No abstract

This work focuses on the activity, selectivity, and characterization of alumina and zirconia supported Ru(2.5%wt.)-Cu(2.5%wt.) bimetallic catalysts to produce 1,2-propanediol (1,2-PDO) from glycerol hydrogenolysis. Characterization techniques included XRD, BET, TEM, H2 chemisorption, TPR and DRIFTS. Turnover frequencies were obtained for batch reactions ran at different temperatures. At 473 K and 2.5 MPa of dihydrogen, a conversion of 45% of glycerol with 94% selectivity towards 1,2-PDO was found when the Ru(2.5%wt.)-Cu(2.5%wt.)/Al2O3 was used. Recycle experiments were done for the monometallic catalysts, in which Ru/Al2O3 showed a better performance.

The kinetics of nitrate hydrogenation in water over niobia- and alumina-supported Pd-Cu catalysts were examined. A Langmuir-Hinshelwood kinetic model fitted concentration data, providing consistent kinetic and thermodynamic parameters. The kinetic model assumed a bimolecular surface reaction as the rate-determining step, with two types of sites. Pd-Cu/gamma-Al2O3 was active and selective under the reaction conditions. However, Pd-Cu/Nb2O5 deactivated during time on stream, and a deactivation function was added to the kinetic model to best fit the experimental data.