GB783042A - Process for the production of substituted para-benzo-quinones - Google Patents

Abstract

Substituted p-benzoquinones are made by treating a p-phenol sulphonic acid which is substituted at least in the o- and o1-positions by halogen atoms, alkyl or cycloalkyl groups with an oxidizing agent. The substituents in the o-and o1-positions may be the same or different. In a modification, the p-benzoquinones are made by oxidizing a reaction mixture obtained by the sulphonation of a phenol substituted at least in the o- and o1-positions by the substituents mentioned above and having a free p-position; the sulphonation may be effected by treatment of the phenol with sulphuric acid monohydrate at elevated temperature. Oxidizing agents specified are chromic acid and pyrolusite in acid solution. In examples, 2 : 6-diethyl phenol is treated with 100 per cent sulphuric acid at elevated temperature, the mixture cooled, unreacted phenol removed and the filtrate, diluted with dilute sulphuric acid, is oxidized with sodium bichromate in (1) with cooling and (5) at reflux temperature, and in (4) with pyrolusite, to yield 2 : 6-diethyl-benzoquinone-(1 : 4); in further examples there are similarly made from the appropriate phenols: (2) 2 - methyl - 6 - ethyl -, (3) 2 : 6 - diisopropyl -, (6) 2 - ethyl - 6 - cyclohexyl -, (7) 2-chloro - 6 - ethyl -, and (9) 3 - methyl - 2 : 6 - diethyl - benzoquinones - (1 : 4), and in (8) 2 : 6-dichlorobenzoquinone-(1 : 4) is made by oxidizing sodium 2 : 6-dichlorophenol-4-sulphonate with sodium bichromate and sulphuric acid.