Liquid Phase Selective Oxidation of Alcohols over VPO Catalysts Supported on Mesoporous Hexagonal Molecular Sieves (HMS) |
| |
Authors: | Vahid Mahdavi Hamid Reza Hasheminasab Sohrab Abdollahi |
| |
Institution: | 1. Department of Chemistry, Surface Chemistry and Catalysis Division, University of Arak, Arak 38156, Iran;2. Department of Chemistry, Payam nour University, Abadeh, Iran |
| |
Abstract: | The vanadium phosphorous oxide (VPO) catalysts, supported on mesoporous hexagonal molecular sieves (HMS) with different vanadium loadings, were prepared by precipitation method on organic phase. Techniques such as XRD, BET and SEM, were used for characterization of the catalyst. The bulk VPO catalyst contains vanadyl pyrophosphate phase ((VO)2P2O7), and a small amount of VOPO4. The high surface area, large pore volume and pore size of HMS in VPO/HMS samples, provide an excellent dispersion of same phase of VPO compound on the support surface. Oxidation of various alcohols was studied in the liquid phase over VPO/HMS catalyst, using tert‐butylhydroperoxide (TBHP) as an oxidant. The activity of VPO/HMS samples were considerably increased with respect to bulk VPO catalyst. At 90 °C, the obtained activities were 0.567 and 6.545 gpro.g?1VPOh?1 over the bulk VPO and 20 wt% VPO/HMS catalysts, respectively. The effects of substrates, reaction time, reaction temperature, solvents, catalyst recycling and leaching of VPO in liquid phase reaction were also investigated. The following order has been observed for the percentage of conversions of alcohols: Benzylic alcohol > Secondary alcohol ~ Primary alcohol. The kinetic of benzyl alcohol oxidation using excess TBHP over VPO/HMS catalyst was investigated at temperatures of 27, 60 and 90 °C, and followed a pseudo‐first order with respect to benzyl alcohol. |
| |
Keywords: | Vanadium phosphorus oxide HMS Benzyl alcohol Alcohol oxidation Supported VPO catalyst |
|
|