A kind of preparation process of dicamba

The present invention relates to a kind of preparation process of dicamba, belongs to and prepare herbicide dicamba technical field.A kind of preparation process of dicamba, including processing step are as follows: using benzene as raw material, by oriented chlorination, catalysis, again generate 1,2,4- trichloro-benzenes after chlorination, rectifying；Again after the hydrolysis of 1,2,4- trichloro-benzenes, 2,5- chlorophenesic acid and 2,4- dichlorophenol mixture are generated, then after separating, purifying, obtain 2,5- chlorophenesic acid；3,6- dichlorosalicylic acid is produced by 2,5- chlorophenesic acid；3,6- dichlorosalicylic acids obtain dicamba after methylation reaction, saponification, acidification reaction etc..By the optimization of processing step and parameter, so that entire preparation process is simple, at low cost, high income, selectivity is high, wastewater flow rate significantly reduces, utilization rate of equipment and installations improves.