| Abstract: | A process has been developed for the oxidation of 4-t-butyltoluene to 4-t-butylbenzaldehyde via an indirect route involving the formation of either 4-t-butylbenzyl bromide or 4-t-butylbenzal bromide. The organic bromides were formed using a photolytic HBr/H2O2 route in the absence of solvent. The bromination steps were found to be highly efficient in that all the substrate could be converted, consuming all the hydrogen peroxide at this stage of the reaction. Partial hydrolysis (up to 50%) of the benzyl bromide to the aldehyde was achieved employing the Sommelet route using hexamethylenetetramine. However, up to 58% aldehyde yield could be afforded from the benzal bromide using a suitable phase transfer agent and a small amount of co-solvent. In both cases, the extent of over-oxidation to 4-t-butylbenzoic acid was reduced by careful control of the bromination step and eliminating dioxygen from the reactor. © 1998 SCI. |
