Synthesis and evaluation of hydroxy- and dihydroxy brominated benzenes, methyl- and ethylbenzenes: Potential metabolites of current-use brominated flame retardants

Knowledge on the presence of occurrence of oxygen containing transformation products (OxyTPs) of the current-use flame retardants hexabromobenzene (HBB), pentabromotoluene (PBT) and pentabromoethyl-benzene (PBEB) is limited due to the lack of standard compounds. For this purpose, we investigated the structures of tri- and tetrabrominated phenols, diphenols, methylphenols and ethylphenols. First, 13 non-brominated or partly brominated (alkyl) phenols and diphenols were brominated with the goal to generate all possible tri- and tetrabrominated isomers. Instead of compound isolation and spectroscopic analysis, the resulting products were interpreted by combinatoric evaluation of GC/MS data, data from undirected syntheses and UV transformation studies as well as theoretical considerations. Altogether, all 44 tri- to tetrabrominated OxyTPs existing in theory could be assigned and fed in a data base. (C) 2022 Published by Elsevier B.V.