Facile synthesis of bis(indolyl)methanes over cordierite honeycomb coated with modified forms of zirconia under microwave irradiation condition

Zirconia (ZrO2), Mo(VI)/ZrO2, W(VI)/ZrO2 and SO42-/ZrO2 have been coated on honeycomb monoliths and used as catalytic material in the microwave-assisted synthesis of various bis(indolyl)methane derivatives via condensation. These catalytic materials have been characterized for their properties such as surface acidity, crystallinity, morphology and elemental analysis by suitable techniques. A correlation between the acidity, crystallinity and the catalytic activity of these catalytic materials is observed. The effect of conventional heating and microwave heating on the synthesis of these derivatives has been studied. Microwave-assisted synthesis of bis(indolyl)methane derivatives over zirconia and its modified forms is found to be a fast and facile catalytic route. Up to 98% yield of bis(indolyl)methanes is obtained in a very short reaction time of 4 min under microwave irradiation, whereas it requires 20 min to obtain 98% yield under conventional heating. The honeycomb monoliths coated with modified forms of zirconia as catalytic materials are efficient, easily reactivable and reusable for at least six reaction cycles.

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

Microwave 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

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

Facile synthesis of bis(indolyl)methanes over cordierite honeycomb coated with modified forms of zirconia under microwave irradiation condition

925-933Zirconia (ZrO2), Mo(VI)/ZrO2, W(VI)/ZrO2 and SO42-/ZrO2 have been coated on honeycomb monoliths and used as catalytic material in the microwave-assisted synthesis of various bis(indolyl)methane derivatives via condensation. These catalytic materials have been characterized for their properties such as surface acidity, crystallinity, morphology and elemental analysis by suitable techniques. A correlation between the acidity, crystallinity and the catalytic activity of these catalytic materials is observed. The effect of conventional heating and microwave heating on the synthesis of these derivatives has been studied. Microwave-assisted synthesis of bis(indolyl)methane derivatives over zirconia and its modified forms is found to be a fast and facile catalytic route. Up to 98% yield of bis(indolyl)methanes is obtained in a very short reaction time of 4 min under microwave irradiation, whereas it requires 20 min to obtain 98% yield under conventional heating.The honeycomb monoliths coated with modified forms of zirconia as catalytic materials are efficient, easily reactivable and reusable for at least six reaction cycles