Catalytic behavior of the WOx-ZrO2 system in the clean selective oxidation of diphenyl sulfide (DPS)

MUÑOZ, MERCEDES; MENDOZA-HERRERA, LUÍS J.; ROMANELLI, GUSTAVO P.; GAZZOLI, DELIA; CABELLO, CARMEN I.

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ELSEVIER SCIENCE BV

Año: 2021 vol. 372 p. 146 - 153

0920-5861

WO x -ZrO 2 (ZWx) based catalysts were prepared by equilibrium adsorption in basic condition(pH 10) with W content of 10.5, 19.7 and 27.0 wt.%, using hydrous zirconia [ZrO 2 (383)] assupport. In order to determine the soluble fraction of W species which did not interact with thesurface, samples were leached with NH 3 , dried and re-calcined [ZWx(NH 3 )y]. The W contentwas determined by spectrophotometric method, before and after the leaching. All catalysts werecharacterized by textural analysis (BET), X-ray diffraction (XRD) and Raman spectroscopy;the acidic strength was determined by potentiometric titration with n-butylamine.The catalytic behavior was analyzed for the selective oxidation of diphenyl sulfide (DPS) todiphenyl sulfoxide (DPSO) or diphenyl sulfone (DPSO 2 ) using H 2 O 2 as oxidizing agent. Highconversion of DPS (~100%) and selectivity to DPSO 2 (>90%) at 60 min of reaction time wereobtained for the ZWx series of catalysts. The ZWx(NH 3 )y series (W content: 3.65, 6.50 and7.50 wt.%, respectively) also showed high selectivity to diphenyl sulfone but the maximumconversion (~100%) was achieved with reaction times longer (30 min) than those of the ZWx(10 min) samples.Polytungstate species strongly interacting with the support, identified by Raman spectroscopy in both series of samples, are considered the active phases.