Kinetics of the hydrogenation of 1-octene catalyzed by [Ni(o-MeO-dppp)(OAc)(2)]

The kinetics of the nickel-catalyzed hydrogenation of 1-octene have been st udied using nickel(II) acetate in combination with the ligand 1,3-bis(di(o- methoxyphenyl)phosphanyl)propane (o-MeO-dppp). The effects of temperature a nd dihydrogen pressure, as well as the influence of the nickel and substrat e concentrations have been studied (T = 30-60 degreesC, p(H-2) = 30-60 bar, [Ni] = 0.35-2.81 mM, [1-octene] = 0.98-3.91 M, ligand/Ni = 1.1 in a mixtur e of dichloromethane and methanol). The kinetic study results in the surpri singly simple rate law r = k(cat)[Ni][1-octene]p(H-2). The kinetic data are consistent with a mechanism in which the terminating hydrogenolysis step o f the nickel-alkyl complex is the rate-determining step of the catalytic cy cle with all preceding steps at equilibrium. The first-order dependence on the substrate is confirmed by the results with other substrates, as the hyd rogenation rate strongly depends on the nature of the substrate. (C) 2001 E lsevier Science B.V. All rights reserved.