Synthesis of Isobutylene from Ethanol in the Presence of Catalysts Containing Zinc Oxide and Zirconia

Abstract

Synthesis of isobutylene from ethanol in the presence of ZnO/ZrO2 catalysts has been studied. The samples have been synthesized by incipient wetness impregnation of zirconium hydroxide derived from zirconyl chloride with zinc nitrate and subsequent calcination at 550°C. The synthesized samples have been studied by low-temperature nitrogen adsorption, SEM, XRD, IR spectroscopy of adsorbed CO, and TGA–DTA. Studies of the effect of the catalyst composition and the test conditions have revealed that, during the synthesis of isobutylene from ethanol, an optimum Zr : Zn molar ratio providing the production of isobutylene with a selectivity of 45–50% is 8–20 and optimum conditions for ethanol conversion to isobutylene are 500°C, a feed space velocity of 3 g/(g h), and a feedstock in the form of a 50% ethanol solution in water. According to thermogravimetric analysis, an increase in the zinc content in the samples leads to a decrease in the amount of coke deposits.