Esterification of Acetic Acid and n-Propanol with Vapor Permeation Using NaA Zeolite Membrane

Carboxylic acid esters are important intermediates in chemical and pharmaceutical industries and mostly produced by esterification reaction. As a reversible reaction, it is beneficial to drive the reaction equilibrium forward by removing one of the products. In this paper, vapor permeation (VP) using NaA zeolite membrane was proposed to intensify the esterification reaction by removing the produced water in a timely manner. The prepared NaA zeolite membrane was characterized by scanning electron microscopy (SEM) images and VP of water/n-propanol mixtures. It showed that the used NaA zeolite membrane had a high selectivity for removing water from the water/n-propanol mixtures. The effects of the reaction temperature, initial molar ratio of reactants, and catalyst loading on the esterification coupled with VP were investigated. It was found that the reaction temperature, initial molar ratio of reactants, and catalyst loading had a significant effect on the conversion of the reaction and the permeate flux. As for the esterification coupled with VP, the final conversion of the reaction increased from 78.2% to 98.6% at alcohol/acid molar ratio 2:1 at 373 K in 420 min. The NaA zeolite membrane showed good VP performance after 400 h.