反式-4-乙酰氨基环己醇催化氧化脱氢生成4-乙酰氨基环已酮反应的研究

Studies on the Catalytic Oxidative Dehydrogenation of Trans-4-acetamidocyclohexanol to 4-acetylaminocyclohexanone

为解决4-乙酰氨基环己酮传统合成工艺大量铬废渣及酸性废液排放的问题,研究了反-4-乙酰氨基环己醇催化氧化脱氢制备4-乙酰氨基环己酮的绿色化新工艺。探讨了反-4-乙酰氨基环己醇在液-固相反应体系中以30%H2O2(质量分数)为氧化剂,催化氧化脱氢生成4-乙酰氨基环己酮的反应规律。实验结果表明,WO3是实现这一反应的主要催化活性组分,二氧化硅是较好的载体;以25%WO3/Si O2(质量分数)为催化剂,氧化剂和原料物质的量之比为5.1,90℃反应4 h时,目标产物4-乙酰氨基环己酮的得率可达96%左右。此工艺过程较传统的铬酸氧化法对环境友好,但实验过程发现活性组分WO3在催化剂重复使用过程中易于流失,催化剂重复使用性能尚有待于改进。

In order to solve the problem of excess amount of chromium residues and acidic water produced by traditional synthetic technology, a new green catalytic synthesis process for the catalytic oxidative dehydrogenation of trans-4-acetamidocyclohexanol to 4-acetamidocyclohexanone is studied in this paper. The effect factors for the catalytic reaction in liquid phase by using 30% H2O2 as oxygenate were investigated. The experimental results indicated that, WO3 is the main catalytic active component and silica is a better carrier for the reaction;the yield to 4-acetamidocyclohexanone could be reached to about 96%by using the catalyst of 25%WO3/SiO2 as the molar ratio of H2O2 to trans-4-acetamidocyclohexanol was 5.1 at 90 ℃ for 4 hours. This is an environment friendly process comparing to the traditional oxidation process by bichromate. However, the experimental results showed the active component WO3 would be lost greatly during the repeated process;the performance for the repeated use of the solid catalyst should be improved in the future.