Dehydrogenation of Isobutane on Cu/BEA Catalysts

Recent work has demonstrated the highly selective conversion of methanol and/or dimethyl ether to branched C₄ and C₇ alkanes, with incorporation of gas phase H₂ into the desired products, over a Cu-modified BEA zeolite catalyst.^{1, 2} These materials contain multiple catalytic functionalities, including cationic and metallic Cu sites and Brønsted acid sites. To further understand and optimize these catalysts, we have investigated the activity of the various catalytic sites in the dehydrogenation of the C₄ product. This functionality is particularly desirable due to the potential opportunity to upgrade the C₄ fraction via reincorporation in the catalytic cycle. In this work, we synthesized and characterized multiple Cu-modified BEA zeolite catalysts targeting specific catalytic sites (i.e., Cu⁰, Cu¹⁺, and Cu²⁺). The ability of each site to activate C-H bonds in isobutane, and the related reaction mechanisms, will be discussed based on the experimentally observed dehydrogenation reactivity and the results of hybrid quantum mechanics/molecular mechanics calculations.

 1. Schaidle, J. A.; Ruddy, D. A.; Habas, S. E.; Pan, M.; Zhang, G.; Miller, J. T.; Hensley, J. E.; ACS Catal., 2015, 5, 1794.

 2. Ahn, J. H.; Temel, B.; Iglesia, E. Angew. Chem., Int. Ed. 2009, 48, 3814.