Theoretical studies on the isomerization and dissociation of the acrolein ions

Nine isomers of the acrolein ion (C3H4O.+) and the relevant transition states connecting them were calculated at HF/6-31G* and B3LYP/6-31G* levels. The nine dissociation channels, C2H4.+ (+CO), C3H3O+ (+H-.), HCO+ (+C2H3.), H2CO.+ (+C2H2), C2H3+ (+HCO.), HCOH.+ (+CH2), C2H2.+ (+H2CO), CO.+ (+C2H4), and C2H2.+ (+HCOH), were studied and the transition states to all product channels were found. The lowest energy dissociation path to CO loss involves a distonic ion, (CH2CH2CO)-C-. and the methylketene ion, CH3CHCO.+ the latter being the most stable C3H4O.+ isomer. The heats of formation of the C3H4O.+ isomers are obtained based on the known heats of formation of C2H4.+ and CO and the calculated relative energies. (C) 2002 Elsevier Science B.V. All rights reserved.