Pyrolysis study of halogen-containing aromatics reflecting reactions with polypropylene in a posttreatment decontamination process.
Halogen-containing aromatics, mainly bromine-containing phenols, are harmful compounds contaminating pyrolysis oil from electronic boards containing halogenated flame retardants. In addition,theirformation increases the potential for evolution of polybrominated dibenzo-p-dioxins (PBDDs) and dibenzofurans (PBDFs) at relatively low temperature (up to 500 degrees C). As a model compound, 2,4-dibromophenol (DBP) was pyrolyzed at 290-450 degrees C. While its pyrolysis in a nitrogen flow reactor or in encapsulated ampules yields bromine-containing phenols, phenoxyphenols, PBDDs, and PBDFs, pyrolysis of DBP in a hydrogen-donating medium of polypropylene (PP) at 290-350 degrees C mainly results in the formation of phenol and HBr, indicating the occurrence of a facile hydrodebromination of DBP. The hydrodebromination efficiency depends on temperature, pressure, and the ratio of the initial components. This thermal behavior of DBP is compared to that of 2,4-dichlorophenol and decabromodiphenyl ether. A treatment of halogen-containing aromatics with PP offers a new perspective on the development of low-environmental-impact disposal processes for electronic scrap.
Balabanovich
Aliaksandr I
AI
Research Institute for Physical Chemical Problems of the Belarusian State University, ul. Leningradskaya 14, 220050 Minsk, Belarus. balabanovich@bsu.by
Hornung
Andreas
A
Luda
Maria P
MP
Koch
Wolfgang
W
Tumiatti
Vander
V
D004581:Electronics; D006219:Halogens; D006841:Hydrocarbons, Aromatic / Q000737:chemistry*; D017745:Incineration; D010636:Phenols / Q000737:chemistry*; D011126:Polypropylenes / Q000737:chemistry; D011312:Pressure; D013696:Temperature
D006219:Halogens; D006841:Hydrocarbons, Aromatic; D010636:Phenols; D011126:Polypropylenes; C013930:2,4-dibromophenol