Thermal decomposition of 4,4′‐isopropylidene bis‐2,6‐dibromophenol (tetrabromobisphenol‐A)

Abstract

Abstract The thermal decomposition of tetrabromobisphenol‐A (TBBPA) was found to proceed via an autocatalytic free‐radical process. The major products of the decomposition are HBr; mono‐, di‐ and tribromobisphenol‐A; phenol; mono‐, di‐, and tribromophenol; and eventually, char. It was generally found that o ‐ and p ‐halophenols are thermally unstable. In contrast, the m ‐bromophenol, 3,5‐dibromo‐2,4,6‐trimethylphenol (dibromomesitol) was found to be quite stable. In addition, o ‐ and p ‐halo‐substituted phenols were found to react with LiI at 250°C to produce I 2 , while m ‐halophenols did not. These results are explained by the formation from o ‐ and p ‐halo‐substituted phenols of a reactive halocyclohexadienone.