Process of inductive crystallization for preparing enriched trans-racemic dichloro-chrysanthemic acid

A technology of permethrin and inducing crystallization, which is applied in the field of preparing trans isomers by crystallization method, can solve the problems such as no report on permethrin, and achieves the effect of easy implementation and improved purity

Inactive Publication Date: 2004-06-09
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The preparation of racemic permethrin by chemical synthesis is a mature method; however, the preparation of trans-rich permethrin by crystallization has not been reported

Method used

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  • Process of inductive crystallization for preparing enriched trans-racemic dichloro-chrysanthemic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Take 1.0 g of racemic permethrin (obtained by chemical synthesis), the composition of its four isomers is: S(-)-cis-body 20.22%, R(+)-cis-body 20.29%, S(-)-trans-body 29.61%, R(+)-trans-body 29.88%, dissolved in warm petroleum ether to form a supersaturated solution, adding a little fine sucrose crystals as induced crystal seeds, in Slow crystallization at room temperature (10-20°C); after drying and derivatization with chiral alcohol, the composition of the four isomers was determined by gas chromatography (10% QF-1 column, 5m, hydrogen flame detector): S(-)-cis-body 6.92%, R(+)-cis-body 8.58%, S(-)-trans-body 42.49%, R(+)-trans-body 42.01%, yield 34.6%, trans The purity of formula permethrin increases to 84.5% by 59.5%, improves 25%; [after mother liquor crystallization is dried, the composition of four kinds of isomers is: S (-)-cis- body 24.10%, R (+) -cis-body 28.05%, S(-)-trans-body 23.82%, R(+)-trans-body 24.04%, yield 67.3%, the purity of cis-permethrin increas...

Embodiment 2

[0018] Take racemic permethrin 1.0g, the composition of its four isomers is: S(-)-cis-body 20.22%, R(+)-cis-body 20.29%, S(-)-trans -body 29.61%, R(+)-trans-body 29.88%, dissolved in warm petroleum ether, after forming a supersaturated solution, add a small amount of fine sodium glutamate crystals as induced crystal seeds, at room temperature ( 10~20℃) slowly crystallize. After drying, according to the method described in Example 1, the composition of the four isomers determined to be crystallized is: S(-)-cis-body 10.18%, R(+)-cis-body 12.10%, S(-)- The trans-body was 38.87%, the R(+)-trans-body was 38.85%, and the yield was 35.9%. The purity of trans-permethrin increased from 59.5% to 77.7%, an increase of 18.2%. After the mother liquor is dried, the composition of the four isomers is: S(-)-cis-body 23.90%, R(+)-cis-body 27.44%, S(-)-trans-body 24.19%, R(+) The -trans- body was 24.47%, and the yield was 63.4%. The purity of cis-permethrin increased from 40.5% to 51.34%, an...

Embodiment 3

[0020] Take racemic permethrin 1.0g, the composition of its four isomers is: S(-)-cis-body 20.22%, R(+)-cis-body 20.29%, S(-)-trans -trans-body 29.61%, R(+)-trans-body 29.88%, dissolved in warm petroleum ether to form a supersaturated solution, add a little fine sodium cystine crystals as induced seed crystals, at room temperature ( 10~20℃) slowly crystallize. After drying, according to the method described in Example 1, the composition of the four isomers determined to be crystallized is: S(-)-cis-body 5.84%, R(+)-cis-body 6.60%, S(-)- The trans-body was 44.17%, the R(+)-trans-body was 43.39%, and the yield was 34.5%. The purity of trans-permethrin increased from 59.5% to 87.56%, an increase of 28%. After the mother liquor is dried, the composition of the four isomers is: S(-)-cis-body 25.32%, R(+)-cis-body 26.64%, S(-)-trans-body 23.70%, R(+) The -trans- body was 24.36%, and the yield was 64.5%. The purity of cis-permethrin increased from 40.5% to 51.96%, an increase of 11...

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Abstract

The present invention relates to a method for preparing enriched trans-racemic-dichlorochrysanthemic acid by induced crystallization, and is characterized by that it uses racemic dichlorochrysanthemic acid as raw material, and dissolves it in organic solvent and makes it form supersaturated solution, then adds small quantity of inductive crystal seed and makes them implement slow and natural crystal precipitation at room temperature. The adoption of said invention can separate four isomers of racemic-dichlorochrysanthemic acid, can obviously increase content of trans-isomer which can be reached to about 95%, and can obviously raise purity of trans-dichlorochrysanthemic acid.

Description

technical field [0001] The invention relates to a crystallization method for preparing trans isomers, in particular to a method for inducing crystallization to prepare rich trans-racemic permethrin. Background technique [0002] The enantiomers were resolved by crystallization. The earliest literature report was found in 1848. Pasteur used the direct crystallization method to resolve the sodium ammonium tartrate for the first time. He picked out its (R) and (S) crystals under a magnifying glass. (Pasteur, L., C.R.Acad.Sci., 26,535 (1848). In 1882, Jungfleisch revealed that in a metastable supersaturated solution, adding pure enantiomer seed crystals can also resolve sodium amine tartrate (Jungfleisch.M.E., J.Pharm.chim., 5e me Ser.5, 345 (1882)); the aggregate crystal of racemization, after adding seed crystals, produced enantiomeric crystals with obvious size differences, which can also be used Separated by screening (Dowlig, B.B., US Pat 2898558, 1959); racemic DL-asparag...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/43C07C61/37
Inventor 邵昌平刘韧白长敏韩梅郑卓
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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