Premium
Kinetics and mechanism of the thermal decomposition reaction of dihydro‐3,6‐diphenyl‐5‐benzyl‐1,2,4,5‐trioxazine
Author(s) -
Cafferata Lázaro F. R.,
Nojima Masatomo,
Yamakoshi Hideyuki
Publication year - 1996
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/(sici)1097-4601(1996)28:1<21::aid-kin3>3.0.co;2-o
Subject(s) - chemistry , thermal decomposition , toluene , reaction rate constant , benzene , decomposition , solvent , kinetics , methanol , scavenger , order of reaction , atmospheric temperature range , reaction mechanism , medicinal chemistry , chemical decomposition , photochemistry , organic chemistry , radical , catalysis , thermodynamics , physics , quantum mechanics
The thermal decomposition reactions of dihydro‐3,6‐diphenyl‐5‐benzyl‐1,2,4,5‐trioxazine (DHT) in the initial concentrations and temperature ranges of 0.004–0.013 M and 353–393 K, respectively, have been investigated in benzene, toluene, and methanol solutions. In these solvents the reaction follows a first‐order kinetic law up to ca. 50% DHT conversions. However, at the higher temperatures and higher initial concentrations, an induced decomposition reaction of the DHT molecule is observed, which is suppresed by the addition of a free radical scavenger. The pseudo‐first‐order rate constant values for the reactions of the trioxazine in acetic acid solution (0.004 M) in the temperature range of 313–323 K, lead to activation parameters significantly different from those of the unimolecular thermolysis in other media. This supports a marked effect of the solvent on that reaction. The kinetics and the nature of the products observed in the DHT thermolysis favors a general stepwise mechanism of decomposition which resembles the type of reaction already postulated for other cyclic peroxides in solution. © 1996 John Wiley & Sons, Inc.