02427nas a2200241 4500008004100000022001400041245013100055210006900186260006900255300001200324490000800336520150300344653002001847653002301867653002601890653001101916100002801927700002701955700002601982700002202008700002502030856013002055 2009 eng d a0254-058400aTin-silicalite-1: synthesis by dry gel conversion, characterization and catalytic performance in phenol hydroxylation reaction0 aTinsilicalite1 synthesis by dry gel conversion characterization  aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcMAR a344-3490 v1143 a

Tin-silicalite-1 (Sn-MFI) has been successfully synthesized by dry gel conversion (DGC) method. The influence of various synthesis parameters such as crystallization time, temperature, water content at the bottom of autoclave, molar ratios of (TPA)(2)O/SiO(2) and SiO(2)/SnO(2) in dry gel on the crystallization kinetics and physico-chemical properties of Sn-MFI materials has been investigated. Powder-X-ray diffraction (XRD),XPS,AAS, DRUV-vis and SEM techniques were employed as characterization tools. Time-dependent studies revealed that, the progressive crystallization of Sn-MFI depend not only on the synthesis time but also on the other various synthesis parameters. Increase in the crystallization temperature, water content at bottom of autoclave (TPA)(2)O/SiO(2) and SiO(2)/SnO(2) molar ratios in dry gel resulted in the lowering of overall crystallization period. A good correspondence between the chemical composition of the surface and the bulk indicated the uniform distribution of Sn(4+) ions. The presence of these ions in tetrahedral coordination has been indicated by DRUV-vis spectral studies. Although, not better but comparable activity has been shown by Sn-MFI prepared by dry gel conversion method with Sn-MFI prepared by conventional hydrothermal crystallization method in the hydroxylation of phenol reaction. Increase in concentration of isolated Sn(4+) ions led to increase in phenol conversion and H(2)O(2) efficiency. (c) 2008 Elsevier B.V. All rights reserved.

10acrystallisation10aDry gel conversion10amicroporous materials10aSn-MFI1 aNiphadkar, Prashant, S.1 aKotwal, Mehejabeen, S.1 aDeshpande, Shilpa, S.1 aBokade, Vijay, V.1 aJoshi, Praphulla, N. uhttps://library.ncl.res.in/content/tin-silicalite-1-synthesis-dry-gel-conversion-characterization-and-catalytic-performance-002723nas a2200277 4500008004100000022001400041245016200055210006900217260007300286300001000359490000800369520166100377653002402038653003202062653001902094653002102113653001902134100002902153700002202182700002802204700002502232700002602257700002102283700002202304856011902326 2013 eng d a0926-860X00aCatalytic upgrading of renewable levulinic acid to ethyl levulinate biodiesel using dodecatungstophosphoric acid supported on desilicated H-ZSM-5 as catalyst0 aCatalytic upgrading of renewable levulinic acid to ethyl levulin aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJUN a90-980 v4603 a

Levulinic acid (LA) is considered as a renewable platform chemical and can be used for the synthesis of variety of important fuels and chemicals. In particular, its esterification with ethanol produces ethyl levulinate (EL) would be green process, as it can be used as diesel miscible biofuel (DMB), preventing global warming by decreasing atmospheric CO2. This study explores the use of modified H-ZSM-5 by desilication viz.; DH-ZSM-5 and dodecatungstophosphoric acid (DTPA) loaded on DH-ZSM-5 for esterification of LA with ethanol aiming to EL. Different degree of desilication of H-ZSM-5 was performed by using aq. NaOH (0.2-1.5 M) at 338 K for 30 min and then DTPA was loaded on these desilicated H-ZSM-5 (DH-ZSM-5) support. H-ZSM-5, DH-ZSM-5 and DTPA on these DH-ZSM-5 samples were characterized by powder x-ray diffraction (XRD), N-2 adsorption-desorption, pyridine chemisorbed IR spectroscopy, Temperature Programmed Ammonia Desorption (TPAD). The increase in conversion of levulinic acid was observed from 28% to 94% with increase of DTPA loading from 0% to 15%. The increased LA conversion may be due to increase in total acidity from 43.14% to 84.31%. The use of DH-ZSM-5 as support for deposition of DTPA may be reported for the first time. The present work also extended to optimize process parameters such as DTPA loading on DH-ZSM-5, catalyst to LA ratio, LA to ethanol molar ratio, speed of agitation, particle size reaction temperature and catalyst reusability. Kinetic study based on pseudo-homogeneous (P-H) model is also presented. The experimental results follow second order kinetics. (C) 2013 Elsevier B.V. All rights reserved.

10adesilicated H-ZSM-510aDTPA on desilicated H-ZSM-510aEsterification10aethyl levulinate10alevulinic acid1 aNandiwale, Kakasaheb, Y.1 aSonar, Shilpa, K.1 aNiphadkar, Prashant, S.1 aJoshi, Praphulla, N.1 aDeshpande, Shilpa, S.1 aPatil, Vilas, S.1 aBokade, Vijay, V. uhttps://library.ncl.res.in/content/catalytic-upgrading-renewable-levulinic-acid-ethyl-levulinate-biodiesel-using-002442nas a2200241 4500008004100000022001400041245010500055210006900160260007300229300001200302490000800314520152400322653002101846653001301867653003301880653002401913653003401937100002401971700002801995700002602023700002502049856012602074 2013 eng d a0926-860X00aDehydrogenation of cyclohexanol over Cu/Al2O3 catalysts prepared with different precipitating agents0 aDehydrogenation of cyclohexanol over CuAl2O3 catalysts prepared  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcOCT a421-4290 v4673 a

Dehydrogenation of cyclohexanol over Cu/Al2O3 catalysts (molar Cu:Al = 1:1) prepared by reduction of mixed oxide precursors synthesized using different precipitating agents viz, potassium carbonate, tetraalkyl ammonium hydroxides (TAAOHs) and urea was investigated. In order to assess the efficacy of TAAOH further, the chain length of tetraalkyl ammonium cations was also varied and the resulted catalysts were evaluated for their catalytic performance. The catalysts were characterized by powder X-ray diffraction, low temperature nitrogen adsorption, temperature programmed desorption of ammonia and UV-visible diffuse reflectance spectroscopy. The dependence of the catalyst performance on the precipitating agent employed during its synthesis has been clearly demonstrated. The use of TAAOH as precipitating agent led to the formation of a catalyst with better catalytic activity than those prepared using potassium carbonate and urea. Further improvement in the catalytic performance was observed when TAAOH with longer alkyl chain ammonium cation was used. The optimum catalyst prepared by reduction of mixed oxide precursor synthesized using tetrapropyl ammonium hydroxide as precipitating agent, showed highest cyclohexanol conversion (81.5%) and cyclohexanone selectivity (79.6%) at 250 degrees C on account of higher Cu+/Cu-0 ratio, well dispersed copper, higher surface area and lower total acidity with higher contribution of sites with moderate strength. (C) 2013 Elsevier B.V. All rights reserved.

10aCharacterization10aCu/Al2O310aCyclohexanol dehydrogenation10aPrecipitating agent10aTetraalkyl ammonium hydroxide1 aTangale, Nilesh, P.1 aNiphadkar, Prashant, S.1 aDeshpande, Shilpa, S.1 aJoshi, Praphulla, N. uhttps://library.ncl.res.in/content/dehydrogenation-cyclohexanol-over-cual2o3-catalysts-prepared-different-precipitating-002179nas a2200265 4500008004100000022001400041245014500055210006900200260007400269300000900343490000800352520117700360653001501537653001801552653001901570653002101589653002801610100002201638700002101660700002801681700002501709700002601734700002401760856012901784 2013 eng d a0049-697900aEnhanced dual-effect of adsorption and photodegradation of SiO2 embedded TiO2 hybrid catalyst for improved decolourization of methylene blue0 aEnhanced dualeffect of adsorption and photodegradation of SiO2 e aVAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDSbSPRINGERcSEP a17260 v2243 a

Dual-effects of adsorption and photodegradation over titania, silica embedded titania, silica and commercial Degussa P-25 samples were studied for the decolourization of methylene blue in aqueous medium. Silica embedded titania and silica were prepared using inexpensive polymeric version of ethyl silicate as a source of silica. Catalysts were characterized by X-ray diffraction, scanning electron microscopy, UV-Vis spectroscopy and low temperature (77 K) nitrogen adsorption measurements. Among all the catalysts, silica embedded titania has exhibited faster decolourization of methylene blue solution on account of the enhancement of adsorption followed by degradation. An amount of the catalyst and the initial dye concentration of MB solution were found to influence the decolourization activity. Compared to titania catalyst, silica embedded titania and Degussa P-25 have shown the red shift in their UV-Vis spectrum. The experimental data of the reaction fitted well to the pseudo first order kinetic model. In present studies, the adsorption mechanism for the decolourization of MB solution was found to be applicable for an intra particle diffusion model.

10aAdsorption10akinetic model10aMethylene blue10aPhotodegradation10aSilica embedded titania1 aSonar, Shilpa, K.1 aWagh, Reshma, V.1 aNiphadkar, Prashant, S.1 aJoshi, Praphulla, N.1 aDeshpande, Shilpa, S.1 aAwate, Shobhana, V. uhttps://library.ncl.res.in/content/enhanced-dual-effect-adsorption-and-photodegradation-sio2-embedded-tio2-hybrid-catalyst-002418nas a2200229 4500008004100000022001400041245013700055210006900192260006700261300001400328490000700342520151900349653002401868653001901892653002101911653001901932100002901951700002801980700002602008700002202034856013202056 2014 eng d a0268-257500aEsterification of renewable levulinic acid to ethyl levulinate biodiesel catalyzed by highly active and reusable desilicated H-ZSM-50 aEsterification of renewable levulinic acid to ethyl levulinate b a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcOCT a1507-15150 v893 a

BACKGROUNDIn the near future, fossil fuel will have limitations in terms of availability and also great concerns over its environmental impact. New routes and related technologies based on renewable feedstocks can overcome most of these problems associated with fossil fuel. Among current biodiesel sources, ethyl levulinate (EL) biodiesel obtained from catalytic esterification of renewable levulinic acid (LA) with ethanol has received a great deal of attention. The use of desilicated H-ZSM-5 (DH-ZSM-5) as heterogeneous acid catalyst for EL biodiesel production in a closed system (under autogeneous pressure) was studied. RESULTSThe effect of reaction parameters such as ethanol to LA molar ratio (4:1 to 10:1), catalyst to LA ratio (0.10-0.25), speed of agitation (100-400rpm), particle size (53-355 mu m), reaction temperature (363-403K) and reaction time (7h) was investigated to maximize LA conversion. CONCLUSIONLevulinic acid conversion reached 95% over DH-ZSM-5 and the catalyst was reusable for up to six cycles. This LA conversion and the catalyst reusability values are higher than others reported in the literature. A pseudo-homogeneous (P-H) kinetic model indicated that reaction rate constants increased with increasing molar ratio, catalyst to LA ratio and reaction temperature. The activation energy decreased from 73.14 to 21.08 kJ mol(-1) when increasing the catalyst to LA ratio from 0.10 to 0.25, which implies a kinetically controlled reaction. (c) 2013 Society of Chemical Industry

10adesilicated H-ZSM-510aEsterification10aethyl levulinate10alevulinic acid1 aNandiwale, Kakasaheb, Y.1 aNiphadkar, Prashant, S.1 aDeshpande, Shilpa, S.1 aBokade, Vijay, V. uhttps://library.ncl.res.in/content/esterification-renewable-levulinic-acid-ethyl-levulinate-biodiesel-catalyzed-highly-active-0