成对电合成苯甲醛和邻氨基苯酚

发布时间：2018-07-10 17:45

本文选题：成对电合成 + 苯甲醇　；参考：《太原理工大学》2017年硕士论文

【摘要】：化学工业产品在改善人们的生活质量中起着关键性作用,影响着人们的方方面面。然而由于它在生产过程中会不可避免的对环境造成破坏,对各国的经济、社会和环境带来了巨大的压力,因此为了避免事态进一步恶化,绿色化学得到了各国广泛的重视,即在生产过程达到污染零排放。由于电化学是以电为能源,在生产过程中主要产生氢气和氧气,对环境的破坏程度小,已经成为绿色化学重要的分支。电化学主要应用在对工业废水的降解处理,土壤的降解和大气颗粒的吸附等方面。而现在越来越多的研究者将电化学技术应用到有机合成。该技术与传统的化学合成方法相比,具有操作过程容易控制,产品纯度高,副产物少,经济优势更高的特点。苯甲醛和邻氨基苯酚都是重要的有机化工产品中间体。其中苯甲醛是杏仁和许多水果中最简单的芳香成分。其广泛的应用于医药、香料、农业和工业等领域。而邻氨基苯酚则广泛应用于染料、医药、印刷业以及生物领域。近年来人们发现邻氨基苯酚也可用于脂肪酸的分析,制备Schiff碱。然而,无论是苯甲醛还是邻氨基苯酚其传统生产工艺都会对环境造成比较大破坏。本实验通过文献调研以及本课题组以往的研究工作,发现苯甲醛和邻氨基苯酚电解制备的反应条件比较接近,都在碱性介质中进行电解,且槽电压也差别不大,故采用绿色、清洁的成对电合成技术,通过阳极电氧化苯甲醇得到苯甲醛,阴极电还原邻硝基苯酚制备邻氨基苯酚,在一个电解过程中同时制备得到了两种具有较高附加值的精细化学品。具体研究内容如下:首先,对阳极工作电极进行了研制。通过查阅相关文献发现:苯甲醇在泡沫镍电极电极表面能够发生氧化反应生成苯甲醛。在对该电极进行循环伏安分析时,此电极对苯甲醇的催化氧化效率不高,为提高电极的催化氧化效率,制备得到更多的目标产品,本实验采用多电流阶跃法以泡沫镍电极为基体,制得了Ni OOH电极,通过对比相同条件下苯甲醇的循环伏安图得出:新制的Ni OOH电极对苯甲醇具有更高的催化氧化活性。其次,通过查阅文献发现没有对阴极电解产物分析的方法,对电解后产物的分析带来不便,因此,本实验在已阅文献的基础上,根据邻硝基苯酚和邻氨基苯酚的性质差异建立了同时测定邻氨基苯酚和邻硝基苯酚的高效液相色谱法,探讨了检测波长,柱温,流动相的配比和流速对检测结果的影响,并最终确定液相色谱分析的最优条件,即流动相为纯甲醇,流速为0.8 min/L,检测波长为285nm,柱温为35℃,将其应用于电还原邻硝基苯酚合成邻氨基苯酚电解液的分析,其加标回收率分别在93.0%~105.6%和90.6%~106.2%之间,相对标准偏差分别≤3.75%和≤1.44%。第三,以Pb片为阳极,Cu片为阴极,NaOH溶液为电解液,研究了邻硝基苯酚在Cu电极表面的电化学行为,实验结果显示,邻硝基苯酚在Cu电极表面有中间产物生成,氧气的存在会发生与邻硝基苯酚争夺电子现象。因此,在电还原邻硝基苯酚制备邻氨基苯酚过程中,需通入氮气进行保护,通过正交试验获得的最佳电解条件为:邻硝基苯酚加入量与理论量的物质的量之比为2:1,NaOH加入量3.0g,反应温度为35℃,电流强度为0.3A,电流效率为在98%以上。第四,在满足阴极制备邻氨基苯酚最大电流效率条件下,将阳极制备苯甲醛的过程与阴极进行配对。在H型电解槽中,以Ni OOH为阳极,Cu为阴极,Na2SO4为电解质,保持阴极电解条件基本不变的基础上,通过正交试验考察了阳极电解过程中苯甲醇加入量与理论量的物质的量之比,反应温度和NaOH加入量对阴阳极电流效率和总电解电流效率的影响情况。实验结果显示:反应温度35℃,电解电流0.3A,邻硝基苯酚加入量为理论量的2倍,阴极碱用量为3.0g,苯甲醇的加入量为理论量的5倍,阳极碱用量2.0g,电解反应的总电流效率最高可达156.95%。为今后工业化生产奠定了良好的理论基础。
[Abstract]:Chemical industry products play a key role in improving people's quality of life, affecting all aspects of the people. However, because it will inevitably cause damage to the environment in the process of production, it has brought great pressure on the economy, society and environment of each country. Therefore, the green chemistry has been obtained to avoid the further deterioration of the situation. All countries attach great importance to the zero emission of pollution in the process of production. Because electrochemistry is the energy source of electricity, hydrogen and oxygen are produced mainly in the production process, and the damage to the environment is small, and it has become an important branch of green chemistry. Electrochemistry is mainly used in the degradation treatment of industrial waste water, soil degradation and atmospheric particles. More and more researchers have applied electrochemical technology to organic synthesis. Compared with traditional chemical synthesis, the technology has the characteristics of easy operation, high purity, less byproducts and higher economic advantages. Both benzaldehyde and O aminophenol are important intermediates of organic chemical products. Benzaldehyde is the simplest aroma component in almond and many fruits. It is widely used in the fields of medicine, spice, agriculture and industry, while o aminophenol is widely used in dyes, medicine, printing and biological fields. In recent years, it has been found that o aminophenol can also be used for the analysis of fatty acids and the preparation of Schiff bases. However, no matter what it is, The traditional production process of benzaldehyde or o aminophenol will cause a lot of damage to the environment. Through literature investigation and previous research work, we found that the reaction conditions of electrolysis of benzaldehyde and O aminophenol are relatively close, both are electrolyzed in alkaline medium and the voltage of the groove is not very different, so it is adopted. Green, clean pair electric synthesis technology, by the anode electrooxidation of benzyl alcohol to obtain benzaldehyde, the cathode electroreduction of O nitrophenol for the preparation of O aminophenol, two kinds of fine chemicals with high added value have been prepared at the same time in an electrolysis process. The specific contents are as follows: first, the anode working electrode was developed. After consulting related literature, it is found that benzyl alcohol can produce benzaldehyde on the surface of foam nickel electrode. When the electrode is analyzed by cyclic voltammetry, the catalytic oxidation efficiency of the electrode to benzyl alcohol is not high. In order to improve the catalytic oxidation efficiency of the electrode, more target products are prepared. This experiment uses a multi current order. The Ni OOH electrode was prepared on the base of nickel foam electrode in the jump method. By comparing the cyclic voltammetry of benzyl alcohol under the same condition, the new Ni OOH electrode has higher catalytic oxidation activity to benzyl alcohol. Secondly, the method of separating the cathode electrolysis products from the cathode electrolysis product is found by consulting the literature, and it is inconvenient for the analysis of the products after electrolysis. On the basis of the literature, the high performance liquid chromatography (HPLC) for simultaneous determination of O aminophenol and O nitrophenol was established on the basis of the properties of O nitrophenol and O aminophenol. The influence of detection wavelength, column temperature, flow phase ratio and flow rate on the determination of the fruit was discussed. The optimum conditions are that the flow phase is pure methanol, the flow rate is 0.8 min/L, the detection wavelength is 285nm, the column temperature is 35 C, and it is applied to the electroreduction of O aminophenol electrolyte by electric reduction of O nitrophenol. The recovery rate is between 93.0%~105.6% and 90.6%~106.2%, respectively, the relative standard deviation is less than 3.75% and less than 1.44%. third, and Pb films are used as anode, Cu as cathode and NaOH solution as electrolyte, the electrochemical behavior of O nitrophenol on the surface of Cu electrode has been studied. The experimental results show that o nitrophenol has intermediate products on the surface of Cu electrode, and the presence of oxygen will compete for the electron phenomenon of O nitrophenol. Therefore, in the process of the preparation of O aminophenol by the electroreduction of O nitrophenol, the process of O aminophenol is prepared by electric reduction of O nitrophenol. The optimum electrolysis conditions obtained through orthogonal test are: the ratio of the quantity of the adjacent nitrophenol to the quantity of the material is 2:1, the NaOH is 3.0g, the reaction temperature is 35, the current is 0.3A, the current efficiency is above 98%. Fourth, under the condition of the maximum current efficiency of the full cathode preparation of the o aminophenol, The process of preparing benzaldehyde with the anode is paired with the cathode. In the H cell, the Ni OOH as the anode, the Cu as the cathode and the Na2SO4 as the electrolyte, on the basis of the basic condition of the cathode electrolysis, the ratio of the amount of benzyl alcohol to the theoretical quantity, the reaction temperature and the NaOH addition in the anode electrolysis process are investigated by orthogonal test. The experimental results show that the reaction temperature is 35, the electrolysis current is 0.3A, the addition of O nitrophenol is 2 times the theoretical amount, the amount of the cathode base is 3.0g, the amount of benzyl alcohol is 5 times the theoretical amount, and the anodic alkali amount is 2.0g, the total current efficiency of the electrolysis reaction can reach 156.95%. It lays a good theoretical foundation for industrial production in the future.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ24

【参考文献】