【作者】 李云丽；

【导师】 汪宝和；

【作者基本信息】 天津大学 ， 化学工艺， 2007， 硕士

【摘要】 甲基丙烯酸甲酯（MMA）是制备有机玻璃（PMMA）和甲基丙烯酸高级酯的原料,由于其优异的性能和广泛的用途,已成为一种极具市场潜力的化工产品。本文对以甲醛和丙醛为原料制备MMA的工艺过程进行了研究。首先采用甲醛和丙醛液相缩合的工艺路线合成了中间体甲基丙烯醛（MAL）,得到纯度达99.8%的产品,并通过红外光谱进行了表征。确定了适宜的反应工艺条件:反应物摩尔比为1.1:1（甲醛/丙醛）,反应时间为50min,反应温度为46℃。在此条件下,丙醛转化率达99.8%,MAL收率91.2%。同时对反应机理进行了研究。其次,制备了用于MAL一步氧化酯化合成MMA的Pd系列催化剂,所用载体为SiO₂-MgO和CaCO₃。考察了反应时间、反应温度、醇醛摩尔比和催化剂加入量对MAL转化率和MMA选择性的影响。采用色谱标样对比法、气相色谱-质谱联用法,并结合工艺反应过程,对氧化酯化产物的组分进行了定性分析,确定了产物中存在的几种杂质分别为:甲基丙酸甲酯、3-甲氧基异丁酸甲酯、MMA二聚物。此前期工作包括催化剂的制备方法、合成反应条件的考察以及产物分析方法的确立,为下一步开发新型催化剂提供了必要的数据与参考。最后,对MAL一步氧化酯化制备MMA的反应过程进行了分析探讨。更多还原

【Abstract】 Methyl methacrylate (MMA) is an important chemical product,which is widely used for manufacturing polymethyl metracrylate or other methacrylic esters. Because of its excellent function and comprehensive application, MMA has huge market potential.The synthesis of MMA from formaldehyde and propionaldehyde was studied in this paper.Firstly, MAL was synthesized as an intermediate by propionaldehyde condensing with formaldehyde in the presence of catalyst in liquid phase. Effects of reactant ratio, reaction temperature and reaction time on the conversion and yield were investigated. The proper reaction conditions were ascertained as follows: the mole ratio of formaldehyde/propionaldehyde=1.1/1; reaction time=50min; reaction temperature=46℃. Under the above conditions, propionaldehyde conversion and MAL yield reached up to 99.8% and 91.2% respectively. The product which had a purity of 99.8% was characterized by IR spectra. The reaction mechanism was also described.Secondly, the Pd catalysts which consist of different carrier were prepared and applied to produce MMA from direct oxidative esterification of MAL. The effects of mole ratio of methanol to MAL, reaction temperature,reaction time and catalyst concentration on MAL conversion and MMA selectivity were studied. The components of the product were determined by means of standard sample comparison and GC-MS. Results showed that the main byproducts were methyl isobutyrate, 3-methoxy-methyl methacrylate and MMA dimer. All these prior studies including preparation of catalyst, optimization of the reaction conditions and establishment of analysis methods can be a reference to the exploration and development of new catalyst.Finally, the reaction process for preparing MMA from direct oxidative esterification of MAL was discussed in this paper.更多还原