Dechlorination of polychlorinated dibenzo- p-dioxins catalyzed by noble metal catalysts under mild conditions

• Published in: Chemosphere (Oxford) Vol. 46; no. 4; pp. 507 - 510
• Main Authors: Ukisu, Yuji, Miyadera, Tatsuo
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 2002; Elsevier
• Subjects: 2-Propanol; Air Pollution - prevention & control; Applied sciences; Atmospheric pollution; Catalysis; Catalytic reaction; Chlorine - chemistry; Combustion and energy production; Dioxins - chemistry; Exact sciences and technology; Hydrodechlorination; Hydrogen - chemistry; Noble Gases; Organic chlorides; Oxidation-Reduction; Pollution; Polychlorinated Dibenzodioxins; Prevention and purification methods; Sodium hydroxide; Organic chlorides; Catalytic reaction; 2-Propanol; Hydrodechlorination; Sodium hydroxide; Mixed catalyst; Dioxin derivatives; Palladium; Oxygen heterocycle; Carbon; Hydrogenation; Supported catalyst; Heterogeneous catalysis; Dechlorination; Rhodium; Incinerator; Organochlorine compounds; Platinum; Chlorine Organic compounds; Reaction mechanism; Physicochemical purification; Flue gas purification
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/S0045-6535(01)00170-9

Dechlorination of polychlorinated dibenzo- p-dioxins such as 2,7-dichlorodibenzo- p-dioxin (2,7-DCDD) and 1,2,6,7-tetrachlorodibenzo- p-dioxin (1,2,6,7-TCDD) was carried out in a solution of NaOH in 2-propanol in the presence of carbon-supported noble metal catalyst (Pd/C or Rh–Pt/C) at temperatures between 23 and 35 °C. At initial concentrations of 140–240 μg/ ml , 2,7-DCDD and 1,2,6,7-TCDD were efficiently converted to a chlorine-free product, dibenzo- p-dioxin (DD), in high yield (60–80%). The conversion of 2,7-DCDD and 1,2,6,7-TCDD and the yield of DD were hardly affected by the atmosphere (N 2 or air). We postulate that the displacement of aromatic chlorines by hydrogen selectively occurs on the catalyst, involving hydrogen-transfer from 2-propanol to the substrates.