TS分子筛的催化氧化性能研究5: 环己酮氨肟化反应

研究了自制的钛硅分子筛(TS-1)催化H~2O~2参与的环己酮氨肟化反应。结果表明,降低反应溶液中H~2O~2的浓度、增加NH~3用量有利于H~2O~2利用率、环己酮肟收率和选择性的提高,适宜的n(H~2O~2):n(酮)<1.0,n(NH~3):n(酮)>2.0。反应时间应控制在3.5h左右。对溶剂的研究显示,叔丁醇在溶剂中所占的体积对反应有较大的影响,在叔丁醇体积分数为0.2到0.8之间,实验获得了较好的结果。当n(NH~3):n(H~2O~2):n(酮)=2.0:1.0:1.0,叔丁醇体积分数为0.5,反应时间2.5h,反应温度353K时,H~2O~2利用率、环己酮肟收率和选择性分别达95%,94%和97%以上。并对空白实验结果和TS-1的重复性试验进行了讨论。

Study on catalytic oxidation activity of TS zeolite 5: Ammoximation of cyclohexanone

Ammoximation of cyclohexanone with ω(H~2O~2)=30% aqueous hydrogen peroxide and ammonia in the presence of a titanium silicalite (TS-1) catalyst was studied. Decreasing the content of H~2O~2 and increasing the amount of NH~3 in the reaction solution, increase the utilization of H~2O~2 and the yield as well as the selectivity of cyclohexanone to oxime. The favorable reaction time is about 3.5h. The effect of the volume fraction of t-butyl alcohol in the solvent on the ammoximation is discussed in detail. The experiment results show that when the molar ratio of n(NH~3):n(H~2O~2):n(ketone) is 2.0:1.0:1.0, the volume fraction of t-butyl alcohol is 0.5, and the reaction time is 2.5h at 353K, the utilization of H~2O~2 and the yield and selectivity of cyclohexanone oxime can reach 95%, 94% and 97% respectively.