02318nas a2200253   4500008004100000022001400041245009700055210006900152260007300221300001200294490000800306520143100314653001501745653002301760653001101783653001901794653001301813100001501826700002201841700002201863700002601885700002801911856012501939       2005                        eng d  a1381-116900aLiquid-phase alkylation of phenol with long-chain olefins over WOx/ZrO2 solid acid catalysts0 aLiquidphase alkylation of phenol with longchain olefins over WOx  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcOCT  a123-1310 v2403 a<p>The liquid-phase alkylation of phenol with 1-dodecene was carried out over WOx/ZrO2 solid acid catalysts. The catalysts were prepared by wet impregnation method using zirconium oxyhydroxide and ammonium metatungstate. Catalysts with different WO3 loading (5-30 wt.%) were prepared and calcined at 800 degrees C and catalyst with 15% WO3 was calcined from 700-850 degrees C. All the catalysts were characterized by surface area, XRD, and FTIR. The catalyst with 15% WO3 calcined at 800 degrees C (15 WZ-800) was found to be the most active in the reaction. The effect of temperature, molar ratio and catalyst weight on dodecene conversion and products selectivity was studied in detail. Under the optimized reaction conditions of 120 degrees C, phenol/1-dodecene molar ratio 2 and time 2 h, the catalyst 15 WZ-800 gave &gt; 99% dodecene conversion with 90% dodecylphenol selectivity. Comparison of the catalytic activity of 15 WZ-800 with sulfated zirconia calcined at 500 degrees C (SZ-500) and HP zeolite showed that activity of SZ-500 was lower than that of 15 WZ-800, while HP zeolite showed negligible activity. It is observed that the presence of water in the reaction mixture was detrimental to the catalytic activity of WOx/ZrO2. The catalyst 15 WZ-800 also found to be an efficient catalyst for alkylation of phenol with long-chain olefins like 1-octene and 1-decene. (c) 2005 Elsevier B.V. All rights reserved.</p>10aAlkylation10along-chain olefins10aphenol10atungsten oxide10aZirconia1 aSarish, S.1 aDevassy, Biju, M.1 aBohringer, Walter1 aFletcher, Jack, C. Q.1 aHalligudi, Shivaraj, B.  uhttps://library.ncl.res.in/content/liquid-phase-alkylation-phenol-long-chain-olefins-over-woxzro2-solid-acid-catalysts-002031nas a2200217   4500008004100000022001400041245006700055210006400122260007300186300001000259490000800269520130600277653001301583653002001596653001901616653001301635100001501648700002201663700002801685856010001713       2005                        eng d  a1381-116900atert-Butylation of p-cresol over WOx/ZrO2 solid acid catalysts0 atertButylation of pcresol over WOxZrO2 solid acid catalysts  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJUL  a44-510 v2353 a<p>The tert-butylation of p-cresol with tert-butanol was carried out over WO3/ZrO2 catalysts under flow conditions, The catalysts were prepared by wet impregnation method using zirconium oxyhydroxide and ammonium metatungstate. Catalysts with different WO3 loading (5-30 wt.%) were prepared and calcined at 800 degrees C and catalyst with 15% WO,, was calcined from 600 to 900 C. The catalysts were characterized by surface area, XRD, FTIR and TEM. The catalyst 15% WO3/ZrO2 calcined at 800 degrees C found to be the most active in the reaction. The effect of temperature, space velocity and molar ratio of the reactants on the conversion of p-cresol and products selectivities were studied. Under the optimized reaction conditions of 130 degrees C, tert-butanol/p-cresol molar ratio of 3 and flow rate of 10 ml h(-1). p-cresol conversion was 69.8% with selectivity to 2-tert-butyl-p-cresol 92.4%, 2,6-di-tert-butyl-p-cresol 6.3% and p-cresol tert-butyl ether 1.3%. The catalytic activity is compared with sulfated zirconia, USY, H beta zeolites and montmorillonite K-10 under the optimized reaction conditions The activity of sulfated zirconia is lower than that of 15% WO3/ZrO2 catalyst calcined at 800 C and other catalysts showed very low activity, (c) 2005 Elsevier B.V.. All rights reserved.</p>10ap-Cresol10atert-butylation10atungsten oxide10aZirconia1 aSarish, S.1 aDevassy, Biju, M.1 aHalligudi, Shivaraj, B.  uhttps://library.ncl.res.in/content/tert-butylation-p-cresol-over-woxzro2-solid-acid-catalysts-001232nas a2200289   4500008004100000022001400041245012700055210006900182260007300251300001400324490000600338520019500344653001100539653001100550653002400561653001900585653002700604653001300631100001900644700001700663700002200680700003500702700002200737700002600759700002800785856012900813       2008                        eng d  a1566-736700aHighly efficient and chemo selective catalyst system for the synthesis of blossom orange fragrance and flavoring compounds0 aHighly efficient and chemo selective catalyst system for the syn  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAPR  a1671-16750 v93 a<p>{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</p>10aAcetal10aacylal10aSilicotungstic acid10atungsten oxide10atungstophosphoric acid10aZirconia1 aJustus, Josena1 aVinu, Ajayan1 aDevassy, Biju, M.1 aBalasubramanian, Veerappan, V.1 aBohringer, Walter1 aFletcher, Jack, C. Q.1 aHalligudi, Shivaraj, B.  uhttps://library.ncl.res.in/content/highly-efficient-and-chemo-selective-catalyst-system-synthesis-blossom-orange-fragrance-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<p>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.</p>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-0