【作者】 吴崖迪；

【导师】 王桂林；

【作者基本信息】 浙江工业大学 ， 工业催化， 2004， 硕士

【摘要】 3，4-二甲基苯胺是一种重要的化工中间体，广泛地应用于医药、农药、染料等领域。本论文以邻二甲苯为起始物，采用选择性硝化制3，4-二甲基硝基苯和低压液相催化氢化制备3，4-二甲基苯胺。内容主要包括以下三部分。 第一部分，对3，4-二甲基苯胺的合成方法进行了较为系统的概述，并对各方法进行了比较和评述。对硝化理论、提高硝化选择性的方法和低压液相催化加氢理论进行了详细的讨论，并对于论文的目的和意义进行了阐述。 第二部分，提高邻二甲苯硝化选择性的研究思路和研究内容。实验结果显示，在多聚磷酸存在的情况下硝化邻二甲苯有较佳的对位选择性。在此条件下对多聚磷酸的浓度、用量和反应温度等条件进行了优化，异构体中3，4-二甲基硝基苯的比例可以由混酸硝化的45％左右提高到83％。同时用甲苯、乙苯等相似芳香族化合物进行了对比性实验，对多聚磷酸硝化选择性做了初步探讨，认为多聚磷酸的位阻是选择性提高的主要原因。 第三部分，利用改性镍催化剂在较低的压力下加氢还原3，4-二甲基硝基苯，加氢转化率可达99.9％，并与钯／碳催化剂进行了比较。对浓浙江工业大学硕士学位论文度、压力、温度和溶剂等影响因素在较低压力下镍催化氢化3，4一二甲基硝基苯进行了简单的动力学研究。更多还原

【Abstract】 In this thesis, 3,4-xylidine which is an important organic intermediates widely applied in pharmacy, pesticide, and dye industries, has been prepared by selective nitration and catalytic hydrogenatuion in low pressure, using o-xylene as start material. The main content consisted of three sections.In the first section, the synthesis of 3,4-xylidine have been reviewed. Selective nitration of o-xylene and catalytic hydrogenation were also mainly discussed.In the second section, the selective nitration of o-xylene had been studied. The experimental results showed that nitration of o-xylene has good para-position selectivity in the presence of polyphosphoric acid. And the technologic conditions such as concentration of phosphoric acid ,temperature and so on were optimized. Under the selected conditions, the ratio of 4-nitro-o-xylene in the product rised from 45% to about 83%. Some other similar aromatic compounds such as toluene and chlorobenzene are also studied.In the third section, synthesis of 3,4-xylidine was studied byhydrogenation of 4-nitro-o-xylene in nickel catalyst, the conversation of 4-nitro-o-xylene was more than 99.9%. Factors such as concentration of 4-nitro-o-xylene, hydrogen pressure, temperature and solvent were studied and simple dynamics of hydrogenation of 4-nitro-o-xylene in low pressure were discussed.更多还原