针对钛硅分子筛(TS-1)催化环己酮氨肟化反应在浆态条件下进行时存在的固液分离和溶剂回收等问题,尝试采用微乳化的方法加以解决。以十六烷基三甲基溴化铵(CTAB)/水/氨水/环己酮的水包油(O/W)型微乳液作为反应介质,实现了TS-1催化环己酮的氨肟化反应。通过实验考察了反应温度及助表面活性剂(叔丁醇)的用量对反应选择性及转化率的影响。结果表明,升高反应温度,在环己酮转化率随之提高的同时,环己酮肟的选择性先升高后降低,且在65℃时达到最高;而助表面活性剂(叔丁醇)的用量对环己酮的转化率没有明显影响,却显著影响了反应的选择性。X射线衍射图和傅立叶变换红外谱图显示,所得的环己酮肟结晶度好、纯度高。
Aiming at the problems of solid-liquid separation and solvent recycle that occurred in the reaction of ammoximation of cyclohexanone over titanium silicate-1 (TS-1) under the slurry condition, ammoximation reaction in microemulsion was tried to solve the problems. An oil-in-water (O/W) microemulsion consisted of cetyhrimethylammonium bromide (CTAB) / water / ammonia/cyclohexanone, as a media to produce cyclohexanone oxime, was prepared, where ammoximation of cyclohexanone was studied firstly. The effects of reaction temperature and the amount of cosurfactant (t-butanol) on the ammoximation of cyclohexanone to cyclohexanone oxime in microemulsion were investigated. The results revealed that with the increase of reaction temperature, the conversion of cyclohexanone increased, while the selectivity of cyclohexanone oxime rose at first and then dropped, the selectivity of cyclohexanone oxime got the peak value when the reaction temperature was 65 ℃. The amount of cosurfactant (t-butanol) had no significant effect on the conversion of cyclohexanone, but its effects on the selectivity of cyclohexanone oxime were notable. The XRD and FT-IR data indicate that the cyclohexanone oxime synthesized in microemulsion has nice crystal form and high purity.