论文总字数：46876字

摘 要

三氯乙烯和四氯乙烯是重要的有机氯产品，广泛用于干洗剂、金属清洗剂、有机溶剂、制冷剂等领域。三氯乙烯、四氯乙烯的合成方法有多种，常见的有二氯乙烷氧氯化法、乙炔两步皂化法、四氯乙烷（TCA）与五氯乙烷（PCA）气相脱HCl法等，其中四氯乙烷、五氯乙烷气相脱HCl法因为其具有的反应条件相对温和，产生三废极少，原料易得，工艺简单等优点，逐步成为了研究热点，而作为反应核心的催化剂，更是得到了非常高的关注度，如何提高催化剂在大空速条件的活性以及稳定性成为了当前难题。

活性炭本身具有一定的脱HCl能力，基于此本文对几种不同活性炭载体测试了其脱HCl的能力，并筛选出了活性较好的活性炭作为催化剂载体，然后在此基础之上对活性炭进行了不同的预处理，使得活性炭的催化活性以及稳定性得到极大提高。研究结果表明，不同种类的活性炭本身的催化活性相差较大，其自身的物理性质对于脱HCl反应有一定的影响，活性最差的与最优的活性炭载体，四氯乙烷转化率相差30%左右，优选4号活性炭为载体；通过使用不同的酸碱溶液对活性炭载体进行预处理，从而影响活性炭表面官能团的数量以及种类，依此改变催化剂活性，实验结果表明，较弱的酸性有助于脱HCl反应的进行，但是当酸性多低时，催化剂的活性反而有所下降，说明活性炭的弱酸性位点可能是其活性中心，经过NH₃·H₂O预处理后，四氯乙烷的转化率由85.96%提高至92.67%；对本文自制的氨水预处理并且负载BaCl₂的活性炭催化剂（BaCl₂/AC-A(0.1)）进行了工艺考察，考察结果表明，相同空速下，随着反应温度的提高，四氯乙烷以及五氯乙烷的转化率随之提高，在反应温度由240 °C升到260 °C时，原料转化率有一个较为明显的升高，因此最优的反应温度为260 °C；相同反应温度时，随着空速的变大，原料转化率逐渐下降，对于原料为四氯乙烷（分析纯）时，反应温度为260 °C、质量空速为6 h^-1时，四氯乙烷转化率接近100 %，因此较为适宜的空速为6 h^-1。BaCl₂/AC-A(0.1)催化剂在空速为10 h^-1，反应温度为260 °C的条件下，活性至少在32 h内不会降低，具有一定的工业应用潜质；将BaCl₂/AC-A(0.1)催化剂与工业催化剂相比较，在相同反应条件的情况下，本文自制的催化剂的性能高于工业催化剂。

对于四氯乙烷脱HCl反应进行了动力学模拟，分别使用了吸脱附机理模型以及经验模型进行了动力学模拟分析，动力学模拟结果表明，对于四氯乙烷脱HCl反应，吸脱附模型最为合适，同时在吸附、表面反应、脱附等步骤当中，以表面反应为速率控制步骤最为合适，结果表明，当以表面反应为速率控制步骤时，模拟值与实验值吻合良好，残差随机分布于0点上下，模拟结果良好，动力学方程为：

关键词：四氯乙烷 五氯乙烷 脱HCl 催化剂 活性炭

Abstract

Trichloroethylene and tetrachloroethylene were important organic chlorinated products which were widely used in dry cleaning, metal cleaning agents, organic solvents and refrigerants. There were various methods for preparation of trichloroethylene and tetrachloroethylene,for example dichloroethane oxychlorination method, traditional saponification method and TCA/PCA dehydrochlorination of gas phase method etal. The method for TCA/PCA dehydrochlorination of gas phase had advantages of warm reaction condition, little waster, raw material easy to get and simple process, thus it was studied more and more. Catalyst as the reaction centre was very important and how improve the catalyst activity and stability at high air speed was a hard problem.

Active carbon (AC) had ability of dehydrochlorination by itself, thus several active carbons were investigated on the ability of dehydrochlorination, and the best AC was selected. Then the selected AC was pretreated by several different methods and the activity of AC was improved. The results showed that the activity of dehydrochlorination of AC ranges with the kind of AC ,because different AC had different physical properties .The best AC was higher 30% than the worst on catalyst activity about conversation of TCA .The NO.4 AC was the best one via experiment test .The activity of AC was changed by pretreated by different acid/base solutions ,as functional group of AC altered .The results showed that the weaker acidity contributed to dehydrochlorination ,but when it was too low the activity of AC decreased ,weaker adcid sites was the active centre .When the AC was pretreated by NH₃·H₂O ,the conversation of TCA from 85.96% up to 92.67% .The reaction conditon was investigated by catalyst which pretreated by NH₃·H₂O and load BaCl₂(BaCl₂/AC-A(0.1)) ,the results showed that ,on same air speed ,the conversation of TCA/PCA enhanced with reaction temperature rised .When reaction temperature from 240 °C up to 260 °C ,conversation of feed stock rised obviously ,so 260 °C was the best reaction temperature .When the reaction temperature was same ,the conversation of feed stock decreased with air speed rised .When the WHSV was 6h^-1 ,the conversation of TCA was almost 100% ,thus 6h^-1 was the best WHSV . The activity of BaCl₂/AC-A(0.1) was stable in 32 h when the WHSV was 10h^-1 and the reaction temperature was 260 °C.Compare BaCl₂/AC-A(0.1) with industry catalyst ,the former was better than the latter about conversation of TCA and selectivity of TCE when the reaction condition was same.

Kinetic was studied about TCA dehydrochlorination ,adsorption- desorption model and experience model were used to dynamic simulation .The results showed that adsorption- desorption model was

目录

第1章 文献综述 3

1.1 前言 3

1.2 TCE、PCE的生产方式 3

1.1.1 两步皂化法 3

1.2.2 二氯乙烷氧氯化法（PPG法） 4

1.2.3 乙烯直接氯化法 5

1.2.4 四氯乙烷、五氯乙烷气相脱HCl法 6

1.3 四氯乙烷、五氯乙烷脱HCl催化剂的研究 7

1.3.1 国外脱HCl催化剂的研究 7

1.3.2 国内脱HCl的研究 8

1.4 活性炭改性 11

1.5 脱HCl动力学 14

1.6 研究思路及内容 14

1.6.1 本文研究思路 14

1.6.2 本文研究内容 15

第2章 实验部分 16

2.1 实验试剂及装置 16

2.1.1 实验所用原料及试剂 16

2.1.2 实验所用仪器 17

2.2 催化剂的表征 17

2.2.1 X射线衍射(XRD) 17

2.2.2 氮气吸附脱附(N₂-Sorption) 17

2.2.3 氨气程序升温脱附(NH₃-TPD) 18

2.2.4 Boehm酸量测定法 18

2.3 催化剂活性评价 19

2.4 产品分析 22

2.4.1 色谱分析条件 22

2.4.2 定性分析 22

2.4.3 定量分析 23

2.4.4 产品计算 25

第3章 脱HCl催化剂的制备考察 26

3.1 活性炭种类的筛选 26

3.1.1 不同AC的催化活性 26

3.1.2 不同活性炭载体催化剂的稳定性 28

3.2 活性炭改性方法的影响 29

3.2.1 不同预处理对于催化剂性能的影响 29

3.2.2 不同预处理对于催化剂稳定性的影响 32

3.3 催化剂制备工艺的考察 33

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