Pervaporative separation of methyl acetate–methanol azeotropic mixture using high-performance polydimethylsiloxane/ceramic composite membrane

Methyl acetate is a very important green solvent, which is often produced by esterification using excess methanol as one of the reagents. Therefore, cost-efficient separation of the methyl acetate/methanol mixture is important. However, the formation of a methanol/methyl acetate azeotrope at atmospheric pressure results in high energy consumption for their separation using distillation such as extractive distillation. In order to reduce the energy consumption, pervaporation (PV) was used to replace the distillation in this study. Two membranes, polydimethylsiloxane and polyoctylmethylsiloxane, were first compared in the PV separation of the methyl acetate/methanol mixture. Then the effects of different operating parameters such as temperature, feed flow rate, permeate pressure, and so on were investigated. Total flux was up to 100 kg/(m²·hr) at 50°C, whereas the separation factor ranges from 1.2 to 5.0. Results showed that the methyl acetate/methanol azeotrope could be broken in the studied concentration range and high flux could be obtained. Furthermore, the change of activation energy with feed methyl acetate concentration and membrane thickness with temperature was investigated. To demonstrate the potential of the industrial applications, the stability in separation of 32 wt.% methyl acetate–methanol mixtures for 15 days was investigated.