| 摘要 |
Prepn. of 2,3,6-trimethylphenol (I) involves contacting meta- substd.-phenolic materials (II) with methanol (III) in the vapour phase at 400-500 deg.C and at 1-10 atmospheres. The (III):(II) mole ratio is 1:10. A MgO catalyst promoted with amorphous Ti and SO4 ions is used. Reaction is pref. in a continuous flow reactor at an LHSV of 0.1-10. The feed mixt. pref. contains 1-15% water. The catalyst suitably contains 2-10% amorphous Ti, 85-98% MgO and 2-10% sulphate, and 1-5% silica or 1-3% graphite may be added, based on the wt. of final catalyst. High reaction rates are achieved, with acceptable catalyst life and a high selectivity of (I) formation. Cpd. (I) is an intermediate in the synthesis of vitamin E, and it is obtd. economically with good purity. |
