Dechlorination of tetrachloro-o-benzoquinone by ozonation catalyzed by cesium loaded metal oxides

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• 作者：Suresh Maddila ; Venkata D.B.C. Dasireddy ; Sreekanth B. Jonnalagadda ; ^{jonnalagaddas@ukzn.ac.za}
• 关键词：3 ; 4 ; 5 ; 6-Tetrachlorocyclohexa-3 ; 5-diene-1 ; 2-dione ; Ozone ; Cesium Oxide loaded ; Alumina ; Silica ; Titania ; 2 ; 3-Dioxosuccinic acid ; Oxalic acid
• 刊名：Applied Catalysis B: Environmental
• 出版年：2013
• 出版时间：17 July, 2013
• 年：2013
• 卷：138-139
• 期：Complete
• 页码：149-160
• 全文大小：5216 K

文摘

Ozone initiated oxidation of tetrachloro-o-benzoquinone (3,4,5,6-Tetrachlorocyclohexa-3,5-diene-1,2-dione, TCCD) in aqueous system catalyzed by different loadings of cesium oxide supported on metal oxides namely; Al₂O₃, SiO₂ and TiO₂ was investigated. Catalyst materials were characterized using different surface techniques including Raman, FT-IR, BET, SEM, TEM, ICP, TPD and XRD. XRD showed that cesium is in three different phases on the surface of the catalysts; and SEM and SEM-EDX indicated that cesium is well dispersed on the surface of the supports. Catalyst testing was done employing varying ozone molar ratios from 1 to 3 in the oxygen stream in a semi-batch reactor. 2,3-Dichloro-4,5-dioxohex-2-enedioic acid (DCA) was an intermediate and 2,3-dioxosuccinic acid (DSA) and oxalic acid (OA) were the main oxidation by-products. The oxidation products were characterized and confirmed by IR, ¹H NMR and Mass spectral data. The product distribution was dependent on the acidity of the supports. Among all the catalysts while 5 % Cs/TiO₂ showed good activity, 1 % Cs/SiO₂ showed relatively poor catalytic activity.