(300f) Zeolite Membrane Permselective to Water Vapor and Its Application to Dehydration Reactions

Several types of zeolite composite membranes have been developing for separation between iso- and n-isomer, olefin and paraffin, inorganic gas and hydrocarbon, and water and alcohol. Particularly, in the water removal for alcohol-water mixture it has been shown that the composite membranes composing of several kind zeolites such as LTA, ERI／OFF (T), CHA, FAU can be synthesized hydrothermally on porous ceramic support. Those have higher water permselectivity, whereby being commercialized in the dehydration process for alcohol-water mixtures.

As an application of zeolite membranes to chemical reactions, various esterification reactions have already been examined mostly in liquid-phase perfectly mixed reactor to aim an equilibrium shift by selective water separation. Differently from such a batch operation, a vapor-phase one, making efficient and continuous production possible, is considered to be advantageous. Dehydration reaction of alcohols, limited thermodynamically, is also industrially important and operated at higher temperatures, producing olefins together with water. This study focuses on vapor-phase esterification and dehydration reaction of alcohol. A membrane reactor incorporated with chabazite (CHA) membrane and solid-acid catalyst is employed for removing water vapor selectively from the reacting mixture. The results in detail will be discussed.