Dehydrogenation of isobutane in the presence of CO2 on CrOx/SiO2 catalyst modified by the metals of the 2nd group

Relevance. Growing demand for olefins, in particular, for isobutylene. Increasing productivity requires an increase in the efficiency of technological processes, as well as catalysts. In the case of chromium oxide catalysts, increased activity and stability are required. In addition, the increase in the use of CO2 greenhouse gas in large-scale production leads to recycling. Aim. To determine the effect of 2nd group metal promoters on the activity and stability of chromium oxide catalysts during oxidative dehydrogenation of isobutane. Methods. A systematic study of Ca, Sr and Ba additives using SiO2 was conducted for Cr-containing isobutane dehydrogenation catalysts in the presence of CO2. To modify the structure of the catalyst and increase the efficiency of dehydrogenation, the 2nd group metals were introduced by the method of equilibrium adsorption as modifying additives. The analysis of the surface of the catalytic systems was carried out by thermoprogrammable reduction. Results and conclusions. A study of a modified chromium oxide catalyst showed that promoters based on the 2nd group metals increase the efficiency of isobutane dehydrogenation in the presence of CO2, reflected in the high yield of the target product. The samples Cr (3%) Ox/RA (10) – Ca/KSKG and Cr (3%) Ox/RA (20) – Ba/KSKG (55 and 54%, respectively) have high yield indicators. The authors have revealed that the content of modifying additives strongly affects the operation of the catalyst, in the case of calcium content growth, an increase in the activity and stability of the catalytic system is observed, which is reflected in an increase in the yield of the target product. Thermoprogrammable reduction of the modified catalyst showed that the introduction of the 2nd group metals reduces the proportion of available chromium on the surface of the carrier.