At present, there are two main methods at home and abroad: photochlorination and non-photothermal chlorination. From the process operations, the two methods have two kinds of intermittent operation and continuous operation. Divided from the reactor structure, continuous operation can be divided into horizontal continuous operation and vertical continuous operation two. Because the toluene continuous photochlorination process has the advantages of easy production in small batches, and the reaction speed is faster than that of the non-photothermal chlorination process, many domestic manufacturers use this process.
1. Toluene Continuous photochlorination The dry, non-ferrous toluene was added to an iron-free reactor and subjected to high temperature chlorination in the light. Then the chlorinated product is fractionated to obtain benzyl chloride, and the by-produced hydrogen chloride is absorbed by water to obtain hydrochloric acid, and the by-product α-dichloromethylbenzene can be hydrolyzed to benzaldehyde. 2. Toluene photothermal chlorination toluene first to stand for more than 6h to remove iron, and then into the chlorination pot through the high tank, to steam heated to stop heating after boiling, chlorine into the chloride, continuous reaction system The benzyl chloride obtained cools down through the bottom overflow pipe and enters the storage tank. 3. Toluene reacts with thionyl chloride in the presence of a catalyst peroxide. 4. Under the catalysis of zinc chloride, benzene ring chloromethylation.