Dissociation dynamics of acetyl chloride and cis-trans isomerisation of methoxychloro carbene and chlorohydroxymethyl carbene

Sumathi, R and Chandra, AK (1994) Dissociation dynamics of acetyl chloride and cis-trans isomerisation of methoxychloro carbene and chlorohydroxymethyl carbene. In: Chemical Physics, 181 (1-2). pp. 73-84.

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Abstract

The potential energy surface of acetyl chloride in its electronic ground and lowest adiabatic triplet $(T^A)$ states has been inves- tigated with ab initio methods, at 3-2lG,6-3lG* and MP2/6-3lG*//6-31G* levels. The molecular elimination of acctyl chloride $(S_o)$ to $CH_3Cl+CO, HCl + CH_2-C-O$ and : $CH_2 + HCOCl,$ the unimolecular rearrangement to methoxychloro carbene and chlo- rohydroxymethyl carbene and the radial dissociation of $S_o$ and $T^A$ states of acetyl chloride to $Cl^. + CH_3C^.$ and $CH_3^. + ^.COCl$ have been examined. All stationary points on the potential energy surfaces have been identified. At all stationary points, the appropriate zero point vibrational energy corrections are taken into account. The equilibrium structures of the lowest adiabatic triplet $(T^A)$ and the transition state for C-Cl cleavage from the triplet state were also examined at the CIS/6-3 lG* (configuration interaction singles) level. On the $T^A$ surface, $CH_3COCl$ has activation barriers of 8-14 kcal/mol for dissociation into various radicals. The hot acetyl chloride molecules on the $S_o$ surface can undergo various processes of which the molecular elimination to ketene and hydrogen chloride is energetically most favourable. The barriers for the rearrangement processes to carbenes in acetyl chloride are very high in contrast to those of acetaldehyde and fluoroformaldehyde. These carbenes, substituted with electron donating groups, $OCH_3$ and OCl, are singlet in their ground state.

Item Type:	Journal Article
Publication:	Chemical Physics
Publisher:	Elsevier
Additional Information:	The copyright of this article belongs to Elsevier.
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	30 Jun 2006
Last Modified:	19 Sep 2010 04:29
URI:	http://eprints.iisc.ac.in/id/eprint/7767

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