Al₁₃–[X–Mo/WO_n] (X = Al, Co, V, P) composites as catalysts in clean oxidation of aromatic sulfides

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• 作者：Mercedes Muñ ; oz ; Gustavo Romanelli ; Irma L. Botto ; Carmen I. Cabello ; Carole Lamonier ; Mickael Capron ; Pascale Baranek ; Pascal Blanchard ; Edmond Payen
• 关键词：Inorganic composites ; Heteropolyoxometalates ; Al₁₃-polycation ; ²⁷Al NMR ; Raman Microprobe ; Selective oxidation of aromatics sulfides ; Diphenylsulfide ; Dibenzothiophene ; Sulfone
• 刊名：Applied Catalysis B: Environmental
• 出版年：2010
• 出版时间：11 October 2010
• 年：2010
• 卷：100
• 期：1-2
• 页码：254-263
• 全文大小：990 K

文摘

Several phases of general formula Al₁₃–[XMo₆] (X = Al(III), Co(III), Cr(III), V(V) and Al₁₃–P/[WO₄]_n) were prepared by combining the [AlO₄Al₁₂(OH)₂₄(H₂O)₁₂]⁷⁺ (Al₁₃) Keggin-type isopolycation with different iso or heteropolymetalates such as [(Al/Co/V)Mo₆O₂₄(H₆)]^x−, [Co₂Mo₁₀O₃₈H₄]⁶⁻, [H₂W₁₂O₄₀]⁶⁻ and [PW₉O₃₄]⁹⁻. The characterization was carried out by means of XRD, ²⁷Al NMR, FTIR and Raman Microprobe techniques. The catalytic activity of bulk composites, structurally constituted by an ordered distribution of the condensed metallic species in an Al(III) oxidic matrix, were proved in two aromatic sulfide oxidation reactions: diphenylsulfide (DPS) to diphenylsulfone in presence of H₂O₂ and dibenzothiophene (DBT) to dibenzothiophenone by means of tert-butyl hydroperoxide (t-BuOOH). Both reactions were carried out in batch at 80 and 75 °C respectively. Results indicated that oxidation activity improved as the electronic density of the sulfur substrate increased, being higher for DPS (over 90 % ) than for DBT. Composites based on Anderson heteropolymolybdates presented a better performance in both reactions. ²⁷Al MAS NMR spectroscopic properties can be associated to the catalytic behavior. On the other hand, catalysts based on polytungstates did not show activity except for that containing P as heteroatom. Besides, by ²⁷Al NMR and Raman Microprobe, it was verified that these phases kept their structure after reaction showing an interesting possibility of being re-used.