Chrysanthemoyl chloride

Chemical Properties

Chrysanthemum chloride is colorless or slightly yellow liquid, (±) trans chrysantoyl chloride bp50～51℃/19pa, 96～96.5℃/16 kpa, n²⁰_D 1.4856; (±)cis chrysanthemoyl chloride bp50～51℃/19pa, 96.5～98℃/16 kpa, n²⁰_D 1.4907, relative density 0.98(31℃ ), decomposed into chrysanthemic acid in case of water, soluble in benzene, toluene and other organic solvents.

Uses

Chrysanthemum chloride is an important intermediate of pyrethroids, which can be used to synthesize pyrethroids such as allethrin, propenthrin, permethrin, fenthrin, and fenothrin.

Synthesis

Chrysanthemoyl chloride can be prepared by the phosgene method:Dissolve chrysanthemic acid in toluene, add catalyst and raise the temperature to about 90°C, pass phosgene under stirring, and after a certain amount reaches the end point, use nitrogen to drive off the remaining phosgene, and to absorb and utilize, move the reaction solution into distillation Desolvate under reduced pressure in the pot to obtain the product. Generally, chrysanthemum chloride prepared by phosgene method is no longer rectified because of its high purity, but the use of phosgene should pay attention to safety, and the tail gas should be destroyed by alkali and catalyst.