of ethoxylation, there is a marked difference in run time between Experiment No. 14 using Calcium Catalyst A and Experiment No. 15 using the sodium methoxide catalyst.
Table 2 below shows comparative examples on the use of Calcium Catalyst A (Procedure 5) versus the use of other catalysts for producing low-mole ethylene oxide adducts of various methyl esters.
TABLE 2__________________________________________________________________________COMPARATIVE EXAMPLES: USE OF CCA.sup.a VS. OTHER CATALYSTSFOR LOW-MOLE EO ADDUCTSExpt. Me EO % w/w.sub.b Cat. GC Run TimeNo. Ester Target Calc. Obsd..sup.c Catalyst g EO No..sup.d Area %.sup.e min.__________________________________________________________________________14 laurate 30 28.8 33.0 CCA 1.5 0 28.7 44 1 8.4 2 14.1 3 15.6 4 13.6 5 11.1 6 8.5DE.sup.f laurate 30 g g HT.sup.h i 0 35.0 45 1 13.5 2 15.8 3 13.6 4 10.7 5 6.5 6 4.8j laurate 30 g g NaOMe.sup.k i 0 67.6 g 1 12.6 2 4.7 3 3.7 4 3.4 5 4.7 6 3.215 laurate 30 29.3 27.6 NaOMe.sup.k 0.75.sup.l 0 72.0 101 1 6.4 2 4.2 3 4.3 4 4.2 5 4.9 6 3.7__________________________________________________________________________ .sup.a The total final reaction mixture weight was 150 g and the reaction temperature was 175.degree. C. Amount of catalyst used was 1.0% w/w based on weight of final reaction mixture. .sup.b Calculated from weight of final reaction mixture. .sup.c These values obtained by nuclear magnetic resonance spectroscopy. .sup.d Number of EO moieties per methyl laurate molecule; 0 represents unreacted starting material. .sup.e Normalized area %; calculated from either gas chromatographic data or German Patent DE 3914131 A1 (HT and NaOMe catalysts). .sup.f German Patent DE 3914131 A1; data in the table were taken from thi patent. .sup.g Data not available. .sup.h Calcined hydrotalcite. .sup.i Number of grams of catalyst not available; amount of catalyst used was 0.5% w/w based on weight of final reaction mixture. .sup.j Data for NaOMe catalyst taken from German Patent DE 3914131 A1. .sup.k Crystalline solid. .sup.l Amount of catalyst used was 0.5% w/w based on a total final reaction mixture weight of 150 g.
As can be seen from the data in Table 2, using the process of Procedure 5 (Calcium Catalyst A), there is a marked increase in conversion as compared with the use of the process of Procedure 3 (calcined hydrotalcite) or the process of Procedure 1 (sodium methoxide). Note for example with respect to Experiment No. 14 that there is only 28.7 percent of unreacted starting material using Calcium Catalyst A as compared with 35 percent of unreacted starting material using calcined hydrotalcite (Experiment No. DE), 67.6 percent unreacted starting material using sodium methoxide (Experiment No. j) or 72 percent unreacted starting material using sodium methoxide (Experiment No. 15). Additionally, far less catalyst (based on active metal content) is required in the case of Experiment No. 14 than in the other experiments shown in Table 2. Note that in Experiment No. DE, the combined weight percent of Al and Mg is about 0.5 percent.
Table 3 shows further comparative examples on ethoxylating methyl esters using the process of Procedure 5 (Calcium Catalyst A) and the process of Procedure 4 (Calcium Catalyst B) as compared with the use of the process of Procedure 3 (hydrotalcite catalyst), the process of Procedure 1 (sodium methoxide catalyst), or the process of Procedure 2 (sodium hydroxide catalyst).
TABLE 3__________________________________________________________________________COMPARATIVE EXAMPLES: USE OF CCA.sup.a AND CALCIUM CATALYST B (CCB.sup.i)VS.USE OF OTHER CATALYSTS FOR HIGH-MOLE EO ADDUCTSExpt. Me EO % w/w.sub.b Cat. GC Run TimeNo. Ester Target Calc. Obsd..sup.c Catalyst g EO No..sup.d Area %.sup.e min.__________________________________________________________________________ 1.sup.a myristate 60 61.2 61.5 CCA 3.0 0 2.5 91 1 1.2 2 1.5 3 3.1 4 6.0 5 10.4 6 15.5 7 19.9 8 20.8 9 19.216.sup.f myristate 60 61.2 61.7 HT.sup.g 1.5 0 53.8 215 1 2.6 2 4.1 3 4.8 4 5.3 5 5.9 6 6.4 7 6.5 8 6.2 9 4.517.sup.h myristate 60 58.1 58.8 CCB 10.0 0 0.3 1076 1 0.8 2 0.8 3 2.8 4 7.0 5 12.8 6 18.0 7 20.4 8 20.3 9 16.818.sup.j myristate 60 57.9 58.6 NaOMe.sup.k 1.0 0 57.1 450 1 9.9 2 7.5 3 7.4 4 5.9 5 7.0 6 5.219.sup.l myristate 60 57.1 59.3 NaOH.sup.m 1.5 0 51.5 353 1 7.2 2 6.1 3 6.5 4 5.7 5 5.5 6 5.6 7 5.8 8 6.2__________________________________________________________________________ .sup.a The total final reaction mixture weight was 300 g and the reaction temperature was 175.degree. C. Amount of CCA catalyst used was 1.0% w/w based on weight of final reaction mixture. No alcohol or alcohol ethoxylate cocatalyst was used. .sup.b Calculated from weight of final reaction mixture. .sup.c These values obtained by nuclear magnetic resonance spectroscopy. .sup.d Number of EO moieties per methyl myristate molecule; 0 represents unreacted starting material. .sup.e Normalized area %; calculated from gas chromatographic data. .sup.f German Patent DE 3914131 A1; the total final reaction mixture weight was 300 g and the reaction temperature was 175.degree. C. No alcohol or alcohol ethoxylate cocatalyst was used. Amount of calcined hydrotalcite catalyst used was 0.5% w/w based on weight of final reaction mixture. .sup.g Calcined hydrotalcite; prepared according to Patent DE 3914131 A1. .sup.h Calcium Catalyst B as per U.S. Pat. No. 4,820,673; the total final reaction mixture weight was 300 g and the reaction temperature was 175.degree. C. Amount of CaObased catalyst used was 3.3% w/w based on weight of final reaction mixture. No alcohol or alcohol ethoxylate cocatalyst was used. .sup.i CaObased catalyst; prepared according to U.S. Pat. No. 4,820,673. .sup.j In this process, the total final reaction mixture weight was 300 g and the reaction temperature was 175.degree. C. ALFOL .RTM..sup.1 12 (ndodecanol) alcohol cocatalyst was used (15.0 g, 5.0% w/w based on weigh of final reaction mixture). Amount of NaOMe catalyst used was 0.3% w/w based on weight of final reaction mixture. .sup.k Crystalline solid. .sup.l In this process the total final reaction mixture weight was 300 g and the reaction temperature was 175.degree. C. ALFOL .RTM. 12 (ndodecanol) alcohol cocatalyst was used (15.0 g, 5.0% w/w based on weigh of final reaction mixture). Amount of NaOH catalyst used 0.5% w/w based o weight of final reaction mixture. .sup.m 50% aqueous solution. .sup.1 Trademark of Vista Chemical Company
As can be seen from the data in Table 3, and with respect to high-mole ethylene oxide adducts of the methyl esters, reaction times are greatly reduced using the process employing Calcium Catalyst A as opposed to processes that use sodium methoxide, sodium hydroxide or hydrotalcite. With respect to both Calcium Catalyst A and Calcium Catalyst B, conversion rates are much higher (note the small amount of unreacted starting material in Experiments 1 and 17 as compared with Experiments 16, 18 and 19). Lastly, use of calcium-based catalysts such as Calcium Catalyst A or Calcium Catalyst B results in an ethoxylated methyl ester which shows greatly enhanced peaking relative to the other catalyst systems employed. The data in Table 3 are graphically demonstrated in FIG. 1 which shows that the most prevalent EO species, i.e. about 8 in the case of Calcium Catalyst A and about 7 in the case of Calcium Catalyst B is greater than 20 percent. This is to be contrasted with the products obtained using the other processes which show virtually no peaking in that range of ethylene oxide adducts.
Table 4 below gives a comparison of reaction time profiles using processes employing Calcium Catalyst A, Calcium Catalyst B, hydrotalcite, sodium methoxide and sodium hydroxide.
TABLE 4__________________________________________________________________________COMPARATIVE EXAMPLES: REACTION TIME PROFILES USINGVARIOUS CATALYSTS FOR HIGH-MOLE EO ADDUCTSExpt. Me EO % w/w.sub.b Cat. Reaction EONo. Ester Target Calc. Obsd..sup.c Catalyst g Time (min.) Reacted (g).sup.d__________________________________________________________________________ 1.sup.a myristate 60 61.2 61.5 CCA 3.0 0 0.0 1 9.0 16 23.2 31 45.0 46 77.2 61 110.6 76 146.6 91 180.016.sup.e myristate 60 61.2 61.7 HT.sup.f 1.5 0 0.0 3 14.2 8 19.3 18 32.2 28 43.7 38 51.4 48 61.7 50 64.3 58 70.7 68 80.4 78 88.1 88 96.4 98 103.5 118 117.0 138 132.5 168 153.0 198 172.3 215 180.017.sup.g myristate 60 58.1 58.8 CCB.sup.h 10.0 0 0.0 2 10.3 32 12.9 69 23.2 96 28.3 122 33.4 152 37.3 212 47.6 272 56.6 336 65.6 416 78.4 452 83.6 812 142.8 872 153.0 932 162.0 992 171.0 1076 180.018.sup.i myristate 60 57.9 58.6 NaOMe.sup.j 1.0 0 0.0 20 9.0 30 24.4 45 32.2 75 54.0 105 81.0 135 104.2 165 120.9 334 167.2 375 173.6 450 180.019.sup.k myristate 60 57.1 59.3 NaOH.sup.l 1.5 0 0.0 2 9.0 17 9.0 42 10.3 82 14.1 102 23.1 117 33.4 132 42.3 147 57.9 162 70.7 192 95.2 229 119.6 253 132.4 260 137.6 302 159.5 327 169.8 347 176.2 353 180.0__________________________________________________________________________ .sup.a The total final reaction mixture weight was 300 g and the reaction temperature was 175.degree. C. Amount of CCA catalyst used was 1.0% w/w based on weight of final reaction mixture. No alcohol or alcohol ethoxylate cocatalyst was used. .sup.b Calculated from weight of final reaction mixture. .sup.c These values obtained by nuclear magnetic resonance spectroscopy. .sup.d The amount of EO listed as "reacted" within the first 1- 2 minutes of the run actually reflects the dead volume of the EO addition line. Tha is, the dead volume of the EO addition line was 9.0 g (of EO) and this amount, listed as "EO Reacted", actually is the amount of EO needed to liquidfill the line and, therefore, is not strictly "reacted" EO. .sup.e German Patent DE 3914131 A1; the total final reaction mixture weight was 300 g and the reaction temperature was 175.degree. C. Amount o calcined hydrotalcite catalyst used was 0.5% w/w based on weight of final reaction mixture. No alcohol or alcohol ethoxylate cocatalyst was used. .sup.f Calcined hydrotalcite; prepared according to German Patent DE 3914131 A1. .sup.g Calcium Catalyst B as per U.S. Pat. No. 4,820,673; the total final reaction mixture weight was 300 g and the reaction temperature was 175.degree. C. No alcohol or alcohol ethoxylate cocatalyst was used. Amount of CaObased catalyst used was 3.3% w/w based on weight of final reaction mixture. .sup.h CaObased catalyst; prepared according to U.S. Pat. No. 4,820,673. .sup.i In this process, the total final reaction mixture weight was 300 g and the reaction temperature was 175.degree. C. ALFOL .RTM.* 12 (ndodecanol) alcohol cocatalyst was used (15.0 g, 5.0% w/w based on weigh of final reaction mixture). Amount of NaOMe catalyst used was 0.3% w/w based on weight of final reaction mixture. .sup.j Crystalline solid. .sup.k In this process the total final reaction mixture weight was 300 g and the reaction temperature was 175.degree. C. ALFOL .RTM. 12 (ndodecanol) alcohol cocatalyst was used (15.0 g, 5.0% w/w based on weigh of final reaction mixture). Amount of NaOH catalyst used 0.5% w/w based o weight of final reaction mixture. .sup.l 50% aqueous solution. *Trademark of Vista Chemical Company.
As can be seen from that data in Table 4, by using the process of Procedure 5 (Calcium Catalyst A) reaction times are significantly decreased. As also shown from the data in Table 4 as well as the previous tables, the amount of catalyst employed, based on active metal content is markedly less in the case of calcium-based catalysts such as Calcium Catalyst A and Calcium Catalyst B as compared with catalysts such as hydrotalcite, sodium methoxide or sodium hydroxide.
Table 5 below gives the results of a comparison of using Calcium Catalyst A wherein a titanium alkoxide is substituted for aluminum alkoxide. In preparing Calcium Catalyst A using titanium alkoxide, the process of Procedure 5 was followed with the exception that titanium alkoxide was used instead of aluminum alkoxide. Experiment No. 23 in Table 5 also demonstrates that the deletion of 2-ethylhexanoic acid from the process of Procedure 5 makes Calcium Catalyst A less effective vis-a-vis run time and peaking but still gives much higher conversion than processes using NaOH, NaOMe or hydrotalcite as catalysts.
TABLE 5__________________________________________________________________________COMPARISON OF USE OF CCA (Using Aluminum Alkoxide) ANDCCA (Using Titanium Alkoxide)Expt. Me EO % w/w.sub.b Cat. GC Run TimeNo. Ester Target Calc. Obsd..sup.c Catalyst g EO No..sup.d Area %.sup.e min.__________________________________________________________________________14.sup.a laurate 30 28.8 33.0 .sup.f 1.5 0 27.0 44 1 7.9 2 13.3 3 14.7 4 12.8 5 10.5 6 8.0 7 6.021.sup.a laurate 30 25.2 25.1 .sup.g 3.0 0 51.7 65 1 8.8 2 11.4 3 9.8 4 7.4 5 5.3 6 3.5 7 2.222.sup.a laurate 30 28.3 31.3 .sup.h 3.0 0 71.8 20 1 3.7 2 4.9 3 4.6 4 4.3 5 4.0 6 3.6 7 3.223.sup.a myristate 60 63.4 .sup.i 3.0 0 9.0 83 1 1.5 2 3.8 3 6.2 4 8.7 5 11.3 6 13.3 7 14.7 8 15.8 9 15.8__________________________________________________________________________ .sup.a For each experiment, the total final reaction mixture weight was 150 g and the reaction temperature was 175.degree. C. No alcohol or alcohol ethoxylate cocatalyst was used. Amount of catalyst used was 1.0% w/w to 2.0% w/w based on weight of final reaction mixture. .sup.b Calculated from weight of final reaction mixture. .sup.c These values obtained by nuclear magnetic resonance spectroscopy. .sup.d Number of EO moieties per methyl laurate or methyl myristate molecule; 0 represents unreacted starting material. .sup.e Normalized area %; calculated from gas chromatographic data. .sup.f Aluminumcontaining CCA catalyst; ratio of Ca:SO.sub.4 :Al is 5:1:1 The amount of catalyst used was 1.0% w/w based on weight of final reactio mixture. .sup.g Titaniumcontaining CCA catalyst; ratio of Ca:SO.sub.4 :Ti is 8:1:2 The amount of catalyst used was 2.0% w/w based on weight of final reactio mixture. .sup.h Titaniumcontaining CCA catalyst; ratio of Ca:SO.sub.4 :Ti is 4:1:2 The amount of catalyst used was 2.0% w/w based on weight of final reactio mixture. .sup.i Aluminumcontaining CCA catalyst, but prepared without 2ethylhexanoic acid and ratio of Ca:SO.sub.4 :Al is 8:1:2. The amount of catalyst used was 2.0% w/w based on weight of final reaction mixture.
As can be seen from the data in Table 5, while the use of the process of Procedure 5 (Calcium Catalyst A with titanium alkoxide) does not result in as peaked a product as the use of aluminum alkoxide in the Calcium Catalyst A formulation, the process nonetheless results in shorter run times and requires less catalyst than prior art processes using catalysts such as sodium hydroxide, sodium methoxide or hydrotalcite. Moreover, the peaking of the product achieved using Calcium Catalyst A using titanium alkoxides is significantly greater than that achieved using such prior art processes employing NaOH or NaOMe as catalysts.
The data above clearly demonstrates that by using the process of the present invention, one can obtain ethoxylated methyl esters which exhibit a desired high degree of peaking, have higher conversion rates and, in the case of Calcium Catalyst A, greatly reduced reaction times. While the use of Calcium Catalyst B actually results, in some cases, in longer reaction times, nonetheless there is a significant increase in the amount of peaking obtained using Calcium Catalyst B as compared with other prior art processes and catalysts.
The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the method steps may be made within the scope of the appended claims without departing from the spirit of the invention.

Number	Name	Date
4754075	Knapf et al.	Jun 1988
4820673	Knapf et al.	Apr 1989
4835321	Leach et al.	May 1989

Number	Date	Country
0478074A2	Apr 1992	EPX
3914131	Oct 1930	DE2
3914131.4	Oct 1990	DEX

Process for alkoxylation of esters and products produced therefrom

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Abstract

Description

Claims

US Referenced Citations (3)

Foreign Referenced Citations (3)