苯甲酸液相催化氧化合成苯酚的研究

【作者】 李陵岚；

【导师】 吴鑫干；

【作者基本信息】 湖南大学 ， 应用化学， 2002， 硕士

【摘要】 苯酚是一种重要的有机化工原料，用途广泛。本文阐述了苯酚的各种性质及生产发展状况，并论述了苯酚的7种合成方法；着重评述了近年来甲苯-苯甲酸合成苯酚的新进展；指出在苯酚的众多合成方法中，甲苯氧化法显示出优势和潜力。本文对甲苯-苯甲酸合成苯酚法进行了技术经济核算。核算结果表明：甲苯法静态回收期约2年左右，在生产规模小时表现出较强的竞争力。在我国一定生产规模的甲苯氧化法制备苯酚有一定利润可图。西南、西北、华中、华南地区都可考虑采用甲苯法制取苯酚。对苯甲酸液相催化氧化合成苯酚进行了热力学计算。由计算结果可知：反应可自发向产物方向进行。反应过程在热力学上十分有利。反应的转化率约为100％，苯甲酸可近似完全反应。对苯甲酸铜的热分解反应进行了研究。研究表明：苯甲酸铜的热分解反应为二级快速反应。反应活化能约为7KJ左右。200～240℃时反应的半衰期约在40min左右。详述了近年来国内外在反应机理上的研究。对苯甲酸液相催化氧化合成苯酚中催化剂进行了研究。研究表明：苯甲酸锰与苯甲酸铜在苯甲酸熔融状态下表现出相似的分解性质。IA、IIA、IIB族元素对苯甲酸铜热分解反应都有促进作用。其中Mg盐促进效果最明显。它们的作用机理可能是由于其外层电子造成的。Cu-Mg系催化剂中两者摩尔比对反应的影响较显著。两者比例中Mg盐越多，单位摩尔Cu能产生更多苯酚，反应转化率较高。而Cu盐较多时，CuO利用率越大，反应选择性较高。Cu-Mg系催化剂用量对反应的影响也较显著。结果表明：CuO占苯甲酸的13.4％(mol)以上时副反应明显增加。n(CuO)：n(MgO)=1：1.5左右为较佳值。体系中CuO总用量约为7.3％(mol)左右且不能超过13.4％(mol)。在上述催化剂条件下进行实验验证，结果表明半连续工业模拟实验结果的重现性较好，收率较高，实验中苯酚的选择性都达到了80％以上。苯甲酸液相催化氧化合成苯酚的精制过程采用加入甲苯共沸精馏法，精制苯酚可达到国家标准中的优级品。为了处理反应残留物设计出以稀HCl溶液作为萃取剂回收物料并取得了良好效果。对于本实验所生成废水设计出共沸精馏法处理，处理前COD(Cr)为2953mg/L，处理后COD(Cr)为300mg/L，可与生化处理的出口效果相比。更多还原

【Abstract】 Phenol, as a essential industrial chemical, is widely used in many fields. This paper expounds kinds of properties and developing condition of phenol; introduces the synthetic methods of phenol; specializes the new developments in the toluene/benzoic acid oxidation. We investigate the techno-economic analysis. The results indicate the yield time in the toluene/benzoic acid oxidation is about two years. So the method by toluene oxidation can gain better profits and has better potential for development. In this paper, we calculate some questions on the thermodynamics of benzoic acid catalytic oxidation in the liquid phase. The reaction can be spontaneous carry on to the productions, and the selection is about 100%; benzoic acid can approximately react in the whole. The kinetics of pyrolysis of cupric benzoate in benzoic acid melt is studied. The pyrolysis of cupric benzoate in benzoic acid melt conforms to fast pseudo second order reaction regime, and is two order with respect to cupric concentration. The activity energy is about 7 KJ, and the half life in 200-240 is 40 min. We also explore the mechanism of phenol formation by benzoic acid catalytic oxidation in the liquid phase. The catalyses in the benzoic acid oxidation process are also studied. The pyrolytic property of manganese benzoate is similar to that of cupric benzoate. The elements of IA IIA IIB can promote the pyrolysis. Among its magnesium oxide shows the best result. The molar ratio between Cu(II) and Mg(II) and amounts of catalyst, as two prominent factors, are studies. When Mg(II) is excess between Cu(II)/Mg(II), the conversion rate is better. When Cu(II) is excess between Cu(II)/Mg(II), the selectivity is better. n(CuO):n(MgO)= 1:1.5; the amount of CuO in the system is about 7.3%(mol). The yields of phenol are 80-85% under this condition in a 2L agitated stainless steel reactor. Purification of products and reuse of input material and catalyst are studies. The product amounts to state standard by melt point and IR spectra analysis.更多还原