The effect of ZrO 2 calcination temperature on its structure and acid-base characteristics was investigated to elucidate their relation to catalytic behaviour in methanol carboxylation. Varying the calcination temperature causes changes in ZrO 2 phase composition and acid-base characteristics. The base properties of ZrO 2 play a prominent role in dimethyl carbonate synthesis. Strong base sites (E CO2 > 78 kJ/mol) are needed to activate СО 2 . Tetragonal modification of zirconium dioxide has a higher basicity than the monoclinic. Thus, the greater the contribution of t-ZrO 2 in the catalyst, the greater its ability to activate СО 2 and therefore result in higher catalytic activity for methanol carboxylation. DMC selectivity was determined by the ratio of catalyst base site to acid site concentration.

The active sites of H-BEA zeolites for ETBE synthesis are the weak Brønsted acid sites representing internal silanol groups.

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-ZrO 2 composites, in which KU-2-8 is a commercial gel-type sulfonic resin. In this article, the acidity of the KU-2-8-ZrO 2 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-ZrO 2 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-ZrO 2 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-ZrO 2 composites with 70−80 wt % of KU-2-8 were found promising for industrial applications.