Improvements in the purification of esters

摘要

The crude esters obtained by the reaction of a carboxylic acid with an alcohol are purified by a process comprising mixing methylene dimethyl ether (methylal) with the crude ester, washing the mixture at least once with aqueous alkali and at least twice with water and then removing the solvent. The preferred alkali is sodium carbonate. The preferred range of proportions is from 3/4 to 2 volumes of methylal per volume of ester. Either pure or commerical methylal (containing about 8 per cent. of methanol) may be used. The washing with alkali and water is preferably carried out at a temperature between 10 DEG and 30 DEG C. In the examples (a) crude isopropyl oleate (b) crude 2 ethyl-hexyl stearate and (c) crude di-ethyl hexyl sebacate are purified according to the process of the invention and also, for comparison by using benzene and isopropyl alcohol as solvents instead of methylal.