WO3/ZrO2 systems were prepared by sol-gel technique using different procedures for the solvent extraction: evaporation in vacuum at RT (xerogel) and extraction in supercritical conditions (aerogel). Two reactions of industrial interest were investigated under mild conditions: (i) acylation of veratrole with acetic anhydride; (ii) acylation of anisole with benzoic anhydride. Several techniques were employed in order to study the influence of the synthetic parameters on texture and catalytic activity: N2 physisorption, FT-IR spectroscopy, XPS, TPR and TPO analyses. The solvent extraction strongly influences metal reducibility, surface area, pores organisation, W/Zr surface density and metal interaction. The aerogel sample shows the best catalytic results for both conversion and yield. The supercritical extraction plays a central role especially in the recycling: by proper air activation, the aerogel sample attains the complete restoration of the catalytic activity even after three runs.

Aerogel and xerogel WO3/ZrO2 samplesfor fine chemicals production

SIGNORETTO, Michela;GHEDINI, Elena;MENEGAZZO, FEDERICA;
2013

Abstract

WO3/ZrO2 systems were prepared by sol-gel technique using different procedures for the solvent extraction: evaporation in vacuum at RT (xerogel) and extraction in supercritical conditions (aerogel). Two reactions of industrial interest were investigated under mild conditions: (i) acylation of veratrole with acetic anhydride; (ii) acylation of anisole with benzoic anhydride. Several techniques were employed in order to study the influence of the synthetic parameters on texture and catalytic activity: N2 physisorption, FT-IR spectroscopy, XPS, TPR and TPO analyses. The solvent extraction strongly influences metal reducibility, surface area, pores organisation, W/Zr surface density and metal interaction. The aerogel sample shows the best catalytic results for both conversion and yield. The supercritical extraction plays a central role especially in the recycling: by proper air activation, the aerogel sample attains the complete restoration of the catalytic activity even after three runs.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10278/30962
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