Production method for extracting pyrethrin from pyrethrum flower

Abstract

The invention relates to a production method for extracting pyrethrin from a pyrethrum flower. The production process comprises the following steps of: (a) carrying out draining drying, smashing and wall breaking on the pyrethrum flower; (b) carrying out multistage reflux pulse extraction; (c) carrying out reflux film evaporation at negative pressure; (d) adsorbing, filtering and separating at negative pressure; and (e) rectifying and purifying at negative pressure. The production method disclosed by the invention greatly increases the yield of the pyrethrin, realizes the large-scale, industrialized and continuous production of the pyrethrin and has the advantages of no environmental pollution, low production cost and enormous economic benefit and social benefit.

Description

technical field [0001] The invention relates to a preparation method of pyrethrins, in particular to a production method of extracting pyrethrins from pyrethrum flowers. Background technique [0002] Pyrethrins are a class of broad-spectrum insecticides that can control a variety of pests, and their insecticidal toxicity is 10-100 times higher than that of older generation insecticides such as organochlorines, organophosphorus, and carbamates. Pyrethroids have a strong contact effect on insects, and some species have stomach poisoning or fumigating effects, but none of them have systemic effects. Its mechanism of action is to disrupt the normal physiology of insect nerves, causing them to die from excitement, convulsions, and paralysis. Pyrethroids are safe for humans and animals because of their small dosage and low concentration, and they have little pollution to the environment. [0003] Pyrethrum flowers are a major source of pyrethrins. At present, the production met...

AI Technical Summary

Problems solved by technology

At present, the production method of extracting pyrethrins from pyrethrum flowers basically uses subcritical liquid butane solvent extraction, and a few also use supercritical CO 2 Extraction, but the disadvantages of these two production processes are high equipment pressure and large equipment investment; small output, intermittent production, and cannot achieve large-scale and continuous production; high solvent consumption and high production costs

[0004] CN102342304A discloses a production method for extracting pyrethrins from pyrethrum. This method uses n-hexane as a solvent extraction production process, but it still has disadvantages: (1) Large solvent ratio and large energy consumption: the solid-liquid ratio is 1:7 ~8, so there are more solvents that need to be evaporated, and more energy is consumed; (2) The extraction rate is low: the extraction rate is only 90%, due to the lack of pretreatment crushing and breaking the wall, pyrethrins (prime) exist in the calyx cells Among them, the hard cell wall makes it difficult for n-hexane solvent to extract pyrethrins; (3) pollute the environment: the residual pyrethrins are inactivated due to the process defect in the desolventization and drying of the pyrethrum residues, and the pyrethrum residues cannot be used. It can only be discarded as waste and pollutes the environment; (4) The activity of the product is low. Pyrethrin is a heat-sensitive substance, and its concentration temperature reaches 90-95°C, which makes its product degrade and lose certain activity

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