The chlorination reaction is often used in the synthesis of organic compounds such as dyes, pesticides, medicines, and perfumes, while the chlorine gas is highly toxic, it is extremely harmful when the leakage of chlorine. The heat of chlorination reaction is large, and the traditional process often leads to high levels of side reactions due to unstable temperature control. On the other hand, the traditional process requires a large excess of chlorine in order to pursue a higher conversion rate; the micro-reactor can control the amount of  chlorine gas well, precise material ratio, reduce the content of polychlorinated by-products, strengthen the reaction process, improve the conversion rate and yield, improve the safety of the reaction.