| Autor: |
Velisoju, Vijay Kumar, Peddakasu, Ganga Bhavani, Gutta, Naresh, Boosa, Venu, Kandula, Manasa, Chary, Komandur V. R., Akula, Venugopal |
| Zdroj: |
The Journal of Physical Chemistry - Part C; July 2018, Vol. 122 Issue: 34 p19670-19677, 8p |
| Abstrakt: |
Ru supported on activated carbon, Al2O3, and MgO was assessed for the hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL). Role of H2O on the hydrogenation activity of Ru was studied by probe-adsorbed diffuse-reflectance infrared Fourier transform (DRIFT) spectroscopy. Ru supported on activated carbon showed a maximum productivity of 1.18 kgGVLkgcatalyst–1h–1with an insignificant loss in the activity after 72 h of continuous operation in the presence of H2O. Using pure LA, GVL rate was decreased by an order of magnitude (0.12 kgGVLkgcatalyst–1h–1) within 6 h of reaction time. The physicochemical characteristics of the catalysts were examined by temperature-programmed desorption of NH3, CO pulse chemisorption, H2-temperature-programmed reduction, and X-ray photoelectron spectroscopy techniques. H2O-adsorbed DRIFT spectroscopic data revealed the reversible generation of surface −OH groups when aqueous LA was used as the substrate; consequently, Ru/C catalyst stability was also improved. Finally, on the basis of the kinetic and in situ spectroscopic data, a plausible surface-reaction mechanism is proposed for the vapor-phase LA hydrogenation to GVL in the presence of H2O over the carbon-supported Ru catalyst. |
| Databáze: |
Supplemental Index |
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