Selective hydrogenation of cinnamaldehyde in supercritical CO2 over Me?CeO2 (Me = Cu, Pt, Au): Insight of the role of Me?Ce interaction

PIQUERAS M.; PUCCIA V.; VEGA DA; VOLPE M.

APPLIED CATALYSIS B-ENVIRONMENTAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 185 p. 265 - 271

0926-3373

The performance of platinum, gold and copper catalysts with low (0.1 wt%) and high (2?3.8 wt%) metalloadings, supported on ceria with high surface area (240 m2/g), are contrasted in the hydrogenation ofcinnamaldehyde. Two reaction solvents were tested: single-phase near critical CO2 + isopropanol mixtureand supercritical CO2, both performed at 323K and 20 MPa. Exceptionally high activities were measuredunder supercritical CO2 for low loaded platinum and gold catalysts, while selectivities to cinnamyl alcoholwere in the range of 80?90%. The same trends, butin a lower degree, were observed for the correspondingcopper sample. The catalytic pattern in near critical condition was between the ones correspondingto supercritical CO2 and classical gas?liquid, as previously reported for platinum based catalysts. Theenhancement of the selectivity can be explained by a combined effect of the supercritical CO2?substrateinteraction and by the adsorption of cinnamaldehyde on sites of the metal?ceria interface. Based on theTPR and XPS characterizations, it was concluded that the rise of the activity would be due to a majorconcentration of these active sites in the low loaded samples.