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<p>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.</p>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-001826nas a2200265   4500008004100000022001400041245014000055210006900195260007300264300001200337490000800349520081600357653001501173653002001188653003801208653003101246653001401277653001101291100002801302700002101330700002401351700002901375700002501404856013101429       2010                        eng d  a1387-181100aMicro-/meso-porous stannosilicate composites (Sn-MFI/MCM-41) via two-step crystallization process: process parameter-phase relationship0 aMicromesoporous stannosilicate composites SnMFIMCM41 via twostep  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcDEC  a115-1250 v1363 a<p>Sn-MFI/MCM-41 composite material was successfully synthesized by monitoring the re-crystallization time in a simple two-step crystallization process. The length of period allowed for the recrystallization of the precursor species was found to be a controlling factor to achieve either the end members viz. Sn-MCM-41 and Sn-MFI or Sn-MFI/MCM-41 composite material. Powder XRD, FTIR, SEM, TEM, nitrogen sorption measurement, DRUV-vis and hydroxyalkylation of p-cresol reaction were used as the characterization tools. Attempts were also made to establish the relationship between type of phase formed and the process parameters such as aging time, re-crystallization temperature, time and molar ratios of TPAOH/SiO(2), CTMABr/SiO(2) and SiO(2)/SnO(2) in the gel. (C) 2010 Elsevier Inc. All rights reserved.</p>10acomposites10aCrystallization10aMicro-/meso-porous stannosilicate10ap-Cresol hydroxyalkylation10aSn-MCM-4110aSn-MFI1 aNiphadkar, Prashant, S.1 aGarade, Ajit, C.1 aJha, Ratnesh, Kumar1 aRode, Chandrashekhar, V.1 aJoshi, Praphulla, N.  uhttps://library.ncl.res.in/content/micro-meso-porous-stannosilicate-composites-sn-mfimcm-41-two-step-crystallization-process-0