2-甲基-1，4-萘醌合成工艺改进

Process Improvement on the Synthesis of 2-Methyl-1,4-Naphthoquinone

以正己烷为溶剂,Cr^(6+)/Cr^(3+)为氧化介质,间接电氧化2-甲基萘得到2-甲基-1,4-萘醌(2-MNQ)和6-甲基-1,4-萘醌(6-MNQ)的混合物,分离出水相后,用亚硫酸氢钠水溶液处理有机相,6-MNQ与亚硫酸氢钠优先反应,生成加成产物溶解在水相,溶解在有机相中的2-MNQ经结晶和精制,得到2-MNQ产品。通过优化工艺条件和采用改进的分离提纯方法,2-MNQ的收率可达72.5%以上,质量分数大于99.5%,回收得到的6-MNQ可以转化为相应的蒽醌加以利用。

The mixture of 2-methyl-1,4-naphthoquinone（2-MNQ） and 6-methyl-1,4-naphthoquinone（6-MNQ） was prepared from 2-methylnaphthalene（2-MN） by indirect electrolytic oxidation using n-hexane as solvent and Cr^6＋/Cr^3＋ as oxidative medium. After the seperation of the aqueous p.hase 6-MNQ was removed from the oxidation mixture of 2-MN by adding aqueous sodium bisulfite solution to n-hexane solution of the mixture and high purity 2-MNQ was obtained by crystallizing and purifying. Under optimal reaction conditions and with an improved purification method, yield of 2-MNQ was＇ over 72.5% and mass fraction of 2-MNQ was more than 99. 5%. The production cost of 2-MNQ was decreased as the by-produced 6-MNQ could be converted to anthraquinone which could be utilized effectively.