Open AccessElectrostatic effects on disproportionation equilibria: dihalogeno and methyl derivatives of benzene
Author(s) -
Zdeněk Friedl
Publication year - 1984
Publication title -
canadian journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.323
H-Index - 68
eISSN - 1480-3291
pISSN - 0008-4042
DOI - 10.1139/v84-398
Subject(s) - disproportionation , chemistry , benzene , steric effects , computational chemistry , gas phase , standard enthalpy of formation , radical disproportionation , thermodynamics , organic chemistry , catalysis , physics
The disproportionation equilibria of benzene derivatives X—Ph—Y (X, Y = F, Cl, CH 3 ) in the gas phase, were calculated from their enthalpies and entropies of formation at 298 K. Calculations of the electrostatic energy based on the point charges approximation method predict reasonably well the reaction enthalpies of all meta-benzene derivatives and predict nearly as well the other fluoro- and methyl-derivatives. The theory fails if strong resonance and/or steric interactions are present. The generally better ability of the electrostatic theory to treat disproportionation or conformational equilibria than the proton transfer reactions is also discussed.