Kinetic isotope effects in oxidation reaction of C2H4 and C2D4 by p-benzoquinone in the Pd2+—HClO4—CH3CN—H2O system

• DOI: 10.1007/s11172-017-1830-8
• Publication Date: 2017-09-23T00:50:41Z
• Authors: I. V. Martynov; G. E. Efremov; O. N. Temkin
• Keywords: Kinetic isotope effect; Cationic polymerization; Benzoquinone

Kinetic 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)3 2+ the ratio between the initial reaction rates $$R_{{C_2}{H_4}} 0/R_{{C_2}{D_4}} 0$$ 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)+).