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The thermal stability and decomposition products of hexabromocyclododecane (HBCD), a widely used aliphatic brominated flame retardant, were investigated. HBCD thermal degradation was carried out in nitrogen and in air at moderate heating rates (10 °C/min) using thermogravimetric analyzers and a laboratory-scale fixed-bed reactor. The identification of decomposition products was based mainly on FTIR and gas-chromatographic/mass-spectrometric techniques. Quantitative data on hydrogen bromide formation and on the bromine distribution among the different product fractions were obtained. For the experimental conditions used in this study, about 75 wt % of the bromine is released as HBr, and 25 wt % is involved in the formation of high-molecular-weight bromo-organic compounds. The main pathways of HBCD thermal degradation were assessed, and a global mechanism for HBCD decomposition was proposed.

This study focused on the investigation of the thermal degradation process of tetrabromobisphenol A (TBBA). The use of combined experimental techniques allowed the quantitative characterization of TBBA decomposition products and the analysis of the thermal degradation rates. The distribution of bromine among the different decomposition product fractions was investigated. In the open configuration used for the experiments, hydrogen bromide, brominated bisphenol A species, and brominated phenols resulted in the main decomposition products. Bromine was mainly evolved as hydrogen bromide, although a relevant quantity resulted present in the primary high molecular weight condensable product fraction, in agreement with the decomposition pathways proposed. The results evidenced that accidents involving TBBA thermal degradation, such as fire or process runaways, may pose relevant safety problems because of the possible release of considerable quantities of hazardous decomposition products.

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