Grzegorz Lewandowski

Influence of reduction time of copper based catalysts: Cu/Al2O3 and CuCr2O4 on hydrogenolysis of glycerol

Influence of reduction time of copper based catalysts: Cu/Al2O3 and CuCr2O4 on hydrogenolysis of glycerol High activity of copper based catalysts for C-O bond hydro-dehydrogenation and their poor activity for C-C bond cleavage1 have prompted an attempt to apply such catalysts in the hydrogenolysis of glycerol to 1,2- and 1,3-propanediol. In the present study the influence of hydrogen reduction time of the Cu/Al2O3 and CuCr2O4 copper catalysts on glycerol conversion and selectivity of transformation to propanediols and by-products was studied. At first a general comparison was made between the commercial catalysts and those prepared by the co-precipitation method. As better results were obtained in the presence of catalysts prepared by co-precipitation, they were selected for further detailed studies of the influence of reduction time. For both prepared catalysts Cu/Al2O3 and CuCr2O4 the reduction time of 8 h was optimal. In the presence of Cu/Al2O3 catalyst the conversion of glycerol was 59.0%, selectivity of transformation to 1,2-propanediol 77.4% and selectivity to 1,3-propanediol 1.9%. In the presence of CuCr2O4 the glycerol conversion was 30.3% and selectivity to 1,2-propanediol 67.3%.

Kinetics of 2-methyl-2-pentene epoxidation with tert-butyl hydroperoxide

The reaction rate at the initial period during the epoxidation of 2-methyl-2-pentene with tert-butyl hydroperoxide in the presence of Mo(CO)6 as catalyst varies linearly in the range of lower concentrations of olefin, hydroperoxide and catalyst. The reaction is losing the first order character in the region of higher concentrations due to the inhibition with the reaction products. This finds the confirmations in a discrepancy between the concentration and the instantaneous (temporal) reaction order.

The Influence of Technological Parameters on Hydrogenolysis of Glycerol in the Presence of CuCr2O4 Catalyst

Abstract Glycerol hydrogenolysis was studied in the presence of CuCr2O4 catalyst both commercially available and prepared by co-precipitation. The two catalysts were characterised by transmission electron microscope (TEM), X-ray diffraction (XRD), Raman spectroscopy and X-ray microanalyses. CuCr2O4 prepared by co-precipitation method was used to study the influence of technological parameters on glycerol hydrogenolysis to 1,2- and 1,3- propanediol. The effect of temperature, hydrogen pressure, glycerol concentration, amount of catalyst and stirring speed was investigated.

Epoxidation of chloromethylbutenes by t-butyl hydroperoxide

The epoxidation of chloromethylbutenes by t-butyl hydroperoxide in the presence of Mo(CO) 6 has been investigated. The influence of important parameters on hydroperoxide conversion, selectivity of transformation to epoxy compound in relation to hydroperoxide used, yield in relation to olefin introduced (response function) has been described by regression equations in the form of a second order polynomial. The optimum values of: temperature, olefin to hydroperoxide molar ratio, reaction time, molar ratio of Mo(CO) 6 catalyst to hydroperoxide, ensuring the maximum values of these functions, have been determined.