Formation of interstellar vinyl alcohol via simple radical processes: Theoretical study

Density functional theory calculations at the B3LYP/6‐31++G( d,p ) level of theory were employed to verify whether the formation of vinyl alcohol (VA) in the interstellar medium can be explained by reactions of common and abundant interstellar species such as acetylene, radicals C 2 , HC C · , · OH, and H · . Several reaction sequences are possible. They include radical combinations, which proceed without activation barriers and are highly exothermic. The reactions of closed‐shell species acetylene and HCC‐OH with hydrogen atoms, as well as H‐transfer and OH‐rotation processes, might require activation energy. Nevertheless, either the corresponding transition states lay below the reactant level or there are alternative routes that involve no transition states at all, such as the reaction sequences C 2 → HCC · → HCCH → trans ‐ syn ‐HC( · )CH‐OH → syn ‐VA; C 2 → HCC · → syn ‐≔CCH‐OH → ( trans or cis )‐ syn ‐HC( · )CH‐OH → syn ‐VA; and C 2 → · CC‐OH → syn ‐:CCH‐OH → ( trans or cis )‐ syn ‐HC( · )CH‐OH → syn ‐VA.