Facile modifications of a polyimide via chloromethylation. I. Novel synthesis of a new photosensitive polyimide

A soluble aromatic polyimide was chloromethylated via a reaction with chloromethyl methyl ether in the presence of tin(IV) chloride to produce a new starting material for the modification of aromatic polyimides. The chemical structure of the resulting polymer was confirmed by ¹H NMR and Fourier transform infrared spectroscopy. The maximum number of chloromethyl groups per repeat unit was 1.81. The chloromethylated polyimide was stable up to 250 °C and soluble in both chloroform and tetrahydrofuran. So that its utilization for further modification could be demonstrated, cinnamic acid was reacted with the formed polyimide, and it produced a new photosensitive polyimide with a cinnamoyl side chain. The photosensitivity of the resulting polyimide was investigated with ultraviolet spectroscopic methods. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 22–29, 2003     

[emim]BF4‐Promoted Chloromethylation of Aromatic Hydrocarbons

The chloromethylation of aromatic hydrocarbons proceeded efficiently using the reusable ionic liquid [emim]BF₄ as promoter. The reactions were completed in 5 h at 70°C with good yields and easy workup.     

Developing a novel alkaline anion exchange membrane derived from poly(ether‐imide) for improved ionic conductivity

We have developed a novel alkaline anion exchange membrane derived from poly(ether‐imide) for improved ionic conductivity. The effects of several important parameters on the chloromethylation of the membrane were investigated. These parameters included reaction temperature, reaction time, concentration of chloromethylation agent, concentration of polymer, and the amount of catalyst. The quaternization of the synthesized chloromethylated polymer was studied as well. The results show that all the studied parameters exhibited significant impacts on chloromethylation. Among them, the concentration of the chloromethylation agent played a key role in increasing the chloromethyl functional group attachment onto the polymer. It was found that the gelation could be avoided if these reaction parameters were controlled. It was also found that using an appropriate quaternization approach could significantly improve the ionic conductivity and optimize the conductivity of the membrane even though the functional chloromethyl groups attached to the polymer are limited. Copyright © 2009 John Wiley & Sons, Ltd.     

芳香烃氯甲基化反应的综述

芳香烃氯甲基化是有机合成中的重要反应。本文综述了芳香烃氯甲基化的反应，并按不同类型的氯甲基化试剂、不同活性的反应催化剂、不同极性的反应介质，及采用相转移催化技术等四方面分别予以讨论     

胶束催化2-氯乙基苯的氯甲基化

采用胶束催化,在油水两相体系中,进行了2-氯乙基苯的氯甲基化反应．通过比较阴离子、阳离子和非离子三种类型表面活性剂的催化效果,探索了2-氯乙基苯氯甲基化反应的机理及胶束催化的作用机理．研究结果表明,胶束催化是实现2-氯乙基苯氯甲基化的有效途径,且阳离子表面活性剂胶束催化的效果最为显著,阳离子表面活性剂的疏水链越长,其催化性能越好;在水相中加入无机电解质,能显著促进胶束催化作用．     

通过原子转移自由基聚合合成可光交联的聚苯乙烯接枝共聚物

聚苯乙烯(PS)在氯化锌(ZnCl_2)做催化剂下,通过氯甲基甲基醚氯甲基化反应,合成了氯甲基化聚苯乙烯(CMPS).在氯化亚铜/联二吡啶(CuCl/bpy)催化下,以CMPS为大分子引发剂引发甲基丙烯酸甲酯(MMA)、甲基丙烯酸酯化查尔酮(MSPK)进行原子转移自由基聚合,成功合成了侧链含有查尔酮结构的光敏聚苯乙烯接枝共聚物(PSMM),所得聚合物结构经过红外光谱(FT-IR)、核磁共振氢谱(~1H NMR)得到确认,通过热重分析(TG)、示差扫描量热法(DSC)测试了该聚合物的热学性能.结果表明,该接枝共聚物具有较好的热学性能及良好的光敏性.     

无定型聚芳醚酮的氯甲基化改性

采用硫酸作溶剂及催化剂,1,4-二氯甲氧基丁烷（BCMB）为氯甲基化试剂,在均相反应体系中对酚酞聚芳醚酮（PEK-C）进行氯甲基化改性。 采用无致癌性的BCMB作为氯甲基化试剂实现了环境友好,并且成本低,效率高。 试验结果表明,反应机理由苯环亲电取代与亲核取代2种反应构成。 为避免交联反应的发生,反应要在较低温度下进行（10~30 ℃）。 在此温度范围内可制得氯甲基化程度达3.4且完全线型的氯甲基化酚酞聚芳醚酮。 通过反应温度及时间可对树脂氯甲基化程度（χCH2Cl-）实施有效的调控。 CMPEK-C的结构由IR和1H NMR进行了表征,测定了CMPEK-C的Tg与χCH2Cl-之间的依赖关系及CMPEK-C的耐热及溶解性能。     

钒电池用季铵化杂萘联苯聚芳醚酮酮阴离子交换膜

以氯甲基辛醚为氯甲基化试剂, 对杂萘联苯聚芳醚酮酮(PPEKK)进行改性, 制备了氯甲基化杂萘联苯聚芳醚酮酮(CMPPEKK). 考察了氯甲基辛醚用量对氯甲基化程度的影响. ¹H NMR表明氯甲基成功引入到聚合物结构中. 采用溶液法制备了CMPPEKK基膜, 然后将其进行三甲胺胺化, 制备了季铵化杂萘联苯聚芳醚酮酮(QAPPEKK)阴离子交换膜. 表征了QAPPEKK的基本性能: 离子交换容量, 含水率, 面电阻. QAPPEKK膜的含水率随离子交换容量增加而升高, 面电阻随离子交换容量的增加而降低. 将QAPPEKK膜应用于全钒液流电池(VRB)中, 电池的能量效率达到85.0%, 电流效率为98.5%, 电压效率为86.3%.     

氯铝酸室温离子液体介质中Blanc氯甲基化反应的研究

在卤化1－烷基吡啶，1－甲基－3－烷基咪唑季胺盐和盐酸三甲胺与无水 AlCl3构成的氯铝酸室温离子液体反应介质中，尝试了苯及其衍生物和氯甲醚的 Blanc氯甲基化反应。结果表明底物的不同对反应有较大影响，苯与氯甲醚反应主 要生成氯甲基化产物，而烷基苯与氯甲醚反应则主要生成二苯基甲烷衍生物。反应 具有适中至高的转化率和选择性，依据底物的不同，反应结束后可以和离子液体系 分层，便于产物分离。氯铝酸离子液体具有一定的重复使用性。     

Alternative Synthesis of 1,2,3,4‐Tetramethoxy‐5‐methylbenzene: A Key Intermediate for Preparing Coenzyme Q Homologs and Analogs

Preparation of 1,2,3,4‐tetramethoxy‐5‐methylbenzene (1) through a new process from pyrogallol is described. In the preparation, a modified mild brominating agent was employed, and a simple introduction of methyl group into aromatic ring through chloromethylation of the corresponding substrate (4), followed by reductive dehalogenation, was achieved successfully with good yields.