Promoter effect of Pd in CuCr2O4 catalysts on the hydrogenolysis of glycerol to 1,2-propanediol

Abstract

CuCr 2 O 4 catalysts containing various amounts of Pd (Pd-CuCr) were prepared by a co-precipitation method and examined for use in the conversion of glycerol to 1,2-propanediol (1,2-PDO). Pd was observed to be highly dispersed in a CuCr 2 O 4 spinel structure and conferred unique reduction characteristics of a CuCr 2 O 4 catalyst. After reduction, the amounts of surface exposed Cu 0 species and occluded hydrogen species were much larger in the case of added Pd, the Pd-CuCr catalyst, compared to a pure copper chromite catalyst. The Pd-CuCr catalyst utilized hydrogen very efficiently, resulting in an enhancement in the catalytic activity for the conversion of glycerol to 1,2-PDO, even at a relatively low hydrogen pressure. The Pd 0.5 -CuCr catalyst (containing 0.5 wt% of Pd) showed a total yield of 93.9%, with a selectivity approaching 100% for 1,2-PDO at a hydrogen pressure of 4 MPa. In a kinetic study, the effects of H 2 pressure and the concentration of glycerol on the initial rate were examined. Based on the results, the palladium promoter (Pd-CuCr) enhanced the rate constant by about 1.7 times compared with copper chromite. The results provide a basis for the production of 1,2-PDO from glycerol using a process which is both environmentally benign and has improved economics.

Recent advancements in catalytic conversion of glycerol into propylene glycol: A review

“…These Ru clusters generated active hydrogen sites that were transferred to the Cu surface via hydrogen spill-over enhancing the hydrogenolysis reactions. Similar hydrogen spill-over phenomena with glycerol conversion more than 88% and 100% PG selectivity was reported by Xia et al and Kim et al using Pd x Cu 0.4 Mg 5.6-x Al 2 (OH) 16 CO 3 ) and Pd-CuCr 2 O 4 catalysts, respectively (86,87). Recently, Liu's group studied the glycerol hydrogenolysis over Ru-Cu catalysts supported on different support materials including SiO 2 , Al 2 O 3 , NaY zeolite, TiO 2 , ZrO 2 , and HY zeolite (88).…”

Vapour phase hydrogenolysis of glycerol to propanediols over Cu/SBA‐15 catalysts

“…This may be due to the presence of strong acidic sites which favor the formation of degradation products. The effect of acidic properties of the catalysts on glycerol hydrogenolysis has been investigated by several researchers . Results suggest that the catalytic performance of Cu/SBA‐15 catalysts is highly attributable to the metal dispersion as well as the acidity of catalysts, as evidenced from N 2 O decomposition and NH 3 ‐TPD results.…”

Nanostructured Metal Catalysts for Selective Hydrogenation and Oxidation of Cellulosic Biomass to Chemicals

“…With negligible adsorption of OH − as the promoter and 1,2‐PDO, this model fitted the experimental data very well in the range of 180–200 °C. An empirical kinetic model was proposed for Pd‐CuCr 2 O 4 catalyst . The addition of Pd to CuCr 2 O 4 facilitated the conversion of glycerol.…”