A kind of preparation method of Abamectin b2a

Abstract

The invention relates to a preparation method of high-purity abamectin B2a, which comprises the steps of concentrating the abamectin B1a crystallization mother liquor under vacuum conditions to no fraction to obtain a thick ointment; adding an extractant for extraction to obtain an extract , and then use saturated brine to wash the extract for 2 to 3 times, remove the water phase to obtain n-butyl acetate solution; cool the obtained n-butyl acetate solution to crystallize, grow crystals, and suction filter to obtain crude crystals of abamectin B2a ; Abamectin B2a coarse crystal recrystallization suction filtration, drying, to obtain high-purity avermectin B2a fine powder. The present invention uses the environment-friendly non-toxic solvent n-butyl acetate to replace the toxic solvent aromatic hydrocarbon to produce abamectin B2a high-quality goods. During the production operation, it causes little harm to the health of on-site employees, and the pollution to the environment is also relatively small. In addition, n-butyl acetate is adopted as B2a as crystallization solvent, and the purity of the obtained abamectin B2a fine powder is above 95%.

Description

Technical field: [0001] The invention relates to a preparation method of biological pesticides, in particular to a preparation method for extracting high-purity avermectin B2a by using an environment-friendly crystallization solvent, and belongs to the technical field of pesticide preparation. Background technique: [0002] Abamectin is a group of 16-membered macrolide antibiotics with similar structure isolated and extracted from the fermentation product of Streptomyces. of the two components. Abamectin B components have extremely high bioinsecticidal activity against nematodes, insects, and mites, but there are significant differences in the insecticidal abilities B1a and B2a of different targets. Abamectin B2a has a good effect on root-knot nematodes. According to reports such as Putter in 1981, in the 8 components of abamectin, B1a and B2a are the most effective agricultural active substances, and wherein B2a has the effect on plant root-knot nematodes. Nematodes are t...

AI Technical Summary

Problems solved by technology

Although this method provides a relatively low production cost and is easy to industrialize the extraction and preparation of Abamectin B2a, the method uses the carcinogen toluene as the crystallization and recrystallization solvent, which causes physical harm to the on-site employees during the production operation. Harmful and pollute the environment

In addition, the purity of B2a crystals obtained by this process through two recrystallizations is relatively low, with a purity of only 90%.

[0004] Chinese patent document CN103333214A discloses a kind of preparation method of abamectin B2a refined powder, adopts 0.25-0.6% tetrabutylammonium bromide aqueous solution to wash sec-butyl acetate extract, makes avermectin purity improve to In this patent, although the purity of abamectin has been improved to a certain extent, the process uses carcinogenic aromatic hydrocarbons as crystallization and recrystallization solvents, which is dangerous to on-site personnel during production operations, and In the process, sec-butyl acetate is firstly used for extraction, and after washing with water, the sec-butyl acetate is vacuum distilled and then crystallized with aromatic hydrocarbons. The process is more complicated and the production cost is higher.

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