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Reaction of phenoxy radical with nitric oxide
Author(s) -
Yu T.,
Mebel A. M.,
Lin M. C.
Publication year - 1995
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.610080110
Subject(s) - chemistry , reaction rate constant , ab initio , equilibrium constant , atmospheric temperature range , activation energy , transition state theory , ab initio quantum chemistry methods , computational chemistry , molecule , kinetics , thermodynamics , organic chemistry , physics , quantum mechanics
The associationof C 6 H 5 O with NO was studied with the cavity‐ring‐down method by directly monitoring the decay of C 6 H 5 O in the presence of varying, excess amounts of NO. The biomolecular rate constant determined in the temperature range 297‐373 K can be effectively rate constant determined in the temperature range 297–373 K can be effectively represented by k 1 = 10 − 12 · 12 ± 0.24 e(194±185)/rcm 3 molecule −1 with a negative activation energy of 0.8 kcal mol −1 (1 kcal = 4.184 kJ). In order to understand better the mechanism of the reaction, ab initio molecular orbital calculations were also carried out at the MP4(SDQ)/6‐31G* level of theory using the HF optimized geometries. The molecular structues and energetics of five C 6 H 5 N 1 O 2 isomers were calculated. Among them, the most likely and stable association product, phenyl nitrite (C 4 H 5 ONO), was found to be 17 kal mol −1 below the reactants, C 6 H 5 O + NO. Combining the measured rate constant and the calculated equilibrium constant for the association reaction, C 6 H 5 O + NO = C 6 H 5 ONO the rate constant for the unimolecular decomposition of C 6 H 5 ONO was obtained as k −1 = 4.6 × 10 15 E −8580/T s −1 . The relatively large frequency factor suggests that a loose transition state was involved in the reaction, akin to those of its alkyl analogs (RONO, R CH 3 , C 2 H 5 , etc.).