Synthesizing Bromobutyl Rubber By a Microreactor System

Abstract

Bromobutyl rubber (BIIR), an important synthetic rubber, not only maintains many desirable characteristics of traditional butyl rubber (IIR), but also has faster vulcanization rate. However, there exists two critical problems in the process of brominating IIR in n-hexane, that are strong corrosion caused by Br₂ and HBr and high reactant viscosity. A PTFE-lined microreactor platform was developed to solve the corrosion problem and obtain high quality BIIR based on excellent mixing ability. The results showed that low reaction temperature and quickly eliminating HBr from the reacting solution were crucial to obtain high selectivity of demanded molecule structure and prevent polymer from decomposition. To remove HBr from the reaction system in time, a water assistant technology was successfully implemented in the microreactor system, which produced high quality BIIR with almost 100% selectivity and less reduced molecule weight.