Preparation of esters of carboxylic acids

摘要

Disclosed is a process wherein a solution of a carboxylic acid in a first solvent and an alcohol are fed to a simulated moving bed reactor (SMBR) containing a solid(s) to produce a first stream comprising a solution of an ester of the carboxylic acid and the alcohol and a second stream comprising the first solvent. The solid(s) present in the SMBR facilitates the esterification reaction and the separation of the first solvent from the carboxylic acid. The process is particularly valuable for the preparation of an alkanol solution of an alkyl 2-keto-L-gulonate ester (AKLG) from an aqueous fermentation broth containing dissolved 2-keto-L-gulonic acid (KLG) by feeding the fermentation broth and an alkanol to a simulated moving bed reactor which contains a solid acidic esterification catalyst to produce a stream comprising an alkanol solution of an ALKG. The alkanol solution of an ALKG may be used directly to convert the ALKG to ascorbic acid (Vitamin C).