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Their complex surface chemistry and high oxygen lattice mobilities place mixed-metal oxides among the most important families of materials. Modulation of stoichiometry in mixed-metal oxides has been shown to be a very powerful tool for tuning optical and catalytic properties. However, accessing different stoichiometries is not always synthetically possible. Here, we show that the thermal decomposition of the recently reported metal-organic framework MUV-101(Fe, Ti) results in the formation of carbon-supported titanomaghemite nanoparticles with an unprecedented Fe/Ti ratio close to 2, not achievable by soft-chemistry routes. The resulting titanomaghemite phase displays outstanding catalytic activity for the production of CO from CO2via the reverse water-gas shift (RWGS) reaction with CO selectivity values of ca. 100% and no signs of deactivation after several days on stream. Theoretical calculations suggest that the reaction proceeds through the formation of COOH∗ species, favoring in this way CO over other byproducts.

A three‐dimensional, mesoporous, silicate containing zirconium, Zr‐TUD‐1, was synthesized by a direct hydrothermal treatment method with triethanolamine as a complexing and templating reagent to ensure that zirconium was incorporated as isolated atoms. The mesoporosity of Zr‐TUD‐1 was confirmed by X‐ray diffraction (XRD), N2sorption and high‐resolution transmission electron micrograph (HR‐TEM) studies. The nature and strength of the Lewis acid sites present in Zr‐TUD‐1 were evaluated by FTIR studies of pyridine adsorption and temperature‐programmed desorption of ammonia. FTIR, X‐ray photoelectron spectroscopic (XPS) and UV/Vis spectroscopic studies showed that, at Si/Zr ratios of 25 and higher, all the zirconium was tetrahedrally incorporated into the mesoporous framework, while at low Si/Zr ratios, a small part of the zirconium was present as ZrO2nanoparticles. Zr‐TUD‐1 is a Lewis acidic, stable and recyclable catalyst for the Meerwein–Ponndorf–Verley (MPV) reaction and for the Prins reaction.

A straightforward process for the preparation of optically active protected cyanohydrins, important building blocks for the synthesis of drugs and agrochemicals, has been established. Lipase B from Candida Antarctica (CAL-B) catalysed the kinetic resolution of racemic cyanohydrin acetates under mild conditions. The resulting labile cyanohydrins were reprotected either by an enzyme-catalysed route involving the addition of vinyl butyrate, or chemically after removal of the enzyme from the reaction mixture. This process gave access to both enantiomers in pure form and in good yields, while considerably reducing the risks due to HCN. A variety of different protection groups have also been introduced. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Bio-oil produced from the pyrolysis of sugarcane bagasse has the potential to be used as a sustainable and renewable energy source. In the present study, a non-isothermal thermo-gravimetric analysis (TGA) of the pyrolysis (in N2atmosphere) and combustion (in the air) of bio-oil from sugarcane bagasse was investigated at three heating rates: 5, 10, and 20 °C/min. The sample was heated from room temperature up to 900 °C and the evolved gases in the TG furnace were carried to a Fourier transform infrared (FTIR) cell where the composition of the gases and the functional groups present there were analyzed. A global kinetic analysis was performed to obtain the Arrhenius kinetic parameters for the pyrolysis and oxidation of the bio-oil using the distributed activation energy model. Three distinct stages, namely; low-temperature oxidation (LTO), fuel decomposition (FD), and high-temperature oxidation (HTO) were observed during the oxidation of bio-oil. The initial devolatilization of the oxygenated compounds observed during pyrolysis was similar to the LTO stage observed during combustion. The intensity of the CO2FTIR peaks seen during the bio-oil combustion was 10 times the intensity of the CO2peaks attained during pyrolysis. The TGA-FTIR analysis of the sugarcane bagasse bio-oil sheds new light on its thermal degradation/oxidation characteristics.