【作者】 张旭；

【导师】 王保伟；

【作者基本信息】 天津大学 ， 化学工艺， 2008， 硕士

【摘要】 乙二醇(EG)和乙醇酸乙酯(MPEG)是重要的有机合成中间体,应用前景十分广阔。由合成气经草酸二乙酯(DEO)进行催化加氢反应不但可以得到上述两种高附加值的化工产品,而且能够充分利用煤和天然气资源,对能源安全和环境保护都具有重要意义。本文对DEO气相加氢催化剂的制备方法和助剂的影响进行了研究。在反应温度240℃、压力1MPa、氢酯摩尔比200、液体空速0.3h-1的条件下,对以方法一制备的各催化剂的性能进行考察。结果表明,Zn的加入有利于提高EG的选择性;加入Cr后DEO转化率和EG选择性都有所提高;引入3%质量分数的Mo能够显著提高催化剂的性能,使DEO转化率和目的产物收率分别达到95.4%和94.0%。以方法二制备了一系列催化剂。评价结果表明Cu25(2)催化剂能够在反应温度220℃、压力2.5MPa、氢酯摩尔比60、液体空速0.6h-1的条件下获得86.9%的DEO转化率和79.0%的目的产物收率。Cr0.05(2)催化剂拥有更长的使用寿命,并能使DEO转化率和目的产物收率分别达到95.8%和74.2%。运用TPR、氮气吸附、XRD、SEM、ICP、XPS等表征方法对催化剂活性组分的含量、助剂的影响等进行了深入的探讨。发现各助剂的作用主要在于对催化剂表面结构的改变:Zn有助于增大催化剂的孔容和孔径;3%的Mo能使催化剂活性位直径减小而且分布得更加均匀;在适量Cr的作用下,Cr0.05(2)催化剂具有更大的比表面积。此催化剂在目的产物选择性、DEO转化率和寿命等方面都有良好的性能。更多还原

【Abstract】 Ethylene glycol (EG) and ethyl glycolate (MPEG) are both versatile organic synthesis intermediates. Not only the economic chemicals can be produced, but also the resources of coal and natural gas can be sufficiently utilized via the hydrogenation of diethyl oxalate (DEO) which can be made from synthesis gas. The technology is very important in both safety of energy sources and protection of environment fields. In this paper, the method of catalysts preparation and the effects of promoters are studied.The catalysts prepared through method 1 were tested as the reaction temperature, pressure, molar ratio of H2/DEO and LHSV were set to 240℃, 1MPa, 200 and 0.3h-1, respectively. The results showed that EG selectivity increased because of the addition of Zn; DEO conversion and EG selectivity increased as the introduction of Cr. 3 wt% of Mo can help DEO convert and the desired product yield reach 95.4% and 94.0%, respectively.A series of catalysts were prepared through method 2. DEO conversion of 86.9% and the desired product yield of 79.0% were obtained by using Cu25(2) catalyst when the reaction temperature, pressure, molar ratio of H2 /DEO and LHSV were 220℃, 2.5MPa, 60 and 0.6h-1. The Cr0.05 (2) catalyst which had a longer serve life can increase DEO conversion and the desired product yield to 95.8% and 74.2%, respectively.Several characterization methods, such as TPR, N2 absorption, XRD, SEM, ICP and XPS, were applied to discuss the content of active component and the effects of the promote elements. It is found that the promoters influence the performances of catalysts mainly by changing the surface configurations. It is indicated that the pore volume and pore size were enlarged by adding Zn, the size of active sites was reduced and the distribution was better due to the influence of 3wt% Mo. The surface of Cr0.05 (2) catalyst was obviously extended because of the effect of Cr. As a result, the catalytic performances were advanced by enhancing desired product yield, DEO conversion or life.更多还原