Ethylbenzene oxidative dehydrogenation on MnO{sub x}/SiO{sub 2} catalysts
- Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Chemical Engineering
- Babes-Bolyai Univ., Cluj (Romania). Dept. of Chemical Technology
Supported MnO{sub x} on high surface area SiO{sub 2} (300 m{sup 2}/g) catalysts were successfully used in ethylbenzene oxidative dehydrogenation. X-ray diffraction and X-ray photoelectron spectroscopy were employed to characterize the structure of fresh and used MnO{sub x}/SiO{sub 2} catalysts. The MnO{sub x} catalysts were prepared using the pore volume impregnation method, with MnO{sub 2} loading varying from 0.7 wt % (Mn/Si = 0.005, atomic ratio) to 30 wt % (Mn/Si = 0.14). The changes in the crystalline structure and dispersion of supported MnO{sub x} were related to the precursor/support interaction and the conditions used during catalyst preparation. A possible mechanism for ethylbenzene conversion to styrene on MnO{sub x}/SiO{sub 2} catalysts is proposed, where lattice oxygen from crystalline MnO{sub 2} can be used in the oxidation or oxidative dehydrogenation processes. The high selectivity in styrene (at 723 K, 24% conversion with 76% selectivity in styrene) was related to the high concentration in the MnO{sub 2} phase from the MnO{sub x}/SiO{sub 2} catalysts. The formation of the Mn{sub 3}O{sub 4} phase, observed on the used catalysts, supports the proposed mechanism. These findings are of potential use for industrial applications, particularly in optimization of various oxidative dehydrogenation processes.
- OSTI ID:
- 345342
- Journal Information:
- Industrial and Engineering Chemistry Research, Vol. 38, Issue 4; Other Information: PBD: Apr 1999
- Country of Publication:
- United States
- Language:
- English
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