01897nas a2200277 4500008004100000022001400041245006400055210006300119260007300182300001400255490000800269520102100277653001501298653000801313653001101321653001801332653002201350100001801372700002801390700002601418700002201444700001801466700002001484700002001504856009501524 2006 eng d a0169-433200aAdsorption of octadecyltrichlorosilane on mesoporous SBA-150 aAdsorption of octadecyltrichlorosilane on mesoporous SBA15 aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAPR a4097-41030 v2523 a

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.

10aAdsorption10aOTS10aSBA-1510aSelf-assembly10athermal stability1 aMirji, S., A.1 aHalligudi, Shivaraj, B.1 aSawant, Dhanashri, P.1 aJacob, Nalini, E.1 aPatil, K., R.1 aGaikwad, A., B.1 aPradhan, S., D. uhttps://library.ncl.res.in/content/adsorption-octadecyltrichlorosilane-mesoporous-sba-15-002039nas a2200253 4500008004100000022001400041245013200055210006900187260007300256300001200329490000900341520110500350653002701455653001901482653001901501653001901520653001101539100002601550700001301576700001901589700001801608700002801626856013101654 2007 eng d a1381-116900aCatalytic performances of silicotungstic acid/zirconia supported SBA-15 in an esterification of benzyl alcohol with acetic acid0 aCatalytic performances of silicotungstic acidzirconia supported  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcOCT a150-1570 v276 3 a

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.

10a12-silicotungstic acid10aBenzyl acetate10aBenzyl alcohol10aEsterification10aSBA-151 aSawant, Dhanashri, P.1 aVinu, A.1 aJustus, Josena1 aSrinivasu, P.1 aHalligudi, Shivaraj, B. uhttps://library.ncl.res.in/content/catalytic-performances-silicotungstic-acidzirconia-supported-sba-15-esterification-benzyl-001722nas a2200229 4500008004100000022001400041245014100055210006900196260007300265300001200338490000800350520085900358653001601217653001101233653001301244653001401257653002101271100002601292700002101318700002801339856012501367 2007 eng d a1387-181100aEffect of pretreatment conditions on the catalytic activity of nano-sized TPA/ZrO2 dispersed in SBA-15 channels in acetylation reactions0 aEffect of pretreatment conditions on the catalytic activity of n aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY a223-2330 v1023 a

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.

10aacetylation10aSBA-1510aTPA/ZrO210averatrole10awet-impregnation1 aSawant, Dhanashri, P.1 aHartmann, Martin1 aHalligudi, Shivaraj, B. uhttps://library.ncl.res.in/content/effect-pretreatment-conditions-catalytic-activity-nano-sized-tpazro2-dispersed-sba-1502438nas a2200241 4500008004100000022001400041245012100055210006900176260007300245300001100318490000800329520157000337653001901907653001601926653001101942653001301953653001401966100002601980700001302006700001702019700002802036856013202064 2007 eng d a1381-116900aTungstophosphoric acid supported over zirconia in mesoporous channels of MCM-41 as catalyst in veratrole acetylation0 aTungstophosphoric acid supported over zirconia in mesoporous cha aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB a98-1080 v2623 a

Tungstophosphoric acid (TPA) over zirconia dispersed uniformly in mesoporous silica (MS) channels of MCM-41 and MCM-48 were synthesized and tested for their catalytic activity in veratrole acetylation. Catalysts with different TPA loadings (5-50 wt.%) on 22.4 wt.%ZrO2/MCM-41 and 15 wt.%TPA on different zirconia loadings (10-70 wt.%)/MCM-41 were prepared and calcined at 1123 K. The physico-chemical characterization of the supported catalysts was done by powder X-ray diffraction (XRD), surface area measurement (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformed-infrared (FT-IR) spectroscopy, UV-vis diffuse reflectance spectra, Temperature programmed desorption (TPD) of ammonia, FT-IR pyridine adsorption and (31) P cross polarization-magic angle spinning (CP-MAS) NMR spectroscopy. The mesoporous silica supports play an important role in stabilizing catalytically active TPA along with tetragonal phase of zirconia. Among the catalysts, 15 wt.%TPA/22.4 wt.%ZrO2/MCM-41 calcined at 1123 K was found to have highest acidity and at least four times more active than neat 15 wt.%TPA/ZrO2 in veratrole acetylation to acetoveratrone by acetic anhydride. Reaction conditions were evaluated with 15 wt.%TPA/22.4 wt:%ZrO2/MCM-41 calcined at 1123 K to get higher conversion of acetic anhydride to acetoveratrone. The reaction was found to be heterogeneously catalyzed and no contribution from homogeneous (leached) TPA into the medium under the reaction conditions. (c) 2006 Elsevier B.V. All rights reserved.

10aacetoveratrone10aacetylation10aMCM-4110aTPA/ZrO210averatrole1 aSawant, Dhanashri, P.1 aVinu, A.1 aLefebvre, F.1 aHalligudi, Shivaraj, B. uhttps://library.ncl.res.in/content/tungstophosphoric-acid-supported-over-zirconia-mesoporous-channels-mcm-41-catalyst-veratrole02980nas a2200289 4500008004100000022001400041245013400055210006900189260007600258300001400334490000700348520191000355653001902265653002502284653001702309653001902326653002402345100002602369700001902395700003502414700002102449700002402470700002002494700002802514700001702542856013102559 2008 eng d a0947-653900aHeteropoly acid encapsulated SBA-15/TiO(2) nanocomposites and their unusual performance in acid-catalysed organic transformations0 aHeteropoly acid encapsulated SBA15TiO2 nanocomposites and their  aCOMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USAbWILEY-BLACKWELLcFEB a3200-32120 v143 a

The preparation of SBA-15/TiO(2) nanocomposites with different loadings of Keggin-type 12-tungsto-phosphoric acid (TPA) nanocrystals in their mesochannels through a simple and effective vacuum impregnation method is reported for the first time. The catalysts have been characterised by various sophisticated techniques, including XRD, HRSEM, and TEM. It has been found that the acidity and the textural parameters of the nanocomposites can be controlled by simply changing the loadings of TPA and TiO(2) or the calcination temperature. TPA and TiO(2) loadings of 15 and 22.4 wt %, respectively, and a calcination temperature of 1123 K have proved to be optimal for obtaining mesoporous nanocomposite materials with the highest acidity. Moreover, the activities of these catalysts in promoting hydroamination as well as Mannich and Claisen rearrangement reactions have been extensively investigated. The results show that the amount of TPA has a great influence on the activity of the nanocomposites in all of the reactions studied. The effects of other reaction parameters, such as temperature and reaction time, on the conversion and product selectivity have also been studied in detail. A kinetic analysis of the formation of the products under various reaction conditions is presented. It has been found that the activity of the nanocomposite composed of 15 wt % TPA deposited on 22.4 wt of TiO(2) on SBA-15 in promoting the studied reaction is remarkably higher than the catalytic activities shown by pure TPA, TiO(2)-loaded SBA-15, or TPA-loaded SBA-15. The results obtained have indicated that the acidity and the structural control of the nanocomposite materials are highly critical for obtaining excellent catalytic activity, and the presented highly acidic nanocomposites are considered to show great potential for use as catalysts in promoting many acid-catalysed organic transformations.

10aBronsted acids10amesoporous materials10ananoreactors10ananotechnology10asupported catalysts1 aSawant, Dhanashri, P.1 aJustus, Josena1 aBalasubramanian, Veerappan, V.1 aAriga, Katsuhiko1 aSrinivasu, Pavuluri1 aVelmathi, Sivan1 aHalligudi, Shivappa, B.1 aVinu, Ajayan uhttps://library.ncl.res.in/content/heteropoly-acid-encapsulated-sba-15tio2-nanocomposites-and-their-unusual-performance-acid-002735nas a2200253 4500008004100000022001400041245013200055210006900187260007700256300001200333490000700345520176600352100002402118700001502142700003502157700002002192700002602212700002302238700002602261700002102287700002802308700001702336856012802353 2008 eng d a1616-301X00aNovel three dimensional cubic Fm3m mesoporous aluminosilicates with tailored cage type pore structure and high aluminum content0 aNovel three dimensional cubic Fm3m mesoporous aluminosilicates w aPO BOX 10 11 61, D-69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcFEB a640-6510 v183 a

Novel three dimensional cubic Fm3m mesoporous aluminosilicates (AIKIT-5) with very high structural order and unprecedented loadings of Al in the silica framework have been successfully prepared for the first time by using non ionic surfactant as a template in a highly acidic medium. The obtained materials have been unambiguously characterized in detail by several sophisticated techniques such as XRD, N, adsorption, HRTEM, HRSEM, EDS, elemental mapping, Al-27 MAS NMR, and NH3-TPD. We also demonstrate that the nature, and the amount of Al incorporation in the silica framework can easily be controlled by simply varying the n(H2O)/n(HCl) and the n(Si)/n(Al), ratios, and the Al sources in the synthesis gel. Among the Al sources examined, the Al isopropoxide (AiPr) is superior over other Al sources. Al-27 MAS NMR results reveal that the amount of tetrahedral Al in the framework can be controlled by simply adjusting the nSi/nAl ratio in the synthesis gel, which increases with increasing the Al incorporation. One of the interesting findings in the work is the increase of the specific surface area, specific pore volume and the pore diameter of AIKIT-5 with increasing the Al incorporation in the silica framework (up to n(Si)/n(Al), ratio of 10) while retaining the well-ordered three dimensional cage type porous structure, and the mechanism for the unusual behavior has been discussed in detail. Finally, the acidity and the catalytic activity in the acetylation of veratrole of the AIKIT-5 catalysts have been studied and the results have been compared with the several zeolites catalysts. Among the catalysts examined, AIKIT-5(10) is found to be superior over the zeolites catalysts such as mordenite, zeolite H-Y, zeolite H-beta, and ZSM-5.

1 aSrinivasu, Pavuluri1 aAlam, Sher1 aBalasubramanian, Veerappan, V.1 aVelmathi, Sivan1 aSawant, Dhanashri, P.1 aBoehlmann, Winfred1 aMirajkar, Subhash, P.1 aAriga, Katsuhiko1 aHalligudi, Shivappa, B.1 aVinu, Ajayan uhttps://library.ncl.res.in/content/novel-three-dimensional-cubic-fm3m-mesoporous-aluminosilicates-tailored-cage-type-pore-002588nas a2200277 4500008004100000022001400041245009400055210006900149260007300218300001200291490000600303520161000309653001401919653002601933653002401959653002401983653001902007653001302026100001502039700002202054700001702076700002602093700003502119700002802154856012802182 2008 eng d a1566-736700aSynthesis of biodiesel over zirconia-supported isopoly and heteropoly tungstate catalysts0 aSynthesis of biodiesel over zirconiasupported isopoly and hetero aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR a696-7020 v93 a

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.

10aBiodiesel10aphosphotungstic acids10aSilicotungstic acid10atransesterification10atungsten oxide10aZirconia1 aSunita, G.1 aDevassy, Biju, M.1 aVinu, Ajayan1 aSawant, Dhanashri, P.1 aBalasubramanian, Veerappan, V.1 aHalligudi, Shivappa, B. uhttps://library.ncl.res.in/content/synthesis-biodiesel-over-zirconia-supported-isopoly-and-heteropoly-tungstate-catalysts-001813nas a2200217 4500008004100000022001400041245013500055210006900190260000900259300001400268490000800282520101600290100001901306700002601325700002301351700002301374700002801397700002801425700001701453856012501470 2021 eng d a1932-744700aDirect synthesis of mesoporous siliceous phosphotungstic acid and its superior catalytic activity on the cyclohexylation of phenol0 aDirect synthesis of mesoporous siliceous phosphotungstic acid an cAPR  a6723-67340 v1253 a

The synthesis of highly active and reusable mesoporous siliceous phosphotungstic acid materials (mPTA-Si) which are prepared through a simple self-assembly between phosphotungstic acid (PTA), the polymeric surfactant, and the silica precursor assisted by KCl for cyclohexylation of phenol is reported. The surface area and the acidity of these materials are tuned with a simple adjustment of PTA in the silica framework. The prepared samples exhibit mesoporous structure with a high surface area, but the structure is collapsed when the loading of PTA is high. It is established that the Keggin structure of PTA is retained on the final mPTA-Si. mPTA-Si with different loadings of PTA are employed as the catalysts for the cyclohexylation of phenol under liquid phase conditions. Among the catalysts studied, 10.0-mPTA-8.3Si calcined at 350 degrees C is found to be highly active, selective, and recyclable and offers 100% conversion of phenol with the highest selectivity for p-cyclohexylphenol (96.8%).

1 aIlbeygi, Hamid1 aSawant, Dhanashri, P.1 aRuban, Sujanya, M.1 aReshma, Kokane, S.1 aUmbarkar, Shubhangi, B.1 aHalligudi, Shivappa, B.1 aVinu, Ajayan uhttps://library.ncl.res.in/content/direct-synthesis-mesoporous-siliceous-phosphotungstic-acid-and-its-superior-catalytic