Real-time Raman monitoring of liquid-phase cyclohexene epoxidation over alumina-supported vanadium and phosphorous catalysts

The solvent-free liquid phase epoxidation of cyclohexene with tert-butyl hydroperoxide over alumina-supported VPO and VPO bulk catalysts has been widely investigated using in situ Raman spectroscopy. Real-time Raman monitoring provides non-invasive insight during epoxidation of cyclohexene in the presence of heterogeneous catalysts in the absence of any solvent. The progress of the reaction was monitored following the changes in intensity of the characteristic Raman bands, which is more reliable than the use of gas chromatography analyses. The results obtained by real-time Raman monitoring confirms the reaction mechanism and provides a mean to monitor the deactivation of catalysts. The interaction between vanadium oxide species and VPO phases generates the active site. Their interaction renders the catalytic system efficient for production of 1,2-epoxycyclohexane.

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► In situ real-time Raman monitors liquid-phase cyclohexene epoxidation.
► Solvent-free epoxidation of cyclohexene with TBHP over Al2O3-supported VPO catalysts.
► Raman monitoring confirms the reaction mechanism of the cyclohexene epoxidation.
► Raman spectroscopy monitors the deactivation of catalysts during reaction.
► Real-time Raman monitoring is more reliable than the use of GC analyses.