反应详情

If the reaction mixture comprising 2,5,6-trimethylcyclohex-2-en- 1-one, alkanol, the catalytic amount of copper oxide and hydrogen halide gas, as described above, is allowed to react for a longer time with air or oxygen, 4-halo-2,3,6-trimethylphenol is obtained in addition to 2,3,6-trimethylphenol. If, instead of isolating this product, the reaction mixture is treated, as described above, with an alkali metal alcoholate, and the oxidation with air or oxygen is continued, the 4-halo-2,3,6-trimethylphenol is also converted to 2,3,5-trimethyl-p-benozoquinone. After the reaction products obtained in step A have been treated with an alkali metal alcoholate, they can also be oxidized with tert.-butyl hydroperoxide instead of air or oxygen. Depending on whether trimethylphenol or halotrimethylphenol is the predominant product, subsequent oxidation with tert.-butyl hydroperoxide gives 2,3,5-trimethyl-p-benzoquinone in a yield of from 65 to 80% of theory.