Synthesis method of N, N-dimethylacetamide

A technology of dimethylacetamide and synthetic method, which is applied in the direction of carboxylic acid amide preparation, chemical instruments and methods, carboxylic acid amide separation/purification, etc., can solve the problem of low yield of DMAC, avoid azeotropic problem, simplify Process flow and the effect of less emission

Inactive Publication Date: 2014-01-22
连云港阳方催化科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In the existing method, the yield of DMAC is low, and there is a large amount of acetic acid in the product

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Embodiment 1, a kind of synthetic method of N,N-dimethylacetamide, adopts batch method to prepare, and its steps are as follows:

[0039] (1) Neutralization and salt formation: In the reactor equipped with vent pipe, thermometer, external cooling bath, and rectification column, add measured glacial acetic acid and catalyst in sequence, and then pass dimethylamine gas through flow meter, buffer bottle Pass in the reactor, carry out neutralization reaction, when the feeding amount of dimethylamine is saturated, stop neutralization reaction, obtain neutralization liquid; The mol ratio of described dimethylamine and glacial acetic acid is 1.05:1, and reaction system The temperature is 120 ℃, and the catalyst dosage is 0.5% relative to the mass fraction of raw material acetic acid; the catalyst uses Lewis acid salt A X B Y One or more of them, where A=A1 3+ , Zn 2十 , Fe 3+ , Cu + , B=Cl - , Br - , F - , SO4 2- , CH 3 COO - ;

[0040] (2) Catalyzed reaction-rectif...

Embodiment 2

[0043] Embodiment 2, a kind of synthetic method of N,N-dimethylacetamide, adopt batch method to prepare, and its steps are as follows:

[0044] (1) Neutralization and salt formation: In the reactor equipped with vent pipe, thermometer, external cooling bath, and rectification column, add measured glacial acetic acid and catalyst in sequence, and then pass dimethylamine gas through flow meter, buffer bottle Pass in the reactor, carry out neutralization reaction, when the feeding amount of dimethylamine is saturated, stop neutralization reaction, obtain neutralization liquid; The mol ratio of described dimethylamine and glacial acetic acid is 1.95:1, and reaction system The temperature is 190°C, and the catalyst dosage is 20% relative to the mass fraction of raw material acetic acid; the catalyst uses Lewis acid salt A X B Y One or more of them, where A=A1 3+ , Zn 2十 , Fe 3+ , Cu + , B=Cl - , Br - , F - , SO4 2- , CH 3 COO - ;

[0045] All the other steps are the sam...

Embodiment 3

[0046] Embodiment 3, a kind of synthetic method of N,N-dimethylacetamide, adopt batch method to prepare, and its steps are as follows:

[0047] (1) Neutralization and salt formation: In the reactor equipped with vent pipe, thermometer, external cooling bath, and rectification column, add measured glacial acetic acid and catalyst in sequence, and then pass dimethylamine gas through flow meter, buffer bottle Pass in the reactor, carry out neutralization reaction, when the feeding amount of dimethylamine is saturated, stop neutralization reaction, obtain neutralization liquid; The mol ratio of described dimethylamine and glacial acetic acid is 1.5:1, and reaction system The temperature is 150°C, and the catalyst dosage is 3% relative to the mass fraction of raw material acetic acid; the catalyst uses Lewis acid salt A X B Y One or more of them, where A=A1 3+ , Zn 2十 , Fe 3+ , Cu + , B=Cl - , Br - , F - , SO4 2- , CH 3 COO - ;

[0048] All the other steps are the same ...

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PUM

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Abstract

The invention relates to a synthesis method of N, N-dimethylacetamide. The method adopts a catalytic reaction distillation technology to improve an acetic acid catalyzed condensation method, and includes: adding well metered glacial acetic acid and a catalyst in order into a four-neck flask equipped with a vent pipe, a thermometer, an external cooling bath and a rectification column, then introducing a dimethylamine gas into a reaction bottle through a flowmeter and a buffering bottle to undergo a neutralization reaction, then adding the neutralization solution into the rectification column bottom connected with cooling water, two-stage cooling, the thermometer and the vent pipe to undergo catalytic reaction-rectification, and then employing intermittent method and continuous method to carry out secondary rectification on a DMAC crude product collected from the reaction rectification. The method provided by the invention makes use of reaction heat, and the reaction process has low energy consumption. The reaction and product separation can be accomplished in a tower, the technological process is simplified, the reaction yield and selectivity are improved, and the product purity can reach 99.7%-99.9%. Also, fewer wastes are discharged in the preparation process, and the product entrainment loss is small.

Description

technical field [0001] The invention relates to a technique for synthesizing amide compounds by reactive distillation, specifically using glacial acetic acid and dimethylamine as main raw materials, and continuously reactive distillation under normal pressure to synthesize high-purity N,N-dimethyl The method of acetamide. Background technique [0002] N,N-Dimethylacetamide (DMAC for short) is a strong polar non-protonated solvent. Compared with DMF, DMAC has lower toxicity and volatility, higher stability and less discoloration. It is widely used in petroleum Processing and organic synthesis industry. DMAC has good solubility to various resins, especially polyurethane resin, polyurethane resin, polyimide resin, etc., and can be used as a solvent for heat-resistant fibers, plastic films, coatings, pharmaceuticals, and catalysts. At present, domestic DMAC is mostly used in the production of spandex fiber, polypropylene clear spinning, polyimide film, soluble polyimide, poly...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C233/05C07C231/02C07C231/24
Inventor 高小兵沈振国姚剑
Owner 连云港阳方催化科技有限公司
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