论文总字数：27722字

摘 要

醋酸与异丁烯直接生成醋酸叔丁酯工艺，由于原子利用率理论上可达到100％，且工艺流程简单、过程中没有水生成，所以拥有着经济和环境的双重优势。为了提高醋酸叔丁酯的选择性，通常需要使用过量的醋酸或者直接在体系之中添加进叔丁醇等极性比较大的溶剂，这就导致防腐蚀设备投资变高、后续产物分离提纯能耗变大。于是，研究出绿色高选择性的催化剂成为解决这些问题的重要途径。在本课题组对丙磺酸改性介孔分子筛催化加成酯化反应研究已取得良好成果的基础上，以KIT-6为载体，采用后改性法合成介孔材料Zr-KIT-6-SO₃H，通过金属掺杂引入新的酸位，来提高醋酸叔丁酯的选择性，并且在此基础上研究异种酸位与催化活性的关系。

本文采用两步水热后改性法制备锆掺杂和磺酸改性的的Zr-KIT-6-SO₃H，通过调变合成的酸性环境pH值，制备酸性环境pH值分别为1,3,5,7时的Zr-KIT-6-SO₃H。通过结构表征表明Zr-KIT-6-SO₃H不仅拥有典型的三维孔道结构，而且有着较好的规整度。磺酸的嫁接在分子筛中引入了中强度的酸位和Brönsted酸位，金属的掺杂增加了弱酸的酸量，同时引入了Lewis酸位。在40℃下，对比5组Zr-KIT-6-SO₃H催化醋酸与异丁烯加成反应催化性能发现反应中醋酸叔丁酯的选择性与催化剂中Brönsted酸和Lewis酸位的含量有关。实验结果表明B酸与L酸之间的协同作用能有效抑制异丁烯的二聚反应，同时能促进醋酸的加成反应。Brönsted酸吸附异丁烯，形成σ-络合物叔碳正离子，进而与醋酸和异丁烯反应生成醋酸叔丁酯和二异丁烯。Lewis酸位同异丁烯发生作用，生成π-络合物，使得能被Brönsted酸位吸附异丁烯的浓度变低，降低了σ-络合物叔碳正离子浓度，使得二异丁烯的生成速率变低。使用金属掺杂和磺酸嫁接改性在材料上形成的Lewis酸位和Brönsted酸位在酸烯酯化反应中存在协同效应，从而提高了醋酸与异丁烯的反应中的醋酸叔丁酯的选择性。因此，高Brönsted酸含量的催化剂在催化加成酯化制备醋酸叔丁酯的反应中，有着很高的催化活性，适当的Brönsted酸和Lewis酸位的含量之比可以获得高的醋酸叔丁酯选择性。

关键词： Zr-KIT-6-SO₃H 加成反应 酸位协同 醋酸叔丁酯

Abstract

The direct addition of acetic acid and isobutylene is an atom economic reaction, the process is simple and the water doesn’t exist during the whole process. As a result, this process of producing tert-butyl acetate is environmental friendly and economic. To increase the selectivity of tert-butyl acetate, it’s common to add excessive acetic acid or polar solvent like tert-butanol which results in higher investment in anti-corrosion equipment and the subsequent separation. Therefore, developing efficient and green catalyst is feasible to improve the selectivity of target reaction. On the basis of research on the catalytic addition of mesoporous molecular sieves of propane sulfonic acid modified mesoporous zeolite, KIT-6 was used as the carrier, and the mesoporous materials Zr-KIT-6-SO₃H, the introduction of new acid sites by metal doping, to improve the selectivity of tert-butyl acetate, and on this basis to explore the relationship between different acid and catalytic activity.

In this paper, doped and sulfonic acid modified Zr-KIT-6-SO3H were prepared by two-step hydrothermal modification method. The pH value of the synthesized acidic environment was 1, 3, 5 and 7 respectively sample. The structural characterization shows that Zr-KIT-6-SO₃H has a typical hexagonal mesoporous structure and good regularity. The grafting of sulfonic acid introduces the medium-intensity acid sites and Brönsted acid sites in the samples. The doping of metals increases the weak acid of the amount of acid, while the introduction of the Lewis acid position. The selectivity of t-butyl acetate in the reaction of 5-group Zr-KIT-6-SO₃H catalyzed by the addition reaction of acetic acid with isobutylene was related to the content of Brönsted acid and Lewis acid in the catalyst at 40 ℃. The experimental results show that the synergistic effect between B acid and L acid can effectively inhibit the dimerization of isobutylene and promote the addition reaction of acetic acid. Brönsted acid adsorption of isobutylene, the formation of σ-complex tertiary carbon positive ions, and then with acetic acid and isobutene reaction of tert-butyl acetate and diisobutylene. Lewis acid site interacts with isobutene to form a π-complex, which reduces the local concentration of isobutene in contact with the active site Brönsted acid in the microenvironment, thereby reducing the reaction rate of isobutylene polymerization and the addition of the esterification reaction The rate is less affected by Lewis acid sites. The synergistic effect of the Lewis acid sites and the Brönsted acid sites formed on the materials modified by metal doping and sulfonic acid grafting in the acid esterification reaction improves the selectivity of t-butyl acetate in the reaction of acetic acid with isobutylene The Thus, the high Brönsted acid content of the catalyst in the catalytic addition of the esterification of t-butyl acetate in the reaction with a high catalytic activity, the appropriate ratio of Brönsted acid and Lewis acid sites can be obtained by high t-butyl acetate selectivity.

Key Words：Zr-KIT-6-SO₃H；Additive reaction；Synergic effect；Tert-Butyl acetate

目 录

摘 要 I

Abstract II

第一章 文献综述 1

1.1 背景介绍 1

1.2 酸烯酯化催化剂 1

1.3 双改性介孔分子筛的探索过展 3

1.3.1 磺酸改性介孔分子筛的合成与应用 3

1.3.2 多种官能团共同改性介孔材料的合成与应用 5

1.4金属杂原子掺杂分子筛过程中的优化 7

1.5 论文选题及研究思路 8

第二章 实验部分 10

2.1 实验原料及试剂 10

2.2 主要实验仪器及设备 10

2.3 催化剂的表征方法 11

2.3.1 傅里叶变换红外光谱(FT-IR) 11

2.3.2 氮气吸附脱附(N2-Adsorption Desorption) 11

2.3.3 X射线荧光光谱 11

2.3.4 紫外-可见漫反射光谱(UV-vis) 12

2.4 催化性能评价及分析方法 12

2.4.1 实验方法 12

2.4.2 分析方法 12

第三章不同pH下Zr-KIT-6-SO₃H的合成、表征及催化性能 14

3.1 Zr-KIT-6-SO₃H的制备 14

3.2 Zr-KIT-6-SO₃H表征结果 15

3.2.1 傅里叶变换红外光谱(FT-IR) 15

3.2.2 氮气吸附脱附(N2-Adsorption-Desorption) 16

3.2.3 X射线荧光光谱 17

3.2.4 紫外-可见漫反射光谱(UV-vis) 18

3.3 Zr-KIT-6-SO₃H的催化性能 19

第四章 结论 22

参考文献 24

致谢 27

第一章 文献综述

1.1 背景介绍

由于羧酸酯具有特别的结构和比较强的活性，于是有很多的优秀聚合物通过它衍生而来，这就导致了它成为了十分好用的化工溶剂。醋酸叔丁酯作为环境友好型溶剂可以有效的降低目标产物的光化学反应活性以及在常温之下的挥发性，从而避免了一些有害物质进入大气之中从而造成环境污染^[1]。醋酸叔丁酯具有良好的耐碱性和疏水性,它不但可以与水混溶 ,而且可以与其它有机溶剂混溶,使用醋酸叔丁酯替换芳香烃和酮类，可以显著的降低由有毒溶剂的排放而造成的臭氧污染物。因而，醋酸叔丁酯是一种环境友好型的化工溶剂，被广泛运用于有机溶剂、表面活性剂等领域。

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