Investigation of Ethanol Conversion on H-ZSM-5 Zeolite by <i>in Situ</i> Solid-State NMR
Shu Zeng, Junjie Li, Nan Wang, Wenna Zhang, Yingxu Wei, Zhongmin Liu, Shutao Xu
Abstract
The process of ethanol conversion on H-ZSM-5 zeolite with different Si/Al ratios was well-studied with the assistance of in situ solid-state 13C NMR experiments under continuous flow (CF) and batch-like conditions, respectively. Except for the adsorbed ethanol and diethyl ether, the surface ethoxy species, triethyloxonium ion, and even cyclopentadienyl cations were captured on the working catalyst and identified as active intermediates in ethanol conversion. The evolution process of these captured intermediates was exhaustively illustrated subsequently. Especially, two kinds of configuration of the adsorbed ethanol, referred to as side-on and end-on orientations, and diethyl ether (DEE) with an activated state were also revealed in this work. In addition, involved as one of the important active intermediates in MTO reaction, the cyclopentadienyl cations were also speculated to play important roles in the ethanol conversion and have close relation to propene formation.