MNDO calculation of reaction heats determininig the mechanism of antioxidant action of the phenols in polyolefins

✍ Scribed by A. Bolotin; P. Pipiraité

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 211 KB
• Volume: 38
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/qua.560380217

✦ Synopsis

Abstract

The quantum chemical substantiation of antioxidant action of the substituted phenols in polyolefins is presented. The electronic structure of the phenols, phenoxy radicals, and model products of polyolefin destruction was calculated by the MNDO method. On the basis of the presumed chemical reactions, the electronic structure criteria determining the antioxidant activity are selected. These are the O—H bond dissociation energy in phenols and the charge on the atoms of π‐system in phenoxy radicals. The competition between these reactions takes place, and the calculation of the reaction heats shows that the reactions with the formation of the substituted quinones are in preference to the reactions in which the peroxycyclo‐hexadienones are formed.