Gas-Phase Chemistry of Chlorinated Phenols − Formation of Dibenzofurans and Dibenzodioxins in Slow Combustion

✍ Scribed by Izabela Wiater−Protas; Robert Louw

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 351 KB
• Volume: 2001
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/1099-0690(200110)2001:20<3945::aid-ejoc3945>3.0.co;2-7

✦ Synopsis

The effects of the introduction of chlorine substituents onto phenol on the rates of, and products from, their slow combustion at 500-550 °C are described. Competitive experiments showed that phenol, ortho-chlorophenol, 2,4,6-trichlorophenol and pentachlorophenol differ little in their overall rates of conversionmainly into CO/CO 2 . Provided that an ortho-H moiety is available, chlorinated dibenzofurans (DFs) rather than dibenzodioxins (DDs) are formed as (cross)condensation products. Overall rates of formation, through (reversible) ortho-C, ortho-C combination of two (chloro)phenoxy radicals, are discussed on a thermokinetic basis, using new data relating to the O-H bond strengths in the target phenols. Chlorinated DDs are the predominant condensation products only when the ortho positions are fully chlorinated, a situation insignificant during thermal combustion of real