title: Formation of PCDD/Fs from oxidation of 2-monochlorophenol over an Fe2O3/silica surface.
abstract: The role of iron in surface-mediated formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from 2-chlorophenol (2-MCP) was investigated over the temperature range of 200-550°C under oxidative conditions. In order to compare and contrast with previous work on copper and ferric oxide-mediated pyrolysis of 2-MCP, identical reaction conditions were maintained (50 ppm 2-MCP, model fly-ash particles containing 5% Fe(2)O(3) on silica). Observed products included dibenzo-p-dioxin (DD), 1-monochlorodibenzo-p-dioxin (1-MCDD), dibenzofuran (DF), 4,6-dichlorodibenzofuran (4,6-DCDF), 2,4- and 2,6-dichlorophenol, 2,4,6-trichlorophenol, quinone, catechol, chloro-o-quinone, chlorocatechol and polychlorinated benzenes. Yields of DD and 1-MCDD were 2 and 5 times higher than under pyolysis conditions, respectively. Although 4,6-DCDF was the major PCDD/F product formed with a yield that was 2.5× greater than under pyrolysis, the yield of non-chlorinated DF, which was the dominant PCDD/F product under pyrolysis, decreased by a factor of 3. Furthermore, the ~2× higher yield of PCDDs under oxidative conditions resulted in a PCDD to PCDF ratio of 0.75 compared to a relatively low ratio of 0.39 previously observed under pyrolytic conditions.
authors.affiliation: Chemistry Department, Louisiana State University, Baton Rouge, LA 70803, USA.
authors.forename: Shadrack
authors.initials: S
authors.lastname: Nganai
authors.forename: Slawo
authors.initials: S
authors.lastname: Lomnicki
authors.forename: Barry
authors.initials: B
authors.lastname: Dellinger
mesh_terms: D001572:Benzofurans / Q000737:chemistry*; D002733:Chlorophenols / Q000737:chemistry*; D000072338:Dibenzofurans, Polychlorinated; D005290:Ferric Compounds / Q000737:chemistry*; D006358:Hot Temperature; D010084:Oxidation-Reduction; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D001572:Benzofurans; D002733:Chlorophenols; D000072338:Dibenzofurans, Polychlorinated; D005290:Ferric Compounds; D000072317:Polychlorinated Dibenzodioxins; C000499:ferric oxide; D012822:Silicon Dioxide; C030683:2-chlorophenol