Process of high purity pyrethrins

Abstract

The production process of high-purity pyrethrin includes adding into the coarse pyrethrin extractive antioxidant BHT in the amount of 2-3 % weight of coarse pyrethrin extractive; dissolving in ethanol or methanol solvent in 5-7 times weight of coarse pyrethrin extractive at 25-30 deg.c for 1-1.5 hr before filtering to eliminate insoluble matter; freezing the solution at temperature below -20 deg.c; decolorizing the frozen liquid and concentrating to obtain ethanol or methanol concentrate while recovering ethanol or methanol; dissolving in petroleum ether solvent in 7-8 times weight of ethanol or methanol concentrate at 30-40 deg.c for 1-1.5 hr before filtering to eliminate insoluble matter; and concentrating to obtain high-purity pyrethrin while recovering petroleum ether solvent. The said process raises the content of pyrethrin in the product, reduces pollution and raises the safety of using the product.

Description

Technical field [0001] The invention relates to the technical field of natural insecticides, in particular to a method for producing high-purity pyrethrins. Background technique [0002] Pyrethrin refers to the total name of six effective insecticidal components in natural pyrethrum chrysanthemum. High-purity pyrethrin refers to yellow-brown oil containing more than 50% of pyrethrin in pyrethrum extract, which is a refined product. At present, only a few companies in the United States, Kenya and other countries can produce this product, and the process is complex, the oil yield is low, and it cannot be industrially produced. For example, the commercial pyrethrin (pyrethrin) produced by the U.S. company only contains 20~ Between 59%: Japan’s Takasago Perfume Company uses centrifugal molecular distillation to purify, but the content of pyrethroid in the product does not exceed 50%, and the production cost is high, which cannot be industrialized: Australia has developed the industry...

AI Technical Summary

Problems solved by technology

At present, there are only a few companies in the United States, Kenya and other countries that can produce this product, and the process is complicated, and the oil yield is low, so it cannot be industrialized. Between 59%: Japan’s Takasago Spice Company uses centrifugal molecular distillation to purify, but the content of permethrin in the product does not exceed 50%, and the production cost is too high to be industrialized: Australia has developed this industry since the 1980s, but its processing The finished product is mainly based on 20% crude oil

It still does not have the ability to produce high-purity permethrin products; currently, nitromethane is often used as a solvent to process permethrin products in the laboratory, and then the permethrin oil is dissolved in petroleum ether to remove insoluble matter to produce high-content permethrin products , its permethrin content reaches more than 90%, but its process is complicated, the oil yield is low, and there is no industrial production

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