负载钴催化剂催化分子氧氧化环己烷

OXIDATION OF CYCLOHEXANE WITH OXYGEN OVER Co ION EXCHANGED ZEOLITES

选用具有不同结构的分子筛Y、Beta、ZSM-5、MOR和MCM-22为载体,采用离子交换法制备了一系列负载Co分子筛催化剂,并采用XRD、UV-vis和元素分析对它们进行了表征。以O2为氧化剂,考察了所制催化剂在液相环己烷氧化反应中的催化性能。结果表明,分子筛载体的性质对制备的负载Co催化剂在液相环己烷氧化反应中的催化性能有很大影响。在相同反应条件下,所制备的5种负载Co分子筛催化剂中,Co/Y催化环己烷氧化反应的环己醇和环己酮混合物(KA油)的选择性最高。在130℃、1.2 MPa O2分压下反应3 h,Co/Y催化环己烷氧化反应的转化率为15.9%,KA油的选择性为79.0%。Co/Y催化剂在所考察的反应条件下具有良好的稳定性,经重复使用5次,仍保持良好的催化性能。

Y, Beta, ZSM-5, MOR, and MCM-22 zeolites, with different structures and surface characteristics, were employed as supports. A series of zeolite supported Co catalysts were prepared by ion-exchange and characterized by XRD, UV-vis and elemental analysis. The catalytic performance of the prepared catalysts in liquid-phase oxidation of cyclohexane by molecular oxygen was investigated. The results showed that the properties of zeolite supports had great influence on catalytic performance of the prepared Co supported catalysts for liquid-phase oxidation of cyclohexane. Among the prepared five zeolite supported Co catalysts, Co/Y exhibited the highest selectivity for the mixture of cyelohexanol and cyclohexanone （KA oil） in cyclohexane oxidation under identical reaction conditions. About 15.9% conversion of cyclohexane and 79.0% selectivity of KA oil could be obtained in cyclohexane oxidation catalyzed by Co/Y catalyst at 130℃ under O2 pressure of 1.2 MPa after reaction of 6 h. Under the investigated reaction conditions, Co/Y was recyclable in cyclohexane oxidation and the conversion and selectivity changed slightly after five runs.