1,4 - Bis (bromomethyl) -2 - Fluorophenyl Synthesis Study

1, 4-Bis(bromomethyl)-2-fluorobenzene is one of the most important polymeric material of light-emitting diodes (LED) and medicinal intermediate. it can synthesize PPV's derivative PFPV, which is an excellent material of LED; and it can prepare the FSB, which can cure Alzheimer's disease (AD).1, 4-Bis(bromomethyl)-2-fluorobenzene was obtained by using p-xylene as starting material via four steps reaction of nitration, reduction, diazotization and bromination. Firstly, p-xylene was nitrified by nitric acid with sulfur acid. Then 2,5-dimethynitrobenzene was hydrogenated by catalyst, which is a high efficiency and clean reduction way. Then 1, 4-dimethyl-2-fluorobenzene was obtained through Balz-Schiemann reaction. Finally, radical bromination of 1, 4-dimethyl-2-fluorobenzene was carried out using N-bromosuccinimide (NBS) in the presence of azobisisiobutyronitrile (AIBN). The target was obtained, and the overall yield is 30%. Specially, comparing with bromination by sunlamp, the time of the last step reaction was decreased from 8 h to 6 h, and the yield was increased from 48% to 55%. This dissertation made a research on the following factors such as reaction temperature, time, catalyst and dosage of all kinds of materials. Finally, the single factor to consummate the technological process and technological condition was introduced, and the optimal process parameters were got. The product can be determined by the ways of analysis such as ~1H-NMR,GC-MS,IR,and HPLC.