Synthesis of isoprene from isobutene and methanol over supported silver catalysts.

Abstract

One-step synthesis of isoprene from isobutene and methanol over suppsoilrvterd catalysts was investigated. Among the various metal oxides, SiO2 was found to be most suitable as catalyst carrier.Highly dispersed Ag on SiO2 produced acid sites of H0>-3.0 at which isoprene was thought to be formed by condensation of isobutene with the formaldehyde produced from methanol by the action of the Ag component. Only a small amount of isoprene was obtained at 280°C in the absence of oxygen; however, at higher temperatures, a considerable amount of isoprene was obtained even in the absence of oxygen, while isopentenes were co-produced probably by alkylation of isobutene with methanol and by hydrogenation of isoprene.