Non-energetic Formation of Ethanol via CCH Reaction with Interstellar H2O Ices. A Computational Chemistry Study
Perrero, Jessica (Universitat Autònoma de Barcelona. Departament de Química)
Enrique-Romero, Joan (Universitat Autònoma de Barcelona. Departament de Química)
Martínez-Bachs, Berta (Universitat Autònoma de Barcelona. Departament de Química)
Ceccarelli, Cecilia (Univiversità Grenoble Alpes. Institut de Planétologie et d'Astrophysique de Grenoble)
Balucani, Nadia (Università di Perugia. Dipartimento di Chimica, Biologia e Biotecnologie)
Ugliengo, Piero (Università Degli Studi di Torino. Dipartimento di Chimica)
Rimola Gibert, Albert (Universitat Autònoma de Barcelona. Departament de Química)

Data:	2022
Resum:	Ethanol (CHCHOH) is a relatively common molecule, often found in star-forming regions. Recent studies suggest that it could be a parent molecule of several so-called interstellar complex organic molecules (iCOMs). However, the formation route of this species remains under debate. In the present work, we study the formation of ethanol through the reaction of CCH with one HO molecule belonging to the ice as a test case to investigate the viability of chemical reactions based on a "radical + ice component" scheme as an alternative mechanism for the synthesis of iCOMs, beyond the usual radical-radical coupling. This has been done by means of DFT calculations adopting two clusters of 18 and 33 water molecules as ice models. Results indicate that CHCHOH can potentially be formed by this proposed reaction mechanism. The reaction of CCH with HO on the water ice clusters can be barrierless (because of the help of boundary icy water molecules acting as proton-transfer assistants), leading to the formation of vinyl alcohol precursors (HCCOH and CHCHOH). Subsequent hydrogenation of vinyl alcohol yielding ethanol is the only step presenting a low activation energy barrier. We finally discuss the astrophysical implications of these findings.
Ajuts:	European Commission 741002 European Commission 865657 European Commission 811312 Agencia Estatal de Investigación CTQ2017-89132-P Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-1323
Nota:	Altres ajuts: acords transformatius de la UAB
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Interstellar medium ; Astrochemistry DFT ; Icoms ; Grains
Publicat a:	ACS earth and space chemistry, Vol. 6, Issue 3 (March 2022) , p. 496-511, ISSN 2472-3452

DOI: 10.1021/acsearthspacechem.1c00369
PMID: 35330630

16 p, 4.4 MB

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