Production Rate of Methyl Tert-Butyl Ether in Vapor Phase on Molten Benzenesulfonic Acid Catalyst

Abstract

Vapor-phase reaction of methanol with isobutylene to produce MTBE (methyl tert-butyl ether) was carried out by use of molten benzenesulfonic acid (in.p. 45°C) as the catalyst at 60120°C under atmospheric pressure. The reaction rate varied remarkably with temperature and partial pressure of methanol due to the dissolution of methanol in the catalyst. The amount of methanol dissolved in the catalyst under the reaction conditions was measured and the variation of acid strength of the catalyst with the dissolution of methanol was investigated by using anthraquinone and benzalacetophenone as indicators. The reaction rates were corrected by considering these variations of acid strength of the catalyst. The dependences of temperature and partial pressure of methanol on these reaction rates were in good agreement with those of the ion exchange resin. Furthermore, it was found that the formation of by-product (diisobutylene) was depressed by dissolving methanol in the catalyst. The state of catalyst on the support was observed with a scanning electron microscope.