Unimolecular dissociation reactions of methyl benzoate radical cation

J Phys Chem A. 2008 Nov 20;112(46):11590-7. doi: 10.1021/jp7108048. Epub 2008 Oct 23.

Abstract

The blackbody infrared radiation induced dissociation of methyl benzoate (C8H8O2(+*)) radical cation was investigated by using a Fourier transfer ion cyclotron resonance mass spectrometer equipped with a resistively heated (wire temperatures of 400-1070 K) wire ion guide. We observed product ion branching ratios that are strongly dependent upon wire temperature. At low temperatures (670-890 K) the major product ion C7H8 (+*) (m/z 92), which is formed by loss of CO2, and at higher temperatures (above 900 K), loss of methoxy radical ((*)OCH3) competes with loss of CO2. The energies of the various reactant ions and transition states for product ion formation were estimated by using density functional theory molecular orbital calculations, and a proposed mechanism for the dissociation chemistry of C8H8O2 (+*) involving a multistep rearrangement reaction is tested using the Master Equation formalism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Benzoates / chemistry*
  • Fourier Analysis
  • Hydrogen / chemistry
  • Infrared Rays
  • Kinetics
  • Quantum Theory
  • Temperature
  • Thermodynamics

Substances

  • Benzoates
  • methyl benzoate
  • Hydrogen