CN101092374A - Method for synthesizing N,N dimethyl acetamide in high purity - Google Patents
Method for synthesizing N,N dimethyl acetamide in high purity Download PDFInfo
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- CN101092374A CN101092374A CN 200610090011 CN200610090011A CN101092374A CN 101092374 A CN101092374 A CN 101092374A CN 200610090011 CN200610090011 CN 200610090011 CN 200610090011 A CN200610090011 A CN 200610090011A CN 101092374 A CN101092374 A CN 101092374A
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- acetic acid
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- dimethylamine
- amine salt
- acid amine
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Abstract
This invention relates to a method for continuously synthesizing high-purity N,N-dimethylacetamide under normal pressure from acetic acid and dimethylamine. The method comprises: performing countercurrent contact neutralization reaction between dimethylamine and acetic acid at a mol. ratio of 1:1 at 35-55 deg.C under normal pressure to obtain ammonium acetate, continuously adding ammonium acetate into a reaction rectification column from the bottom, adding catalyst ZnCl2, ZnAc2 or MgCl2 3.2-10 wt.% of ammonium acetate when ammonium acetate is 1/4-1/3 the volume of the reaction rectification column, introducing dimethylamine by bubbling dispersion at dimethylamine/ammonium acetate ratio of (0.5-2.5):1, heating, continuously adding ammonium acetate at 150-190 deg.C, decomposing to obtain N,N-dimethylacetamide and water at the overhead, and continuously rectifying under normal pressure to obtain high-purity product. The method has such advantages as high reactant conversion rate, high selectivity, high product yield, and high product purity (higher than 99.90%).
Description
Technical field
The present invention relates to a kind of is raw material with Glacial acetic acid and dimethylamine, the method for continuous synthesis of high purity N,N-dimethylacetamide under condition of normal pressure.
Background technology
DMAC is a kind of high boiling point, strong polarity, non-protonization solvent, have strong, excellent thermostability of dissolving power and chemical stability, volatility low, not facile hydrolysis, not easy to change, characteristics such as corrodibility is low, toxicity is little, can be widely used in refining of petroleum and organic synthesis industrial circle, mainly be used as the solvent of synthon such as spandex and acrylic fibers, plastics film, coating, pharmacy, catalyzer.
Not shortcoming such as have long reaction time, production efficiency is low and product yield is low in the technology of existing preparation DMAC, have severe reaction conditions exactly, to equipment requirements height, deficiency that cost of investment is high, the process for refining complexity that also has DMAC, can not make with extra care by the method for purification of routine, need just can obtain qualified product through operations such as neutralization, filtration and distillations.It is the technology of raw material synthetic DMAC under 1～5Mpa pressure with acetic acid and dimethylamine that JP123853 (CN1298382 A) provides a kind of, it is legal to belong to high compression, the main deficiency of this technology is to need to select the high-tension unit of corrosion resistant special substance manufacturing, to the equipment requirements height, the investment cost height, and be batch technology.The DMAC synthesis technique that WO00/73251 proposes improves technology by the automatic pressure control valve, but reaction still needs to carry out under 2-10pisg pressure.Wang Xiaoli etc. are in " reaction rectification method synthesizes N,N-dimethylacetamide " of the last report of " petrochemical complex Journal of Chinese Universities " P20-23, and the technology that is adopted is semi-continuous process, product purity 95%.
Summary of the invention
The objective of the invention is to consider on the basis of the problems referred to above of prior art, providing a kind of is the synthetic N of raw material normal pressure continuous catalytic reaction rectifying with Glacial acetic acid and dimethylamine, the method of N-N,N-DIMETHYLACETAMIDE, this method has shortened traditional normal pressure condensation reaction time widely, greatly improved the yield of normal pressure condensation method reaction-ure conversion-age, selectivity and product, made quality product 〉=99.90%.
To achieve these goals, the technical solution used in the present invention is:
A kind of is the synthetic N of raw material normal pressure catalytic reaction rectification with Glacial acetic acid and dimethylamine, the continuation method of N-N,N-DIMETHYLACETAMIDE, with dimethylamine and Glacial acetic acid according to the equivalent mol ratio, join continuously in the salt-forming reaction tower, the acetic acid amine salt that reverse contact neutralization reaction generates under 35～55 ℃ of normal pressures, by joining in the reaction fractionating tower continuously at the bottom of the tower, when the acetic acid amine salt amount that adds reaches reactive distillation Tata still volume 1/4～1/3, add catalyzer, the catalyzer add-on be this moment reaction and rectification device in acetic acid amine salt gross weight 3.2～10%, feed dimethylamine in bubbling dispersive mode again, in the continuous acetic acid amine salt molar weight that adds of unit time, dimethylamine: acetic acid amine salt=0.5～2.5: 1, heat up, under 150～190 ℃ of normal pressures, add the acetic acid amine salt continuously and carry out decomposition reaction, obtain DMAC and water, obtain the DMAC product of purity 〉=99.90% again through continuous atmospheric distillation in the reactive distillation column overhead.
Above-mentioned method, the decomposition reaction temperature of its described acetic acid amine salt in reaction and rectification device is 160～180 ℃.
Above-mentioned method, its described catalyzer that Ammoniom-Acetate salt decomposition reaction is used in reaction and rectification device is zinc chloride, zinc acetate, magnesium chloride or aluminum chloride.
Above-mentioned method, unreacted dimethylamine is recovered and recycles in the reaction process, and Glacial acetic acid is transformed fully.
The mechanism of action of the present invention is:
With Glacial acetic acid and dimethylamine is raw material, synthetic DMAC under catalyst action, and reaction equation is as follows:
This be one by the N-acylation reaction of acetic acid as acylating agent.Have the part positive charge on the acyl group C atom in the acetic acid, interact, form the transition state complex compound, change into acid amides at last with not share electron pair on the N atom in the dimethylamine.
CH
3COOH+NH(CH
3)
2——→CH
3COOHNH(CH
3)
2+ΔH-----(1)
CH
3COOHNH(CH
3)
2——→CH
3CON(CH
3)
2+H
2O-ΔH-----(2)
Reaction (1) is a simple acid-base neutralisation reaction.Reaction (2) is the thermo-negative reaction that an amine salt is dehydrated into acid amides, and its caloric receptivity is the committed step of decision total reaction greater than the thermal discharge of reaction (1).According to thermomechanical analysis, in entire reaction course, improve temperature of reaction, increase the mole proportioning of raw material dimethylamine and acetic acid and in time water generation reaction is got rid of from system, all can help the generation of acid amides.
Advantage of the present invention is mainly reflected in following several respects:
1. can realize efficient normal pressure serialization production, greatly improve production efficiency, overcome in the past because of the low defective of long reaction time production efficiency.
2. compare with traditional normal pressure condensation method, adopt normal pressure catalytic reaction rectification technology, realized the part coupling of reaction and rectification cell operation, technological process is simplified, utilization of Heat of Reaction is abundant.
3. this technological process has been avoided the azeotropic problem of DMAC product and acetic acid effectively, and thick product purification is handled simple, reaction-ure conversion-age of the present invention and selectivity height, and the product yield height, product purity can reach more than 99.90%.
4. this technology waste discharge is few, environmental friendliness.
Embodiment
Embodiment 1
Glacial acetic acid and dimethylamine add 600g Glacial acetic acid and 450g dimethylamine continuously according to the equivalent mol ratio in the salt-forming reaction tower, be neutralized into reactant salt under 35～55 ℃ of normal pressures.Then, in reaction fractionating tower, add 300g salt-forming reaction product and 12g zinc chloride, heat up, enter reaction fractionating tower continuously with 50g/h salt-forming reaction product and 18L/h dimethylamine again, under 170～180 ℃ of normal pressures, carry out decomposition reaction, DMAC that decomposition generates and water get 831g DMAC product by the continuous extraction of reactive distillation column overhead through normal pressure continuous rectification purification processes, and its purity is 99.95%.
Embodiment 2
According to the same steps as of embodiment 1, except adding the 12g zinc acetate, all the other conditions remain unchanged, and have obtained 770g DMAC product, and its purity is 99.80%.
Embodiment 3
According to the same steps as of embodiment 1, except adding the 12g magnesium chloride, all the other conditions remain unchanged, and have obtained 761g DMAC product, and its purity is 99.68%.
Embodiment 4
According to the same steps as of embodiment 1, except adding 12g aluminum chloride, all the other conditions remain unchanged, and have obtained 729g DMAC product, and its purity is 99.40%.
Embodiment 5
Glacial acetic acid and dimethylamine add 10800g Glacial acetic acid and 8100g dimethylamine continuously according to the equivalent mol ratio in the salt-forming reaction tower, be neutralized into reactant salt under 35～55 ℃ of normal pressures.Then, in reaction fractionating tower, add 300g salt-forming reaction product and 12g zinc chloride, heat up, add reaction fractionating tower continuously with 100～105g/h salt-forming reaction product and 24L/h dimethylamine again, under 170～180 ℃ of normal pressures, carry out decomposition reaction, DMAC that decomposition generates and water get the DMAC product by the continuous extraction of reactive distillation column overhead through normal pressure continuous rectification purification processes.This successive reaction has been carried out 180h, and the DMAC product purity of acquisition is 99.96%, and product yield is 96.25%.
Claims (2)
1, a kind of synthesis of high purity N, the method of N-N,N-DIMETHYLACETAMIDE, it is characterized in that: with dimethylamine and Glacial acetic acid according to the equivalent mol ratio, join continuously in the salt-forming reaction tower, reverse contact neutralization reaction generates the acetic acid amine salt under 35～55 ℃ of normal pressures, continuously join in reaction fractionating tower at the bottom of by tower the acetic acid amine salt, when the acetic acid amine salt amount that adds reaches reactive distillation Tata still volume 1/4～1/3, add catalyzer, the catalyzer add-on be this moment reaction and rectification device in acetic acid amine salt gross weight 3.2～10%, feed dimethylamine in bubbling dispersive mode again, in the continuous acetic acid amine salt molar weight that adds of unit time, dimethylamine: acetic acid amine salt=0.5～2.5: 1, heat up, under 150～190 ℃ of normal pressures, add the acetic acid amine salt continuously and carry out decomposition reaction, obtain N,N-dimethylacetamide and water in the reactive distillation column overhead, obtain high purity N through continuous atmospheric distillation again, N-N,N-DIMETHYLACETAMIDE product, catalyzer are zinc chloride, zinc acetate or magnesium chloride.
2, according to claim 1 described method, the decomposition reaction temperature of its described acetic acid amine salt in reaction and rectification device is 160～180 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CNB2006100900119A CN100537521C (en) | 2006-06-23 | 2006-06-23 | Method for synthesizing N,N dimethyl acetamide in high purity |
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|---|---|---|---|
| CNB2006100900119A CN100537521C (en) | 2006-06-23 | 2006-06-23 | Method for synthesizing N,N dimethyl acetamide in high purity |
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| CN101092374A true CN101092374A (en) | 2007-12-26 |
| CN100537521C CN100537521C (en) | 2009-09-09 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103381359A (en) * | 2013-07-29 | 2013-11-06 | 张家港市大伟助剂有限公司 | Preparation method for catalyst for N,N-dimethyl-caprylamide/decanamide |
| CN104628589A (en) * | 2015-02-03 | 2015-05-20 | 天津河清化学工业有限公司 | Continuous production process and system for synthesizing N, N-dimethyl propanamide |
| CN105418447A (en) * | 2015-12-17 | 2016-03-23 | 烟台国邦化工机械科技有限公司 | DMAC (dimethylacetamide) rectification device and technique |
| CN107903183A (en) * | 2017-11-15 | 2018-04-13 | 福州大学 | Method of comprehensive utilization and device containing sour DMF solution |
| CN112521301A (en) * | 2020-12-21 | 2021-03-19 | 安徽金禾实业股份有限公司 | Synthesis device and synthesis method of DMAC (dimethylacetamide) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4139557A (en) * | 1976-12-27 | 1979-02-13 | Neduv Mikhail B | Method of preparing dimethylacetamide in presence of MoO3 catalyst |
| US4258200A (en) * | 1980-03-11 | 1981-03-24 | Air Products And Chemicals, Inc. | Production of carboxylic acid amides and carbamates using cobalt catalysts |
| CA2329241A1 (en) * | 1998-04-20 | 1999-10-28 | Mitsubishi Rayon Co., Ltd. | Process for producing dimethylacetamide |
| DE102004058888A1 (en) * | 2004-12-06 | 2006-06-08 | Basf Ag | Process for the preparation of N, N-dimethylacetamide (DMAC) |
-
2006
- 2006-06-23 CN CNB2006100900119A patent/CN100537521C/en active Active
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103381359A (en) * | 2013-07-29 | 2013-11-06 | 张家港市大伟助剂有限公司 | Preparation method for catalyst for N,N-dimethyl-caprylamide/decanamide |
| CN104628589A (en) * | 2015-02-03 | 2015-05-20 | 天津河清化学工业有限公司 | Continuous production process and system for synthesizing N, N-dimethyl propanamide |
| CN105418447A (en) * | 2015-12-17 | 2016-03-23 | 烟台国邦化工机械科技有限公司 | DMAC (dimethylacetamide) rectification device and technique |
| CN107903183A (en) * | 2017-11-15 | 2018-04-13 | 福州大学 | Method of comprehensive utilization and device containing sour DMF solution |
| CN107903183B (en) * | 2017-11-15 | 2019-11-12 | 福州大学 | Method of comprehensive utilization and device containing sour DMF solution |
| CN112521301A (en) * | 2020-12-21 | 2021-03-19 | 安徽金禾实业股份有限公司 | Synthesis device and synthesis method of DMAC (dimethylacetamide) |
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| CN100537521C (en) | 2009-09-09 |
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