Collect. Czech. Chem. Commun. 1987, 52, 2492-2499

A mathematical modelling of acid catalyzed decomposition of 3-methyl-1,3-diphenyltriazene

Oldřich Pytela, Petr Svoboda and Miroslav Večeřa

Department of Organic Chemistry, Institute of Chemical Technology, 532 10 Pardubice


The effect of acids on the decomposition of 3-methyl-1,3-diphenyltriazene has been studied in aqueous ethanol (40% (v/v) ethanol). The dependences found between the rate constant and acid concentration have been analyzed by means of non-linear regression using models including the specific and general catalysis and formation of associates between the substrate and the buffer components. The substrate has been found to form electrostatic associates with the conjugated base of acid. The complex formed is decomposed with the assistance of the proton or a general acid in the rate-limiting step to form the product. The Bronsted coefficient α = 0.81 has been found. Investigation of the activation parameters supports the earlier conclusions, indicating a dependence between the reaction mechanism and composition of the aqueous organic solvent.