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基于咔唑和三苯胺的微孔有机骨架合成及应用研究
其他题名
谷春阳
导师阳仁强 研究员
2016-06
学位授予单位中国科学院研究生院
学位授予地点青岛
学位专业化学工程
关键词微孔聚合物 咔唑 三嗪 比表面积 气体吸附分离
摘要有机微孔材料是一类孔尺寸小于 2 nm的新型孔材料,其具有比表面积大, 化学稳定性高,比容高等优点,在存储分离中具有潜在的应用价值,引起了科学家的热切关注。有机多孔材料主要由 C,H,O,N,B等轻质元素组成,与传统的无机材料相比较,可以在较大范围内通过化学修饰的方法实现材料骨架结构的改变,从而可实现气体的高密度存储。本论文的工作主要是设计合成了两类共轭微孔聚合物,并通过固体核磁,氮气吸附等温线表征聚合物基本结构,通过CO2,H2,CH4,在不同温度下的吸附等温线研究各种聚合物对上述气体的吸附存储,及选择分离能力。论文主要包括以下内容:第一章:微孔有机聚合物的综述。第二章:四个咔唑基共轭微孔聚合物PCz-Cn-Cz(n=3-6)由FeCl3氧化偶联聚合得到。这四个聚合物的BET比表面积分别为862 m2 g-1、870 m2 g-1、768 m2 g-1和785 m2 g-1,有趣的是,尽管这四个聚合物的结构是由不同的柔性亚烷基链连接刚性的咔唑基团构成的,但是它们的孔径分布都集中在0.5 nm处,我们推测这可能是因为柔性的亚烷基链容易扭曲,导致分子内的夹层和孔隙填充。气体吸附曲线表明,在77 K/1 bar,最大的H2吸附量是1.33 wt%;273 K/1 bar,CO2的吸附量可达到16.8 wt%;273 K/1 bar,CH4的最大吸附量是2.11 wt%;298 K/1 bar,CO的吸附量可达到1.37 wt%。273 K,CO2 / N2和CO2 / CH4的最大分离比分别是47.7和14.0;298 K,CO2 / N2和CO2 / CH4的最大分离比分别是33.8和7.3。第三章:四种共价三嗪骨架聚合物(PCTF-1至PCTF-4)在ZnCl2的催化下用离子热反应聚合而成,前三种聚合物的BET表面面积分别为853 m2 g-1、811 m2 g-1、391 m2 g-1,与支链的长度相悖,这表明单体的支链越长,能够更有效堆积,从而导致材料的密度更高,表面积更低。PCTF-4与PCTF-2相比,仅仅是把PCTF-2支链上中间的苯换成了苯并噻二唑,然而N2吸附曲线测得PCTF-4的比表面积为1404 m2 g-1,接近PCTF-2的两倍。富氮的C3N3环与CO2的作用力强,增加了对CO2的吸附,特别是PCTF-4,在273 K/1 bar,CO2的吸附量是20.5 wt%,这个值在共价三嗪骨架聚合物中是最大的,这个结果表明,强极性基团(噻二唑)引入到聚合物骨架是一种有效的策略来增强微孔有机聚合物与CO2分子的作用力。另外,这些共价三嗪骨架聚合物有着很好的物理化学稳定性,在273 K显示了很高的CO2 / N2和CO2 / CH4分离比,最高分别是14-56,11-20。然而,在水蒸气的存在下,这些材料的CO2吸附量都减少了,这可能是由于聚合物与水形成了氢键作用,这个现象表明在干燥条件下表现良好的材料在更接近实际的条件下可能不是最有前途的材料。第四章:本论文总结。
其他摘要Microporous organic polymers (MOPs) can be defined as a series of porous materials with pore sizes smaller than 2 nm on average, which are comprised of light elements such as C, H, O, N, B and exhibit very high physical surface areas. To compare with inorganic pore materials the MOPs can be easily chemically modified the backbone of the bulk phase and show good performance in gas storage. Part I: a general over view of the microporous organic polymers. Part II: Four carbazole-spacer-carbazole polymers PCz-Cn-Cz (n=3-6) with the similar topological model structures were designed and prepared by FeCl3 oxidative coupling polymerization. The Brunauer-Emmett-Teller (BET) specific surface areas of the obtained polymers are 862, 870, 768 and 785 m2 g-1, respectively, which are competitive with the reported conjugated microporous polymers. Interestingly, there are no obvious differences in the domain pore width (centred at 0.5 nm) and the pore size distribution among the four polymers, although they have different length soft alkylene chains to interlink same rigid backbone carbazole. This may be ascribed to the soft alkylene chains, which are easy to bend and result in intramolecular intercalation and pore filling. Gas (H2, CO2, CH4 and CO) adsorption isotherms show that the H2 storage of the polymers can be up to 1.33 wt% at 1.0 bar and 77 K, the uptake capacity for CO2 can reach 16.8 wt% at 1.0 bar and 273 K, the CH4 uptake can reach 2.11 wt% at 1.0 bar and 273 K and the CO uptake performance can be up to 1.37 wt% at 298 K and 1.0 bar. Selective adsorption of CO2/N2 and CO2/CH4 calculated using the initial gas uptake slopes shows that these networks display good selectivity with a maximum value of 47.7 (33.8) and 14 (7.3) at 273 K (298 K).Part III: Four covalent triazine-based frameworks (PCTF-1 to PCTF-4) were synthesized by a consolidated ionothermal reaction between aromatic nitriles under the catalysis of ZnCl2. The Brunauer-Emmett-Teller (BET) specific surface area values of PCTF-1 (853 m2 g-1), PCTF-2 (811 m2 g-1) and PCTF-3 (391 m2 g-1) are against with the increasing length of branched arm, indicating using monomers with longer branches are able to pack more efficiently, resulting in higher density materials with a lower surface area. PCTF-4, compared with PCTF-2, just changed the middle benzene of the branches to benzothiadiazole, however, N2 adsorption isotherms showed its BET specific surface area value (1404 m2 g-1) is the highest among the PCTFs, almost two times than that of PCTF-2. The nitrogen-rich characteristics of C3N3 triazine rings feature the frameworks strong affinity for CO2 and thereby high CO2 adsorption capacity. Especially for PCTF-4 with the benzothiadiazole, it exhibited the highest CO2 uptake (20.5 wt%) at 273 K and 1 bar, this value is one of the highest reported for covalent triazine-based frameworks. The results demonstrate that the introduction of strong polar groups (benzothiadiazole) into a polymer skeleton is an efficient strategy to produce CO2-philic microporous organic polymers with enhanced binding affinity with CO2 molecules. In addition, such PCTFs with high physical-chemical stability and comparable BET surface areas exhibited good ideal CO2/N2 selectivities (14-56) and CO2/CH4 selectivities (11-20) at 273 K, showing these materials are potential candidates for gas storage and separation. However, in the presence of water vapor, these performance of CO2 uptake all decreased due to via hydrogen bonding with water, suggesting materials that perform well in dry conditions may not always be the most promising materials under more practical conditions. Part IV: the conclusion of the thesis.
作者部门先进有机功能材料团队
学科领域化工
公开日期2016-07-01
学位类型硕士 ; 学位论文
语种中文
文献类型学位论文
条目标识符http://ir.qibebt.ac.cn/handle/337004/9777
专题先进有机功能材料研究组
作者单位中科院青岛生物能源与过程研究所
推荐引用方式
GB/T 7714
谷春阳. 基于咔唑和三苯胺的微孔有机骨架合成及应用研究[D]. 青岛. 中国科学院研究生院,2016.
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