Synthesis Of Lactofen And Fluazifop-butyl

Lactofen is one of the diphenyl ether chemical family. It is used in controlling or killing broadleaf in post-emergency for cereal corps. It have high activity, broad spectrum in controlling grasses, low toxicity. Lactofen was first manufactured by PPG in 1965.Lactofen was synthesized from starting materials m-hydroxybenzoic acid and 3,4-dichlorobenzotrifluoride via four steps including salification, etherification, nitration, condensation etc. The selection of synthesis route have been depend on materials, practical probability of technological process, cost of product.The key intermediate is 3-(2-chloro-4-trifluoromethylphenoxy) benzoic acid. The optimum technological conditions, such as reactant proportion, solvent, catalyst, reacting temperature, reacting times, ect, have been obtained. The yield and purity of 3-(2-chloro-4-trifluoromethylphenoxy) benzoic acid and Lactofen were respectively 84.5%, 90%; 50%, 86.8%.Fluazifop-butyl is registered under the Pest Control Products Act as a herbicide for the control of grasses in various broadleaf crops as a post-emergent treatment. It has many advantages such as high efficiency, easily degraded, low pollution and so on.In this paper the manufacture process of Fluazifop-butyl has been studied, and the method of condensation (S)-butyl 2-(methylsulfonyloxy)-propanoate with 4-(5-(trifluoromethyl)pyridin-2-yloxy)phenoI was selected. The total yield was 40% and purity determined by HPLC was 93.0%. In general, the synthesis of Fluazifop-butyl is start from the material 2-chloropropionic acid, followed by chemical resolution. But this method have big disadvantage that the product has low yield, about 30% and low e.e.%. We used L-lactic acid as row material, reacting with methanesulfonyl chloride to gain (S)butyl 2-(methyllsulfonyloxy)propanoate, that can substitute (S)butyl 2-chloropropanoate. Thismethod has many advantages such as low cost, simpler separation process, high yield and suitable for industrial scale manufacturing.