以1,4-二氯甲氧基丁烷为氯甲基化试剂合成线型氯甲基化聚苯乙烯

SYNTHESIS OF LINEAR CHLOROMETHYLATED POLYSTYRENE WITH 1,4-BIS(CHLOROMETHOXYL) BUTANE AS CHLOROMETHYLATION REAGENT

采用自制的氯甲基化试剂——1,4-二氯甲氧基丁烷(BCMB),使用Lewis酸催化剂,在均相反应体系中高效地实现了聚苯乙烯的氯甲基化.研究了反应机理,考察了各种因素对氯甲基化反应的影响规律,优化了反应条件,通过红外光谱法与Volhard分析法表征了产物的化学结构与组成.实验结果表明,反应机理可能由苯环亲电取代与伴随着醚键断裂的亲核取代两类反应构成,氯甲基化试剂用量、催化剂的酸性与用量、溶剂的性质与用量及反应温度等因素对反应都有显著的影响,其一,会影响聚苯乙烯的氯甲基化程度,其二,会导致或避免大分子链之间通过Friedel-Crafts反应而发生交联.以四氯化碳为溶剂、以SnCl4为催化剂并在较低温度(18℃)下进行反应,可制得氯甲基化程度达80%且完全线型化的氯甲基化聚苯乙烯.

The chloromethylation of polystyrene （PS） was performed high effectively in a homogeneous system using self-made 1,4-bis（chloromethoxyl）butane （BCMB）as the chloromethylation reagent and adopting Lewis acid catalysts. The reaction mechanism was investigated, the effects of various factors on the chloromethylation reaction were examined, and the optimum reaction conditions were determined. The chemical structure and composition of the products were characterized with infrared spectrum and Volhard method. The experimental results show that the reaction mechanism consists of two kinds of reactions possibly, electrophilic substitution on benzene ring and nucleophilic substitution accompanying by ether linkage fission. All the used amount of BCMB, the property and used amount of the catalysts, the property and used amount of solvents and temperature influence distinctly the chloromethylation of polystyrene. There are two types of effects of reaction conditions on the chloromethylation of polystyrene, one is the influence on PS chloromethylation degree, and the other is the influence on the remaining linearity for PS. The chloromethylated polystyrene （CMPS） with 80% of chloromethylation degree and complete linearity was obtained under the optimum reaction conditions.