Organic–Inorganic Composites Based on Gel-Type Sulfonic Resin KU-2-8 and Zirconia: Acid and Catalytic Properties in the Etherification Reaction of iso-Butylene with Ethanol

Although acid and catalytic properties of the sulfonic resins and zirconia are well-characterized, a little is known about their composites, particularly about the KU-2-8-ZrO2 composites, in which KU-2-8 is a commercial gel-type sulfonic resin. In this article, the acidity of the KU-2-8-ZrO2 composites has been studied by the ammonia quasi-equilibrium thermo-desorption technique and their catalytic characteristics in etherification of isobutylene with ethanol were defined. The KU-2-8-ZrO2 productivity in this reaction was found to be an order of magnitude higher compared to KU-2-8 and several times higher compared to the commercial macroporous sulfonic resin Amberlyst 15. A high productivity of the KU-2-8-ZrO2 composites is achieved by the improved accessibility of the sulfonic resin acid sites for reagents. The composites do not swell in the polar medium and show high resistance to osmotic shock. The KU-2-8-ZrO2 composites with 70–80 wt % of KU-2-8 were found promising for industrial applications.