John Theodore Hewitt, Norman Walker
1907 Journal of the Chemical Society Transactions  
it has been shown that hydroxyazo-compounds, when submitted to the action of substitutiag agents such as nitric acid or bromine, regularly behave as azophenols rather than as quinonehydrazones, except in such cases where the non-hydroxylated aromatic nucleus has a free paraposition and the substance is not protected against the action of strong mineral acids. In the simplest case, that of benzeneazophenol, bromine acts on the substance in glacial acetic acid solution, giving
more » ... p-bromobenzeneazo-o-o-dibromophenol when no precautions are observed t o prot substance against the influence of the hydrogen bromid luring the reaction, whilst if fused sodium acetate be a then benzeneazo-o-o-dibromophenol may be obtained in near ntitative yield. Similarly, p-nitrobenzeneazophenol is obtained in dissolving benzeneazophenol in an excess of concentrated sulphuric acid and adding one molecular proportion of nitric acid, whilst on warming benzeneazophenol with
doi:10.1039/ct9079101138 fatcat:bwmhwfiypbd5fos7vny7yzocum