New reactors and methods for the investigation of homogeneous catalysis

New methods and reactors for the kinetic investigation of homogeneous catalysis are described. These are oriented towards the minimisation of the amount of catalyst required for testing new catalytic reactions, kinetics determination and/or catalyst selection. The use of the centrifugal partition chromatograph (CPC) as a chromatographic catalytic reactor for steady-state and transient kinetics is reported. Examples are given which involve monophasic and biphasic reductions. The former is the enantioselective reduction of acetophenone to 2phenylethanol by isopropanol catalysed by a Rh/chiral diamine system. The biphasic reductions are: (i) the reduction of benzaldehyde into benzylic alcohol catalysed with a Ru/TPPTS complex and (ii) the reduction of dimethylitaconate into dimethylmethylsuccinate catalysed with a Rh/TPPTS complex, both reductions taking place in cyclohexane/water mixtures with sodium formate as the hydrogen transfer reagent. Finally, for first order reactions, analytical solutions are found which demonstrate that kinetic parameters can be readily obtained by using the CPC as a chromatographic reactor in the transient (pulse) mode. (C) 1998 Elsevier Science S.A. All rights reserved.