Co/Cu-USY分子筛制备及催化乙苯氧化性能

Catalytic performance of bimetal modified Co/Cu-USY zeolite for ethylbenzene oxidation reaction

以硝酸铜为铜源,硝酸钴为钴源,对超稳分子筛(USY)进行单金属和双金属的改性,采用浸渍法制备一系列金属改性的USY分子筛催化剂,并对其进行X射线衍射(XRD)、N2吸附脱附、傅里叶红外光谱分析(FTIR)、扫描电子显微镜(SEM)的表征分析。以乙苯氧化制苯乙酮为探针反应,在间歇式反应釜中催化氧化乙苯,考察金属负载量以及双金属改性对USY分子筛催化剂催化氧化性能的影响。结果表明,钴对于铜在USY分子筛上的均匀分布以及活性中心铜对乙苯氧化的催化作用具有协同促进作用,当Co和Cu的负载量分别为5%和20%时,5%Co/20%Cu-USY(质量分数)催化剂对乙苯催化氧化反应的性能最优,其乙苯的转化率和苯乙酮的选择性分别达到29.8%和87.2%。催化剂重复使用4次后其活性和选择性无显著降低,具有良好的结构稳定性。

A series of USY zeolite catalysts modified by single and bimetal metals were prepared by impregnation method. Copper nitrate and cobalt nitrate serve as the copper and cobalt source,repsectively. The obainted catalysts were characterized by XRD, FTIR, BET and SEM, and subsquently used for the catalytic oxidation of ethylbenzene to acetophenone in a btach reactor. The effcts of the metal loading dosage and bimetallic modification of the USY catalysts on the reaction were investiaged. The results showed that cobalt element has a synergistic effect on the uniform distribution of copper on the USY zeolite. The 5%Co/20%Cu-USY catalyst has the best catalytic performance for oxidation of ethylbenzene when the loading（mass percent）of Co and Cu was 5% and 20%,respectively. The conversion of ethylbenzene and the selectivity of acetophenone reached 29.8% and 87.2%,respectively. Recycle run results suggested that 5%Co-20%Cu-USY was stable for at least 4 cycles without obvious changes of catalytic activity and selectivity.