【作者】 赵建宏；

【导师】 王福安；

【作者基本信息】 郑州大学 ， 化学工艺， 2006， 博士

【摘要】 随着社会的进步和医药、橡胶、染料等工业的快速发展，对氨基苯酚（PAP）作为重要的医药、橡胶、染料和精细化工中间体，国内外需求量逐年递增，缺口甚大，合成新方法研究相当活跃。有“绿色技术”美称的硝基苯（NB）直接电还原合成技术具有成本低、无污染、投资少、收率高、产品质量好等其它工艺无法比拟的优点，成为国内外学者研究的热点。作为河南省重点科技攻关项目（No．03223023800）的一部分，本文以NB为原料，进行直接电还原合成PAP过程的反应液分析、阴极材料电催化性能与选择、电化学反应器的选择及流体流动特性、工艺条件优化、离子膜的污染与清洗再生、相关流体相平衡、体积性质、粘度性质及相应模型等基础研究，具有重要的学术理论意义和工程应用前景。 直接电还原合成PAP过程的反应液为PAP、苯胺、未反应的NB及H₂SO₄水溶液，反应液中PAP和苯胺的同时快速分析尚未见报道。本文将等吸收点双波长紫外分光光度法和气相色谱法相结合，建立了可同时对电合成PAP反应液中PAP、苯胺、未反应的NB进行定量分析的新方法。 阴极是电合成PAP过程的催化剂，又是电催化反应的场所，针对NB直接电还原合成PAP体系的特点，采用循环伏安、稳态极化曲线及控制电位电合成等手段，系统研究了硝基苯在Cu、Ni、Monel合金和Cu-Hg四种阴极上的电化学还原特性，表明Cu-Hg电极和Monel合金电极有较高的析氢过电位、较好的电催化活性和优良的PAP选择性，考虑到Hg污染等因素，Monel合金是电合成PAP较理想的阴极。 根据NB电化学还原机理和反应工程原理分析，硝基苯电还原合成对氨基苯酚用反应器的流体流动状况应接近理想置换流。据此，设计自制板框式电化学反应器。通过停留时间分布模拟实验和直接电化学合成实验，当阴极液流量接近300L．h^-1时，流型接近理想置换流，此时的PAP收率和电流效率最大。 使用板框式电催化反应器，Nafion427阳离子交换膜，Monel合金阴极，铅锑合金阳极，在阳极液硫酸浓度20wt％、流量300L／h、极间距3mm、阴极液中乳化剂用量0.12wt％、反应前以200ml／min的速度鼓入高纯N₂ 20min的条件下，运用正交实验设计和较精细的单因素实验得到最佳工艺条件为：电流密度500A／m²；电解温度85℃；阴极液硫酸浓度20wt％；阴极液NB的浓度6.75wt％；通电量100A．h：更多还原

【Abstract】 p-Aminophenol（PAP） is an important medicine, rubber and dye intermediate with wide uses and optimum application prospects. With the development of medicine, rubber and dye industry, the need for p-aminophenol was yearly increased both in China and abroad, however the supply is insufficient. The technology of direct electrochemical synthesis of PAP is characterized by mild reaction conditions, high product purity and reduced waste, and is called as "Green Technology". So the studies to fluid phase equilibria, volumetric and viscosity properties, the analysis method, the electro-catalytic activity and selectivity of cathode materials, the design and flow characteristic of reactor, the technological conditions optimization and the fouling and cleaning processes of Nafion membrane etc. have a great science and applied significance for electrochemical synthesis of p-aminophenol using nitrobenzene （NB） as raw material. The research contents of this paper are one of subjects funded by Henan Key Research Projects （No. 03223023800） in 2003.In the electro-synthesis process of p-aminophenol, supporting electrolytes were sulfuric acid aqueous solution, and the reaction solution were the mixtures consisting of p-aminophenol, water, H₂SO₄, aniline and un-reacted NB. The analysis method that can simultaneously and rapidly analyzes the contents of p-aminophenol and aniline in reaction mixture liquid was not found in literature. In this paper, a new analysis method that can simultaneously analyzes the contents of p-aminophenol and aniline in reaction mixture liquid was proposed by combining gas phase chromatography method with equivalence absorbency double-wavelength UV spectrophotometry method.The cathode is the catalyst and a reaction field for electro-catalytic reaction. Base on the properties of the electro-synthesis process of p-aminophenol and with the methods of CV, steady-state polarization curve and controlled potential electrochemical reduction, the electro-catalytic properties of Cu, Ni, Monel alloy and Cu-Hg electrode were investigated, respectively. It was found that the Monel alloy and Cu-Hg cathodes exhibited higher overpotential to hydrogen evolution, better electro-catalytic activity and p-aminophenol selectivity, and can be applied in the electro-synthesis process of p-aminophenol. Further thinking of the factor of mercury pollution aspect, Monel alloy was finally selected as the cathode material for electrochemical reduction NB to p-aminophenol.According to the analysis of the chemical reaction engineering theory and the NB electrochemical reduction mechanism, the fluid flow patterns in the electrolyzer used as direct electrochemical reduction NB to p-aminophenol should be close to plug-flow. Based on the outcome, the Plate and frame electrolyzer that can be used in direct electrochemical reduction NB to p-aminophenol was designed. In terms of the results of the residence time distribution（RTD） experiments and the direct electrochemical reduction experiments of NB, it can be known, when the catholyte flow rate is 300L.h^-1, the fluid flow patterns in the electrolyze are close to plug-flow and both the current efficiencies and the yield of PAP are the highest.In this study, using Nafion 427 cation-exchange membrane as membrane, Monel alloy as cathode and Pb-Sb alloy as anode, the technology conditions for synthesizing更多还原