Thermokinetic study on the inactivation reactions of 1-methylphthalazinium ylids

The present paper consists in a thermokinetic study on the dimerization reactions of 1-methylphthalazinium ylids with NO2 (ylid 1) and, respectively, O CH3 (ylid 2) substituents in the p position of the benzoyl radical bound to the ylidic carbanion. From experimental data, the reaction order and rate constants have been calculated. The reaction order n = 2 confirmed the ylids dimerization reactions, while the values of the rate constants, k2 = 3.093×10-2 L/mol s and, respectively, 2.16×10-1 L/mol s for the dimerization of ylids 1 and 2 made evident the higher reactivity of ylid 2 versus ylid 1. The same conclusion is also supported by the results of the thermodynamic study based on the chemical affinity of the two reactions, when Aodim,1 < Aodim,2.