Application of a sodalite membrane reactor in esterification—Coupling reaction and separation

A tubular hydroxy sodalite (SOD) membrane was successfully applied in the esterification of acetic acid with ethanol and acetic acid with 1-butanol, to selectively remove water by pervaporation and to overcome the thermodynamic equilibrium limitation of the esterification. The reactions were carried out using equimolar solutions of acetic acid with the appropriate organic alcohol at 363 K using Amberlyst 15 as acid catalyst. The hybrid process drove the esterification reactions almost to completion. The special feature of the SOD-membrane is that it showed absolute selectivity towards water and retained its stability under the reaction conditions. The membrane exhibited a stable water pervaporation performance at pH values above 2.9 for acetic acid–water mixtures.