02017nas a2200229   4500008004100000022001400041245009200055210006900147260007300216300001200289490000800301520122000309653001501529653002701544653001501571653001201586653000801598653001301606100001901619700002801638856012101666       2005                        eng d  a1381-116900aAlkylation of benzene with alpha-olefins over zirconia supported 12-silicotungstic acid0 aAlkylation of benzene with alphaolefins over zirconia supported   aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAUG  a137-1450 v2373 a<p>Liquid phase alkylation of benzene to linear alkyl benzene (LAB) with alpha-olefins has been investigated with 12-silicotungstic acid supported on zirconia (STA/ZrO2) as the catalyst. Among the catalysts, 15 wt.% STA/ZrO2 calcined at 750 degrees C was found to be most active than others in the alkylation reaction. The total amount of acid sites of different STA loaded catalysts were estimated by TPD of NH3 and 15 wt.% STA/ZrO2 calcined at 750 degrees C was found to have the highest acidity and more active in the reaction. The optimization of reaction conditions of alkylation of benzene with 1-dodecene was performed with 15 wt.% STA/ZrO2 calcined at 750 degrees C by varying catalyst concentration (1-5 wt.% of reaction mixture); temperature, 373-423 K and benzene: 1-dodecene (1-dd) molar ratio, 5-15 in a Parr autoclave under N-2 pressure. Under the optimized reaction conditions, conversion of 1-dodecene (50.8%) gave high selectivity to 2-phenyl dodecane (47.1%) and the remaining 3-, 4-, 5- and 6-phenyldodecanes in 4 h. The reaction was found to be heterogeneously catalyzed and no contribution from homogeneous (leached) STA into the reaction medium. (c) 2005 Elsevier B.V. All rights reserved.</p>10a1-dodecene10a12-silicotungstic acid10aAlkylation10aBenzene10aLAB10aZirconia1 aSawant, D., P.1 aHalligudi, Shivappa, B.  uhttps://library.ncl.res.in/content/alkylation-benzene-alpha-olefins-over-zirconia-supported-12-silicotungstic-acid-002262nas a2200241   4500008004100000022001400041245010100055210006900156260007300225300001200298490000700310520141400317653001501731653001301746653001601759653001101775100001301786700001901799700002101818700002101839700002801860856013201888       2005                        eng d  a1387-181100aBenzylation of benzene and other aromatics by benzyl chloride over mesoporous AlSBA-15 catalysts0 aBenzylation of benzene and other aromatics by benzyl chloride ov  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY  a195-2030 v803 a<p>Aluminum-containing mesoporous molecular sieves AISBA-15 with different n(Si)/n(Al), ratios and AIMCM-41 have been synthesized hydrothermally and characterized in detail by physicochemical methods, viz. XRD, N(2) adsorption and (27)Al NMR spectroscopy. The low angle XRD and N2 adsorption measurements reveal that the structural order of SBA-15 was retained after the incorporation of Al. The increase of the unit cell parameter with increasing aluminum content and (27)Al MAS NMR spectroscopy confirm the incorporation of aluminum in the framework. Benzylation of benzene and substituted benzenes reaction employing benzyl chloride as the alkylating agent over AISBA-15 and AIMCM-41 have been investigated. The influence of various reaction parameters such as reaction temperature, reactant feed ratio and catalyst amount affecting the activity and selectivity of AISBA-15, have been studied. Among the mesoporous catalysts studied, AISBA-15(45), where the number in parentheses indicates the molar nsilnA, ratio, shows both high conversion and high selectivity for the benzylation of benzene. The activity of this catalyst for the benzylation of different aromatic compounds is in the following order: benzene &gt; toluene &gt; p-xylene &gt; mesitylene &gt; anisole. Kinetics of the benzene benzylation over different catalysts have also been investigated. (c) 2005 Elsevier Inc. All rights reserved.</p>10aAlkylation10aAlSBA-1510aBenzylation10aSBA-151 aVinu, A.1 aSawant, D., P.1 aAriga, Katsuhiko1 aHartmann, Martin1 aHalligudi, Shivappa, B.  uhttps://library.ncl.res.in/content/benzylation-benzene-and-other-aromatics-benzyl-chloride-over-mesoporous-alsba-15-catalysts-002787nas a2200265   4500008004100000022001400041245019900055210006900254260006800323300001400391490000700405520175200412653001402164653003502178653001302213100002102226700001702247700001502264700001702279700001902296700002802315700002502343700002702368856012602395       2005                        eng d  a0021-899500aComparison of the pervaporation separation of a water-acetonitrile mixture with zeolite-filled sodium alginate and poly(vinyl alcohol)-polyaniline semi-interpenetrating polymer network membranes0 aComparison of the pervaporation separation of a wateracetonitril  a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcJUN  a1968-19780 v963 a<p>The pervaporation (PV) separation performance of ZSM-5- and Na-Y-type zeolite-filled sodium alginate (NaAlg) membranes were compared with those of pure NaAlg and semi-interpenetrating polymer network (semi-IPN) membranes of poly(vinyl alcohol) (PVA) with polyaniline (PANI) for the dehydration of acetonitrile. The PV separation characteristics of the zeolite-filled membranes showed a dependence on the nature of the zeolites. The variation of the acidity function of the ZSM-5 zeolite had an influence on the flux and selectivity of the membranes when compared to unfilled membranes. The crosslinked membranes were characterized by differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. Increasing the PANI content of the semi-IPN network increased the separation selectivity. Among the NaAlg membranes, the plain NaAlg membrane showed the highest selectivity of 414 at 30 mass % water in the feed mixture, whereas the Na-Y- and ZSM-5 (40)-filled NaAlg membranes exhibited much lower values of selectivity, that is, 7.3 and 4.3, respectively for 30 mass % water in the feed. When the flux and selectivity data of ZSM-5 (250)-filled NaAlg membranes were compared with that of Na-Y- or ZSM-5 (40)-filled NaAlg membranes, a noticeable increase in the selectivity for the ZSM-5 (250)filled NaAlg membrane was observed, but a somewhat comparable flux was observed compared to the plain NaAlg membrane. For the first time, PANI was polymerized with PVA to yield a semi-IPN. The total flux and water flux increased systematically, whereas the selectivity decreased greatly from 251.87 to 5.95 with increasing amounts of water in the feed. (c) 2005 Wiley Periodicals, Inc.</p>10aDiffusion10ainterpenetrating network (IPN)10azeolites1 aNaidu, B., V. K.1 aBhat, S., D.1 aSairam, M.1 aWali, A., C.1 aSawant, D., P.1 aHalligudi, Shivaraj, B.1 aMallikarjuna, N., N.1 aAminabhavi, Tejraj, M.  uhttps://library.ncl.res.in/content/comparison-pervaporation-separation-water-acetonitrile-mixture-zeolite-filled-sodium-002478nas a2200217   4500008004100000022001400041245009700055210006900152260007100221300001400292490000700306520167900313100001301992700001902005700002102024700002002045700002802065700002102093700001502114856013102129       2005                        eng d  a0897-475600aDirect synthesis of well-ordered and unusually reactive FeSBA-15 mesoporous molecular sieves0 aDirect synthesis of wellordered and unusually reactive FeSBA15 m  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcOCT  a5339-53450 v173 a<p>Large-pore hexagonal SBA-15 molecular sieves partially substituted with iron(III) have been synthesized for the first time in highly acidic media. The degree of iron(III) incorporation into SBA-15 can easily be controlled by a simple adjustment of the molar ratio of water and hydrochloric acid. All the materials have been characterized by XRD, N-2 adsorption, UV-Vis DRS, ESR, and XANES spectroscopy. The characterization of the FeSBA-15 materials by UV-Vis DRS, ESR, and XANES spectroscopies suggests that the iron atoms are highly dispersed and mostly occupy isolated tetrahedral sites. XANES studies revealed that the proportion of tetrahedrally coordinated Fe atoms decreases with decreasing n(Si)/n(Fc) ratios. Benzylation of benzene (or substituted benzenes) using benzyl chloride as the alkylating agent over FeSBA-15 with different n(Si)/n(Fe) ratios was investigated as was the same reaction using AISBA-15 as catalyst. The influence of parameters such as reaction temperature, reactant feed ratio, and the presence of electron-donating substituents on the activity and selectivity of AISBA-15 was studied. Under optimized reaction conditions, the FeSBA-15 catalyst showed a superior catalytic performance in the benzylation of benzene and other aromatics using benzyl chloride, with a clean conversion of benzyl chloride to the monoalkylated product (100% selectivity) with a very high rate constant when compared to other mesoporous materials such as AISBA-15 and FeHMS. Interestingly, use of FeSBA-15(21) resulted in quantitative conversion of benzyl chloride with a high rate constant of 2420.5 x 10(-4) min(-1) under the optimized reaction conditions.</p>1 aVinu, A.1 aSawant, D., P.1 aAriga, Katsuhiko1 aHossain, K., Z.1 aHalligudi, Shivappa, B.1 aHartmann, Martin1 aNomura, M.  uhttps://library.ncl.res.in/content/direct-synthesis-well-ordered-and-unusually-reactive-fesba-15-mesoporous-molecular-sieves-002439nas a2200241   4500008004100000022001400041245017000055210006900225260009500294300001200389490000800401520147800409653001401887653003201901653002101933653001301954100001901967700001301986700002201999700001702021700002802038856013102066       2005                        eng d  a0021-951700aFormation of nanosized zirconia-supported 12-tungstophosphoric acid in mesoporous silica SBA-15: a stable and versatile solid acid catalyst for benzylation of phenol0 aFormation of nanosized zirconiasupported 12tungstophosphoric aci  a525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USAbACADEMIC PRESS INC ELSEVIER SCIENCEcOCT  a341-3520 v2353 a<p>A nanosized zirconia-supported 12-tungstophosphoric acid (TPA) in SBA-15 composite was prepared by wet impregnation of TPA/ZrO2 nanoparticles inside the mesoporous channels of SBA-15. The resulting composite material was calcined at 1123 K and characterized by elemental analysis, powder X-ray diffraction, nitrogen adsorption isotherms, transmission electron microscopy (TEM), scanning electron microscopy (SEM), solid-state P-31 CP-MAS NMR, Si-29 MAS NMR, UV-vis diffuse reflectance spectra, FTIR, TPD of ammonia, FTIR pyridine adsorption, and thermogravimetric analysis (TG-DTG). The synthesized TPA/ZrO2/SBA-15 showed a well-ordered hexagonal inesoporous structure and mesoporous support SBA-15 stabilized ZrO2-t (tetragonal) phase with crystal size in the range of 3-4 nm. SBA-15 was a better support than MCM-41 and MCM-48 because it retained its mesostructure even after high TPA loading and high calcination temperatures. Mesoporous silica support plays an important role in stabilizing the catalytically active tetragonal phase of zirconia, which gave the most active catalysts. The catalysts were examined for their catalytic activities in the liquid phase benzylation of phenol with benzyl alcohol and the catalyst 15 wt% TPA/ 22.4 wt% ZrO2/SBA-15 calcined at 1123 K was found to have high acidity and to be 10 times more active than neat TPA/ZrO2 Under the reaction conditions studied in benzylation of phenol. (c) 2005 Elsevier Inc. All rights reserved.</p>10ananosized10aphenol benzylation reaction10aterragonal phase10aTPA/ZrO21 aSawant, D., P.1 aVinu, A.1 aJacob, Nalini, E.1 aLefebvre, F.1 aHalligudi, Shivappa, B.  uhttps://library.ncl.res.in/content/formation-nanosized-zirconia-supported-12-tungstophosphoric-acid-mesoporous-silica-sba-15-002744nas a2200265   4500008004100000022001400041245012400055210006900179260007300248300001200321490000800333520176200341653001002103653001102113653003802124653002902162653002002191653001902211653003002230100001902260700002102279700001902300700002802319856013102347       2006                        eng d  a1381-116900aChemoselective anti-Markovnikov hydroamination of alpha,beta-ethylenic compounds with amines using montmorillonite clay0 aChemoselective antiMarkovnikov hydroamination of alphabetaethyle  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY  a210-2170 v2503 a<p>The catalytic activity of montmorillonite clays as a catalyst for the hydroamination of alpha,beta-ethylenic compounds with amines was tested. Aniline and substituted amines reacted with alpha,beta-ethylenic compounds in the presence of catalytic amount of commercially available clay to afford exclusively anti-Markovnikov adduct in excellent yields. Aniline reacted with ethyl acrylate to yield only anti-Markovnikov adduct N-[2-(ethoxycarbonyl)ethyl] aniline (mono-addition product). No Markovnikov adduct (N-[1-(ethoxycarbonyl)ethyl]aniline and double addition product N,N-bis[2-(ethoxycarbonyl)ethyl]aniline were formed under selected reaction conditions. For a better exploitation of the catalytic activity in terms of increased activity and improved selectivity for the mono-addition product, the reaction parameters were optimized in terms of temperature, solvent, reactant mole ratio. Under optimized reaction conditions, montmorillonite clay K-10 showed a superior catalytic performance in the hydroamination of ethyl acrylate with aniline with a conversion of aniline to mono-addition product (almost 100% chemoselectivity) with a high rate constant 0.3414 min(-1) compared to the reported protocols. The dependence of conversion of aniline over different types of montmorillonite clays (K-10, K-20, K-30, Al-Pillared clay and untreated clay) has also been discussed. The activities of clay for the hydroamination of different aromatic and aliphatic amines have also been investigated. Under harsh reaction conditions (increased temperature and long reaction time) small amounts of di-addition products were observed. The kinetics data has been interpreted using the initial rate approach model. (c) 2006 Elsevier B.V. All rights reserved.</p>10aalpha10aamines10aanti-Markovnikov addition product10abeta-ethylenic compounds10achemo-selective10ahydroamination10aK-10 montmorillonite clay1 aJoseph, Trissa1 aShanbhag, G., V.1 aSawant, D., P.1 aHalligudi, Shivappa, B.  uhttps://library.ncl.res.in/content/chemoselective-anti-markovnikov-hydroamination-alphabeta-ethylenic-compounds-amines-using-1