@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:000240521800008, title = {Adsorption of methanol on Si(100)/SiO(2)and mesoporous SBA-15}, journal = {Colloids and Surfaces A-Physicochemical and Engineering Aspects}, volume = {287}, number = {1-3}, year = {2006}, month = {SEP}, pages = {51-58}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Adsorption of methanol on SiO(100)/SiO2 substrate and mesoporous SBA-15 has been studied by using Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). Contact angle technique is employed to study the adsorption kinetics of methanol on SiO(100)/SiO2 and thermal stability of adlayer. Thermogravimetric (TGA) technique is used to understand the thermal behavior of methanol layer on SBA-15. Adsorption kinetics fit fairly well with Langmuir isotherms giving adsorption rate constant, k(a) = 0.0021 W s(-1). FTIR results show formation of methoxy silicon (SiOCHA silicon polyhydride (SiH2), carboxylate, molecular water and hydroxyl groups on Si(100)/SiO2 surface and only methoxy silicon on SBA-15. XPS results confirm methanol adsorption and support FTIR results. The methanol adlayers are found to be thermally stable up to a temperature of similar to 262 degrees C on both Si(100)/SiO2 and SBA-15 and decompose between 262 and 450 degrees C. (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {Adsorption, desorption, kinetics, Methanol, SBA-15, Si(100)/SiO2, thermal stability}, issn = {0927-7757}, doi = {10.1016/j.colsurfa.2006.03.021}, author = {Mirji, S. A. and Halligudi, Shivaraj B. and Mathew, Nevin T. and Ravi, V. and Jacob, Nalini E. and Patil, K. R.} } @article { ISI:000237835100010, title = {Adsorption of octadecyltrichlorosilane on mesoporous SBA-15}, journal = {Applied Surface Science}, volume = {252}, number = {12}, year = {2006}, month = {APR}, pages = {4097-4103}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Adsorption of octadecyltrichlorosilane (OTS) on mesoporous SBA-15 has been studied by using Brunauer-Emmett-Teller (BET) surface area analysis, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermo-gravimetric analysis (TGA) techniques. BET surface area analysis shows decrease of surface area from 930 to 416 m(2)/g after OTS adsorption. SEM pictures show close attachment of SBA-15 particles. EDAX measurements show increase of carbon weight percentage and decrease of oxygen and silicon weight percentage. XPS results closely support EDAX analysis. FTIR spectra shows presence of methyl (-CH3) and methylene (-CH2) bands and oriented OTS monolayer on SBA-15. Thermo-gravimetric analysis shows that the OTS adsorbed on SBA-15 are stable up to a temperature of 230 degrees C and that the OTS monolayers decompose between 230 and 400 degrees C. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {Adsorption, OTS, SBA-15, Self-assembly, thermal stability}, issn = {0169-4332}, doi = {10.1016/j.apsusc.2005.06.009}, author = {Mirji, S. A. and Halligudi, Shivaraj B. and Sawant, Dhanashri P. and Jacob, Nalini E. and Patil, K. R. and Gaikwad, A. B. and Pradhan, S. D.} } @article { ISI:000242511300022, title = {Adsorption of methanol on mesoporous SBA-15}, journal = {Materials Letter}, volume = {61}, number = {1}, year = {2007}, month = {JAN}, pages = {88-92}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The adsorption of methanol onmesoporous SBA-15 has been studiedbyrising Brunauer-Emmett-Teller (BET) surface area analysis, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray photoclectrom spectroscopy (XPS) and tbennogravimettic analysis (TGA). The BET surface area analysis shows decreases of the surface area from 387 to 383 m(2)/g, pore volume from 0.88 to 0.81 cm(3)/g and pore diameter from 9.07 to 8.4 mm after methanol adsorption. The appearance of strong IR bands at 2862 and 2964cm(-1) due to methyl (-CH3) symmetric and asymmetric stretching demonstrate the presence of methanol and evidence of successful methanol adsorption. XPS results show increase of carbon and oxygen content on the surface of SBA-15. Thermogravirriettic analysis shows that the methanol adsorbed on SBA-15 is stable up to a temperature of 265 degrees C and that the methanol adlayers decompose between 265 and 588 degrees C. (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {Adsorption, Electron microscopy, Methanol, SBA-15, Surfaces, thermal stability}, issn = {0167-577X}, doi = {10.1016/j.matlet.2006.04.012}, author = {Mirji, S. A. and Halligudi, Shivaraj B. and Mathew, Nevin T. and Jacob, Nalini E. and Patil, K. R. and Gaikwad, A. B.} } @article { ISI:000249949800020, title = {Catalytic performances of silicotungstic acid/zirconia supported SBA-15 in an esterification of benzyl alcohol with acetic acid}, journal = {Journal of Molecular Catalysis A-Chemical }, volume = {276 }, number = {1-2}, year = {2007}, month = {OCT}, pages = {150-157}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Liquid phase esterification of benzyl alcohol (BA) to benzyl acetate (Peach fragrance) with an acetic acid (AA) has been investigated with 12-silicotungstic acid supported on zirconia embedded inside SBA-15 (STA/ZrO2/SBA- 15) as the catalyst. Catalysts were unambiguously characterized by XRD, N-2 adsorption-desorption, FF-IR pyridine adsorption techniques and the total amount of acidity of different STA loaded catalysts was estimated by TPD of NH3. The optimization of reaction conditions of an esterification of BA with AA was performed with 15 wt.\% STA/22.4 wt.\% ZrO2/SBA-15 calcined at 1123 K by varying catalyst concentration (1-10 wt.\% of reaction mixture); temperature, 353-383 K and AA:BA molar ratio as 0.5-3. The 15 wt.\% STA/22.4 wt.\% ZrO2/SBA-15 calcined at 1123 K was found to have the highest acidity and more active in the reaction. Under the optimized reaction conditions, the 15 wt.\% STA/22.4 wt.\%ZrO2/SBA-15 calcined at 1123 K gave 59\% BA conversion with selectivity for benzyl acetate as high as 96\% within 2 h of reaction time. (c) 2007 Elsevier B.V. All rights reserved.

}, keywords = {12-silicotungstic acid, Benzyl acetate, Benzyl alcohol, Esterification, SBA-15}, issn = {1381-1169}, doi = {10.1016/j.molcata.2007.07.001}, author = {Sawant, Dhanashri P. and Vinu, A. and Justus, Josena and Srinivasu, P. and Halligudi, Shivaraj B.} } @article { ISI:000246727900022, title = {Effect of pretreatment conditions on the catalytic activity of nano-sized TPA/ZrO2 dispersed in SBA-15 channels in acetylation reactions}, journal = {Microporous and Mesoporous Materials}, volume = {102}, number = {1-3}, year = {2007}, month = {MAY}, pages = {223-233}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Acetylation of an aromatic compounds such as veratrole (1,2-dimethoxybenzene), anisole, thioanisole, isobutyl benzene and 2-methoxynaphthalene with acetic anhydride has been investigated over a nano-sized 12-tungstophosphoric acid (TPA)/22.4 wt.\%ZrO2/SBA- 15 catalysts in the liquid phase conditions. Catalysts with different (\%) TPA and zirconia loadings calcined at different temperatures were prepared by wet-impregnation and characterized by XRD, N-2 adsorption-desorption, FT-Rarnan, X-ray photoelectron spectroscopy (XPS). The acidic behavior of the catalyst was studied by TPD of ammonia and FT-IR pyridine adsorption. Among the catalysts, 15 wt.\%TPA/22.4 wt.\%ZrO2/SBA- 15 calcined at 1123 K had the highest acidity and was the most active catalyst in veratrole acetylation with acetic anhydride. (C) 2007 Elsevier Inc. All rights reserved.

}, keywords = {acetylation, SBA-15, TPA/ZrO2, veratrole, wet-impregnation}, issn = {1387-1811}, doi = {10.1016/j.micromeso.2006.12.046}, author = {Sawant, Dhanashri P. and Hartmann, Martin and Halligudi, Shivaraj B.} } @article { ISI:000265811500009, title = {Mesoporous silica immobilized cobalt complex: an efficient catalyst for epoxides ring opening by aromatic amines under ambient conditions}, journal = {Catalysis Communications}, volume = {10}, number = {10}, year = {2009}, month = {MAY}, pages = {1398-1403}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

{Cobalt complex, CobpbH(2)Cl(2)2H(2)O [where

}, keywords = {beta-Amino alcohols, CobpbH(2)Cl(2)2H(2)O complex, Epoxide ring opening, Immobilization, SBA-15}, issn = {1566-7367}, doi = {10.1016/j.catcom.2009.03.005}, author = {Bordoloi, Ankur and Hwang, Young Kyu and Hwang, Jin-Soo and Halligudi, Shivaraj B.} }