Technical and economical feasibility of zeolite NaA membrane-based reactors in liquid-phase etherification reactions

This paper describes the pervaporation performance of film-like zeolite NaA membranes synthesized in our laboratory by template-free seeded hydrothermal towards the dehydration of n-pentanol/water and n-pentanol/water/DNPE mixtures (DNPE = di-n-pentyl ether, C10H22O). DNPE is a linear symmetric ether that can be used as blending additive in reformulated diesel fuels and that can be produced from C4 feedstocks via n-pentanol, obtained in its turn by selective hydroformylation of linear butenes. The membranes showed selectivities up to 3000 in the dehydration of n-pentanol/water binary mixtures, and water/DNPE and n-pentanol/DNPE selectivities approaching infinity (i.e. DNPE does not pervaporate) in the dehydration of n-pentanol/water/DNPE ternary mixtures. On the basis of the separation results presented in this work, and using experimental reaction kinetics data, we discuss the feasibility of zeolite NaA membrane reactors to carry out the liquid-phase etherification reaction of n-pentanol to di-n-pentyl ether (DNPE) catalyzed by ion-exchange sulfonated resins. These catalysts suffer from strong deactivation in the progress of the reaction due to the generation of water.