无机钛硅原料体系合成钛硅分子筛及其修饰改性TS-1催化环己酮氨氧化反应性能

Study on Ammoximation of Cyclohexanone Catalyzed by TS-1 Modified in Secondary Crystallization and Synthesized from Inorganic Titanosilicate System

采用无机钛硅原料体系合成了钛硅分子筛TS-1.用XRD、FT-IR、SEM对所制备的TS-1样品进行了表征分析.结果表明:在2θ为24.5°和29.5°这两处的双衍射峰变为属于正交晶系的单衍射峰;在960 cm-1出现了一明显的特征吸收峰;晶体结构完整,钛进入了分子筛的骨架中,构成了钛硅分子筛TS-1催化活性中心.用二次晶化方法对合成的无机钛硅分子筛TS-1进行了修饰改性,并考察了二次晶化后TS-1催化环己酮氨氧化反应性能及其稳定性.在n(氨)∶n(酮)∶n(过氧化氢)=2.0∶1∶1.5,m(催化剂)∶n(环己酮)=18 g/mol,反应温度75℃,反应时间4 h的条件下,过氧化氢的转化率、环己酮的转化率及环己酮肟的收率可分别达到98.87%、98.46%和97.29%.二次晶化法可显著提高分子筛TS-1催化活性和稳定性.

The TS-1 zeolite was synthesized from inorganic titanosilicate system. After pretreated with acid, the TS-1 zeolite was re-crystallized. The prepared TS-1 samples were characterized by XRD, IR and SEM. These results showed that the double diffraction apex became two single diffraction apexs at 24.5° and 29.5° in 2 t9 and there was a remarkble absorbtion at the 960 cm^-1. The structure of TS-1 was perfect. Ti was incorporated into the zeolite framework and composed of the centre of catalytic activity. The catalytic performance and stabiliy of TS-1 zeolite for ammoximation of eyelohexanone reaction were studied and the optimized condition was abtained. The results showed that this catalyst had a 98.87 % H2O2 conversion, a 98. 46% eyelohexanone conversion and a 97.29% eyelohexanone oxime yield at 75℃ for 4. 0 h reaction when the ammonia/eyelohexanone/ H2O2 ratio was 2.0 ：1 ： 1.5 and the catalyst/eyelohexanone ratio was 18 g/mol. The catalytic activity and stabiliy of TS-1 zeolite reerystallized were dramatically improved.