ISSN:
1434-193X
Keywords:
Dioxins
;
Gas-phase reactions
;
Diphenyl ether
;
Hydrogen abstraction
;
ipso Substitution
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
-The title reactions have been studied to scrutinize rate data recently inferred for the two reverse steps - reaction of phenoxy radicals with chlorobenzene and bromobenzene - which were at variance with commonly accepted model values. Both with chlorine and bromine atoms, splitting to halobenzene and phenoxy radical was found to occur in competition with abstraction of o-, m-, p-hydrogen atoms. On this basis, the displacements of Cl and Br from the benzene ring by phenoxy radicals must have activation energies above 20 kcal/mol, and are therefore slow. As a consequence, formation of “dioxins” from halogenated phenols, in (slow) combustion, should proceed by combination of two (halo)phenoxy radicals rather than by displacement of (ortho-)halogen in a halophenol molecule.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
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