02053nas a2200229   4500008004100000020001800041022001400059245009100073210006900164260012300233300001200356490000800368520119500376100001901571700002201590700002101612700001301633700002801646700001501674700001701689856011701706       2005                        eng d  a0-444-51748-0  a0167-299100aImmobilized molybdovanadophosphoric acids on SBA-15 for selective oxidation of alkenes0 aImmobilized molybdovanadophosphoric acids on SBA15 for selective  a Niagara Falls, CanadabElsevier Science BV, Sara Burgerhartstraat 25, Po Box 211, 1000 AE Amsterdam, NetherlandscJUN  a769-7780 v1563 a<p>Vanadium substituted molybdophosphoric acids have been immobilized on amine functionalized SBA-15 and characterized by different techniques. Small angle X-ray scattering analysis and SEM technique provide evidence for the structural integrity of the samples. UV-Vis, NMR and IR data confirm the incorporation of molybdovanadophosphoric acids onto the amine functionalized SBA-15. The textural properties of these materials were studied by nitrogen sorption studies. Oxidation of cyclooctene and norbornene was carried out with oxidants in aqueous (aq. H2O2) and non-aqueous (TBHP extracted in dichloroethane) medium. The reactions were carried out with both the neat catalysts (homogeneous) and the immobilized catalysts (heterogenized) and the results were compared. The selectivity of the desired products was always &gt; 99% with the immobilized catalyst with both aq.H2O2 and TBHP. However, while the leaching was negligible in the non-aqueous medium, the aqueous medium leads to considerable leaching. The immobilized catalysts could be separated after the reaction and the reusability of the catalyst has also been demonstrated especially with oxidant in the nonaqueous medium.</p>1 aRaj, N., K. K.1 aDeshpande, S., S.1 aIngle, Rohit, H.1 aRaja, T.1 aManikandan, Palanichamy1 aSayari, A.1 aJaroniec, M.  uhttp://library.ncl.res.in/content/immobilized-molybdovanadophosphoric-acids-sba-15-selective-oxidation-alkenes-001825nas a2200217   4500008004100000022001400041245016400055210006900219260007100288300001600359490000800375520093400383100002301317700001901340700001501359700002101374700002801395700002401423700003201447856012801479       2009                        eng d  a1932-744700aImmobilization of phosphotungstic acid (PTA) on imidazole functionalized silica: evidence for the nature of PTA binding by solid state NMR and reaction studies0 aImmobilization of phosphotungstic acid PTA on imidazole function  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcDEC  a21114-211220 v1133 a<p>Phosphotungstic acid (PTA) immobilized onto imidazole functionalized fumed silica and was used its an efficient catalyst for epoxidation of a variety of olefins using aqueous H(2)O(2) as all oxidant. Negligible leaching of PTA under the reaction conditions employed indicates a strong interaction between PTA and imidazole The immobilized catalysts Could be separated and reused after the catalytic cycle Evidence for the heterogenization of PTA oil the imidazole functionalized fumed silica has been inferred from different spectroscopic techniques like IR, UV-vis, and NMR. Importantly, the nature of binding of PTA oil the support has been studied in detail by solid state NMR spectroscopy using (15)N labeled imidazole Support. It is clear from the NMR Studies that the effective heterogenization of PTA is mainly due to imidazolium ion Formation oil the support by the acidic protons of PTA and the resultant ion pair</p>1 aSofia, L., T. Aany1 aKrishnan, Asha1 aSankar, M.1 aRaj, N., K. Kala1 aManikandan, Palanichamy1 aRajamohanan, P., R.1 aAjithkumar, Thalasseril, G.  uhttp://library.ncl.res.in/content/immobilization-phosphotungstic-acid-pta-imidazole-functionalized-silica-evidence-nature-0