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Method for producing high-purity N-alkyl imidazole

A technology for the production of alkylimidazoles and methods, applied in the field of preparation of high-purity N-alkylimidazoles, achieving the effects of high purity, simple process, and increased income

Inactive Publication Date: 2013-04-03
JIANGNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] Based on the above literature, there is still a lack of an economical, simple and easy method to synthesize high-purity N-alkylimidazoles
And the halides of alkali metals or alkaline earth metals generally have hygroscopic properties, which can remove the water formed in the reaction. The method of simplifying the reaction steps by using this characteristic has not been reported at home and abroad.

Method used

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  • Method for producing high-purity N-alkyl imidazole
  • Method for producing high-purity N-alkyl imidazole
  • Method for producing high-purity N-alkyl imidazole

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Take imidazole (68.0g, 1.0mol) and sodium hydroxide (40.0g, 1.0mol) in a 1000mL three-necked flask with a thermometer, stir vigorously at 90°C for 20 hours, then cool down to 24°C, add 300mLTHF, and then add chlorine Substitute n-butane (92.0g, 1.0mol), react at 70°C for 12 hours, filter after the reaction, wash the solid three times with 10% of the original volume of THF, combine the organic phase, and finally distill 285mLTHF under normal pressure for recycling , the remaining liquid was subjected to vacuum distillation (80-82° C., 1 torr), to obtain 105.0 g of high-purity product N-n-butylimidazole, with a yield of 85% and a purity of 99.6%. The obtained NaCl was dissolved in 150 mL of hot water, cooled and crystallized for purification, filtered, and dried to obtain 50 g of white sodium chloride solid with a yield of 85%.

Embodiment 2

[0032] Take imidazole (6.8g, 0.1mol) and sodium hydroxide (4.0g, 0.1mol) in a 1000mL three-necked flask with a thermometer, stir vigorously at 90°C for 20 hours, then cool down to 0°C, add 680mL of THF, and then add olefin Propyl chloride (7.6g, 0.1mol), reacted at 20°C for 12 hours, filtered after the reaction, washed the solid three times with 10% THF of the original volume, combined the organic phase, and finally distilled 696mLTHF under normal pressure for recycling. The remaining liquid was subjected to vacuum distillation (76-78° C., 1 torr) to obtain 9.5 g of high-purity N-allylimidazole with a yield of 88% and a purity of 99.1%. The obtained NaCl was dissolved in 15 mL of hot water, cooled and crystallized for purification, filtered and dried to obtain 5.1 g of white sodium chloride solid with a yield of 87%.

Embodiment 3

[0034] Take imidazole (68.0g, 1.0mol) and sodium hydroxide (40.0g, 1.5mol) in a 250mL three-necked flask with a thermometer, stir vigorously at 150°C for 0.2 hours, then cool down to 0°C, add 68mLTHF, and then add a Methyl bromide (85.5g, 0.8mol), reacted at 20°C for 4 hours, filtered after the reaction, washed the solid three times with 10% of the original volume of THF, combined the organic phase, and finally distilled 60mLTHF under normal pressure for recycling, and the remaining liquid Rectification under reduced pressure (46-48° C., 1 torr) yielded 60.6 g of high-purity N-methylimidazole with a yield of 92% and a purity of 99-8%. The obtained NaCl was dissolved in 150 mL of hot water, cooled and crystallized for purification, filtered, and dried to obtain 47.6 g of white sodium chloride solid, with a yield of 90%.

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Abstract

The invention discloses a method for producing high-purity N-alkyl imidazole, comprising the following steps of: a, putting imidazole and alkali metal hydroxide or alkaline-earth metal hydroxide into a reaction bottle in a mol ratio ranging from (1: 0.5) to (1: 1.5); violently agitating at 90-150 DEG C for 0.2-24 hours; b, reducing the temperature to 0-60 DEG C and adding tetrahydrofuran (THF), wherein the ratio of the volume THF to the mass of the imidazole is (1-100): 1; c, adding alkyl halide according to the mol ratio ranging from (1: 0.8) to (1: 1.5) (imidazole to RX); reacting at 20-80 DEG C for 4-48 hours, wherein R is any one of straight-chain alkyl with a carbon number of 1-16, naphthenic base with a carbon number of 3-8, allyl, propargyl and benzyl, and X is any one of chlorine and bromine; d, after the reaction, filtering; utilizing the THF which is 10% of the previous volume to wash a solid for three times; dissolving the solid into a suitable amount of hot water to carry out crystallization and purification, and obtaining a by-product to be stored for other use; and e, distilling the THF from an organic phase, and recycling; and finally, rectifying residual liquid to obtain a high-purity product. The method disclosed by the invention has the advantages that 1, the process is simple to operate; water-removing operation is not needed after a first-step reaction, and a second-step reaction is directly carried out; 2, the product is high-purity colorless transparent liquid or white solid; and 3, the synthesizing time is short, suitable conditions are wide and pollution to the environment is small, so that the method is suitable for industrial production.

Description

technical field [0001] The invention belongs to the production technical field of fine chemicals, and relates to a preparation method of high-purity N-alkylimidazoles. Background technique [0002] N-alkylimidazole series compounds are a very important class of fine chemicals, which can be widely used in the synthesis of medicines and pesticides. For example, they are the core skeleton of fungicides such as miconazole and clotrimazole. N-alkylimidazole has a lone electron pair on a nitrogen atom on the five-membered heterocyclic ring, which has certain basic and nucleophilic properties, so it can also be used as an organic ligand and catalyst in organic synthesis. N-alkylimidazoles with medium and long carbon chains have good surface properties and are one of the most commonly used cationic functional groups in amphoteric surfactants. It is also the most important starting material for imidazolium-based ionic liquids, through which various ionic liquids can be synthesized. ...

Claims

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Application Information

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IPC IPC(8): C07D233/58C01D3/04C01D3/10C01F5/30C01F11/24C01F11/34
Inventor 李炜高伟胡学一夏咏梅方云
Owner JIANGNAN UNIV
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