Patent GB-797357-A (GB)
Title: Improvements in or relating to treatment of glyceryl esters
IPC: C11C3/04
Filed: 1955-03-02
Abstract: A fatty acid ester having from 5 to 40 carbon atoms in the fatty acid radical and glycerol are obtained by reacting a glyceryl ester of a fatty acid having from 5 to 40 carbon atoms with an aliphatic (including cycloaliphatic and araliphatic) monohydric alcohol containing at least two carbon atoms in the presence of an alkaline alcoholysis catalyst and of at least 20 per cent by weight based on the weight of glyceryl ester used, of an inert hydrocarbon solvent for said glyceryl ester and for the alcohol used but in which glycerol is insoluble or only slightly soluble, whereby two layers are formed, one comprising essentially glycerol and the other comprising the fatty acid ester and solvent and separating the glycerol layer from the other layer by decantation or centrifugation. The invention also comprises methylisobutyl carbinyl esters of mixed tallow fatty acids.  The ester product can be recovered by distillation from the solvent or by extraction with a dissimilar solvent and can be reduced, if desired without separation from the inert solvent, by treatment with an alkali metal in the presence of an alcohol to produce an alcohol derived from the fatty acid portion of the ester molecule. The glycerol ester is generally reacted with about 1.0 to 4.5 equivalents of the aliphatic alcohol.  In a preferred embodiment the glycerol ester is reacted with 1.5 to 3 equivalents of a C2-C10 aliphatic monohydric alcohol in the presence of an alkali metal alcoholate as the alcoholysis catalyst and in the presence of 0.2 to 1 part by weight of inert hydrocarbon solvent per part of glyceryl ester treated.  The glyceryl ester may be a mono-, di- or tri-glyceride, the latter being preferred. The fatty acid residues in the di- or tri-glycerides may be the same or different and may be saturated or unsaturated.  The glycerides may be pure esters or may be natural or synthetic fats or oils.  Specified acids from which the glycerides may be derived are capric, lauric, myristic, palmitic, stearic, oleic, linoleic, linolenic, elaeostearic and stearolic and specified fats and oils are coconut, sperm, cotton seed, linseed, tung, cacahuananche, babassu, oiticica, sesame, wool fat, palm, olive, whale, shark, sardine, sugar cane, menhaden, okra seed and rice bran oils, and tallow.  The monohydric alcohol may be primary, secondary or tertiary, e.g. ethanol, propanol, isopropyl alcohol, n-butyl-, isobutyl-, secondary butyl- and tertiary butyl-alcohols, the various primary, secondary and tertiary amyl, hexyl, heptyl, octyl, nonyl and decyl alcohols, phenylmethylcarbinol, phenylethylcarbinol, phenyl-n-propylcarbinol, diphenylcarbinol, phenyl-p-tolylcarbinol, phenyl benzyl carbinol, cyclopentanol, cyclohexanol, 2-, 3- or 4-methyl cyclohexanol, cyclopentenol, and cyclohexenol.  The preferred alcohol is methylisobutyl carbinol. Specified alcoholysis catalysts are alcoholates, alkali metal-hydroxides, -amides and -hydrides, and alkali metals such as sodium or potassium.  The hydrocarbon solvent used should preferably boil within the range 100-200 DEG  C. and may be aliphatic, cycloaliphatic or aromatic, e.g. benzene, toluene, xylene, ethyl benzene, trimethyl benzene, kerosene, octane, iso-octane, heptane, diisobutylene, decahydronaphthalene or heavy alkylate.  The alcoholysis is preferably effected at temperatures of 100 DEG  to 200 DEG  C. and the pressure may be atmospheric, sub-atmospheric or superatmospheric.  The ester product can be reduced with an alkali metal, e.g. sodium, and an alcohol without removing it from the solvent-ester layer formed in the alcoholysis and if an excess of the alcohol is used for the alcoholysis the excess of alcohol can be used as the reducing alcohol and if desired more solvent may be added before the reduction step.  The reducing alcohol is preferably the same alcohol as is used in the alcoholysis step but a different alcohol may be used.  The process may be carried out continuously. Thus a stream of tallow, methylisobutyl carbinol containing sodium as the alcoholate of methylisobutyl carbinol, and toluene may be fed to a reactor wherein they are agitated at 110-120 DEG  C. and the reaction mixture withdrawn continuously from the reactor and treated continuously with mineral acid to neutralize the catalyst.  The glycerol layer is continuously separated from the solvent layer and the methylisobutylcarbinyl esters can be separated from the unreacted alcohol and toluene by distillation or the entire ester-solvent phase can be fed continuously along with sodium to a continuous ester-reduction reactor operated at elevated temperature and the product mixture continuously withdrawn and hydrolysed with water to yield the fatty alcohol corresponding to the tallow fatty acids.  In other examples: (1) tallow is reacted with methylisobutylcarbinol in the presence of added sodium and of toluene, iso-octane, diisobutylene and xylene respectively as solvent and the glycerol and ester product recovered; (2) glycerol trioleate is reacted with excess methylisobutylcarbinol in the presence of toluene as solvent and of the sodium salt of methylisobutyl carbinol as catalyst to form a reaction mixture which, after removal of glycerol, comprises methylisobutylcarbinyl oleate, methylisobutyl carbinol and toluene which is then treated with finely dispersed sodium at 115 DEG  C. and the product hydrolysed to form oleyl alcohol which is left as residue in the organic phase after removal of the toluene and methylisobutyl carbinol by distillation.  Other specified ester products obtainable by the alcoholysis process are the methylisobutylcarbinyl esters of the fatty acids derived from linseed oil, sardine oil and soybean oil respectively, and of lauric, stearic, palmitic, linoleic and linolenic acids respectively, and the methylamylcarbinyl and methylbutylcarbinyl esters of lauric, stearic and oleic acids respectively.  The ester products may be used as additives to lubricating oils, or to paints or varnishes and as plasticizers in various plastic formulations.  The methylisobutylcarbinyl esters of mixed tallow fatty acids may also be obtained by reacting mixed tallow fatty acids with methylisobutylcarbinol in the presence of an esterification catalyst, e.g. sulphuric acid, or by transesterification of primary monohydric alcohol esters of mixed tallow fatty acids with methylisobutylcarbinol.ALSO:Glycerol and a fatty acid having from 5 to 40 carbon atoms in the fatty acid radical are obtained by reacting a glyceryl ester of a fatty acid having from 5 to 40 carbon atoms with an aliphatic (including cycloaliphatic and araliphatic) monohydric alcohol containing at least two carbon atoms in the presence of an alkaline alcoholysis catalyst and of at least 20 per cent by weight based on the weight of glyceryl ester used, of an inert hydrocarbon solvent for said glyceryl ester and for the alcohol used but in which glycerol is insoluble or only slightly soluble, whereby two layers are formed, one comprising essentially glycerol and the other comprising the fatty acid ester and solvent and separating the glycerol layer from the other layer by decantation or centrifugation.  Further quantities of glycerol can be recovered by treating the ester phase with water.  The glyceryl ester may be a mono-, di- or triglyceride and the fatty acid residues in the di- or triglycerides may be the same or different and may be saturated or unsaturated.  The glycerides may be pure esters or may be natural fats or oils.  Specified acids from which the glyceride may be derived are capric, lauric, myristic, palmitic, stearic, oleic, linoleic, linolenic, elaeostearic and stearolic and specified fats and oils are coconut, sperm, cotton seed, linseed, tung, cacahuanauche, babassu, oiticica, sesame, wool fat, palm, olive, whale, shark, sardine, sugar cane, menhaden, okra seed and rice bran oils and tallow.  The monohydric alcohol may be primary, secondary, or tertiary, e.g. ethanol, propanol, isopropyl alcohol, n-butyl-, isobutyl-, secondary butyl-, and tertiary butyl alcohols, the various primary, secondary and tertiary amyl, hexyl, heptyl, octyl, nonyl and decyl alcohols, phenylmethylcarbinol, phenylethylcarbinol, phenyl n-propyl carbinol, diphenylcarbinol, phenyl p-tolyl carbinol, phenyl benzyl carbinol, cyclopentanol, cyclohexanol, 2-, 3- or 4-methyl cyclohexanol, cyclopentenol, and cyclohexenol.  The preferred alcohol is methylisobutylcarbinol.  Specified alcoholysis catalysts are alcoholates, alkali metal-hydroxides, -amides and -hydrides, and alkali metals such as sodium or potassium.  The hydrocarbon solvent used should prefer ably boil within the range 100-200 DEG  C. and may be aliphatic, cycloaliphatic or aromatic, e.g. benzene, toluene, xylene, ethyl benzene, trimethyl benzene, kerosene, octane, iso-octane, heptane, diisobutylene, decahydronaphthalene or heavy alkylate.  The alcoholysis is preferably effected at temperatures of 100 DEG  C. to 200 DEG  C. and the pressure may be atmospheric, subatmospheric or superatmospheric.  An excess of the alcohol reactant is preferably used, e.g. about 1.0 to 4.5 equivalents of the alcohol are suitable.  The ester product can be reduced by treatment with an alkali metal and an alcohol to form the alcohol corresponding to the fatty acid portion of the glyceride (see Group IV (b)).  The process may be carried out continuously.  Thus, a stream of tallow, methylisobutylcarbinol containing sodium as the alcoholate of methylisobutyl carbinol and toluene, may be fed to a reactor wherein they are agitated at 110-120 DEG  C. and the reaction mixture withdrawn continuously from the reactor and treated continuously with mineral acid to neutralize the catalyst.  The glycerol layer is then continuously separated from the ester-solvent layer by decantation or centrifugation.  Other examples are given for the production of glycerol by alcoholysis of tallow with methylisobutylc