Effect of Acid–Base Characteristics of Zeolite Catalysts on Oxidative Dehydrogenation of Propane with Carbon Dioxide

Effect of Surface Acidity/Basicity of Cr/Zn−BEA Zeolite Catalysts on Performance in CO2‐PDH Process

“…The surface of the Cr/ZnAlBEA sample is characterized by the highest overall acidity, which naturally decreases with the degree of dealumination of the initial zeolite for the other samples [9,14,15] . At the same time, for all specimens, the share of acid sites of medium strength (about the total relative concentration), which is the largest for the fully dealuminated Cr/ZnSiBEA sample (0.82), prevails over the share of weak and strong sites.…”

“…The activity and selectivity of catalysts largely depend on their acid–base characteristics, determined in zeolites by the Si/Al ratio and the nature of incorporated heteroelements [2,8,9,12,13] . Regulation of acid–base properties by dealumination of the zeolite has increased the catalyst selectivity for the target product of CO 2 −PDH over Cr/Beta and Zn−BEA catalysts [9,14,15] . In particular, it is shown in the paper [9] that the dealumination of Beta zeolite followed by an introduction of chromium resulted in active/selective catalysts for the production of propylene in the CO 2 −PDH process.…”

“…[2,8,9,12,13] Regulation of acid-base properties by dealumination of the zeolite has increased the catalyst selectivity for the target product of CO 2 À PDH over Cr/Beta and ZnÀ BEA catalysts. [9,14,15] In particular, it is shown in the paper [9] that the dealumination of Beta zeolite followed by an introduction of chromium resulted in active/ selective catalysts for the production of propylene in the CO 2 À PDH process. High selectivity (> 80 %) of propylene formation was achieved on the CrSiBeta catalyst with lower surface acidity, while the highest acidity of CrAlBeta promoted the cracking of propane and target alkene.…”

“…The influence of BEA zeolite preliminary dealumination on the acid-base characteristics and catalytic performance of ZnÀ BEA compositions in CO 2 À PDH is shown in. [14,15] Full dealumination resulted in a twofold decrease in the total acidity as well as basicity of Zn-BEA, and the formation of Lewis acid sites (LAS) and basic sites of predominantly medium strength with the removal of Brønsted acid sites (BAS) from the surface. In the presence of the ZnSiBEA catalyst with the lowest total acidity and basicity, the obtained selectivity of 86-94 % and yield of 30-33 % for propylene (923 K, RM (vol .…”