Immobilization of phosphotungstic acid (PTA) on imidazole functionalized silica: evidence for the nature of PTA binding by solid state NMR and reaction studies

TitleImmobilization of phosphotungstic acid (PTA) on imidazole functionalized silica: evidence for the nature of PTA binding by solid state NMR and reaction studies
Publication TypeJournal Article
Year of Publication2009
AuthorsSofia, LTAany, Krishnan, A, Sankar, M, Raj, NKKala, Manikandan, P, Rajamohanan, PR, Ajithkumar, TG
JournalJournal of Physical Chemistry C
Volume113
Issue50
Pagination21114-21122
Date PublishedDEC
ISSN1932-7447
Abstract

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

DOI10.1021/jp906108e
Type of Journal (Indian or Foreign)

Foreign

Impact Factor (IF)

4.520

Divison category: 
Catalysis and Inorganic Chemistry
Central NMR Facility