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Palladium exchanged molybdophosphoric acid supported on silica is reported as a highly effective catalyst for direct reductive amination of carbonyl compounds. The catalysts are characterized by X-ray diffraction and FT-infrared spectroscopy. The characterization results support the existence of Keggin ion of heteropoly molybdate on silica. The catalyst is facile, water tolerable and environmentally benign for reductive amination. A variety of secondary and tertiary amines can be synthesized over this catalyst in excellent yields under mild reaction conditions. A plausible reaction mechanism is proposed for the reductive amination of carbonyl compounds over this catalyst.

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Tantalum exchanged tungstophosphoric acid (Ta x TPA) catalysts were prepared and studied for the synthesis of glycerol carbonate from glycerol and urea. These catalysts were characterized by FT-IR, X-ray diffraction, Laser Raman, pyridine adsorbed FT-IR and temperature programmed desorption of ammonia. The characterization results indicate that the Keggin ion structure of tungstophosphoric acid (TPA) is intact. The activity towards the synthesis of GC over the Ta x TPA catalysts depended on the number of Ta 5? ions exchanged in the secondary structure of heteropoly tungstate. Presence of Ta in TPA leads to the generation of Lewis acidic sites. Catalysts with partially exchanged Ta with the protons of TPA showed high activity due to the presence of both Brønsted and Lewis acidic sites. Different reaction parameters such as reaction temperature, glycerol to urea molar ratio and catalyst loading were studied and optimum conditions were established. These catalysts exhibited reusability. Graphical Abstract1 2 3 4 5 0 10 20 30 40 50 60 70 80 90 100 Selectivity (%) Conversin (%) Reaction time (h) 0 10 20 30 40 50 60 70 80 90 100

Vanadium-incorporated molybdophosporic acid catalysts supported on titania were prepared and characterized by FT-IR, X-ray diffraction and laser Raman spectroscopy. Characterization data reveals the incorporation of vanadium into the primary structure of Keggin ion of MPA. Catalysts activities were evaluated for oxidation of 1,2-benzenedimethanol using H 2 O 2 and O 2 as oxidants. Vanadium-containing catalysts showed high activity compared to their parent heteropoly acids. Oxidation ability depended on the number of V atoms present in Keggin heteropoly molybdate. Effect of reaction parameters on the oxidation ability was also evaluated.

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