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Preparation method of crystalline N-acetoacetanilide

A technology of acetoacetanilide and crystalline form, which is applied in the field of preparation of crystalline N-acetoacetanilide, to achieve the effects of reducing production energy consumption, uniform crystal shape, and improving cooling effect

Inactive Publication Date: 2018-02-02
NANTONG ACETIC ACID CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This drying device reduces the damage of crystals from the post-processing section, but it is not controlled from the source

Method used

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  • Preparation method of crystalline N-acetoacetanilide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Add 3000L of 95% ethanol and 550kg (5.9kmol) of aniline into a 5000L condensation kettle, then add 556kg (6.49kmol) of diketene dropwise at <10°C, after the reaction is over, add 0.5kg of diketene to the condensation kettle Acetic acid, then heat up to 60°C, turn on the system vacuum, the vacuum degree starts from 760mmHg, gradually increases to 572mmHg, maintains at this vacuum degree for 30 minutes, then continues to increase the vacuum degree to 385mmHg, wait until the temperature drops below 40°C, then at 0.5 Continue to increase the vacuum degree to 100mmHg within an hour, finally reduce the vacuum degree to 10mmHg, and maintain it for 15 minutes. Stop the vacuum pump, ventilate the system, centrifuge, and dry to obtain 1035kg of N-acetoacetanilide finished product in the shape of quicksand with uniform crystallization. 99.93%, stacked for 120 days without caking.

Embodiment 2

[0047]Add 3000L of 40% ethanol and 550kg (5.9kmol) of aniline into a 5000L condensation kettle, then add 556kg (6.49kmol) of diketene dropwise at <10°C, after the reaction is over, add 0.2kg of diketene to the condensation kettle Sulfuric acid, then heat up to 70°C, turn on the system vacuum, the vacuum degree starts from 760mmHg, gradually increases to 460mmHg, maintains at this vacuum degree for 50 minutes, then continues to increase the vacuum degree to 310mmHg, wait until the temperature drops below 40°C, and then in 1 Continue to increase the vacuum degree to 85mmHg within an hour, finally reduce the vacuum degree to 8mmHg, and maintain it for 15 minutes. Stop the vacuum pump, ventilate the system, centrifuge, and dry to obtain 1037kg of N-acetylacetanilide finished product with uniform crystallization and the shape of quicksand. 99.92%, stacked for 120 days without caking.

Embodiment 3

[0049] Add 3000L of 95% methanol and 550kg (5.9kmol) of aniline into a 5000L condensation kettle, then add 556kg (6.49kmol) of diketene dropwise at <10°C, and after the reaction is over, add 0.8kg of diketene to the condensation kettle Propionic acid, then heat up to 55°C, turn on the system vacuum, the vacuum degree starts from 760mmHg, gradually increases to 610mmHg, maintains at this vacuum degree for 40 minutes, then continues to increase the vacuum degree to 385mmHg, wait until the temperature drops below 40°C, and then Continue to increase the vacuum degree to 122mmHg within 1.5 hours, finally reduce the vacuum degree to 10mmHg, maintain for 30 minutes, stop the vacuum pump, the system is ventilated, centrifuged, and dried to obtain 1033kg of N-acetylacetanilide finished product with uniform crystallization and quicksand shape. The content is 99.91%, and it will not agglomerate after 120 days of stacking.

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Abstract

The invention discloses a preparation method of crystalline N-acetoacetanilide. The method comprises the following steps: reacting aniline with diketene, carrying out condensation on the aniline and diketene, adding an acid accounting for 0.01-0.1% of the weight of the above obtained condensation solution into a condensation kettle, heating the obtained solution to 40-70 DEG C, starting the vacuumof a system, gradually increasing the vacuum degree to 610-460 mmHg from 760 mmHg, keeping the vacuum degree at 610-460 mmHg for 10-50 min, and continuously increasing the vacuum degree to 385-310 mmHg; and decreasing the temperature to 40 DEG C or less, continuously increasing the vacuum degree to 160-85 mmHg within 0.5-2 h, finally reducing the vacuum degree to 10-5 mmHg, keeping the vacuum degree for 15-30 min, shutting down a vacuum pump, and carrying out system emptying, centrifuging and drying to obtain the finished uniformly-crystalline quicksand-like N-acetoacetanilide product. A specific crystallization technology adopting a crystallization assistant is developed in the invention, so the product has the advantages of easiness in crystallization formation, high purity, uniform particles, good fluidity, and no agglomeration after long-term storage. The quality of downstream products is improved.

Description

technical field [0001] The invention relates to a preparation method of crystalline N-acetylacetanilide, which belongs to the field of chemical synthesis. Background technique [0002] N-Acetoacetanilide [0003] Alias: acetoacetanilide; acetylacetanilide; α-acetylacetanilide; diethylaniline [0004] English name: N-acetylaniline [0005] Appearance properties: white or light yellow powder. [0006] Solubility: Soluble in ethanol, chloroform, ether, hot benzene, hot petroleum ether, acid and alkali hydroxide solution, slightly soluble in water; [0007] CAS number: 102-01-2 [0008] Molecular formula: C10H11NO2 [0009] [0010] Molecular weight: 177.1998 [0011] Melting point (°C): 83~88 [0012] Boiling point (°C): 329 [0013] Relative density (water=1): 1.26 [0014] Relative vapor density (air=1): 6.1 [0015] Flash point (℃): 162.8 [0016] Function and use: [0017] The molecule of N-acetoacetanilide contains active methylene groups, which can be used ...

Claims

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Application Information

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IPC IPC(8): C07C231/04C07C231/24C07C235/80
CPCC07C231/04C07C231/24C07C235/80
Inventor 庆九刘芳朱小刚薛建锋
Owner NANTONG ACETIC ACID CHEM
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