Coupling of in-situ pervaporation for the enhanced esterification of propionic acid with isobutyl alcohol over cenosphere based catalyst

Abstract

In the present work, pervaporation assisted esterification of propionic acid and isobutyl alcohol, to produce isobutyl propionate and water was investigated in an in-situ type pervaporation reactor. A commercial polymeric hydrophilic PVA-PES membrane was used to shift the conversion of equilibrium limited esterification reaction by the removal of water from the reaction mixture. Catalyst developed from cenosphere (waste material) was used in the study. The effects of process parameters viz; reaction temperature, catalyst loading, alcohol/acid molar ratio and a ratio of effective membrane area to initial reaction volume (S/V) were studied.Catalyst characterization elucidated that the catalyst exhibited significant silica content, surface acidity with a considerable surface area. The membrane showed a significant selectivity towards the water removal which subsequently enhanced the pervaporation performance. A substantial enhancement in the conversion of esterification reaction from 67% to 88% was observed by the incorporation of pervaporation at a temperature of 353K. The membrane and catalyst revealed a significant stability up to four and three reaction runs respectively. Results revealed that all process parameters linearly affected the conversion and permeate flux of pervaporation assisted esterification. The maximum esterification conversion was obtained to be 92% at a reaction temperature of 353K, catalyst loading of 20g/L, alcohol/acid molar ratio of 2.5 and S/V ratio of 19.63m−1.