Cordierite honeycomb coated with solid acids such as ZrO 2 , Mo/ZrO 2 and W/ZrO 2 were synthesized. These solid acid catalysts were also synthesized in their powder forms. The catalytic materials were characterized for their physicochemical properties such as surface area, surface acidity, crystallinity and morphology by using techniques such as BET, NH 3 -TPD/n-butylamine back titration, powder XRD and SEM respectively. The catalytic activity of these catalytic materials was determined in an acid catalyzed transesterification reaction of methyl salicylate with phenol to synthesize phenyl salicylate (salol). The effect of concentration of Mo or W ions on ZrO 2 , nature of the catalyst (whether honeycomb coated or powder form), reaction temperature, reaction time and reusability of the catalytic material in transesterification was studied. Formation of diphenyl ether as a byproduct was observed on increasing the concentration of Mo or W ions on ZrO 2 and also at higher reaction temperature. The catalytic activity of catalytic materials was correlated with surface acidity and the crystalline phases of catalytic material. Transesterification reactions were also carried out with methyl salicylate and benzyl alcohol or cyclohexanol to synthesize their respective salicylate esters. A probable mechanism of transesterification of methyl salicylate with an alcohol is also proposed. The honeycomb catalysts were found to be efficient, ecofriendly, economical and reusable catalysts compared to their powder forms.ß 2012 Published by Elsevier Masson SAS on behalf of Acade ´mie des sciences.

ZrO 2 -Al 2 O 3 containing 80 mole% of ZrO 2 was prepared by solution combustion, impregnation and precipitation methods. All the prepared catalytic materials were characterized by PXRD, NH 3 -TPD, N 2 adsorption isotherms, FTIR, TEM, SEM, EDAX and ICP-OES techniques. These prepared catalytic materials were used in a rapid, simple, versatile and efficient synthesis of 2,4,5-trisubstituted imidazoles under solvent-free conditions at moderate temperature in shorter reaction time (20 min). This is achieved by three-component cyclo-condensation of benzil, aldehydes and ammonium acetate with excellent yields. The derivatives of quinoxalines and 1,5-benzodiazepines were synthesized effectively by cyclo-condensation of 1,2-diamine with α-diketones and carbonyl compound with O-phenylenediamines respectively over ZrO 2 -Al 2 O 3 at moderate temperature (80 °C) for the reaction time of 20-40 min in presence of ethanol as a solvent. The present method is experimentally simple, non-toxic and involves inexpensive reagents, clean reaction pathways and eco-friendly catalyst. The catalytic materials used can be easily separated from the reaction mixture and reused for several reaction cycles without much loss of catalytic activity.

In this article production of biodiesel from Madhuca indica oil (MI-oil) containing high % of free fatty acids (FFA) by transesterification process with methanol over basic zeolites such as NaY loaded with 5-25% KOH is presented. The zeolites were characterized by PXRD, BET and CO 2 -TPD methods prior to their catalytic activity studies. Optimization of reaction conditions for transesterification was conducted in order to get highest possible yield of biodiesel. 1HNMR and FTIR analysis confirms the conversion of MI-oil to biodiesel. The physico-chemical properties of MI-biodiesel were found to be comparable with that of the standard biodiesel. The NaY and KOH/NaY zeolites were found to be efficient and reusable catalysts without much loss of their catalytic activity when used for several times in biodiesel production.

A series of solid acids such as ZrO 2 , 5% Mo(VI)/ZrO 2 , 10% Mo(VI)/ZrO 2 , 20% Mo(VI)/ZrO 2 and SO 4 2-/ZrO 2 were prepared. These solid acids were characterized by BET, NH 3 -TPD / nbutylamine back titration, powder-XRD, FT-IR spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and ICP-OES techniques. The catalytic performance of these solid acids was evaluated in the synthesis of novel aromatic esters by the assistance of microwave irradiation and the catalytic activity of these solid acids was compared with pTsOH. The results clearly indicated that the zirconia based solid acids are efficient green catalysts for esterification reactions, which gave maximum yield of ester in shorter reaction time and comparable to the catalytic activity of pTsOH Brönsted acid. Kinetic studies were carried out to calculate the temperature coefficients (1.66 and 1.56) and energy of activation (66.

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