IE33399B1 - Esterification and extraction process - Google Patents

Abstract

1282926 Esterification and extraction EL PASO PRODUCTS CO 7 Oct 1969 [10 Oct 1968 19 Aug 1969] 49255/69 Heading C2C In a process for the separation of esterifiable aliphatic carboxylic acids admixed in aqueous solutions, the mixture is (a) contacted with an alkyl alcohol (1-5 C), alkylene glycol, or their ether derivatives at from 25 degrees to B.P. in the presence of an esterification catalyst and (b) simultaneously and countercurrently contacted with a water-immiscible organic solvent to extract the esters as formed, (c) partitioning to an organic phase containing at least a portion of the esters and an aqueous phase containing excess water-miscible solvent, unesterified organic acids and water, (d) layering out and separating the two phases, (e) distilling the organic phase to recover the solvent and the esters and (f) distilling the aqueous phase to recover any excess water-miscible solvent and the residue. The aqueous solution may be mixtures of at least two monocarboxylic, saturated or unsaturated, substituted or unsubstituted acids, a dicarboxylic acid which is saturated or unsaturated substituted or unsubstituted, and tri- or polycarboxylic acids and many are listed, for example, the mixed acids obtained by the nitric acid oxidation of cyclohexanol and cyclohexanone, and of fats and fatty acids; the oxidation of paraffins; the hydration of maleic acid; the fermentation processes yielding lactic, oxalic or citric acids; and carbohydrate degradation processes yielding levulinic acid. The water-immiscible solvents may be aliphatic, cycloaliphatic and aromatic hydrocarbons and halogenated aliphatic or aromatic hydrocarbons. The process is illustrated using apparatus comprising a series of three feed tanks, three extractors and two settlers to provide a continuous system. Examples describe the extraction of dimethyl esters of mixed succinic, glutaric and adipic acids from the nitric acid oxidation of cyclohexanol and cyclohexanone, and the nitric acid oxidation of cyclohexane; esters from oleic and tall oil oxidation acids; mixed maleic and cyanacetic acid esters, esters from mixed oxalic, malonic, succinic, glutaric and alipic acids, esters of mixed acids from the hydration of maleic acid; esters of technical grade aconitic, lactic and levulinic acids and of the acids derived from the hydrolysis of sucrose. [GB1282926A]