Method for preparing diethyl succinate catalyzed by pyridine ionic liquid

A technology of diethyl succinate and ionic liquids, applied in chemical instruments and methods, preparation of organic compounds, preparation of carboxylate, etc., can solve the problems of difficult recovery of catalysts, harsh reaction conditions, cumbersome post-treatment, etc., and achieve Effects that are easy to control, have short reaction times, and are inexpensive

Inactive Publication Date: 2011-12-07
HEBEI UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] The technical problem to be solved in the present invention is to provide a method for preparing diethyl succinate catalyzed by pyridine ionic liquids. The catalysts used in the prior art have problems such as corrosion equipment, harsh reaction conditions, low esterification rate, many side reactions, difficult recovery of catalysts, cumbersome post-treatment, and environmental pollution. Green and efficient esterification of acid alcohols under mild conditions has been realized. The preparation is simple, the cost is low, and the catalyst can be recycled and reused

Method used

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  • Method for preparing diethyl succinate catalyzed by pyridine ionic liquid
  • Method for preparing diethyl succinate catalyzed by pyridine ionic liquid

Examples

Experimental program
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Effect test

Embodiment 1

[0047] Example 1 The method for preparing pyridine diethyl succinate catalyzed by pyridine ionic liquid

[0048] Add 0.05mol succinic acid, 0.15mol ethanol, and 0.295g N-picoline hydrogen sulfate into a three-necked flask equipped with reflux condensation (the order of adding the three substances is not limited), magnetic stirring (stir while heating , the purpose is to make the reaction more uniform, increase the reaction rate and reduce the reaction time at the same time, the stirring method is not limited to magnetic stirring, other stirring methods can be used);

[0049] React at 60°C for 2h; then

[0050] Add the extractant diethyl ether, pour out the mixed solution in the upper layer, and remove the diethyl ether and excess ethanol by rotary evaporation under reduced pressure at 40-55°C to obtain the crude product of diethyl succinate;

[0051] Cool and crystallize at 0°C for 1 hour, and centrifuge to remove the crystallized solid succinic acid to obtain pure diethyl s...

Embodiment 2

[0053] Example 2 The method for preparing diethyl succinate catalyzed by pyridine ionic liquid

[0054] Add 0.05mol of succinic acid, 0.15mol of ethanol, and 0.31g of N-ethylpyridine bisulfate into a three-necked flask equipped with reflux condensation, and stir magnetically.

[0055] React at 65°C for 2h; then

[0056] Add the extractant diethyl ether, pour out the mixed solution in the upper layer, and remove the diethyl ether and excess ethanol by rotary evaporation under reduced pressure at 40-55°C to obtain the crude diethyl succinate;

[0057] Cool and crystallize at 5°C for 1.5h, and centrifuge to remove the crystallized solid succinic acid to obtain a pure product. The esterification rate is 94.32%, and the selectivity is 100%.

[0058] The ionic liquid in the lower layer of the extract can be used again as a catalyst in the next cycle after simple rotary evaporation treatment, thus being reused.

Embodiment 3

[0059] Example 3 The method for preparing diethyl succinate catalyzed by pyridine ionic liquid

[0060] Add 0.05mol succinic acid, 0.15mol ethanol, and 0.325g N-propylpyridine tetrafluoroborate into a three-necked flask equipped with reflux condensation, and stir magnetically.

[0061] React at 60°C for 2.5h; then

[0062] Add the extractant diethyl ether, pour out the mixed solution in the upper layer, and remove the diethyl ether and excess ethanol by rotary evaporation under reduced pressure at 40-55°C to obtain the crude product diethyl succinate;

[0063] Cool and crystallize at 10°C for 4 hours, and remove the crystallized solid succinic acid to obtain a pure product. The esterification rate is 93.16%, and the selectivity is 100%.

[0064] The ionic liquid in the lower layer of the extract can be used again as a catalyst in the next cycle after simple rotary evaporation treatment, thus being reused.

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Abstract

The invention discloses a method for preparing diethyl succinate catalyzed by a pyridine ionic liquid. The method is to mix succinic acid and ethanol with a molar ratio of 1:3, add Brφnsted acidic pyridine ionic liquid catalyst, and the catalyst The amount is 5-8% of the mass of succinic acid, the reaction temperature is 60-70°C, the reaction time is 2-3h, and the catalyst and product are separated by ether extraction. The pyridine ionic liquid used in the present invention has high catalytic activity, good selectivity, low price, and stable properties, and can be reused after simple rotary evaporation and water removal treatment, which not only realizes green synthesis, but also reduces manufacturing costs and improves economic efficiency. benefit. The invention can be used for synthesizing butanediol diethyl ester and is suitable for large-scale industrial production.

Description

technical field [0001] The invention belongs to the field of compound synthesis, in particular to a method for synthesizing esters, in particular to a method for preparing diethyl succinate catalyzed by pyridine ionic liquids. Background technique [0002] Diethyl succinate, also known as diethyl succinate, can be used as a synthetic flavor and food additive, as a solvent for preparing berry flavors and fruit flavors, as an intermediate in organic synthesis and pharmaceutical synthesis, and as a stationary liquid for gas chromatography. , spices, daily chemicals, pharmaceuticals, coatings, rubber, plastics and other industries have been widely used. In addition, diethyl succinate also has the functions of antibacterial, anti-ulcer, detoxification, and inhibition of the central nervous system. [0003] The traditional synthesis process of diethyl succinate is to use succinic acid and absolute ethanol as raw materials, and concentrated sulfuric acid as a catalyst. This method...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/40C07C67/08
Inventor 赵地顺刘猛帅徐智策张娟付江涛任培兵
Owner HEBEI UNIVERSITY OF SCIENCE AND TECHNOLOGY
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