聚溴化3-噻吩甲基-N,N-二甲基-N-烷基铵的合成及其在LGB光催化降解的应用

发布时间：2019-06-28 20:38

【摘要】：共轭聚合物是具有离域大π键的有机半导体材料。由于它们具有独特的物理化学性质,得到了研究者广泛的关注。常见的共轭聚合物有聚苯胺、聚吡咯、聚乙炔和聚噻吩。这些材料可以通过引入侧链的方式,改变聚合物的性质,从而改善材料的性能,还扩大了共轭聚合物材料的门类。因为共轭π键的存在使得聚合物的能隙很低,容易吸收紫外可见光,同时低能隙可以让共轭聚合物拥有较高的电荷分离能力和低的电子空穴复合率。当该类聚合物与无机半导体光催化材料杂化,可以降低无机材料的带隙,提高电荷分离能力和降低电子空穴对的复合率,以达到提高光催化材料的光催化性能。因此,探究新的共轭聚合物的合成以及在光催化方面的应用有很重要的意义。本文合成了溴化3-噻吩甲基-N,N-二甲基-N-烷基铵(目标产物标记为s-n,n=10、12、14、16),通过化学氧化聚合方法合成了相应的聚合物(标记为Ps-n,n=10、12、14、16)。制备了Ps-12/ZnO光催化材料,并探讨了该复合材料在紫外光下降解酸性绿50的光催化活性。具体内容如下:通过简单的季铵化反应,以3-溴甲基噻吩为原料合成了s-n,并通过核磁共振谱图和红外光谱对s-n的结构进行了表征,并用MS测得其分子量。从量子化学计算结果可知,随着烷基链的增加,目标产物的反应活性增加,动力学稳定性降低。但是,烷基链的改变对这种影响很小。从Fukui函数可知,目标产物的反应活性位点主要分布在噻吩环上的碳原子和硫原子上,这与化合物的结构特征一致。通过FeCl3氧化催化法合成了聚合物Ps-n。通过UV-vis光谱测试,相比于s-n,发现聚合物的紫外吸收范围增大,说明聚合物分子中形成了更大的共轭体系,从侧面证实了s-n发生了聚合。红外光谱表明,相对于单体,聚合物中3080 cm-1左右处未出现噻吩环上的α位C-H的伸缩振动吸收峰,这表明了s-n发生了聚合反应生成了Ps-n。XRD分析结果表明制备的四种聚合物均为非晶型结构。从量子化学计算结果可知,随着目标产物的烷基链增长,目标产物的反应活性增加,动力学稳定性降低。从Fukui函数可知,Ps-n的反应活性位点主要分布在噻吩环上的碳原子和硫原子上。这与聚合物的结构特征一致。通过比较了s-10和Ps-10的理论计算数据,我们发现Ps-10噻吩环上的自然原子电荷低于s-10,这说明聚合物的共轭体系使电子云密度平均化,提高了分子的稳定性。从量子化学参数可知,s-10的化学活性高于Ps-10,Ps-10比s-10更稳定。通过化学吸附法,制备了Ps-12-杂化ZnO材料,通过XRD、SEM、DRS、FT-IR和PL等方法对其晶体结构、形貌特征、光学特性等进行了表征分析。杂化后,Ps-12-杂化ZnO材料中氧化锌的晶体结构没有发生改变。杂化材料子紫外光下对酸性绿50的降解率达96.6%。降解过程中的主要活性物种为超氧负离子自由基。在降解酸性绿50的过程中Ps-12-杂化ZnO材料表现出良好的稳定性,重复使用5次,催化性能保持87%。在光催化机理中,Ps-12可能作为光敏剂来降低光生-电子空穴对的复合和提高光生-电子空穴对的分离来提高光催化活性。
[Abstract]:The co-conductive polymer is an organic semiconductor material having a defield large-scale bond. Because of their unique physical and chemical properties, the researchers have received extensive attention. Common copolymeric polymers are polyanilines, polypropylenes, polyacetylene, and polyacetylene. These materials can modify the properties of the polymer by introducing side chains in order to improve the properties of the material and also to expand the range of co-polymer materials. Because of the existence of the co-polar bond, the energy gap of the polymer is low, the ultraviolet visible light can be easily absorbed, and meanwhile, the low-energy gap can make the co-polar polymer have higher charge separation capacity and low electron-hole recombination rate. When the polymer is hybridized with the inorganic semiconductor photocatalytic material, the band gap of the inorganic material can be reduced, the charge separation capacity can be improved, and the recombination rate of the electron hole pair can be reduced, so that the photocatalytic performance of the photocatalytic material can be improved. Therefore, it is of great significance to explore the synthesis of new co-polymer and its application in photocatalysis. Brominated 3-methyl-N, N-dimethyl-N-alkyl (labeled as s-n, n = 10,12,14,16) were synthesized and the corresponding polymers (labeled Ps-n, n = 10,12,14,16) were synthesized by chemical oxidative polymerization. The photocatalytic material of Ps-12/ ZnO was prepared, and the photocatalytic activity of the composite was discussed. In this paper, the structure of s-n is synthesized by a simple and seasonal reaction, and the structure of s-n is characterized by the nuclear magnetic resonance spectrum and the infrared spectrum, and the molecular weight of the s-n is measured by the MS. The result of the quantum chemical calculation shows that with the increase of the alkyl chain, the reaction activity of the target product is increased, and the kinetic stability is reduced. However, the change in the alkyl chain is very small for this effect. It can be seen from the Fukui function that the reactive sites of the target product are mainly distributed on the carbon and sulfur atoms on the alicyclic ring, which is consistent with the structural characteristics of the compound. The polymer Ps-n were synthesized by the FeCl3 oxidation catalytic process. By UV-vis spectroscopy, it was found that the ultraviolet absorption range of the polymer increased as compared with s-n, indicating that the polymer molecule formed a larger co-polymerization system, and it was confirmed that s-n had been polymerized from the side. The infrared spectra show that the expansion vibration absorption peak of C-H is not present at 3080 cm-1 in the polymer, which shows that the generation of Ps-n by the polymerization of s-n. The results of the XRD analysis show that the prepared four polymers are amorphous. The result of the quantum chemical calculation shows that with the increase of the alkyl chain of the target product, the reaction activity of the target product is increased, and the kinetic stability is reduced. As can be seen from the Fukui function, the reactive sites of Ps-n are mainly distributed on the carbon and sulfur atoms on the alicyclic ring. This is consistent with the structural features of the polymer. By comparing the theoretical calculation data of s-10 and Ps-10, we find that the natural atom charges on the Ps-10 and Ps-10 are lower than s-10, which means that the common system of the polymer can average the density of the electron cloud and improve the stability of the molecules. From the quantum chemical parameters, the chemical activity of s-10 is higher than that of Ps-10 and Ps-10 is more stable than that of s-10. The crystal structure, morphology and optical properties of the Ps-12-hybrid ZnO material were characterized by means of chemical adsorption, XRD, SEM, DRS, FT-IR and PL. The crystal structure of the zinc oxide in the Ps-12-hybrid ZnO material has not changed after the hybridization. The degradation rate of the acid green 50 was 96.6% under the sub-ultraviolet light of the hybrid material. The main active species in the degradation process are superoxide anion free radicals. In the process of degradation of the acid green 50, the Ps-12-hybrid ZnO material exhibits good stability, can be used for 5 times, and the catalytic performance is maintained for 87%. In the light catalytic mechanism, Ps-12 may be used as photosensitizers to reduce the recombination of photo-generated-electron-hole pairs and to improve the separation of photo-generated-electron-hole pairs to improve the photocatalytic activity.
【学位授予单位】：西华师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;O644.1

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