Rajesh Gopinath

Hydrodechlorination of chlorobenzene on Nb2O5-supported Pd catalysts influence of microwave irradiation during preparation on the stability of the catalyst

Catalytic hydrodechlorination of chlorobenzene was studied on Pd/Nb2O5 catalysts prepared by the conventional and the microwave heating techniques. The catalysts were characterized by X-ray diffraction (XRD), BET surface area, hydrogen chemisorption and scanning electron microscopy (SEM). The time-on-stream studies reveal that the microwave-irradiated catalyst exhibits better resistance towards deactivation than the conventionally prepared catalyst. Microwave irradiation also seems to be preferable than the high-temperature reduction adopted to increase the particle size. The microwave-irradiated catalyst also shows higher residual activity than the electrically heated catalyst at all reaction temperatures studied. This is attributed to the formation of larger particles of palladium which is in conformity with the basic observation made in the literature that hydrodechlorination is more facile on low-dispersed Pd catalysts.

Influence of ammonium salt formation on the activity and selectivity of the 12-molybdophosphate heteropolyacid catalyst prepared by solid–solid interaction in the ammoxidation of 2-methylpyrazine

The ammonium salt of 12-molybdophosphoric acid has been prepared by the solid-state interaction of the ammonium salts of molybdenum and phosphorus. The catalysts obtained by pretreatment of the precursor at various temperatures, have been characterized by nitrogen adsorption, X-ray diffraction (XRD), Fourier-transformed infrared (FTIR) spectroscopy and temperature-programmed decomposition (TPD) of the catalysts. Ammoxidation of 2-methylpyrazine has been carried out on these catalysts. The amount of ammonium salt present in the catalyst has been correlated with the activity and selectivity of the catalysts.

Studies on microwave irradiated Pd/Nb2O5 catalysts: Effect of palladium chloride precursor on the chlorobenzene hydrodechlorination activitya

Catalysts containing 10 wt. % Pd supported on Nb2O5 were prepared by microwave irradiation and conventional electrical heating, using palladium chloride as the precursor for Pd. Whereas higher residual chloride content decreased the activity and stability of the microwave irradiated catalyst, formation of PdO during calcination in air improved the performance of the conventionally heated catalyst. Calcination after microwave irradiation offers the highest activity and stability.

Interaction-induced enhancement in the activity and selectivity of a titania-supported ammonium salt of a 12-molybdophosphoric acid catalyst during ammoxidation of 2-methylpyrazine.

A titania-supported ammonium salt of 12-molybdophosphoric acid has been synthesized, and the salt-support interaction, which enhanced the reaction rate, has been correlated with the activity of the catalyst in the ammoxidation of 2-methylpyrazine.