Decomposition of Benzene during Impacts in N-2-dominated Atmospheres

0570785 - ÚFCH JH 2024 RIV GB eng J - Journal Article
Petera, Lukáš - Knížek, Antonín - Laitl, Vojtěch - Ferus, Martin
Decomposition of Benzene during Impacts in N-2-dominated Atmospheres.
Astrophysical Journal. Roč. 945, č. 2 (2023), č. článku 149. ISSN 0004-637X. E-ISSN 1538-4357
R&D Projects: GA ČR(CZ) GA21-11366S
Institutional support: RVO:61388955
Keywords : laboratory astrophysics * infrared spectroscopy * exoplanet atmospheres
OECD category: Physical chemistry
Impact factor: 4.9, year: 2022
Method of publishing: Open access

Benzene is a simple neutral aromatic compound found in molecular clouds, comets, and planetary atmospheres. It has been confirmed on Jupiter, Saturn, Titan, and is expected on exoplanets. In this paper, the decomposition of benzene in a simulated asteroid or comet impact into an N-2-dominated atmosphere was investigated. The impact plasma was simulated with laser-induced dielectric breakdown and the gas phase decomposition products were observed using high-resolution Fourier transform infrared spectroscopy. The gas phase decomposition products involve mainly HCN, C2H2, and smaller amounts of CH4 with yields of 3.1%-24.0%, 0-11.7%, and 0.5%-3.3%, respectively. Furthermore, in presence of water, benzene also produces CO and CO2 with yields of 2.4%-35.1% and 0.01%-4.8%, respectively. The oxidation state of the product mixture is proportional to the water content. Apart from that, a black-brownish solid phase is formed during the experiments, which makes up about 60% of the original carbon content. Our results therefore show that in anoxic N-2-dominated planetary atmospheres, impacts might lead to the depletion of benzene and the formation of HCN, C2H2, and CH4 and, in the presence of water, to the formation of CO and CO2.
Permanent Link: https://hdl.handle.net/11104/0342126