Patent ID: 6720447
Filing Date: 2004-04-13
Classification: C07C

Abstract:
A process for the preparation of esters of the general formula I from compounds of the general formula II contained in aqueous solutions which comprisesa) extracting the compounds of the general formula II directly or after liberation from their salts in the presence of a C1-C8-alcohol and a water-immiscible solvent and b) then esterifying with the C1-C8-alcohol in the presence of a catalyst and of an entraining agent under the conditions of an azeotropic distillation, where the process steps (a) and (b) can be carried out separately in terms of time and space or else in a successive continuous or batchwise sequence and where the variables and substituents in the formulae I and II have the following meanings:R1=F, Cl, â€”OH, â€”OC1-C10-alkyl, R2=H, C1-C10-alkyl, R3=C1-C8-alkyl, Q=â€”OH, â€”Oâˆ’K+, where K+ is an alkali metal cation or alkaline earth metal cation or an amine, n=0, 1 or 2.