| Name | 2-(4-difluoromethoxy)phenyl-3-methyl butyric acid |
| Synonyms | 2-(4-difluoromethoxy)phenyl-3-methyl butyric acid |
| CAS | 70124-99-1 |
| Physical and Chemical Properties | The chemical product is white crystal. M. p.61 ~ 63 ℃,[α]= 39.5, insoluble in water, soluble in benzene, toluene and other organic solvents. |
| Use | Use S-2-(4-difluoromethoxy) phenyl -3-methyl butyric acid is an important intermediate of fenvalerate and delfluthrin. |
| Raw Materials | 1,4-Dioxane Benzeneacetonitrile Difluorochloromethane Isovaleric acid Cyanogen bromide 2-(P-HYDROXYPHENYL)ISOVALERIC ACID |
The preparation method can use 4-difluoromethoxy toluene as raw material, through bromination, nitration, alkylation, and then hydrolysis to obtain 2-(4-difluoromethoxy) phenyl -3-Methylbutyric acid.
However, in this method, the yield is not high when phenylacetonitrile is alkylated with a phase transfer catalyst. In addition, when the nitrile is hydrolyzed into an acid with alkali, the ether bond will be broken to generate 2-phenyl-3-methylbutyric acid. Generally, 2-(4-difluoromethoxy) phenyl-3-methylbutyric acid is commonly used in industry 2-(4-hydroxyphenyl)-3-methylbutyric acid and freone-22 in alkaline solution.
Add 100g of 2-(4-hydroxyphenyl)-3-methylbutyric acid, 19.5g of sodium hydroxide, 600mL of dioxane and 300mL of water into a three-mouth bottle equipped with a reflux condenser tube, thermometer and ventilation catheter, heat to 80 ℃, introduce Freon -22 under stirring, keep the temperature (80±5)℃, ventilate for 4-5h, cool and pour into ice water, neutralize with concentrated HCl, extract with ether for 3 times, the extract is washed with water, dried with anhydrous Na2SO4, the solvent is evaporated, 300mL of dichloromethane and petroleum ether (1: 1, volume ratio) are added, refluxed for 5min, left overnight, filtered out unreacted hydroxy acid, and the filtrate is desolted to obtain 2-(4-difluoromethoxyphenyl)-3-methylbutyric acid.