@article { ISI:000254979800027, title = {Highly efficient and chemo selective catalyst system for the synthesis of blossom orange fragrance and flavoring compounds}, journal = {Catalysis Communications}, volume = {9}, number = {7}, year = {2008}, month = {APR}, pages = {1671-1675}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

{Acetal and acylal formation reactions of organic compounds are efficiently catalyzed by zirconia-supported mixed oxide systems under liquid-phase reaction conditions. 15WZ-750 (where

}, keywords = {Acetal, acylal, Silicotungstic acid, tungsten oxide, tungstophosphoric acid, Zirconia}, issn = {1566-7367}, doi = {10.1016/j.catcom.2008.01.025}, author = {Justus, Josena and Vinu, Ajayan and Devassy, Biju M. and Balasubramanian, Veerappan V. and Bohringer, Walter and Fletcher, Jack C. Q. and Halligudi, Shivaraj B.} } @article { ISI:000253450900027, title = {Synthesis of biodiesel over zirconia-supported isopoly and heteropoly tungstate catalysts}, journal = {Catalysis Communications}, volume = {9}, number = {5}, year = {2008}, month = {MAR}, pages = {696-702}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The liquid-phase synthesis of biodiesel by transesterification of sunflower oil with methanol is carried out by using zirconia-supported isopoly and heteropoly tungstates (HPAs) as catalysts. The isopoly and heteropoly tungstate catalysts were prepared by suspending zirconium oxyhydroxide in water/methanol solution of ammonium metatungstate/silicotungstic acid, phosphotungstic acid (WO3/HPA loading, 15\%,,) followed by drying and calcination at 750 degrees C. The catalysts were characterized by XRD, Raman spectroscopy, IR spectroscopy, NH3-TPD and FTIR pyridine adsorption spectroscopy. XRD results indicate that the presence of isopoly and heteropoly tungstates stabilizes ZrO2 in tetragonal phase. Raman and IR spectra of the catalysts show that tungstate species exist as zirconia-anchored octahedral mono-oxotungstate. The acidity measurements by NH3-TPD and FTIR pyridine adsorption spectroscopy show that zirconia-supported phosphotungstate has the highest total acidity and zirconia-supported isopoly tungstate has the highest Bronsted acidity. The zirconia-supported isopoly tungstate shows superior catalytic performance compared to zirconia-supported heteropoly tungstate catalysts. Under the reaction conditions of 200 degrees C and methanol/oil molar ratio 15, 15\% WO3/ZrO2 calcined at 750 degrees C gave 97\% conversion of oil. This catalyst also efficiently catalyzes methanolysis of other vegetable oils like mustard oil and sesame oil. The deactivated catalyst could be regenerated by calcination without appreciable loss in activity. (c) 2007 Elsevier B.V. All rights reserved.

}, keywords = {Biodiesel, phosphotungstic acids, Silicotungstic acid, transesterification, tungsten oxide, Zirconia}, issn = {1566-7367}, doi = {10.1016/j.catcom.2007.08.007}, author = {Sunita, G. and Devassy, Biju M. and Vinu, Ajayan and Sawant, Dhanashri P. and Balasubramanian, Veerappan V. and Halligudi, Shivappa B.} } @article { ISI:000262657300010, title = {Comparative study on liquid phase alkylation of 2-methylnaphthalene with long chain olefins using different solid acid catalysts}, journal = {Applied Catalysis A-General}, volume = {352}, number = {1-2}, year = {2009}, month = {JAN}, pages = {74-80}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A comparative study has been made over a variety of solid acid catalysts, which include isopoly and heteropoly ions supported on various supports such as zirconia, titania, a large variety of zeolites and a couple of mesoporous materials for liquid phasealkylation of 2-methylnaphthalene with 1-octene.All the catalyst systems were characterized by nitrogen sorption analysis, X-ray diffraction and NH(3)-TPD. Inspite of their high acid amounts zeolites gave poor catalytic performance due to their diffusional constraints; on the other hand mesoporous materials lacked diffusional constraints but due to their low acid amounts resulted in poor conversions. lsopoly and heteropoly ions supported on zirconia and titania were found to be catalytically active for the reaction due to total surface acidity. Among them, isopolytungstate supported on zirconia exhibited the best catalytic activity and was used for further optimization of reaction conditions. Excellent conversions of all olefins (\>92\%) with high selectivity of monoalkylmethylnaphthalene (\>95\%) was obtained under optimized reaction conditions. The catalyst could be recycled for several times without any obvious loss of its activity. (C) 2008 Elsevier B.V. All rights reserved.

}, keywords = {2-Methylnaphthalene, Alkylation, Long chain olefins, Zirconia}, issn = {0926-860X}, doi = {10.1016/j.apcata.2008.09.032}, author = {Lucas, Nishita and Bordoloi, Ankur and Amrute, Amol P. and Kasinathan, Palraj and Vinu, Ajayan and Bohringer, Walter and Fletcher, Jack C. Q. and Halligudi, Shivaraj B.} }