- Ag-TiO2/clay composite photocatalyst for the oxidation-cyclization of 1,2-diamine compounds with propylene glycol or alcohols
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Silver-loaded TiO2 (Ag-TiO2) and acidic clay (K10 montmorillonite) composite photocatalyst has been successfully applied for the light-induced conversion of o-phenylenediamine (OPD) and its derivatives to substituted benzimidazoles with various alcohols in acetonitrile using UV-A and solar light. The influence of the various photocatalysts, solvents, and substituents on the yield and selectivity of the products has been investigated. The mechanism of photocatalysis is proposed. Loading silver on TiO2 enhances product yield and selectivity both in UV and solar light. In the presence of primary alcohols, 2-aminothiophenol forms only disulfide and hence Ag-TiO2/ clay can be used as a green catalyst for the synthesis of disulfides.
- Selvam, Kaliyamoorthy,Annadhasan, Mari,Velmurugan, Rengasamy,Swaminathan, Meenakshisundaram
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experimental part
p. 831 - 837
(2010/09/06)
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- The Thermolysis of Polyazapentadienes. Part 2. Formation of Quinoxalines from 5-Aryl-1-phenyl-1,2,5-triazapentadienes
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Thermolysis in the gas phase of 5-(p-substituted phenyl)-1-phenyl-1,2,5-triazapentadienes at 600 deg C and 10-2 Torr gives 6-substituted quinoxalines.The yield is ca. 30 percent, and is independent of the electronic nature of the substituent.The corresponding 5-(o-substituted) derivatives give 5-substituted quinoxalines, though the yield is lower, and quinoxaline itself is a major contaminant, due to ipso attack and ejection of the substituent. 5-(m-Substituted) derivatives give mixtures of 5- and 6-substituted quinoxalines on pyrolysis.The 5-isomer is dominant for compounds with m-alkyl substituents, while the 6-isomer is the major product for those with electron-withdrawing or electron-donating m-substituents.
- McNab, Hamish
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p. 1941 - 1946
(2007/10/02)
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