Patent ID: 7973196

Claim:
A process for recycling 3-isobutyl glutaric anhydride comprising: a) preparing a compound of formula 24 from 3-isobutyl glutaric anhydride by a process comprising i) combining a chiral amine of the following formula 23, wherein Ar is a C 6-10 aromatic group, and R is a straight or branched C 1-4 alkyl, ester, or carboxylic acid, an organic solvent selected from at least one of C 6-10 aromatic hydrocarbons, substituted aromatic hydrocarbons, C 2-8 ethers, halogenated hydrocarbons, straight or branched C 1-4 alcohols, C 3-8 esters, straight, branched or cyclic C 1-6 alkanes, or C 3-8 ketones, and at least one base, to obtain a mixture; ii) cooling the mixture to a temperature of about −70° C. to about 10° C.; iii) adding 3-isobutyl glutaric anhydride to the mixture; iv) maintaining the mixture at a temperature of about −70° C. to about 10° C. for at least about one hour to obtain the compound of formula 24 and v) recovering the compound of formula 24 from the mixture; b) crystallizing the recovered compound of formula 24 from an organic solvent; c) removing the crystals from the organic solvent; d) combining the remaining organic solvent with an acid to obtain a first mixture; e) maintaining the first mixture at a temperature of about 60° C. to about 130° C., to obtain 3-isobutyl glutaric acid; f) combining the 3-isobutyl glutaric acid with acetic anhydride to obtain a second mixture; g) heating the second mixture to a temperature of about 125° C. to about 145° C. to obtain 3-isobutyl glutaric anhydride; and h) recovering the 3-isobutyl glutaric anhydride from the second mixture.