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Method for catalytically synthesizing diethyl maleate by using acidic ionic liquid

A technology of diethyl maleate and acidic ionic liquid, which is applied in the field of organic synthesis fine chemicals, can solve problems such as increasing production cost, large amount of water, side reactions, etc., and achieves improved reaction conversion rate, high catalytic activity, and thermal stability. high sex effect

Pending Publication Date: 2020-06-12
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

However, the use of sulfuric acid as a catalyst has disadvantages that cannot be ignored: 1. The use of concentrated sulfuric acid is easy to cause carbonization of raw materials and products, and side reactions will occur during the esterification reaction, which makes the color and luster of the product poor, and the yield is also limited. 2. Concentrated sulfuric acid will cause serious corrosion to the reaction equipment, and the equipment needs to be regularly maintained against acid corrosion, which increases the production cost
3. In the subsequent treatment process, water washing and deacidification need to consume a relatively large amount of water, and the treatment of sewage has become a relatively large trouble
However, the low cost performance of ion exchange resin makes it difficult to realize industrial application

Method used

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  • Method for catalytically synthesizing diethyl maleate by using acidic ionic liquid

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] as per figure 1 The structure shown builds the reaction apparatus.

[0029] Add 9.80 g (0.10 mol) of maleic anhydride, 18.43 g (0.40 mol) of absolute ethanol, 15 mL of cyclohexane (as a water carrier) and 3.22 g (0.02 mol) of acidic ionic liquid A in a 50 mL three-necked flask (i.e. ionic liquid [Hmim-PS] [HSO 4 ]). The temperature was raised to 85°C for reflux, and the reaction was stopped for 8 h. The reaction system is obviously layered, the lower layer is the catalyst, and the upper layer is the ester layer, which can be separated after cooling and pouring, and the recovered catalyst can be reused. Use 0.2 mol·L -1 The ester layer was titrated with KOH solution, and the esterification rate was calculated to be 92.6%. The upper ester layer was sequentially washed with 0.10mol·L -1 Wash with dilute aqueous sodium carbonate and distilled water, then rotary evaporate and dry to obtain diethyl maleate product.

Embodiment 2

[0031] as per figure 1 The structure shown builds the reaction apparatus.

[0032]Add 9.80 g (0.10 mol) of maleic anhydride, 18.43 g (0.40 mol) of absolute ethanol, 15 mL of cyclohexane (as a water carrier) and 3.22 g (0.02 mol) of acidic ionic liquid B into a 50 mL three-necked flask (i.e. ionic liquid [Hmim-PS][PTSA]). The temperature was raised to 85°C for reflux, and the reaction was stopped for 8 h. The reaction system is obviously layered, the lower layer is the catalyst, and the upper layer is the ester layer, which can be separated after cooling and pouring, and the recovered catalyst can be reused. Use 0.2 mol·L -1 The ester layer was titrated with KOH solution, and the esterification rate was calculated to be 85.6%. The upper ester layer was sequentially washed with 0.10mol·L -1 Wash with dilute aqueous sodium carbonate and distilled water, then rotary evaporate and dry to obtain diethyl maleate product.

Embodiment 3

[0034] as per figure 1 The structure shown builds the reaction apparatus.

[0035] Add 9.80 g (0.10 mol) of maleic anhydride, 18.43 g (0.40 mol) of absolute ethanol, 15 mL of cyclohexane (as water carrier) and 2.95 g (0.02 mol) of acidic ionic liquid C into a 50 mL three-necked flask (i.e. ionic liquid [Hmim-PS][CH 3 SO 3 ]). The temperature was raised to 85°C for reflux, and the reaction was stopped for 8 h. The reaction system is obviously layered, the lower layer is the catalyst, and the upper layer is the ester layer, which can be separated after cooling and pouring, and the recovered catalyst can be reused. Use 0.2 mol·L -1 The ester layer was titrated with KOH solution, and the esterification rate was calculated to be 79.4%. The upper ester layer was sequentially washed with 0.10mol·L -1 Wash with dilute aqueous sodium carbonate and distilled water, then rotary evaporate and dry to obtain diethyl maleate product.

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Abstract

The invention discloses a method for catalytically synthesizing diethyl maleate by using acidic ionic liquid. The method comprises the following steps: using maleic anhydride and absolute ethyl alcohol as raw materials, using the acidic ionic liquid as a catalyst and using cyclohexane as a water-carrying agent to be added into a reaction bottle, heating, stirring, reacting, condensing and refluxing; after the reaction is finished, standing and layering into a reaction product layer and a catalyst layer, washing the reaction product layer with a sodium bicarbonate aqueous solution and distilledwater in sequence, and drying to obtain a diethyl maleate product, wherein the acidic ionic liquid is one of the following components. The method has the advantages of high product yield, high product purity, good catalyst separation efficiency and the like, and the recovered catalyst can be reused. The method can effectively reduce the cost of subsequent treatment of wastewater pollution and theuse cost of the catalyst and has a very good application prospect.

Description

technical field [0001] The invention belongs to the field of organic synthesis fine chemicals, in particular to a method for catalytically synthesizing diethyl maleate with an acidic ionic liquid. Background technique [0002] Diethyl maleate is a colorless transparent liquid, also known as diethyl maleate (2-Butenedioic acid (2Z)-1,4-diethyl ester), often referred to as DEM, Its boiling point (101.3kPa) is 223°C, its melting point is -8.8°C, and its density is 1.07g / ml. At room temperature, it can be miscible with various organic solvents, and can be partially miscible with benzene and chloroform. At 30°C, the solubility in water is 1.4%, and the solubility in water is 1.9% in diethyl maleate. It can form an azeotropic mixture with 88.2% water, and the azeotropic point is 99.65°C. [0003] Diethyl maleate is widely used in organic intermediates, plasticizers, anti-corrosion additives, surfactants and other fields. [0004] Sulfuric acid catalyzes the direct esterificatio...

Claims

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Application Information

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IPC IPC(8): C07C67/08C07C67/48C07C69/60B01J31/02
CPCC07C67/08C07C67/48B01J31/0284B01J31/0279C07C2531/02B01J2231/49C07C69/60
Inventor 郭红云金春晖张启源潘鹏施信
Owner ZHEJIANG UNIV OF TECH
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