Verifying the mechanism of the ethene-to-propene conversion on zeolite H-SSZ-13

• DOI: 10.1016/j.jcat.2014.03.006
• Publication Date: 2014-04-19T12:20:14Z
• Authors: Weili Dai; Xiaoming Sun; Bo Tang; Guangjun Wu; Landong Li; Naijia Guan; Michael Hunger
• Keywords: Propene; Chabazite; Carbenium ion

Several types of microporous molecular sieves with similar nSi/nAl ratios (except for SAPO-34) and different pore structures were prepared and applied as ethene-to-propene (ETP) catalysts. H-SSZ-13 zeolite consisting of chabazite cages connected via 8-ring windows possessed the highest adsorption capacity for ethene and exhibited the best activity in the ETP conversion. The decreasing amount of Bronsted acid sites after dealumination of H-SSZ-13 caused a prolonged lifetime of the catalyst in the ETP reaction. The reaction mechanism and deactivation behavior of H-SSZ-13 catalysts during the ETP process were investigated by in situ FT-IR, UV/Vis, GC–MS, TGA and 1 H MAS NMR methods. Ethene was rapidly oligomerized and converted into naphthalene-based carbenium ions, playing a significant role in the ETP reaction. The accumulation of these species lead to the formation of polycyclic aromatics, which are responsible for a total blocking of H-SSZ-13 pores, and cause the deactivation of the catalyst.