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Mechanism of acid‐catalysed decomposition of 3‐alkyl‐1,3‐diphenyltriazenes by trichloroacetic acid in hexane
Author(s) -
Pytela Oldřich,
Bednář Roman,
Kaválek Jaromír
Publication year - 2004
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.734
Subject(s) - chemistry , trichloroacetic acid , isopropyl , triazene , dimer , solvent , reaction rate constant , alkyl , decomposition , hexane , monomer , reaction mechanism , medicinal chemistry , organic chemistry , photochemistry , kinetics , catalysis , polymer , physics , quantum mechanics
Eight 3‐alkyl‐1,3‐diaryltriazenes with methyl, ethyl, propyl, butyl, pentyl, isopropyl, sec ‐butyl and cyclohexyl substituents were synthesized and their rate constants of decomposition by trichloroacetic acid (0.01–0.25 mol dm −3 ) in hexane at 25°C were measured. The kinetic model and mechanism thereof were studied by modelling of the dependences of k obs on the concentration of trichloracetic acid. On the basis of this kinetic model and the interpretation of solvent effects, a reaction mechanism was suggested according to which the triazene reacts with monomer and obviously also opens the dimer of trichloroacetic acid in a single reaction step. At the same time, a non‐reactive associate between the N1 nitrogen of triazene and two molecules of trichloroacetic acid is formed in the reaction mixture. The equilibrium and rate constants depend on the addition of trichloroacetic acid as the co‐solvent. Copyright © 2004 John Wiley & Sons, Ltd.