Abstract Azoesters of the type PhR 1 R 2 CN= NC R 2 R 1 Ph (R 1= alkyl, R 2= rest of carboxylic acids) were synthesized; their 10h-half-life-temperatures and energies of activation of the decomposition were determined. The decomposition of the azo compounds follows a law of first order. The variation of the substituents R 1 and R 2 gives information about the effect on the decomposition of the azo compounds. The azoesters of acetic acid ...