Kinetic Solvent Effects in the Decomposition of Diphenyldiazomethane with Chloranil and 2,5-Dichloro-p-benzoquinone

Abstract

Abstract A kinetic study was made of the reactions of diphenyldiazomethane (DDM) with chloranil and 2,5-dichloro-p-benzoquinone (DCQ) at 30 °C in 20 and 22 aprotic solvents respectively (19 solvents are common). The chloranil reaction gave poly(tetrachlorohydroquinone benzhydryl ether) alone, obeying the second-order kinetic law. On the other hand, the DCQ reaction afforded bicyclic dione and poly(2,5-dichlorohydroquinone benzhydryl ether), also obeying the second-order kinetic law. All these rate constants generally increased with the solvent polarity and decreased with the solvent basicity. The kinetic solvent effects can be interpreted in terms of the effects of the polarity and the basicity of the solvents respectively to the transition and to the initial states. Thus, the multiple liner correlations of the logarithmic rate constants with a suitable function of the polarity and the basicity of the solvents are fairly successful. It was found that the basicity is more pronounced in the chloranil reaction than in the DCQ reaction, whereas the reverse can be said for the solvent polarity. These results were compared to those of the reactions of DDM with 2,3-dichloro-5,6-dicyanobenzoquinone and tetracyanoethylene.