Cu–Co Synergism in Cu1−xCoxFe2O4—Catalysis and XPS Aspects

Vapour phase alkylation of phenol with methanol was carried out in a fixed-bed flow reactor over thermally calcined magnesium aluminium hydrotalcites, with Mg/Al atomic ratios from 3 to 10. The main products were anisole, o-cresol, and 2,6-xylenol. The influence of phenol-to-methanol molar ratio, reaction temperature and contact time on the product yields were examined. The activity of these catalysts was compared with MgO, Al2O3 and physically mixed MgO-AL2O3. Of the catalysts studied, Mg-Al 4.0:1 calcined hydrotalcite (CHT) was the most active. These catalysts are more active than magnesia and γ-alumina. On the basis of the results obtained, a suitable reaction pathway was proposed. The participation of combined acidic and basic sites in the calcined hydrotalcites for the alkylation of phenol with methanol over magnesium-aluminium calcined hydrotalcites has been suggested. Prior to the reaction, the catalyst precursors were characterised by X-ray powder diffraction and surface area measurements.

Alkylation of phenol with methanol over magnesium-aluminium calcined hydrotalcites

Ortho-Selective Methylation of Phenol Catalyzed by CeO2-MgO Prepared by Citrate Process

Selective ortho-methylation of phenol with methanol over copper manganese mixed oxide spinel catalysts

Supported metal single atom catalysts (SACs) present an emerging class of low-temperature catalysts with high reactivity and selectivity, which, however, face challenges on both durability and practicality. Herein, we report a single-atom Pt catalyst that is strongly anchored on a robust nanowire forest of mesoporous rutile titania grown on the channeled walls of full-size cordierite honeycombs. This Pt SAC exhibits remarkable activity for oxidation of CO and hydrocarbons with 90% conversion at temperatures as low as ~160 oC under simulated diesel exhaust conditions while using 5 times less Pt-group metals than a commercial oxidation catalyst. Such an excellent low-temperature performance is sustained over hydrothermal aging and sulfation as a result of highly dispersed and isolated active single Pt ions bonded at the Ti vacancy sites with 5 or 6 oxygen ions on titania nanowire surfaces. Supported metal single-atom catalysts face challenges on both durability and practicality. Here, the authors demonstrate that a sustained 90% diesel oxidation conversion at ~160 oC is achieved by single-atom Pt on TiO2 nanowire-array integrated catalytic converter.

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Activating low-temperature diesel oxidation by single-atom Pt on TiO 2 nanowire array.

Alkylation of phenol over simple oxides and supported vanadium oxides

Selective alkylation of phenol to 2,6-xylenol over vanadia—chromia mixed oxide catalysts

Propane combustion was studied on Pt(0.4%)/V2O5–Al2O3 catalysts containing up to 20% V2O5. The density, strength and nature of surface acid sites were determined by TPD of NH3 and FTIR spectra of adsorbed pyridine. The sample acidity increased with the vanadium content, essentially because the addition of vanadium oxide generated Bronsted acid sites. The Pt dispersion as determined by H2 chemisorption increased with increasing V2O5 loading. The sample activity for propane combustion was evaluated through both conversion versus temperature (light-off curves) and kinetically-controlled conversion versus time catalytic tests. The propane combustion turnover rate on Pt/V2O5–Al2O3 increased with the amount of vanadium, probably because the intrinsic Pt oxidation activity increases with the sample acidity.

Effect of V2O5 Loading on Propane Combustion over Pt/V2O5–Al2O3 Catalysts

A correlation of vanadia-chromia catalyst composition with acidity and selective C-alkylation activity of phenol

Fil: Garetto, Teresita Francisca. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Santa Fe. Instituto de Investigaciones en Catalisis y Petroquimica ; Argentina. Universidad Nacional del Litoral. Facultad de Ingenieria Quimica; Argentina

V. Venkat Rao

Papers

Alkylation of phenol over simple oxides and supported vanadium oxides

Selective alkylation of phenol to 2,6-xylenol over vanadia—chromia mixed oxide catalysts

Effect of V2O5 Loading on Propane Combustion over Pt/V2O5–Al2O3 Catalysts

A correlation of vanadia-chromia catalyst composition with acidity and selective C-alkylation activity of phenol

Deep Oxidation of Benzene on Pt/V2O5–TiO2 Catalysts