预处理条件及金属离子改性对H-MOR分子筛的DME羰基化性能影响

详细了考察不同预处理条件及反应温度对丝光沸石(H-MOR)分子筛二甲醚(DME)羰基化制取醋酸甲酯(MA)的催化活性和稳定性的影响。研究结果表明,在氮气气氛中500℃预处理2 h、反应温度为180℃时H-MOR催化剂的DME转化率最高,可达20.5%。虽然提高反应温度可以进一步提高催化剂的DME转化率,但易产生积炭,快速失活。此外,还考察了金属离子改性对H-MOR催化剂DME羰基化活性的影响。采用离子交换法制备了Cu、Ni、Fe和Co等金属离子交换的H-MOR催化剂,活性测试结果表明:IE-Cu催化剂活性最好,DME转化率为36.9%;IE-Ni催化剂的活性最稳定,DME转化率稳定在24.5%。还原温度对IE-Cu催化剂DME羰基化活性有重要影响,450℃还原后的IE-Cu催化剂活性要明显高于300℃还原的IE-Cu。

Influence of pretreatment and metal cation modification of H-MOR zeolite on performance of DME carbonylation

The influence of the pretreatment conditions and reaction temperature of the H-MOR zeolite on the performance of DME carbonylation was investigated. It was found that after the sample was pretreated in N₂ flow at 500℃ for 2 h, the DME conversion reached 20.5% at 180℃. The DME conversion of the H-MOR increased with increasing reaction temperature, but the serious coking at higher temperatures resulted in the deactivation of the catalyst. Additionally, Cu, Fe, Ni and Co cations were used to modify the H-MOR zeolite, and to explore the influence of metal cation modification of the H-MOR zeolite on the performance of DME carbonylation. The catalytic tests showed that the IE-Cu catalyst was more active with the DME conversion of 36.9%, while the IE-Ni catalyst was more stable with the DME conversion of around 24.5% at the whole reaction period. Moreover, the influence of reduction temperature of the IE-Cu zeolite on the performance of DME carbonylation was also studied. The catalytic activity of the pre-reduced IE-Cu at 450℃was higher than that pre-reduced at 300℃.