甲基丙烯醛氧化酯化整体式催化剂制备及评价

针对甲基丙烯醛氧化酯化浆态床反应过程中颗粒催化剂易破碎、活性组分易流失等缺点,采用浸渍法在电沉积到泡沫镍合金表面的氧化铝-氧化镁涂层上负载活性组分,制备了Pd_xPb_y/Al₂O₃-MgO/泡沫镍合金整体式催化剂。研究分析了铝溶胶含量、Al₂O₃含量、沉积电压和沉积时间等条件对涂层负载的影响,并对载体和催化剂进行了BET、XRD、SEM、ICP和TEM表征和气-液-固固定床反应性能评价。结果表明,当铝溶胶的体积含量为35%～40%,Al₂O₃含量为25～30 g·L^-1,沉积电压为10～12 V,沉积时间为8～12 min,搅拌速度为200～250 r·min^-1时可得到稳定的涂层。在温度为80℃、压力为0.3 MPa、醇醛摩尔比为8:1、液相物料进口流量为0.5 ml·min^-1、氧气进口流量为35 ml·min^-1、反应时间为2 h条件下,整体式催化剂上甲基丙烯醛转化率最高为76.1%,甲基丙烯酸甲酯选择性为81.2%。研究结果可为甲基丙烯醛氧化酯化制甲基丙烯酸甲酯的生产工艺优化提供科学数据。     

甲醛和丙醛缩合制备甲基丙烯醛反应动力学

通过气相色谱和傅里叶红外光谱仪分析,考察了不同仲胺化合物对甲醛和丙醛缩合制备甲基丙烯醛的催化性能. 结果表明,二乙胺催化效率最高,甲基丙烯醛的收率高达94%. 进一步研究了以二乙胺为催化剂缩合制备甲基丙烯醛的反应动力学规律,得出反应级数为2.456,反应活化能和指前因子分别为62.45 kJ/mol和8.182′107 (mol/L)-1.456/s. 并通过在线红外光谱仪和气质联用仪证实生成了中间体曼尼希碱,为进一步研究反应机理奠定了基础.     

The Intermetallic Catalysts for Oxidative Esterification of Methacrolein to Methyl Methacrylate

A series of supported intermetallic Pb-Pb catalysts were prepared with the impregnation method by changing the support (silica, molecular sieve or g-alumina ) and the pore size. The chemical states of the two metals were characterized by XPS analysis, the process for producing methyl methacrylate based on the direct oxidative esterification of methacrolein with methanol in the presence of oxygen was performed in a slurry reactor with the above-mentioned catalysts. The influence of the calcination temperature and the kinds of support as well as the pore size on catalytic activity had been extensively investigated. Under the conditions of temperature at 80℃, catalyst 3.8% (w) and the reaction time 2 h, the conversion rate of methacrolein reached 85%, the selectivity and the yield of methyl methacrylate were 90% and 76.5%, respectively.     

烯烃氢甲酰化反应研究进展

氢甲酰化反应是目前生产醛醇化合物最重要的反应之一,本文综述了烯烃氢甲酰化反应的发展概况,介绍了催化剂的研究进展和现有工艺的特点及运行情况,对烯烃氢甲酰化技术应用的实际情况进行了分析,并针对现存不足指出了均相催化反应多相化的必然趋势,同时还对该工艺的发展前景进行了展望.