芳胺通过还原胺化反应合成N-甲基芳胺类化合物的研究
Study on the Synthesis of N-Methyl Aromatic Amine by Reductive Amination

N-烷基芳胺类化合物是重要的精细化工、有机合成和药物中间体。本文以苯胺和多聚甲醛为原料，采用还原胺化反应，通过控制变量法进行单因素实验，分别考察了碱的种类及用量、缩合反应温度及时间、回流时间等因素对N-甲基苯胺产率的影响。最终通过实验探究得出苯胺与多聚甲醛在硼氢化钠作用下进行还原胺化反应的较佳反应条件为：苯胺与5 equiv多聚甲醛，4.0 equiv甲醇钠为碱，以10 mL甲醇为溶剂，在60℃下反应8 h，随后加入2.0 equiv硼氢化钠后回流2 h。在该反应条件下，分别考察苯环上取代基的电子效应和空间效应对反应的影响，实验结果表明：取代基的空间效应对反应影响较大，取代基的电子效应对反应影响较小。
N-alkyl aryl amines are important intermediates in fine chemicals, organic synthesis and pharmaceuticals. In this paper, single-factor experiments were carried out using aniline and paraformaldehyde as raw materials, using reductive amination and controlled variable methods. The effects of the type and amount of base, condensation temperature and time, and reflux time on the yield of n-methylaniline were investigated. The optimal reaction conditions for the reductive amination reaction of aniline with polyformaldehyde under the action of sodium borohydride, as determined by experimental exploration, are as follows: aniline with 5 equiv polyformaldehyde and 4.0 equiv sodium methoxide as the base, using 10mL of methanol as the solvent, reacting at 60？C for 8 hours, and then adding 2.0 equiv of sodium borohydride and refluxing for 2 hours. Under these conditions, the electronic effect and the spacing effect of the substituents on the benzene ring were investigated respectively. The experimental results showed that the space effect of the substituents had a great influence on the reaction and the electronic effect of substituent has little effect on the reaction.