The formation of ethylidene in the thermal decomposition of ethane: a theoretical and experimental study Nadav Genossara b , Sharona Atlasa a,c , Dana Breskera a , Shani Har-Lavana a , Uri Zamira a , Patrick Hembergerd d , Thanh Lam Nguyene e , Joshua H. Barabana a a Department of Chemistry, Ben-Gurion University of the Negev, Israel, b IAEC, Tel Aviv, Israel, c NRCN, Beer Sheva, Israel, d Laboratory for Synchrotron Radiation and Femtochemistry, Switzerland, e Quantum Theory Project, Department of Chemistry, USA The unimolecular decomposition of ethane remains incompletely characterized, despite being a fundamental reaction in various thermal processes. Experimental data based on direct observations of the various decomposition products such as ethyl radical or ethylidene is lacking, in particular. We present experimental results from a microreactor study performed at the Swiss Light Source, including isotopically labeled experiments. Using a coincidence detection setup, we manage to observe the formation of the various isotopologues of ethylene, methyl radicals, and ethyl radicals, the latter directly observed in this reaction system for the first time, to the best of our knowledge. Along with CFD simulations coupled to high-accuracy ab initio kinetic analyses based on semi-classical transition state theory, we infer that the mechanism for the formation ethane occurs through two subsequent H atom loss steps, and recover hints for the formation of the elusive high-energy isomer of ethylene, ethylidene, during the reaction.
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© The Author(s), 2022
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