Oxidative Dehydrogenation of Propane with CO2 Over Cr/H[B]MFI Catalysts

• Published in: Catalysis letters 2011-05, Vol.141 (5), p.670-677
• Main Authors: Zhu, Qingjun, Takiguchi, Makoto, Setoyama, Tohru, Yokoi, Toshiyuki, Kondo, Junko N., Tatsumi, Takashi
• Format: Article
• Language: English
• Subjects: Boron; Carbon dioxide; Catalysis; Catalysts; Catalytic activity; Chemistry; Chemistry and Materials Science; Dehydrogenation; Exact sciences and technology; General and physical chemistry; Industrial Chemistry/Chemical Engineering; Ion-exchange; NMR; Nuclear magnetic resonance; Organometallic Chemistry; Physical Chemistry; Propane; Propylene; Silicalite; Stability; Steaming; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Transformations; Trivalent chromium; Zeolites: preparations and properties
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-011-0566-6

Cr/silicalite-1 and Cr/H[B]MFI catalysts were prepared by the impregnation method, and Cr/H[B]MFI were further treated by steaming. The catalysts were employed for the oxidative dehydrogenation of propane to propylene with CO 2 as the oxidant. Cr/H[B]MFI showed significantly higher catalytic activity than Cr/silicalite-1, and steamed Cr/H[B]MFI was superior in the reaction stability to Cr/H[B]MFI. The nature of the supported chromium species have been characterized by a number of physicochemical techniques, such as Raman, UV–vis and NMR. It is concluded that the steaming led to the auto-reduction of some Cr 6+ to Cr 3+ , and resultant Cr 3+ species might be located near the boron center in the borosilicate framework to counterbalance the negative charge of the framework. The transformation of Cr 6+ species to Cr 3+ species, facilitated by the steaming process and the presence of boron in the catalyst, is responsible for the enhanced stability of oxidative dehydrogenation of propane to propylene with carbon dioxide as the oxidant. Graphical Abstract Steaming treatment of Cr/H[B]MFI resulted in enhanced catalytic stability in the dehydrogenation of propane to propylene with CO 2 as oxidant, probably due to the transformation of some Cr 6+ species to Cr 3+ ones.