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将5次固态交换制备的Co2+-NaX于500℃焙烧6 h,再进行一次固态交换制备高稳定性催化剂,ICP分析表明其Co2+含量为9.13%,高于5次固态交换Co2+-NaX的平衡Co2+含量(8.42%)。采用XRD、N2吸附-脱附对催化剂进行表征,结果表明,分子筛离子交换后其骨架结构没有受到破坏,然而随交换进入分子筛Co2+含量增多,其有序性下降越明显。通过正交实验对该催化剂催化苯乙烯环氧化进行考察,确定了优化的反应条件:苯乙烯用量6 mL,催化剂1.0 g,溶剂48 mL,反应温度80℃,反应时间6 h。在此条件下,环氧苯乙烷平均收率为39.5%。采用该法制备催化剂其活性能够进一步提高,且重复使用活性保持不变。
Co2 + -NaX prepared by five solid-state exchange calcinations at 500 ℃ for 6 h followed by a solid-state exchange to prepare a high-stability catalyst. ICP analysis showed that the Co2 + content was 9.13%, higher than the equilibrium Co2 + Content (8.42%). The catalyst was characterized by XRD and N2 adsorption-desorption. The results showed that the molecular structure of the zeolite was not destroyed after its ion-exchange. However, the orderliness of Co2 + decreased with the increase of the content of Co2 +. Orthogonal experiment was carried out to study the epoxidation of styrene catalyzed by this catalyst. The optimal reaction conditions were as follows: styrene 6 mL, catalyst 1.0 g, solvent 48 mL, reaction temperature 80 ℃ and reaction time 6 h. Under these conditions, the average yield of styrene oxide was 39.5%. The activity of the catalyst prepared by this method can be further improved, and the reusable activity remains unchanged.