Two phase preparation of carboxylic acid esters

摘要

The methyl and ethyl esters of trifluoroacetic acid or chlorodifluoroacetic acid can be prepared in a technically simple manner from the corresponding acid chlorides and methanol or ethanol, respectively, in the presence of an "onium" salt of the acid as a catalyst. The alcohol is used in a stoichiometric excess, namely the molar ratio of alcohol to acid chloride is selected such that operation is in the region of a two-phase reaction. One of the phases is formed by the desired ester product, which is obtained in a high purity without any distillation.