Dreijer-Van Der Glas S M, Schalekamp T, De Jong H J, Bult A
Pharm Weekbl Sci. 1983 Apr 29;5(2):70-3. doi: 10.1007/BF01960079.
Bromination with a large excess of bromine results in the formation of a tetrabromo product for phenol and a pentabromo derivative for resorcinol. It is possible to determine the active bromine in the tetrabromo product after its isolation by filtration. This can also be done in the presence of resorcinol as its pentabromo derivative does not precipitate. The method gives good results (96-97% +/- 1%) for quantities of 8 mg and higher of phenol in the presence of a maximum of 25 mg resorcinol. From the 1H- and 13C-NMR spectra of the bromination products it could be concluded that they have a quinoidal structure.
