A comparative study of methanol carbonation on unsupported SnO₂ and ZrO₂

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• 作者：Daniel Aymes ; Danielle Ballivet-Tkatchenko ; Kul ; ailevu Jeyalakshmi ; Lucien Saviot ; Sivakumar Vasireddy
• 关键词：Methanol ; Dimethyl carbonate ; Carbon dioxide ; Nanoparticles ; Tin oxide ; Zirconium oxide
• 刊名：Catalysis Today
• 出版年：2009
• 出版时间：30 September 2009
• 年：2009
• 卷：147
• 期：2
• 页码：62-67
• 全文大小：313 K

文摘

The aim of this work was to explore the catalytic properties of SnO₂ in the coupling of methanol with carbon dioxide to afford dimethyl carbonate. SnO₂ nanopowders were produced by hydrolysis of tin tetra-tert-butoxide dissolved in n-butanol. The samples were much more active than a commercial one due to their higher surface areas. In addition, they exhibited excellent recyclability. However, comparison with ZrO₂, prepared and tested under the same experimental conditions, showed that zirconia-based catalysts were more selective and are, among the heterogeneous catalysts already reported, still the more selective. SnO₂ also catalyzed the formation of dimethyl ether likely due to lower rates in the formation of the key intermediate CH₃OC(O)O–Sn and its subsequent alkylation by activated methanol. This lack of selectivity contrasts with that of soluble organotin(IV) which are totally selective to DMC formation. Structural characterization of SnO₂ was performed by X-ray powder diffraction, laser Raman spectroscopy, transmission electron microscopy, and nitrogen isotherm. As found from X-ray diffraction line broadening, the crystallite size of all powders was in the nanometric range (cassiterite structure) which was confirmed by transmission electron microscopy. Moreover, the low-frequency Raman scattering allowed to determine an average particle size diameter of 4 nm.