| Molecular Formula | C11H18O2 |
| Physical and Chemical Properties | Chemical properties Methyl chrysanthemum acid is a light yellow or colorless oily liquid. (+) trans chrysanthemum acid methyl ester B. p.65 ~ 70 ℃/400 pa,n22D 1.4540, insoluble in water, soluble in ethanol, methanol, benzene, acetone and other organic solvents. |
| Use | Use of pyrethroid methyl ester is an important intermediate of pyrethroid, which can be used to synthesize the pyrethroid such as allyl, propargthrin, furthrin, pyrethroid, fenthrin, fenthrin and so on |
The industrial production methods of methyl chrysanthemum acid include diazoacetic acid method and isopentenyl sulfone method (also known as Martel method), which are described as follows.
Diazoacetate method
Add 2, 5-dimethyl -2, 4-hexadiene into the reaction bottle, use copper powder with a diene dosage of 59/6 as a catalyst, add a little hydroquinone as an antioxidant, heat to 120 ℃ under nitrogen, drop to add nitrogen methyl acetate solution under rapid stirring, release N2 during dropping, control the reaction speed, continue stirring for 0.5h after dropping, and cool, distillation removes the excess diene, and then increases the vacuum degree to evaporate methyl chrysanthemum, and the recovered diene can be recycled.
Isopentenyl sulfone method
Sodium benzenesulfonate is dissolved in anhydrous dimethyl sulfoxide, chloropentene is added dropwise at room temperature, the reaction temperature is not more than 30 ℃, after the dropwise is completed, the reaction is 3h, and then the low fraction is removed under reduced pressure (1.33~2.66 kPa). After cooling, add a considerable amount of dimethyl sulfoxide, add methyl isopentenoic acid, gradually add sodium formate below 10 ℃ and under nitrogen flow, after the feeding is completed, let it naturally heat up and stir for 16 h, the reaction is over, acidify with HCl below 20 ℃, separate out the organic layer, then extract in aqueous solution with solvent, combine the organic layer, wash, wash, dry with 5% NaCO3, and evaporate, the fraction of 65~70 ℃/400 Pa was collected by vacuum distillation as methyl chrysanthemum with a yield of 60% ~ 65%.