论文总字数：17043字

摘 要

苯酚的氧化产物对苯二酚和邻苯二酚是附加值较高的酚类化学品，在香料、照相、杀虫剂和复合药物等有机合成行业以及橡胶、阻聚剂等聚合物领域发挥着巨大作用。苯二酚的常规工业生产主要是通过无机酸、简单金属离子及其配合物作为催化剂来均相催化苯酚羟基化，通常需要多个反应阶段，这是一个操作繁琐且污染严重的过程。在温和条件下苯酚被过氧化氢直接氧化得到苯二酚被认为是最经济、最环保、最具潜力的生产方法。常用的催化剂，比如分子筛、酸、碱、多相酸、金属氧化物、沸石等，价格昂贵，难以回收，催化性能低和其他缺点抑制了它们的广泛应用，人们不得不寻求更加经济有效的催化剂用于苯酚羟基化反应。而水滑石作为有着优良性能的催化材料吸引了大量关注，极大地改善了多副产物和选择性低等问题，极具探索价值。

水滑石是一类阴离子型层状复合金属氢氧化物，结构具有可调控性，通过调变酸/碱活性中心可有效改善其催化性能，可作为高效酸/碱催化剂。本论文采用双滴共沉淀法合成了五组CuZnFeAl-LDHs，这些水滑石样品的铜含量从5%到25%不等。利用X-ray diffraction (XRD)、Scanning electron microscope (SEM)、Fourier transform infrared spectoscopy (FT-IR)、Brunner−Emmet−Teller (BET)、Inductive coupled plasma emission spectrometer (ICP)和TG-DSC等手段对所制备催化材料进行了表征分析，并将该催化剂应用于苯酚的羟基化反应中以考察其催化性能。

表征结果表明该催化剂具有典型的水滑石层状结构，热稳性随着Cu² 含量的增加而下降。将所制备的催化剂用于苯酚低浓度水溶液羟基化反应中，在不添加任何弱还原剂的条件下，20/CuZnFeAl-LDHs样品表现出极佳的催化活性。反应过程研究发现，以底物的5%作为催化剂参与反应的使用量，苯酚与H₂O₂的物质的量相等，当反应在50°C下进行30 min时，可以实现苯酚转化率和苯二酚的选择性分别保持在66.9%、71.3%。将水滑石回收再利用，5次之后，苯酚的转化率和苯二酚的选择性分别维持在62.5%、66%，催化性能下降不大，稳定性良好。

关键词：水滑石 共沉淀法 苯酚羟基化 催化氧化

Preparation of nano-quaternany hydrotalcite and Study on phenol oxidation properties

ABSTRACT

Hydroquinone is an important intermediate compound in the chemical industry, and plays an important role in the field of organic synthesis such as perfumes, pesticides and pharmaceuticals, and in the field of polymers such as rubber. Hydrogen peroxide is used as an oxidant. Direct hydroxylation of phenol under mild conditions is recognized as the most economical, environmentally friendly and potential benzene in the world. Diphenol synthesis method. Acid, alkali, molecular sieve, metal oxide, heteropoly acid and other catalysts have high cost, difficult to recycle, poor activity and other defects, and the excellent performance of hydrotalcite in the field of catalysis provides new ideas for the development of the new catalyst for the reaction. It has improved the problems of many by-products and low selectivity, and it has great exploration value.

Hydrotalcite is a kind of anionic layered composite metal hydroxide with structure controllability.By adjusting the acid/base active center, the catalytic performance can be effectively improved, and it can be used as a high-efficiency acid or base catalyst. In this paper, five groups of copper, zinc, iron and aluminum hydrotalcites were synthesized by double-drop coprecipitation. The copper content of these hydrotalcite are different. XRD, SEM,FT-IR, BET, ICP and TG-DSC were used to characterize the prepared catalytic materials, and the catalyst was applied to the hydroxylation of phenol. In order to examine its catalytic performance.

The characterization results show that the catalyst has a typical hydrotalcite layered structure, and the thermal stability decreases with the increase of Cu² content. The prepared catalyst was used in the hydroxylation reaction of a low concentration aqueous solution of phenol, and the 20/CuZnFeAl-LDHs sample showed excellent catalytic activity without adding any weak reducing agent. The reaction process study found that when the amount of catalyst is 5% of the substrate, the ratio of the amount of phenol to H₂O₂ is 1:1, and the conversion of phenol can reach 66.9% when reacted at 50℃ for 30 min. The selectivity to phenol was 71.3%. After five cycles of catalyst use, the conversion of phenol can still reach 62.5%, the selectivity of benzenediol is 66%, and still have good catalytic performance.

Key words: hydrotalcite;coprecipitation method;phenol hydroxylation;catalytic oxidation

目录

第一章 文献综述 1

1.1 前言 1

1.2 纳米四元水滑石的性质 2

1.3 纳米四元水滑石的制备方法 2

1.4 本课题的研究目的和意义 4

1.4.1 研究目的 4

1.4.2 意义 4

第二章 实验部分 5

2.1 实验药品及仪器 5

2.2 催化剂的制备 5

2.3 催化剂的表征 6

2.4高效液相色谱 7

2.5 苯酚氧化反应 7

第三章 结果与讨论 10

3.1 催化剂的表征 10

3.1.1 XRD和SEM表征 10

3.1.2 FT-IR表征 10

3.1.3 ICP和BET表征 11

3.1.4 TG热分析 12

3.2 催化剂的性能测试 12

3.2.1 Cu含量的影响 12

3.2.2 催化剂用量的影响 13

3.2.3 反应时间的影响 14

3.2.4 H₂O₂用量的影响 14

3.2.5 反应温度的影响 15

3.2.6 催化剂的重复使用性 16

第四章 结论与展望 17

4.1 结论 17

4.2 展望 17

参考文献 18

致 谢 20

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