Anharmonic Effect of N‐Propyl Peroxy Dissociation. Issue 12 (18th November 2016)

• Record Type: Journal Article
• Authors: Song, Liguo; Pan, Xinxiang; Li, Qian; Ding, Yang; Yao, Li; Lin, Sheng‐Hsien
• Is Part Of: Journal of the Chinese Chemical Society. Volume 63:Issue 12(2016:Dec.)
• Page Start: 1038
• Page End: 1050
• Publication Date: 2016-11-18
• Subjects: Rate constant -- RRKM theory -- Anharmonic effect; Chemistry -- Periodicals; Electronic journals; 540.5
• DOI: 10.1002/jccs.201600091
• Languages: English
• ISSNs: 0009-4536

Abstract

Abstract : The anharmonic and harmonic dissociation rate constants of alkylperoxy (RO2 ) in different pathways, as well as those for the reactions of the n ‐propyl peroxy radical, were calculated using the Rice–Ramsperger–Kassel–Marcus (RRKM) theory. When the temperature/total energy increased, the rate constants of the different pathways varied independently, causing changes in the dominating/leading products. Anharmonic rate constants were larger than harmonic rate constants, and their difference increased with increasing temperature/energy. Therefore, the anharmonic effect cannot be neglected. The rate‐determining steps of CH3 CH2 CH2 OO dissociation are discussed. Then the anharmonic effect was found clearly for CH3 CH2 CH2 OO dissociation, especially for the hydroperoxyalkyl radical (QOOH) dissociation. At low temperature, the rate constants were similar to those found from experiment, which indicated the RRKM theory was suitable for calculating the dissociation rates of RO2 species. Abstract : Harmonic and anharmonic rate constants of n ‐propyl peroxy dissociation were calculated under canonical and microcanonical cases. The anharmonic effect was enhanced with the increase of temperature or energy. The QOOHs reactions were found faster than CH3 CH2 CH2 OO dissociation, which indicated that CH3 CH2 CH2 OO dissociation was the rate‐determining step of the reaction.