Direct Alkane-Benzene Coupling Reactions with Bifunctional Zeolite-Encapsulated Metal Catalysts with Subnanoscale Intimacy.

Alkylbenzenes are one of the largest commodity chemicals in the current chemical industry, whose production relies on separated alkane dehydrogenation at high temperatures and benzene alkylation reactions, resulting in a high energy consumption and complex process design. Herein, a bifunctional Pt catalyst confined in aluminosilicate MEL-type zeolite is designed for the direct coupling of benzene and C2-C4 alkanes, in which the Pt and zeolite serve as the redox sites for the alkane dehydrogenation reaction and benzene alkylation reaction, respectively. The morphology of the MEL zeolite support, location, and chemical compositions of Pt clusters, and intimacy between Pt and acid sites are optimized to enhance the mass transport and catalytic properties. The optimal catalyst can achieve record-high productivity rates of alkylbenzenes in the direct coupling of benzene and C2-C4 alkanes, and high selectivity to desired alkylbenzenes, as well as excellent stability for >1000 h during consecutive reaction-regeneration cycles.