Catalytic Synthesis of 2,4-D Butyl Ester by Molecular Lodine

Herbicide 2,4-D butyl ester(butyl 2,4-dichlorophenoxyacetate) was synthesized from 2,4-dichlorophenoxyacetic acid(2,4-D)and n-butanol with molecular iodine as catalyst.The effects of molar ratio of alcohol to acid,reaction time and amount of catalyst on product yield were investigated.The optimal conditions were as follows:molar ratio of alcohol to acid 10:1,reflux reaction time 2.0 h,and catalyst amount 0.3g(based on 0.02 mol of 2,4-dichlorophenoxyacetic acid).The ester yield was up to 98.7%.This method has the advantages of simple operation,mild reaction conditions and high purity and yield of the product.Over the existing alternatives,this research is applicable in industrial production.