(583f) Removal of Bromine from Tetrabromobisphenol a in an Amine Aqueous Solution Under Hydrothermal Conditions

Tetrabromobisphenol A (TBBPA) is widely employed as one of the common flame-retardants, and the large amounts contained in consumer electronical products have been discharged year by year. The disposal by incineration or landfill results in emission or evolution of toxic compounds produced. Supercritical water was subjected to electrical products containing brominated flame-retardants. While the debromination was effectively occurred, the reactor corrosion may often be observed. Thus, a new effective debromination process is demanded.

In this study, a new debromination process is demonstrated such that a hot compressed water in the presence of amine as a nucleophilic reagent is subjected to a brominated flame-retardant compound such as TBBPA under hydrothermal conditions. Using a small bomb-type batch reactor, TBBPA and a certain amount of an amine aqueous solution were loaded in the reactor, and the reactor was heated in a molten salt bath. After the intended time elapsed, the reactor was removed from the bath, and quickly cooled by water. The products recovered were analyzed by a total organic carbon analyzer, an ion chromatograph, a GC-MS and an HPLC.

Various amine species were found to be effective for the debromination, and methylamine (MA) was the most effective. For, example, 92 % bromine in the ion form in TBBPA with MA was recovered in the product solution at 260 deg C for 25 min while 48% bromine was removed in an aqueous solution of sodium hydroxide at the same condition. According to the analysis of the products the reaction can be considered to proceed via the scission of C-C bonds to form a single aromatic compound along with the debromination. In the presentation debromination of actual electric substrate was also demonstrated in a MA aqueous solution.