Synthetic method for 5-acetylsalicylamide

A technology of acetylsalicylic amide and synthesis method, which is applied in the preparation of carboxylic acid amides, chemical instruments and methods, preparation of organic compounds, etc. The effect of short time, high yield and high product quality

Inactive Publication Date: 2015-04-29
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Since the raw materials and products are generally in the form of solids, a large amount of organic solvents are required, such as dichloromethane, nitrobenzene, nitromethane, etc., which are difficult to reuse and highly toxic.
For this reason, some studies have improved the process, literature (Chen, W.; Yin, H.; Zhang, Y.; Lu, Z. et al. Acylation of salicylamide to 5-acetylsalicylamide using ionic liquids as dual catalyst and Solvent.Journal od Industrial and Engineering Chemistry, 2010,16(5),800-804) using 1-butyl-3-methylimidazole chloroaluminate and N-butylpyridine chloroaluminate as solvent and catalyst, Catalyze the reaction of salicylamide to generate 5-acetylsalicylamide, and the yield can reach more than 80%, but the cost of ionic liquid used in this method is high, it is difficult to recycle, and the production cost is high

Method used

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  • Synthetic method for 5-acetylsalicylamide
  • Synthetic method for 5-acetylsalicylamide
  • Synthetic method for 5-acetylsalicylamide

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Experimental program
Comparison scheme
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Embodiment 1-1

[0039] Embodiment 1-1: a kind of synthetic method of 5-acetyl salicylamide, carry out following steps successively:

[0040] 1), NaCl-AlCl 3 Preparation of low melting point mixed molten salt system:

[0041] Place a 100ml three-neck flask, a mechanical stirrer, a condenser (linked to the tail gas HCl absorption device), a 0-200°C thermometer, and a constant pressure dropping funnel in a constant temperature oil bath; quickly weigh 0.0648mol (about 8.64g ) anhydrous aluminum chloride and 0.0648mol (about 3.79g) sodium chloride were added into the flask, mechanical stirring was started, and the temperature was raised to 140°C until the solid in the system melted and the temperature stabilized.

[0042] Remarks: After about 25 minutes, both anhydrous aluminum chloride and sodium chloride are in a molten state.

[0043] 2) Weigh 0.036 mol (about 5.00 g) of salicylamide into the above-mentioned flask (the flask is kept at 140° C.) under stirring conditions, and melt it until the...

Embodiment 1-2

[0049] Example 1-2, the equivalent of anhydrous aluminum chloride remains unchanged, and the "anhydrous aluminum chloride: sodium chloride = 1:1 molar ratio" in Example 1-1 is changed to: anhydrous chlorination Aluminum: sodium chloride = 2:1, 3:2, 1:2, 1:3; and adjust the corresponding temperature according to the stability of the system melt, as follows:

[0050] When the mol ratio of aluminum chloride anhydrous: sodium chloride=2:1, the temperature of step 1)~step 3) is all changed to 167 ℃;

[0051] When the mol ratio of aluminum chloride anhydrous: sodium chloride=3:2, the temperature of step 1)~step 3) is all changed to 125 ℃;

[0052] When the molar ratio of anhydrous aluminum chloride:sodium chloride=1:2, the temperature of step 1)~step 3) still keeps 140 ℃;

[0053] When the molar ratio of anhydrous aluminum chloride:sodium chloride=1:3, the temperature of step 1) to step 3) is still kept at 140°C.

Embodiment 1

[0056] Embodiment 1-3, keeping NaCl-AlCl 3 The molar ratio of aluminum chloride and sodium chloride in the low melting point mixed molten salt system is 1:1, and the equivalents of aluminum chloride in Example 1 are respectively changed to 1.0eq, 1.5eq, 2.0eq, 2.5eq, 3.0eq, All the other contents are equal to embodiment 1-1; The yield comparison of the 5-acetyl salicylamide of final gain figure 2 shown.

[0057] When the aluminum chloride equivalent is less than 1.8eq, the raw material cannot be completely converted, especially when the equivalent is 1.0eq, because the solvent is too little, the reaction system is easily coked to generate a large amount of by-products, so the product yield is low. And when the aluminum chloride equivalent is greater than 1.8eq, the catalyst amount is excessive, and the excess molten salt only exists as a solvent, and it is unnecessary to increase the equivalent of anhydrous aluminum chloride. Therefore, the aluminum chloride equivalent is o...

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Abstract

The invention discloses a synthetic method for 5-acetylsalicylamide. The method comprises the following steps: putting anhydrous aluminum chloride and sodium chloride into a container, and performing heating and stirring until both anhydrous aluminum chloride and sodium chloride are fused to obtain low-melting-point NaCl-AlCl3 mixed fused salt; adding salicylamide into the low-melting-point NaCl-AlCl3 mixed fused salt, and stirring until salicylamide is fused; dropwise adding an acylation reagent, and after finishing the dropwise-adding process, producing a heat preservation reaction; immediately and slowly adding acid liquor into an obtained reaction product, and after finishing the process of adding the acid liquor, continuously stirring at the room temperature until no new solids are generated; filtering obtained turbid liquid to obtain a filter cake, and performing washing and drying on the filter cake to obtain a crude product of 5-acetylsalicylamide; purifying the crude product to obtain 5-acetylsalicylamide. The synthetic method for 5-acetylsalicylamide has the advantages of high yield, simple post-treatment, elimination of organic solvents and the like.

Description

technical field [0001] The present invention relates to a kind of new synthetic method of 5-acetyl salicylamide. Background technique [0002] 5-acetyl salicylamide (5-acetyl-2-hydroxybenzamide) is a white powder that is insoluble in water but soluble in organic solvents such as ethanol and acetone. Its structural formula is shown in the following formula. It is an important Organic pharmaceutical intermediates, which can be used to synthesize labetalol, an antihypertensive drug. [0003] [0004] The synthesis of 5-acetyl salicylamide is mainly through the Friedel-Crafts acylation reaction of salicylamide, that is, under the catalysis of anhydrous aluminum trichloride and other catalysts, an acyl group is introduced on the benzene ring. The current production of 5-acetylsalicylamide in the industry mainly uses nitrobenzene and chlorinated alkanes as solvents, anhydrous aluminum chloride as a catalyst to catalyze the Friedel-Crafts acylation reaction of salicylamide and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C235/84C07C231/12
Inventor 陈新志王亚纳钱超
Owner ZHEJIANG UNIV
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