温和条件下DMF催化苯乙烯空气环氧化的研究

Study of DMF catalytic air epoxidation of styrene under mild conditions

不加任何其他催化剂,N,N-二甲基甲酰胺(DMF)既为溶剂又为催化剂,在温和条件下催化苯乙烯的空气环氧化反应。探讨了反应温度、反应时间、反应介质及不同的氧化剂对苯乙烯的环氧化效果的影响。结果表明,反应温度对选择性生成环氧苯乙烷的影响较大,低温不利于反应的进行,但是温度过高,有部分的苯乙烯会发生聚合;随着反应时间的延长,转化率缓慢增加,环氧苯乙烷的选择性变化不大;同时对比了其他氧化剂如过氧化氢、次氯酸钠、叔丁基过氧化氢和纯氧等氧化苯乙烯的实验结果,发现空气明显优于另外几种氧化剂。以空气为氧源,DMF为溶剂,控制110℃反应4 h,苯乙烯的转化率和选择性分别达到了12.6%和72.6%。

Styrene was epoxidized by air under mild conditions using N, N - dimethyl formamide as both catalyst and solvent for reaction medium. Effects of reaction temperature, reaction time, different reaction media and different oxidizing agent on the conversion and selectivity of the epoxidation were investigated. Experimental results showed that effect of reaction temperature on the selectivity for styrene oxide formation is fairly big, lower temperature is not favorable to the reaction, but if the temperature is too high, part of the styrene will polymerize. Following the extension of reaction time, conversion will increase slowly while the change of selectivity is not significant. Various oxidizing agents such as hydrogen peroxide, sodium hypochlorite, tertiary butyl hydrogen peroxide and pure oxygen were tested and compared. Results showed that air plays the best performance. Under conditions： air used as oxygen source, DMF being the catalyst, temperature 110 ℃ for 4 h, the conversion and selectivity achieves 12. 6% and 72. 6% respectively.