The dehydration of methanol and ethanol catalyzed by polystyrene sulfonate resins

Abstract

Initial rates of the reaction of methanol and of ethanol to give water and the corresponding ether were obtained utilizing a packed-bed flow reactor. The reactions were conducted isothermally at 1 atm total pressure, as vapor-phase reactants contacted catalyst at temperatures from 80 ° to 120 °C. The catalyst was a sulfonated styrene-divinylbenzene copolymer (Dowex 50). The hydrogen form resin was altered by successively replacing hydrogen exchange ions with lithium ions in one series, and with sodium ions in another series. Reaction rate depression became complete at complete replacement of hydrogen ions. Lithium-containing catalysts were more active than sodium-containing catalysts of the same hydrogen content. A bimolecular rate-determining reaction step is indicated, with hydrogen ions being required for catalyst activity. A structure is proposed for the reaction intermediate.