01826nas a2200217   4500008004100000022001400041245016400055210006900219260007100288300001600359490000800375520093400383100002301317700001901340700001501359700002101374700002801395700002401423700003201447856012901479       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.  uhttps://library.ncl.res.in/content/immobilization-phosphotungstic-acid-pta-imidazole-functionalized-silica-evidence-nature-0