Continuous preparation method of herbicide intermediate of 2, 4-dichlorophenol

The invention provides a continuous preparation method of an herbicide intermediate of 2, 4-dichlorophenol. The method includes the steps of continuously and reversely feeding phenol and chlorine gas in a mass ratio of 1: (1.4-1.5), subjecting fed materials to continuous chlorination reaction through a multistage chlorination tower, enabling reacted liquid materials to flow into a 2, 4-dichlorophenol receiving tank, and recycling the gas with water through a tail gas absorption tower. The continuous preparation method replaces existing batch type mode to prepare the intermediate 2, 4-dichlorophenol of 2, 4-D acid, operation is simple, safety of preparation is controllable, discharge of three wastes is reduced, power consumption is reduced, and unit time output is increased. Simultaneously, the preparation can further improve yield of products, and recycle by-product acid with concentration of 30.5% during the reaction.