Process for synthesizing specific complete mixed polyol esters

Abstract

Reacting a partial polyol monocarboxylic acid ester with an acidic anhydride in the presence of a catalytic amount of hydrogen bromide to produce specific complete mixed polyol esters, especially confectioner's hard butter.

What is claimed is: 
     
       1. A process for preparing specific complete mixed polyol esters from .[.unsymmetrically substituted.]. partial polyol esters with substantially no ester group rearrangement comprising esterifying .[.said.]. .Iadd.a .Iaddend.partial polyol .[.esters.]. .Iadd.ester .Iaddend.with an acid anhydride in the presence of a catalytic amount of a hydrogen bromide source.[...]..Iadd., said partial polyol ester being from the group consisting of partial polyol esters from aliphatic diols having the hydroxyl groups unsymmetrically substituted with respect to the carbon chain and partial polyol esters from aliphatic polyol containing at least three hydroxyl groups. .Iaddend. 
     
     
       2. A process according to claim 1 wherein the hydrogen bromide source is selected from the group consisting of aqueous hydrobromic acid and gaseous hydrogen bromide. 
     
     
       3. A process according to claim 1 comprising admixing:  (1) a polyol selected from the group consisting of aliphatic diols wherein the hydroxyl groups are unsymmetrically substituted with respect to the carbon chain and aliphatic polyols containing at least three hydroxyl groups, said polyols having been partially esterified with a monocarboxylic acid containing about 8 to 24 carbon atoms, with; (2) a member selected from the group consisting of acidic lipid anhydrides of the formula ##EQU10## wherein X is a substituent selected from the group consisting of: (1) alkyl and alkenyl groups containing from 7 to 23 carbon atoms and having the formula R--   (2) residues of alkyl half-esters of a dicarboxylic acid having the formula ##EQU11## (3) residues of monoacyl diol half-esters of a dicarboxylic acid having the formula ##EQU12## (4) residues of diacyl glyceride half-esters of a dicarboxylic acid having the formula ##EQU13## and (5) residues of monoacyl derivatives of a primary monohydroxy monocarboxylic acid having the formula ##EQU14## wherein in (1)-(5) above: R is an alkyl or alkenyl group containing 7 to 21 carbon atoms;   R 1  is an alkylene group containing 2 to 4 carbon atoms;   R 2  is an alkylene group containing 0 to 4 carbon atoms;   R 3  is an alkylene group containing 2 to 5 carbon atoms;   Z is a substituent selected from the group consisting of hydrogen and methyl; and   Y is a substituent selected from the group consisting of benzyl, p-nitrobenzyl, and phosphoryl ester; and (3) a catalyst selected from the group consisting of hydrogen bromide and hydrogen bromide sources, at a molar ratio of said catalyst to acidic lipid anhydride of at least about 0.01 to 1.     
     
     
       4. The process of claim 1 which is carried out at a temperature from 0° F. to 212° F. 
     
     
       5. The process of claim 1 which is carried out using a molar excess of the acid anhydride. 
     
     
       6. The process of claim 1 wherein the partial polyol ester is a partial glyceride ester. 
     
     
       7. The process of claim 1 wherein the partial polyol ester is a 1,3-diglyceride. 
     
     
       8. The process of claim 1 wherein the partial polyol ester is a partial ester of 1,2-propylene glycol. 
     
     
       9. The process of claim 1 wherein the acid anhydride is symmetrical. 
     
     
       10. The process of claim 1 wherein the acid anhydride is an alkyl anhydride wherein the alkyl group contains from 7 to about 23 carbon atoms. 
     
     
       11. The process of claim 1 wherein the acid anhydride is oleic anhydride. 
     
     
       12. The process of claim 1 wherein the partial polyol ester is a monoglyceride and the reaction is carried out in an organic solvent selected from the group consisting of benzene and pyridine. 
     
     
       13. A process for preparing a synthetic cocoa butter comprising acylating the 2-hydroxy group of 1-palmitoyl-3-stearoyl glycerol with oleic anhydride in the presence of a catalyst selected from the group consisting of hydrogen bromide and hydrogen bromide sources, and crystallizing and separating the synthetic cocoa butter thus formed. 
     
     
       14. A process for preparing a confectioner's hard butter comprising acylating the 2-hydroxy groups in a mixture comprising 1-palmitoyl-3-stearoyl glycerol, 1,3-distearoyl glycerol and 1,3-dipalmitoyl glycerol with oleic anhydride in the presence of a catalytic amount of hydrogen bromide. 
     
     
       15. A process for preparing a confectioner's hard butter comprising: (1) admixing substantially completely hydrogenated palm oil with glycerol in the presence of a sodium methoxide catalyst and separating and crystallizing the 1,3-diglycerides formed; (2) acylating the 2-hydroxy groups of the 1,3-diglycerides prepared in step (1) with oleic anhydride in the presence of a catalyst selected from the group consisting of hydrogen bromide and hydrogen bromide sources; and (3) crystallizing and separating the hard butter thus formed. 
     
     
       16. The process of claim 15 wherein the catalyst is a member selected from the group consisting of hydrogen bromide gas and aqueous hydrobromic acid. 
     
     
       17. The process of claim 15 wherein the catalyst-to-oleic anhydride molar ratio is at least 0.01:1. 
     
     
       18. The process of claim 15 which is carried out at from about 0° F. to about 212° F. 
     
     
       19. The process of claim 15 which is carried out in the presence of a molar excess of oleic anhydride.