ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Effect of chelating agents on catalytic performance of Cr/γ-Al₂O₃ dehydrogenation catalysts

Guangjian Wang, Xingyuan Sun, Xinshan Niu, Fanfei Meng, and Fang Wang

Qingdao University of Science and Technology, Qingdao, People’s Republic of China

E-mail: guangjianwang@126.com

Abstract: Chromia/alumina (Cr₂O₃/γ-Al₂O₃) catalysts with addition of chelating agents (citric acid or oxalic acid) were prepared by the incipient impregnation method. The resulting catalysts with different citric acid (CA) or oxalic acid (OA) contents were applied to the dehydrogenation of isobutane to isobutene. The influence of chelating agents on the catalysts was investigated by means of BET, SEM, H₂-TPR, NH₃-TPD, and TG-DTG. The results showed that the Cr₂O₃/γ-Al₂O₃ catalysts with addition of CA or OA exerted slightly increase on specific surface area. The addition of the chelating agents as expected, determined a general decrease in the surface acidity. The catalysts with CA or OA have a better anti-coking ability by inhibiting the side reaction of cracking and carbon formation. The addition of CA or OA for preparing these catalysts resulted in a beneficial effect on the reducibility of the Cr species to diminish the reduction temperature. The appropriate content of chelating agents could improve dispersion of metal species in the γ-Al₂O₃ support. The catalytic activity showed an important enhancement when the metal species was impregnated in the presence of CA or OA.

Keywords: Cr₂O₃/γ-Al₂O₃ ; Impregnation method ; Chelating agents ; Isobutane dehydrogenation ; Coke formation 

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-017-0335-0

Chemical Papers 72 (4) 921–928 (2018)