Chloromethyl Styrene Synthesis

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.