Thermal decomposition of co-precipitated Ni-Fe-HT materials led to the formation a mesoporous Ni-Fe-HT catalyst and we have demonstrated here its active role as solid and active catalyst for the Knoevenagel condensation reaction of various aldehydes with active methylene compounds (R-CH2-CN, where R=CN or CO2Et). High product yields are obtained at moderate temperature under solvent-free conditions and the catalyst can be easily separated from the reaction mixture, simply by filtration and reused several times without a significant loss of its activity. Since these mesoporous metal oxides derived from the NiFe hydrotalcites, their basicity mediated abstraction of the acidic protons from the active methylene compounds was responsible for their catalytic activity under solvent-free conditions.
View Article and Find Full Text PDFGold nanoparticles are deposited on basic CaO supports as catalysts for the selective conversion of styrene into styrene oxide. Synthetic methods, gold loading and calcination temperatures are varied to permit an understanding of their influence on gold nanoparticle size, the presence of cationic gold species and the nature of interaction between the gold nanoparticles and the CaO support. Based on these studies, optimal conditions are designed to make the Au/CaO catalyst efficient for the selective epoxidation of styrene.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
April 2008
The considerable recent interest in the conversion of stranded methane into transportable liquids as well as fuel cell technology has provided a renewed impetus to the development of efficient processes for the generation of syngas. The production of syngas (CO/H2), a very versatile intermediate, can be the most expensive step in the conversion of methane to value-added liquid fuels. The catalytic oxy reforming of methane, which is an energy-efficient process that can produce syngas at extremely high space-time yields, is discussed in this Review.
View Article and Find Full Text PDFHydrogen peroxide in high yields can be generated with high efficiency at mild conditions (25 degrees C and atmospheric pressure) with the formation of only environment-friendly by-products (N2 and H2O) by a reduction of O2 by hydrazine from its hydrate/salt with its complete conversion in a short reaction period (
Incorporation of bromide anions (1.0 wt%) in supported Pd catalysts (viz. Pd supported on Al2O3, ZrO2, SiO2, H-beta or Ga2O3) leads to a drastic increase in their selectivity for H2O2 formation in the direct oxidation of H2 to H2O2 by O2(at room temperature) in an aqueous acidic (0.
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