Chemistry Department, University of Ottawa, Ottawa, Ontario, K1N 6N5 Canada.
J Phys Chem A. 2011 Sep 29;115(38):10576-86. doi: 10.1021/jp202721k. Epub 2011 Sep 1.
This study examines critically the present state and utility of the Benson additivity schemes for estimating the enthalpy of formation of organic compounds. Old and new group additivity values (GAV) for a wide variety of compounds containing C, H and O are described and are revised where appropriate. When new terms are proposed, or old ones significantly altered, the rationale for so doing is provided. Corrections for such items as cis-isomer effects, gauche interactions, ring strain energies, double-bond position, conjugation effects, steric hindrance in aromatic molecules, etc. are included and discussed. Also provided are the thermochemical consequences of functional group replacements, in which one group in a molecule is substituted by another, thus providing quick short cuts to estimating new Δ(f)H(0) values. Results derived from the new additivity terms are consistent with those produced by computational chemistry methods in general use.
本研究批判性地考察了 Benson 加和规则在估算有机化合物生成焓方面的现状和效用。文中描述了各种含 C、H 和 O 的化合物的旧的和新的基团加和值 (GAV)，并在适当的情况下进行了修订。当提出新术语或对旧术语进行重大修改时，文中提供了这样做的基本原理。还包括并讨论了顺式异构体效应、 gauche 相互作用、环张力能、双键位置、共轭效应、芳香分子中的空间位阻等项的修正。此外，文中还提供了官能团取代的热化学后果，其中一个分子中的一个基团被另一个基团取代，从而为估算新的Δ(f)H(0)值提供了快捷的捷径。新加和项得出的结果与一般使用的计算化学方法得出的结果一致。
