3099.金属盐改性活性炭催化某些精细有机合成反应的研究论文.doc

金属盐改性活性炭催化某些精细有机合成反应的研究Study on the Synthesis of Some Fine Organic Reaction by Activated Carbon Modified with Mental Salts摘 要本论文以xxx太西煤厂的柱状煤基活性炭(AC)为原料，分别采用对活性炭扩孔后进行金属盐改性和在稀硫酸溶液中对活性炭进行金属盐改性的两种表面改性方法，改性前的活性炭即空白活性炭记作AC，改性后的活性炭分别记作AC-Fe-1，AC-Fe-Cu-2，FeCl3/H2SO4(稀)/AC，Al2(SO4)3/H2SO4（稀）/AC，H2SO4（稀）/AC（未加金属盐）。本论文研究内容分两部分。第一部分，对活性炭扩孔后进行金属盐改性，即AC-Fe-1和AC-Fe-Cu-2。首先对扩孔和改性的条件进行研究，并将AC-Fe-1和AC-Fe-Cu-2分别用于环戊酮乙二醇缩酮和环己酮-1，2-丙二醇缩酮的催化合成反应中，对活性炭表面特性与催化活性的关联进行研究。结果讨论如下：应用IR、XRD、SEM 、BET以及表面酸性官能团的测定这些分析方法，对改性前后的活性炭进行表征。研究结果表明，活性炭经改性后，其表面特性发生了很大的变化。1、表面酸性官能团的测定和红外谱图显示表明，总的酸性官能团的含量都有很大程度的增加，有酚羟基、羧基等的特征吸收峰，以及羟基特征吸收。这正是酸性增强的原因所在；2、氮气等温吸脱附测定结果说明，改性后活性炭BET比表面积、总孔容、平均孔径有增加，孔向中孔的发展变化明显，即改性后中孔的数目增多；3、XRD衍射图可以看出，改性后的活性炭出现了新的衍射峰，改性过程中晶相结构部分被破坏，未出现金属盐的特征衍射峰，这也说明金属盐已负载在活性炭之上并形成无定形复合结构；5、由SEM 照片可以看出，改性后活性炭的表面形貌发生了很大程度的破坏，孔容、孔径增大，并且Fe-Cu-2表面有大块的平面层状结构，好像是一层一层的平面层状重叠而成。在缩酮合成反应中，系统地探讨了影响其反应收率的各种因素。研究结果表明：AC-Fe-1是催化合成环戊酮乙二醇缩酮的良好催化剂，收率达75.6%，比目前报道的碘催化合成的产率高；用AC-Fe-Cu-2催化合成环己酮-1,2-丙二醇缩酮收率达85.8%，也优于文献中的相关报道。该催化剂与目前报道的催化剂对比，具有催化剂制备及反应后序处理简单，原料来源丰富且价格低廉，催化活性高，可重复使用等特点，显示出良好的应用前景，尤其是先扩孔后改性的催化剂与直接进行金属盐改性的催化剂相比，具有金属盐不易脱附、催化活性高、可重复使用的优点。原因可能是改性后中孔数目增多，有利于金属离子的吸附，而且酸性官能团数目增多、多种含氧基团增加，这些对改性后AC的测定结果都说明了改性后活性炭酸性大大增强，在催化体系中表现出良好的催化性能。第二部分，在稀硫酸溶液中对活性炭进行金属盐改性。本实验小组以往都是在浓硫酸的条件下进行常温或高温的改性，本文采用在稀硫酸溶液中对活性炭进行金属盐改性，引进B酸和L酸，来考察两种酸的共同协同作用，分别制成FeCl3/H2SO4(稀)/ AC，Al2(SO4)3/H2SO4（稀）/AC，H2SO4（稀）/AC（未加金属盐）三种催化剂,并对其催化性能进行研究，考察并探讨活性炭表面特性的变化与催化性能之间的关系。表征手段同第二部分，结果表明：1、总酸性官能团的含量都有很大程度的增加；2、改性后活性炭BET比表面积、总孔容、平均孔径相应增加；3、改性后的活性炭分别有酚羟基、-SO3H、羧基等的特征吸收峰；4、由XRD衍射图可以看出，改性后的活性炭出现了新的衍射峰，未出现金属盐的特征衍射峰，可能是它们已负载在活性炭之上并形成无定形复合结构；5、由SEM 照片可以看出，改性后活性炭的表面形貌发生了很大的破坏，孔容、孔径增大，并且FeCl3/H2SO4(稀)/ AC，Al2(SO4)3/H2SO4（稀）/ AC表面有大块的平面层状结构，这与第一部分有金属盐改性的SEM图有类似的晶貌变化。并将制得的活性炭作为催化剂来催化合成苯乙酮-1,3-丙二醇缩酮和草酸二丁酯，都取得了良好的催化效果，催化活性高，制备简单，具有好的应用前景。显著的特点就是反应中催化剂重复使用效果优良，使用多次后，收率或产率保持稳定。原因可能是改性后酸性官能团增多，在活性炭的孔内或其表面形成金属离子和磺酸基的活性中心，反应过程中，B酸和L酸相互协同作用，抑制了彼此活性组分的脱落和流失，从而在反应体系中保持优良的催化性能。关键词：金属盐改性煤基活性炭；催化合成；酯化；缩酮ABSTRACTThis thesis focuses on activated carbon (AC) of coal-based manufactured by Taixi Activated Carbon Factory of Ningxia as raw material.Modified the activated carbon as the solid acid with two surface modification method.There were modified activated carbon with metal salts after expanding mesopore and in diluted sulfuric acid solution.Assigning modified activated carbon and the original activated carbon as Fe-1,Fe-Cu-2,FeCl3-H2SO4(diluted)-AC,Al2(SO4)3-H2SO4（diluted）-AC,H2SO4（diluted）-AC(without metal salts),AC respectively.The research of the paper included two parts.The first part was mainly to modified the activated carbon with metal salts after expanding mesopore. There were AC-Fe-1 and AC-Fe-Cu-2.And had carried out the synthesis of cyclopentanone ethylene ketal and cyclohexanone 1,2-propanediol ketal using AC-Fe-1 and AC-Fe-Cu-2 as the catalysts respectively. Using the analysis methods of IR,XRD,SEM,BET and the numbers of surface acid function groups characterized the surface properties of modified activated carbon.The study showed the surface properties of the modified activated carbon changed greatly. 1. Compared with the AC,the number of surface acid function groups increased after modified by the measurement of surface acid group and the IR spectrum, the phenol hydroxyl 、carboxyl and the hydroxyl appeared on the modified activated carbon; 2. The result of Nitrogen Adsorption-Desorption measurement indicated that the surface area,pore volume and the average pore diameter were increased. And the numbers of mesopore was increased greatly. 3. The XRD spectrum showed that it was appeared new peaks of diffraction. The micro crystal structure had been partly destroyed in the course of modification; 5. The SEM picture showed that the surface of modified activated carbon destroyed pore volume and diameter increased. In the reactions, the influences of reaction conditions were also investigated. The results indicated that the Fe-1 and Fe-Cu-2 were showed high activity. The yields of the products were 75.6% and 85.8% respectively. They were higher than the relative reports. The results indicated that the modified activated carbon was excellent catalysts. The advantages of these catalysts were in the following aspects：the manufacturing and afterward-treatment of these catalysts were simpler; their raw material was more available and cheaper, had high activity, they could be reused and recycled. They showed some potential value. Especially,compared with the modified activated carbon without expending mesopore, the catalysts we modified had some advantages, such as the mental salt was not easy to drop, activity was higher and they can reused, etal.The reason was that the number of surface acid function groups and the mesopore increased greatly.They were benefit for the catalysts to show high activity The second part mainly aimed about modifying activated carbon with metal salts in diluted sulfuric acid solution. Oth