02003nas a2200217 4500008004100000022001400041245010200055210006900157260009800226300001200324490000700336520117300343653004001516653001701556653001101573653002301584653000801607100001901615700002501634856012601659 2006 eng d a0959-810300aSilica-supported bis(imino)pyridyl iron(II) catalyst: nature of the support-catalyst interactions0 aSilicasupported bisiminopyridyl ironII catalyst nature of the su aTHE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLANDbJOHN WILEY & SONS LTDcAUG a854-8610 v553 a

Ethylene polymerizations were performed using silica-supported 2,6-bis[1-(2,6-diisopropylphenylimino) ethyl] pyridine iron(II) dichloride with methylaluminoxane (MAO) as co-catalyst. Silica was calcined at 600, 400 and 200 degrees C under vacuum for 8 h. The effect of calcination temperature of silica on the polymerization activity and the properties of the polymers obtained were examined. Catalyst-support interactions were examined by both a chemical method and XPS. It was observed that upon supporting the catalyst on the surface of silica, there is an increase in the binding energy of the metal center. However, no change in the metal binding energy was observed on supporting the catalyst to silica calcined at different temperatures. Ethylene polymerizations were performed using MAO as co-catalyst. Catalysts were also prepared by first pretreating silica with NIAO, followed by addition of the Fe(II) catalyst and contacting a complex of Fe(II) catalyst-MAO with silica previously calcined at 400 degrees C for 8 h. The results indicate that there is no chemical bonding between the support and the catalyst. (C). 2006 Society of Chemical Industry.

10abis(imino) pyridyl iron(II) complex10aPolyethylene10asilica10asupported catalyst10aXPS1 aRay, Saptarshi1 aSivaram, Swaminathan uhttp://library.ncl.res.in/content/silica-supported-bisiminopyridyl-ironii-catalyst-nature-support-catalyst-interactions-101996nas a2200253 4500008004100000022001400041245013800055210006900193260007300262300001200335490000800347520105500355653002101410653001301431653003301444653001101477653001401488653002401502653002201526100002101548700002401569700001801593856013101611 2007 eng d a0022-309300aStructural evolutions of hydrothermally prepared mesostructured MCM-48 silica using differently manufactured amorphous silica powders0 aStructural evolutions of hydrothermally prepared mesostructured  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB a194-1990 v3533 a

The hydrothermal synthesis of Si-MCM-48 mesoporous molecular sieves was carried out using a ternary SiO2:CTAOH:H2O System wherein differently manufactured amorphous silica powders such as fumed silica (FMDS), spray dried precipitated silica (SDPS) and flash dried precipitated silica (FDPS) were used as silica source materials. The changes in structural/textural properties were evaluated using powder XRD, N-2 adsorption-desorption and scanning electron microscopy techniques. Studies on the progressive development of MCM-48 mesophases revealed that, the reactivity of the silica source follow the trend: FMDS > SDPS > FDPS. MCM-48 synthesized using low cost FDPS has exhibited thicker pore walls but poorer orderness, while MCM-48 prepared from relatively expensive FMDS has thinner pore walls and more ordered structure. Moreover, the extent of contraction caused by calcinations, agglomerate size and structural stability were found to depend on the reactivity of the silica source used. (c) 2006 Elsevier B.V. All rights reserved.

10along-range order10amicelles10ascanning electron microscopy10asilica10asilicates10asol-gels (xerogels)10aX-ray diffraction1 aTaralkar, U., S.1 aJha, Ratnesh, Kumar1 aJoshi, P., N. uhttp://library.ncl.res.in/content/structural-evolutions-hydrothermally-prepared-mesostructured-mcm-48-silica-using-differently02125nas a2200241 4500008004100000022001400041245011400055210006900169260000800238300001000246490000600256520133800262653001901600653002501619653001101644653000901655653002001664100002201684700001501706700001801721700001901739856012501758 2018 eng d a2062-249X00aContinuous flow synthesis of micron size silica nanoparticles: parametric study and effect of dosing strategy0 aContinuous flow synthesis of micron size silica nanoparticles pa cJUN a59-670 v83 a

This work for the first time reports continuous flow synthesis of silica nano-particles of size over 1 mu m using a simple tubular reactor. The systematic approach involves the study of effect of various parameters like: ammonia concentration, water concentration, electrolyte concentraton, temperature, solvent, residence time and mode of TEOS injection over a wide range. A combination of ethanol and butanol was used as the medium with relatively lower polarity. Various process parameters were optimized to obtain highly monodispersed particles of size up to 600 nm and high yield (up to 90%). Attempts of reducing the reaction time by increasing temperature or concentrations of any of the reagents resulted in significant polydispersity and even in the formation of random shape agglomerates. At the optimized conditions almost complete conversion of TEOS happenned within 40 min and further growth of particles was achieved by adding TEOS using multipoint injection approach. While multipoint dosing resulted in the formation of very small number of secondary particles, the larger particles continued to grow beyond 800 nm. Further reduction in the polarity of reaction medium was achieved by adding 20% v/v of toluene, which without changing homogeneity of the solution resulted in particles as large as 0.9-1.1 mu m.

10aFlow synthesis10aMultipoint injection10asilica10aTEOS10aTubular reactor1 aJundale, Rajashri1 aBari, Atul1 aThara, Chinnu1 aKulkarni, Amol uhttp://library.ncl.res.in/content/continuous-flow-synthesis-micron-size-silica-nanoparticles-parametric-study-and-effect02376nas a2200229 4500008004100000022001400041245010200055210006900157260000800226300001200234490000700246520158300253653002601836653002601862653001801888653001101906100002601917700002801943700002701971700002601998856012202024 2019 eng d a0944-134400aProcess development of silica extraction from RHA: a cradle to gate environmental impact approach0 aProcess development of silica extraction from RHA a cradle to ga cJAN a492-5000 v263 a

India is one of the major rice-producing countries. Rice husk is a major agricultural by-product from rice production, which is used as a fuel in boilers. Its use as fuel produces huge amounts of silica-rich rice husk ash (RHA). This paper aims at providing an overall assessment of environmental impacts associated with the extraction of silica from RHAa process developed by our study group. The functional unit used in this study is production of 100kg of silica. The analysis included the extraction and transportation of other raw materials; RHA was assumed to be processed at the site. The study was conducted in accordance with the international ISO 14040 procedural framework. LCA is performed using GaBi Education software, and five midpoint indicators are chosen to assess the environmental impacts of silica extraction. The overall climate change (CC) of the extraction process is 7.26kg CO2 equivalent per kg of silica produced. A high contribution of calcination to CC is attributed to the use of electricity. The comprehensive environmental impacts of silica-rich RHA resulting from processing of RHA and improvement options to achieve sustainable production are presented. The negative impacts that can be avoided during silica extraction are also discussed. It is observed that calcination is a major contributor to the overall environmental indicators. The work also stresses on the use of renewable energy for electricity generation, which would help in decreasing the overall greenhouse gas emissions during extraction while ensuring waste utilization.

10aEnvironmental impacts10aLife cycle assessment10aRice husk ash10asilica1 aJoglekar, Saurabh, N.1 aKharkar, Rhushikesh, A.1 aMandavgane, Sachin, A.1 aKulkarni, Bhaskar, D. uhttp://library.ncl.res.in/content/process-development-silica-extraction-rha-cradle-gate-environmental-impact-approach