A new mechanistic proposal for the aromatic cycle of the MTO process based on a computational investigation for H-SSZ-13. Issue 11 (6th May 2022)

• Record Type: Journal Article
• Authors: Plessow, Philipp N.; Enss, Annika E.; Huber, Philipp; Studt, Felix
• Is Part Of: Catalysis science & technology. Volume 12:Issue 11(2022)
• Page Start: 3516
• Page End: 3523
• Publication Date: 2022-05-06
• Subjects: Catalysis -- Periodicals; 541.395
• DOI: 10.1039/d2cy00021k
• Languages: English
• ISSNs: 2044-4753

Abstract

Abstract : The paring mechanism of the aromatic cycle of the hydrocarbon pool is reinvestigated based on the heptamethylbenzenium cation adsorbed within H-SSZ-13 using quantum chemical calculations. Abstract : The paring mechanism of the aromatic cycle of the hydrocarbon pool is reinvestigated based on the heptamethylbenzenium cation adsorbed within H-SSZ-13 using quantum chemical calculations. Based on the outcome of our calculations we propose a modified mechanism to that presently existing in the literature, where ring contraction starts from hexamethylmethylenecyclohexadiene. After protonation and ring contraction, the unsaturated methylene side chain remains throughout this mechanism. This new mechanistic proposal avoids the formation of antiaromatic intermediates present in current proposals for the paring mechanism. The barriers for the modified paring mechanism are found to be significantly lower than those for the original proposal, being in the range from 130–150 kJ mol −1 at 400 °C and are thus accessible at typical MTO conditions.