Oxidative catalytic versatility of a trivacant polyoxotungstate incorporated into MIL-101(Cr)

authors	Granadeiro, CM; Barbosa, ADS; Ribeiro, S; Santos, ICMS; de Castro, B; Cunha-Silva, L; Balula, SS
nationality	International
journal	CATALYSIS SCIENCE & TECHNOLOGY
keywords	LIQUID-PHASE OXIDATION; HETEROGENEOUS CATALYSTS; KEGGIN-TYPE; COMPLEX HETEROPOLYTUNGSTATES; DEEP DESULFURIZATION; LIMONENE EPOXIDATION; PHOSPHOTUNGSTIC ACID; POLYOXOMETALATE; H2O2; PERFORMANCE
abstract	The first immobilization of the trivacant Keggin-type polyoxometalate ([A-PW9O34](9-), PW9) to prepare a novel heterogeneous oxidative catalyst is here reported. PW9 was incorporated into the cavities of the chromium terephthalate metal-organic framework MIL-101(Cr). Characterization of the composite PW9@MIL-101 by powder X-ray diffraction, SEM-EDX, FT-IR, FT-Raman spectroscopy, N-2 adsorption-desorption isotherms and P-31 solid-state NMR confirmed that the structures of MIL-101 and the polyoxometalate anion were retained after immobilization. The composite PW9@MIL-101 revealed versatility as a heterogeneous catalyst to oxidize efficiently monoterpenes as well as to reach a complete desulfurization of a model oil containing the most refractory sulfur compounds in fuel, using in both systems acetonitrile as the solvent and H2O2 as the oxidant. Complete conversion of geraniol to 2,3-epoxygeraniol was achieved after the first 30 min at room temperature, while the total desulfurization of the model oil containing 1707 ppm of sulfur was attained after 2 h. In both systems the catalyst was recyclable for various cycles without a significant loss of activity. The stability and heterogeneity of the catalyst were confirmed by several techniques and by leaching tests.
publisher	ROYAL SOC CHEMISTRY
issn	2044-4753
year published	2014
volume	4
issue	5
beginning page	1416
ending page	1425
digital object identifier (doi)	10.1039/c3cy00853c
web of science category	Chemistry, Physical
subject category	Chemistry
unique article identifier	WOS:000335893200026