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Recycling of ionic liquid in key reaction for cantharidin preparation

An ionic liquid, key reaction technology, applied in organic compound/hydride/coordination complex catalysts, organic chemistry, physical/chemical process catalysts, etc., can solve the problems of difficult target product separation, high price, etc. The effect of low cost and lower production cost

Inactive Publication Date: 2018-03-23
CHONGQING ACAD OF CHINESE MATERIA MEDICA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, the use of ionic liquids also has the following disadvantages: as the price is more expensive, it is difficult to separate from the target product

Method used

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  • Recycling of ionic liquid in key reaction for cantharidin preparation
  • Recycling of ionic liquid in key reaction for cantharidin preparation
  • Recycling of ionic liquid in key reaction for cantharidin preparation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Cantharidin intermediate synthesis:

[0028] 100g 2,5-dihydrothiophene-3,4-dicarboxylic anhydride, 600ml furan, 400ml ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, catalytic amount of boron trifluoride ether , added to the reactor, heated to 50° C. and stirred for 18 hours, then cooled to room temperature to obtain a reaction system.

[0029] Ionic liquid recovery:

[0030] The reaction system was extracted three times with acetonitrile, the amount of acetonitrile used was 600 ml, and the temperature of the extraction system was kept at 40°C. After mixing the extracts, they were distilled under reduced pressure to obtain the recovered ionic liquid.

[0031] Ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate recovery rate is 80%; HPLC figure ( figure 1 )

[0032] The yield of cantharidin intermediate was 94%.

[0033] It can be seen from the data that the cantharidin intermediate product in the key step of cantharidin is effectively separated, ...

Embodiment 2

[0035] Cantharidin intermediate synthesis:

[0036] 50g of 2,5-dihydrothiophene-3,4-dicarboxylic anhydride, 175ml of furan, 100ml of reclaimed ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate recovered in Example 1), A catalytic amount of boron trifluoride diethyl ether was added into the reactor, stirred and reacted at room temperature for 25 hours, and cooled to room temperature to obtain a reaction system.

[0037] Ionic liquid recovery:

[0038] The reaction system was extracted three times with acetonitrile, the total amount of acetonitrile was 875 ml, and the temperature of the extraction system was kept at 25°C. After mixing the extracts, they were distilled under reduced pressure to obtain the secondary recovery ionic liquid.

[0039] Secondary reclaiming ionic liquid after this application, its ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate rate of recovery is 70%; HPLC figure ( figure 2 ).

[0040] The yield of cantharidin intermediate is ...

Embodiment 3

[0043] Cantharidin intermediate synthesis:

[0044] 20g 2,5-dihydrothiophene-3,4-dicarboxylic anhydride, 120ml furan, 60ml ionic liquid 1-butyl-3-methylimidazole bis(trifluoromethylsulfonimide), catalytic amount of Boron trifluoride diethyl ether was added into the reactor, heated to 35°C and stirred for 20 hours, then cooled to room temperature to obtain a reaction system.

[0045] Ionic liquid recovery:

[0046] The reaction system was extracted 3 times with acetonitrile, the total amount of acetonitrile was 60ml, and the temperature of the extraction system was kept at 30°C. After mixing the extracts, they were distilled under reduced pressure to obtain the recovered ionic liquid.

[0047] The recovery rate of the ionic liquid 1-butyl-3-methylimidazole bis(trifluoromethylsulfonimide) was 91%; the yield rate of the cantharidin intermediate was 92%.

[0048] The same product can be obtained by repeating the reaction of the ionic liquid according to the above steps, and a c...

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Abstract

The invention provides an ionic liquid recycling method adopting a simple process and aims to solve the problem of difficulty in product separation and the problem about recycling of an ionic liquid in synthesis of a cantharidin intermediate from the ionic liquid. According to the method, most ionic liquid is extracted from a cantharidin intermediate reaction system with acetonitrile as an extracting liquid and is distilled, and recycled ionic liquid is obtained and can be continuously used in synthetic steps of the cantharidin intermediate circularly. The ionic liquid extraction and recoveryprocess is simple and easy to operate; effective separation of the cantharidin intermediate product in key steps for cantharidin as well as effective recovery of the ionic liquid and the extracting liquid can be guaranteed; the ionic liquid is recycled in the synthesis process, the effect of the recycled ionic liquid is equivalent to that of the original ionic liquid, so that the cost of a production system can be low, the production cost is reduced, and favorable conditions are provided for industrial production of cantharidin.

Description

technical field [0001] The invention relates to the recovery of ionic liquids, in particular to a method for recycling ionic liquid solutions in the process of preparing cantharidin with ionic liquids as solvents. Background technique [0002] Compared with traditional solvents, ionic liquids have a high boiling point, are non-volatile, can exist as liquids in a wide temperature range, and have good thermal stability, and can be changed by selecting a suitable combination of anions and cations. Its physical and chemical properties are good solvents for many organic, inorganic and polymer materials. As a green solvent, ionic liquid is widely used in the fields of electrochemistry, organic synthesis, catalysis and separation. For example, in the D-A reaction, ionic liquid is an excellent medium, which can be used together with Lewis acid to change the D-A product. The ratio of isomers; the solvent containing part of water has no effect on the D-A reaction. Patent 20161117146...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D493/18C07D495/18C07D233/58B01J31/02
CPCC07D493/18B01J31/0284B01J31/0298C07D233/58C07D495/18
Inventor 刘晓玲谭春斌杜洪飞
Owner CHONGQING ACAD OF CHINESE MATERIA MEDICA
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