THE KINETICS AND MECHANISM OF HOMOGENEOUS HYDROGEN TRANSFER FROM ALCOHOLS TO BENZYLIDENEACETONE CATALYZED BY DICHLOROTRIS(TRIPHENYLPHOSPHINE)RUTHENIUM(II)

Article abstract of DOI:10.1016/S0022-328X(00)82237-8

Dichlorotris(triphenylphosphine)ruthenium(II) catalyzes the hydrogen transfer from alcohols to olefins.Kinetic studies were carried out at 170-190 deg C using the ruthenium(II) complex as homogeneous catalyst, benzyl alcohol, diphenylcarbinol, methylphenylcarbinol and benzoin as the hydrogen donors, benzylideneacetone as the hydrogen acceptor, and dibenzyl ether as a solvent.The IR spectra and GLC were used to monitor the reaction and the isotope effects were determined in order to elucidate the role of the catalyst and the mechanism of hydrogen transfer.In the reaction mixture RuCl2(PPh3)3 is converted by the alcohols into RuH2(CO)(PPh3)3, which then hydrogenates benzylideneacetone.The kinetic data are compatible with the expression. reaction rate = k_obs The rate-determining step of this reaction is considered to be the transfer of hydrogen from the alcohol to a ruthenium species.