Thermochemical properties and bond dissociation energies of C3-C5 cycloalkyl hydroperoxides and peroxy radicals: Cycloalkyl radical + 3O 2 reaction thermochemistry

Document Type

Article

Publication Date

7-19-2012

Abstract

Cyclic aliphatic hydrocarbons are major components in modern fuels; they can be present in the reactants, and they can be formed during the gas-phase oxidation processes. In combustion and thermal oxidation processes, these cyclics will form radicals that react with 3O 2 to form peroxy radicals. In this study, density functional theory and higher level ab initio calculations are used to calculate thermochemical properties and bond dissociation energies of 3-5-membered cycloalkanes, corresponding hydroperoxides, hydroperoxycycloalkyl radicals, and cycloalkyl radicals that occur in these reaction systems. Geometries, vibration frequencies, and thermochemical properties, δH f 298°, are calculated with the B3LYP/6-31 g(d,p), B3LYP/6-31 g(2d,2p), composite CBS-QB3, and G3MP2B3 methods. Standard enthalpies of formation at 298 K are evaluated using isodesmic reaction schemes with several work reactions for each species. Group additivity contributions are developed, and application of group additivity with comparison to calculated values is illustrated. Entropy and heat capacities, S°(T) and C p°(T) (5 K ≤ T ≤ 5000), are determined using geometric parameters and frequencies from the B3LYP/6-31 g(d,p) calculations. © 2012 American Chemical Society.

Identifier

84863899289 (Scopus)

Publication Title

Journal of Physical Chemistry A

External Full Text Location

https://doi.org/10.1021/jp302699s

e-ISSN

15205215

ISSN

10895639

First Page

7550

Last Page

7563

Issue

28

Volume

116

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