对氯甲基苯乙烯合成研究

【作者】 李江；

【导师】 陆明；

【作者基本信息】 南京理工大学 ， 应用化学， 2008， 硕士

【摘要】 对氯甲基苯乙烯（p-CMS）是一种很重要的双官能团单体,可以合成多种功能性高分子化合物。本文合成p-CMS的方法为:以乙苯为起始原料,经过光溴化、氯甲基化、脱除溴化氢三步反应合成p-CMS。在光溴化反应中,对直接溴化法、溶剂溴化法、H₂O₂氧化溴化法进行比较,考察反应温度、加溴时间、物料比、溶剂等因素对乙苯光溴化反应的影响。氯甲基化反应采用胶束催化,以相转移催化和路易斯酸催化为对照,考察搅拌速率、反应温度、反应时间、氯甲基化试剂、胶束浓度以及表面活性剂种类对α-乙苯氯甲基化反应的影响,并设计实验研究胶束催化氯甲基化反应的机理。在脱溴化氢反应中,对氯甲基-α-溴乙苯在不同强碱作用下脱去HBr合成p-CMS。通过物理性质检测,化学实验验证,GC、HPLC、MS、IR、NMR等分析检测方法,进行定性定量分析,确定各步反应的目标产物。实验结果表明:CCl₄溶剂光溴化法效果最好,收率为96.7%。胶束催化是实现α-溴乙苯氯甲基化的有效方法,仅用3.35g/L的十六甲基三甲基溴化铵（CTAB）,反应5h,收率可达92.2%;研究表明氯甲基化反应主要发生在阳离子胶束内部和阴离子胶束-水界面;阳离子表面活性剂比阴离子表面活性剂的催化效果好,且阳离子表面活性剂分子的疏水链越长,对氯甲基化反应的催化效果越好。在叔丁醇钾作用下,对氯甲基-α-溴乙苯进行消除反应脱去HBr,得到p-CMS,收率为90.4%。该合成路线方法总收率为80.6%,有一定的实用价值。更多还原

【Abstract】 4-Chloromethylstyrene （p-CMS） is a very important dual-functional monomer in the synthesis of various functionalized polymers. In this dissertation, p-CMS was synthesized from starting materials ethyl benzene via three steps: photobromination, chloromethylation, and dehydrobromination. Direct bromination, solvent bromination and H₂O₂ oxidative bromination were compared. The influences of factors, such as reaction temperature, time of adding bromine, ratio of raw material, the amount and types of solvent, on the yield of product were discussed. Micellar catalysis was employed for chloromethylation, and comparison with phase transfer catalyst or Lewis acid catalyst was made. The effects of stirring speed, reaction temperature, reaction time, chloromethylation reagents, micelle concentration and the types of surfactant on the yield of products were also investigated. The mechanism of chloromethylation catalyzed by micelle was studied through preplanned experiment. Strong bases were employed in eliminating HBr to obtain p-CMS. The desired products of each step were determined by the detection of physical nature, chemical experimental verification, by GC, HPLC, MS, IR, and NMR respectively.The experimental results show that CCl₄ is the preferred solvent. 96.7% of yield for the product was obtained. Micellar catalysis is an effective way to realize the chloromethylation ofα-bromoethylbenzene, and only 3.35g/L CTAB is needed for the reaction yield up to 92.2%. Chloromethylation reaction is carried out mainly in the internal of cationic micelle and the interface of anionic micelle-water. The catalysis effect of cationic surfactant is better than that of anionic surfactant. Furthermore, the longer the hydropobic chain is, the better catalysis effect is. For the dehydrobromination reaction, the use of potassium t-butoxide as the dehydrobrominating agent is quite essential, yield to 90.4%. The total yield of this method is 80.6%, which has potentially applied value.更多还原