Thermal behavior of brominated and polybrominated compounds I: closed vessel conditions

Israel is one of the leading manufacturers of organic brominated compounds, hence the very intensive manufacturing of such compounds creates both, hazardous industrial refuge and large amounts of brominated byproducts. Environmentally the storage of these huge amounts of materials may lead to major hazards: (a) water reservoirs contamination; (b) land contamination. It is suggested to incinerate the accumulated and presently produced organic wastes by the existing organic hazardous wastes incineration plants, one should take into account the fact that polybrominated compounds are fire retardants! The thermal behavior of the C-Br bond was scantly investigated up-to-date. In the present work and those to follow we report on our examinations of various brominated organics pyrolysis experiments e.g. bromohexane (BH) bromocyclohexane (BCH), bromonaphthatene, 4,4'-isopropylidene bis(2,6-dibromophenol) measurements were carried out only for the solid and polybrominated compounds whereas time and temperature experiments were conducted under closed vessel conditions (quartz ampoules). The analyses of the pyro-products were initially monitored by gas, extractables and solids using both selective detectors (FID, ECD), GC and GC/MS (for gases and liquids). Experiments were conducted between 400 and 1000degreesC, and pyrolysis exposure times from 10 s to 1 h. We present the results obtained for single compound and hydrogen donor mixed with compound. The conclusions drawn as presented in the concluding remarks are: (1) most of the released bromine is in HBr form and probably the reason for retardation; (2) At 1000degreesC the organic products are low molecular weight gases and char; (3) The amounts of dibenzodioxins and dibenzofurans are minute and thermally unstable; (4) the aliphatic brominated compounds are thermally less stable than the aromatics; (5) Under oxygen conditions the formation of large amounts of HBr is acting as retardant even in the presence of excess hydrogen donors; (6) the presence of hydrogen donors is conducive to the formation of HBr, increase of rate and quantity. (C) 2002 Elsevier Science B.V. All rights reserved.