LAUSR

AbstractKinetic isotope effects (KIE) have been measured for oxidation reactions of ethylene by p-benzoquinone in Pd2+—MeCN—H2O—HClO4 system. Under the conditions of preferred formation of complex Pd(MeCN)(H2O)32+ the ratio between the initial reaction rates $$R_{{C_2}{H_4}} 0/R_{{C_2}{D_4}} 0$$RC2H40/RC2D40 is equal to 1.14±0.06 and is close to the KIE for classical chloride systems. Based on the obtained results and previous data for C2H4—C2D4 and H2O—D2O (0.97±0.12) systems, the slow step was proposed in the reaction mechanism–a trans-addition of water molecule to the cationic p-complex LPd(H2O)2(CH2CH2)2+ with formation of metalcarben-ium ion solvated by water molecule (LPd(H2O)2(CH2CH2O+H2)+).