Cordierite honeycomb supported Mo(VI)/ZrO2 for microwave assisted Pinacol-Pinacolone rearrangement

181-188ZrO2, Mo(VI)/ZrO2, SO42-/ZrO2 and Pt-SO42-/ZrO2 supported on honeycomb monoliths have been prepared and characterized for their physico-chemical properties such as surface acidity, crystalinity, functionality and morphology. These materials have been used as solid acid catalysts in the pinacol rearrangement of benzopinacol under microwave irradiation. A few diols have also been subjected to pinacol rearrangement to obtain a good conversion of rearrangement products with high selectivity. Optimization of reaction conditions has also studied to determine the most suitable reaction conditions for the effective synthesis of pinacolone derivatives. Up to 98% conversion of benzopinacol is observed under a set of optimized reaction conditions. A reactivation and reusability study of zirconia based solid acid catalysts has also performed

Catalytic synthesis of benzimidazole derivatives over modified forms of zirconia

1465-1470The solid acid catalysts, ZrO2, Mo(VI)/ZrO2 and Pt-SO42-/ZrO2 have been prepared and characterized for their surface area by BET, total surface acidity by NH3-TPD/ n-butyl amine back titration and crystallinity by powder XRD methods. These solid acid catalysts have been used in the synthesis of various benzimidazole derivatives. The results have been interpreted based on the variation of acidic properties and powder XRD phases of zirconia on incorporation of Mo(VI) or Pt-SO42– ions. Mo(VI)/ZrO2 is found to be an efficient solid acid catalyst for the synthesis of benzimidazoles with up to ~98% yield. These solid acids were found to be reusable up to at least 5 reaction cycles. Plausible mechanism for the formation of benzimidazoles over protonic acid sites of the solid acid catalysts is proposed

Microwave assisted transesterification of waste cooking oil over modified forms of zirconia coated on honeycomb monolith

373-378Microwave assisted transesterification of waste cooking oil over honeycomb monoliths coated with zirconia based catalysts such as MgO/ZrO2 and CaO/ZrO2 to synthesize biodiesel is reported. For comparison, biodiesel synthesis via transesterification using conventional heating method has also been carried out. The solid acid Al2O3/ZrO2 coated on a honeycomb has also been used as a catalyst to reduce the percentage of free fatty acid in waste cooking oil via esterification using conventional heating. The honeycomb monoliths have been coated with solid bases and characterized for their physico-chemical properties such as surface acidity, surface basicity, crystalinity and morphology using suitable techniques. The honeycomb monoliths coated with solid catalysts are found to be highly efficient and reusable in the process of synthesizing biodiesel from waste cooking oil. A maximum yield of biodiesel (98%) is obtained at 60 °C in 10 min by keeping the molar ratio of oil:methanol ratio at 1:6 under microwave irradiation

Synthesis of salicylate esters over cordierite honeycomb monoliths coated with zirconia based solid acids in vapour phase

390-395Solid acid catalysts such as ZrO2, Mo(VI)/ ZrO2, Pt-SO42-/ ZrO2 has been coated on honeycomb monoliths and characterized for their physico-chemical properties such as total surface acidity by NH3-TPD, crystalinity by powder XRD, functionality by FT-IR and morphology by SEM techniques. These solid acid catalytic materials are employed in the vapor phase transesterification of methyl salicylate with different alcohols. The catalytic property of these solid acids has been correlated with their physico-chemical properties. These catalytic materials are found to be very efficient in the transesterification reaction with up to ~98% yield of the desired transester. Reaction conditions are optimized to get highest possible yield of the desired transester