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

Autor: Qingjun Zhu, Toshiyuki Yokoi, Junko N. Kondo, Makoto Takiguchi, Takashi Tatsumi, Tohru Setoyama
Rok vydání: 2011
Předmět:
Zdroj: Catalysis Letters. 141:670-677
ISSN: 1572-879X
1011-372X
DOI: 10.1007/s10562-011-0566-6
Popis: 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 CO2 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 Cr6+ to Cr3+, and resultant Cr3+ species might be located near the boron center in the borosilicate framework to counterbalance the negative charge of the framework. The transformation of Cr6+ species to Cr3+ 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. Steaming treatment of Cr/H[B]MFI resulted in enhanced catalytic stability in the dehydrogenation of propane to propylene with CO2 as oxidant, probably due to the transformation of some Cr6+ species to Cr3+ ones.
Databáze: OpenAIRE