@article { ISI:000227853700025, title = {Highly active and selective AlSBA-15 catalysts for the vapor phase tert-butylation of phenol}, journal = {Applied Catalysis A-General}, volume = {281}, number = {1-2}, year = {2005}, month = {MAR}, pages = {207-213}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Hexagonally ordered mesoporous AISBA-15 catalysts having n(Si)/(nA]) ratios from 7 to 215 have been synthesized hydrothermally using a cheap non-ionic block copolymer as the structure-directing agent. The obtained materials were analyzed by XRD and nitrogen adsorption to determine the structural order and the textural properties. It has been observed by Al-27 MAS NMR spectroscopy that aluminum atoms are exclusively in tetrahedral coordination for all samples except AISBA-15(7), where octahedral aluminum has been detected to some extent. Temperature-programmed desorption of pyridine showed that AISBA-15(45) has a higher number of strong acid sites as compared to other mesoporous materials such as FeMCM-41, AIMCM-41 and FcAlMCM-41. The catalyst AlSBA-15(45)showed superior performance in the acid-catalyzed tertiary butylation of phenol employing tert-butanol as the alkylation agent. A high phenol conversion of 86.3\% is observed for this catalyst at a reaction temperature of 150 degrees C. Over AISBA-15(45), the 4-TBP yield amounts to 40.5\% and the 2,4-DTBP yield corresponds to 37.9\%. (c) 2004 Elsevier B.V. All rights reserved.

}, keywords = {Acidity, AlSBA-15, aluminum incorporation, butylation of phenol, SBA-15}, issn = {0926-860X}, doi = {10.1016/j.apcata.2004.11.031}, author = {Vinu, A. and Devassy, Biju M. and Halligudi, Shivaraj B. and Bohlmann, W. and Hartmann, Martin} } @article { ISI:000240365800049, title = {Heteropoly acid supported on titania as solid acid catalyst in alkylation of p-cresol with tert-butanol}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {256}, number = {1-2}, year = {2006}, month = {AUG}, pages = {324-334}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Butylation of p-cresol with tert-butanol was investigated on titania modified with 12-tungstophosphoric acid (TPA/TiO2) catalyst under vapor phase conditions. Catalysts with different TPA loadings (10-25 wt.\%) and calcination temperatures (650-750 degrees C) were prepared by suspending titanium hydroxide in methanol solution of TPA followed by drying and calcination. These catalysts were characterized by surface area, XRD, P-31 MAS NMR, XPS, NH3-TPD, and FTIR pyridine adsorption. XRD results indicated that the presence of TPA retarded the crystallization of titania and stabilized TiO2 in anatase phase. P-31 MAS NMR indicated the presence of TPA in various forms (dispersed, highly fragmented and Keggin intact). These catalysts showed both Bronsted and Lewis acidity, and 20\% TPA on TiO2 calcined at 700 degrees C (from here after words 20\% TT 700) had the highest Bronsted as well as total acidity. Further, the catalytic activities were examined in tert-butylation of p-cresol with tent-butanol. The catalytic activity depended on TPA coverage, and the highest activity corresponded to the monolayer of TPA on titania. The most active catalyst 20\% TT-700 gave 82\% conversion of p-cresol and 89.5\% selectivity towards 2-tert-butyl cresol (TBC), 2,6-di-tert-butyl cresol (DTBC) 7.5\% and cresol-tert-butyl ether (CTBE) 3\% under optimized conditions. The activity was always higher than that of WO3/ZrO2, sulfated zirconia (SZ), USY, H-beta zeolites and montmorillonite K-10 (K-10mont) under similar conditions. (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {2, 2-tert-butyl-p-cresol, 6-di-tert-butyl-p-cresol, Alkylation, heteropoly acid, p-Cresol, tert-butanol, titania}, issn = {1381-1169}, doi = {10.1016/j.molcata.2006.05.024}, author = {Kumbar, Suresh M. and Shanbhag, G. V. and Lefebvre, F. and Halligudi, Shivaraj B.} } @article { ISI:000260978000009, title = {Heteropoly acid-based supported ionic liquid-phase catalyst for the selective oxidation of alcohols}, journal = {Journal of Catalysis}, volume = {259}, number = {2}, year = {2008}, month = {OCT}, pages = {232-239}, publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE}, type = {Article}, address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA}, abstract = {

A supported ionic liquid strategy has been applied for the immobilization of a heteropolyacid, molybdovanadophosphoric acid, onto ionic liquid-modified mesoporous silica SBA-15. The immobilized catalyst demonstrated high activity in the aerobic oxidation of primary and secondary alcohols to aldehydes and ketones, respectively. No overoxidation of the primary alcohols to carboxylic acids was observed. Secondary alcohols were chemoselectively oxidized to ketones in the presence of primary alcohol, hetero atom, and allyl groups. This catalyst could be recycled five times without obvious loss of activity. (C) 2008 Elsevier Inc. All rights reserved.

}, keywords = {Air as an oxidant, Mesoporous silica SBA-15, Molybdovanadophosphoric acid, Selective oxidation, Supported ionic liquid}, issn = {0021-9517}, doi = {10.1016/j.jcat.2008.08.010}, author = {Bordoloi, Ankur and Sahoo, Suman and Lefebvre, F. and Halligudi, Shivaraj B.} } @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.} }