Kinetic Effects of Electrolytes in Oxidation of Sodium,Potassium,and Tetrabutylammonium 1-Acetonyl-2,4-dinitrocyclohexa-2,5-dienides with 1,4-Benzoquinone

摘要

The kinetics of oxidation of sodium, potassium, and tetrabutylammonium 1-acetonyl-2,4-dinitrocyclohexa-2,5-dienides with 1,4-benzoquinone in acetonitrile and tetrahydrofuran was studied spectrophotometrically. The reaction is of the first order with respect to the substrate and quinone and of the total second order. In the course of the process, a charge-transfer complex with an absorption maximum at about 716 nm is formed, accelerating the reaction. The rates of its accumulation and consumption increase with increasing concentrations of reactants and decrease on addition of sodium or tetrabutylammonium perchlorate. The factors facilitating association of #sigma# adducts in solution (increase of the concentration in THF,addition of NaClO_4 or [N(C_4H_9)_4]ClO_4), decelerate oxidation owing to decrease of the negative charge in the cyclohexadienide ring of the contact ion pair of the #sigma# adduct as compared to the free ion.