CN101328132B

CN101328132B - Continuous production method of N,N-dimethylacetamide

Info

Publication number: CN101328132B
Application number: CN 200810041082
Authority: CN
Inventors: 詹家荣; 宋振
Original assignee: Shanghai Chemical Reagent Research Institute SCRRI
Current assignee: Shanghai San'aisi Reagent Co., Ltd.
Priority date: 2008-07-28
Filing date: 2008-07-28
Publication date: 2013-12-25
Anticipated expiration: 2028-07-28
Also published as: CN101328132A

Abstract

The invention discloses a method for continuously producing N, N-dimethylacetamide. The method takes trimethyl amine and carbon monoxide as raw materials and takes DMAC as a reaction solvent. The raw materials and the DMAC are subjected to carbonyl synthesis in the presence of catalysts of rhodium trichloride and iridium chloride and a cocatalyst of methyl iodide; and the reaction mixture is subjected to distillation and rectification so that the target product of N, N-dimethylacetamide with a purity more than 99.5 percent is produced continuously. Compared with the prior art, the method greatly reduces the separating difficulty of the reaction mixture, can recycle low boiling point cut fraction raw material of trimethyl amine which is not converted, reduces the pollution to the environment, has low production cost and high purity of the product, and ensures that the continuous production of the N, N-dimethylacetamide is realized.

Description

The continuous production method of N,N-dimethylacetamide

Technical field

The present invention relates to a kind of continuous production method of N,N-dimethylacetamide, refer to more specifically a kind of can be continuously produced, obtain the production method of N,N-dimethylacetamide based on oxo process.

Background technology

N, N-N,N-DIMETHYLACETAMIDE (being called for short DMAC) is a kind of important organic synthesis intermediate and good polar solvent, its Heat stability is good, facile hydrolysis not, toxicity is little, and corrodibility is low, and various kinds of resin is had to good dissolving power, application is very widely arranged at aspects such as petrochemical complex and organic syntheses, and its structural formula is as follows:

In prior art, the clear 46-43526 of Japanese Patent Publication has reported that with Trimethylamine 99 be raw material, cobalt octacarbonyl or cobalt are catalyzer, acetonitrile or propionitrile are promotor, in the temperature range of 240-270 ℃, with carbon monoxide, reacted, then isolate unreacted raw material Trimethylamine 99 from reaction product, obtain reaction product DMAC.Owing to using acetonitrile or interior nitrile, introduced different compounds, increased the separating difficulty of reaction product.

U.S. Pat: 3407231 have reported that take Trimethylamine 99 and carbon monoxide is raw material, iron, and cobalt, the iodide of nickel or bromide are catalyzer, under nitrogen atmosphere, 225 ℃ of reactions 16 hours, obtain reaction product DMAC.This reaction process is rhythmic reaction, and without separation system, long reaction time, the raw material Trimethylamine 99 is loaded down with trivial details with the receipts process.

DMAC oxo process technology still is confined to laboratory stage, and industrialization quantity-produced report is not arranged, and therefore, need to have a kind of easy and simple to handlely, and good separating effect, be suitable for the method for suitability for industrialized production.

Summary of the invention

The technical problem that the present invention solves is to provide a kind of continuous production method of N,N-dimethylacetamide, undesirable to overcome in prior art reaction product DMAC separating effect, reaction process is rhythmic reaction, without separation system, removal process is loaded down with trivial details, is difficult to the deficiency that serialization is produced.

Technical conceive of the present invention is such: take Trimethylamine 99, carbon monoxide is raw material, DMAC is reaction solvent, at rhodium chloride, iridium chloride catalyzer, the methyl iodide promotor carries out oxo process under existing, reaction mixture is through distillation, rectifying, serialization obtains the target product N,N-dimethylacetamide.

Reaction equation of the present invention is as follows:

Production method of the present invention comprises the steps:

Trimethylamine 99-DMAC solution is added in zirconium material autoclave, add rhodium chloride under-20--10 ℃, the iridium chloride catalyzer, the methyl iodide promotor, be pressed into 25-30kg/cm ²carbon monoxide carries out oxo process at the temperature of 245-265 ℃, reaction 3.5-4.5 hour, and in reaction process, the carbon monoxide top pressure is 50-65kg/cm ², the reaction mixture obtained is through distillation, rectifying, and serialization obtains the target product N,N-dimethylacetamide.

According to the present invention, said Trimethylamine 99 refers to the trimethylamine aqueous solution that concentration expressed in percentage by weight is 25-33%, and preferably the concentration expressed in percentage by weight of Trimethylamine 99 is 30%.Said Trimethylamine 99-DMAC solution is 1 according to the mol ratio mol/mol of Trimethylamine 99 and DMAC reaction solvent: the ratio of 1.5-2.5 is formulated.

The said rhodium chloride of the present invention, the iridium chloride catalyzer, the consumption of methyl iodide promotor is Trimethylamine 99: rhodium chloride: iridium chloride: methyl iodide=1000: 5-15: 3-6: 50-100, mmol/mmol.

Reaction mixture of the present invention is through distillation, rectifying, and serialization obtains the target product N,N-dimethylacetamide and comprises the steps: that reaction mixture is in room temperature, 4-6kg/cm ²still is depressed and is pressed into the still kettle distillation, low boiler cut (mainly containing the raw material Trimethylamine 99) returns to zirconium material autoclave recycled through transfer tank, and high boiling fraction, through rectifying, is collected the cut of 164-166 ℃, serialization obtains the target product N,N-dimethylacetamide.

The N,N-dimethylacetamide purity obtained by production method of the present invention reaches more than 99.5%, with the raw material Trimethylamine 99, calculates, and transformation efficiency is 85-95%.

Beneficial effect:

Changed the present situation that not yet realizes in the prior art that serialization is produced, the serialization production of N,N-dimethylacetamide is become a reality.

Take DMAC as reaction solvent, greatly reduce the separating difficulty of reaction mixture, in production process, capable of circulation the applying mechanically of unconverted low boiler cut raw material Trimethylamine 99, reduced the pollution to environment, and production cost is low, and good product purity is suitable for suitability for industrialized production.

The accompanying drawing explanation

Fig. 1 is production technological process of the present invention, and wherein 1 is zirconium material autoclave; 2 is still kettle; 3 is rectifying still; 4 is transfer tank.

Embodiment

Below by embodiment, the invention will be further described, but embodiment does not limit the scope of the invention.

Embodiment 1

By be chilled in advance-20--10 ℃ of 200L zirconium material autoclave, add respectively the 15.34kg30wt% Trimethylamine 99 (containing Trimethylamine 99 4.6kg, 78mol) with 15L DMAC (14.1kg, 162mol) the reaction solvent preparation obtains Trimethylamine 99-DMAC solution, rhodium chloride 120g, iridium chloride 120g, (corresponding Trimethylamine 99 1mol adds 7.4mmol to methyl iodide 800g respectively, 5.2mmol, 72.3mmol), stir and be pushed down into 25kg/cm ²cO (carbon monoxide converter) gas, heat temperature raising, control 250-260 ℃ of reaction of temperature 4 hours gradually, and in reaction process, the carbon monoxide top pressure is 50kg/cm ²; Reactor is cooled to room temperature, when the still internal pressure is down to 5kg/cm ²the time, by pressure pump, reaction mixture being pressed into to still kettle is distilled, collect the low boiler cut (mainly containing the raw material Trimethylamine 99) of 100 ℃, push back zirconium material autoclave by transfer tank, high boiling fraction after filtration, the solid-phase catalyst obtained reclaims after concentrating, liquid phase is pressed into rectifying still and carries out rectifying, collect the cut of 164-166 ℃, obtain target product N,N-dimethylacetamide 5.79kg (having deducted the DMAC added as reaction solvent), purity 99.61% (analyzing by the GC marker method), with the raw material Trimethylamine 99, calculate, transformation efficiency is 85.1%.

Embodiment 2

In the 200L zirconium material autoclave of be chilled in advance-20--10 ℃, add in embodiment 1 containing the low boiler cut of raw material Trimethylamine 99 and the Trimethylamine 99 of embodiment 1 identical proportioning-DMAC solution, this Trimethylamine 99-DMAC solution sampling is analyzed, actual in Trimethylamine 99 6.18kg (105mol), add rhodium chloride 120g, iridium chloride 100g, (corresponding Trimethylamine 99 1mol adds 5.5mmol to methyl iodide 800g respectively, 3.2mmol, 53.8mmol), stir and be pushed down into 25kg/cm ²cO (carbon monoxide converter) gas, heat temperature raising, control 255-265 ℃ of reaction of temperature 3.5 hours gradually, and in reaction process, the carbon monoxide top pressure is 60kg/cm ²; Reactor is cooled to room temperature, when the still internal pressure is down to 5.5kg/cm ²in time, is pressed into still kettle by pressure pump by reaction mixture and distilled, collect the low boiler cut (mainly containing the raw material Trimethylamine 99) below 100 ℃, push back zirconium material autoclave by transfer tank, high boiling fraction after filtration, the solid-phase catalyst obtained reclaims after concentrating, liquid phase is pressed into rectifying still and carries out rectifying, collect the cut of 164-166 ℃, obtain target product N, N-N,N-DIMETHYLACETAMIDE 8.23kg (having deducted the DMAC added as reaction solvent), purity 99.58% (analyzing by the GC marker method), calculate with the raw material Trimethylamine 99, and transformation efficiency is 90.0%.

Embodiment 3

In the 200L zirconium material autoclave of be chilled in advance-20--10 ℃, add in embodiment 2 containing the low boiler cut of raw material Trimethylamine 99 and the Trimethylamine 99 of embodiment 1 identical proportioning-DMAC solution, this Trimethylamine 99-DMAC solution sampling is analyzed, actual in Trimethylamine 99 5.1kg (86.5mol), add rhodium chloride 200g, iridium chloride 120g, (corresponding Trimethylamine 99 1mol adds 11.1mmol to methyl iodide 1000g respectively, 4.7mmol, 81.5mmol), stir and be pushed down into 28kg/cm ²cO (carbon monoxide converter) gas, heat temperature raising, control 245-255 ℃ of reaction of temperature 4 hours gradually, and in reaction process, the carbon monoxide top pressure is 65kg/cm ²; Reactor is cooled to room temperature, when the still internal pressure is down to 5.5kg/cm ²in time, is pressed into still kettle by pressure pump by reaction mixture and distilled, collect the low boiler cut (mainly containing the raw material Trimethylamine 99) below 100 ℃, push back zirconium material autoclave by transfer tank, high boiling fraction after filtration, the solid-phase catalyst obtained reclaims after concentrating, liquid phase is pressed into rectifying still and carries out rectifying, collect the cut of 164-166 ℃, obtain target product N, N-N,N-DIMETHYLACETAMIDE 6.38kg (having deducted the DMAC added as reaction solvent), purity 99.65% (analyzing by the GC marker method), calculate with the raw material Trimethylamine 99, and transformation efficiency is 95.0%.

Embodiment 4

By be chilled in advance-20--10 ℃ of 200L zirconium material autoclave, add respectively the 18.4kg25wt% Trimethylamine 99 (containing Trimethylamine 99 4.6kg, 78mol) with 15L DMAC (14.1kg, 162mol) the reaction solvent preparation obtains Trimethylamine 99-DMAC solution, rhodium chloride 120g, iridium chloride 120g, (corresponding Trimethylamine 99 1mol adds 7.4mmol to methyl iodide 800g respectively, 5.2mmol, 72.3mmol), stir and be pushed down into 25kg/cm ²cO (carbon monoxide converter) gas, heat temperature raising, control 250-260 ℃ of reaction of temperature 4 hours gradually, and in reaction process, the carbon monoxide top pressure is 50kg/cm ²; Reactor is cooled to room temperature, when the still internal pressure is down to 5kg/cm ²the time, by pressure pump, reaction mixture being pressed into to still kettle is distilled, collect the low boiler cut (mainly containing the raw material Trimethylamine 99) below 100 ℃, push back zirconium material autoclave by transfer tank, after filtration, the solid-phase catalyst obtained reclaims after concentrating high boiling fraction, liquid phase is pressed into rectifying still and carries out rectifying, collect the cut of 164-166 ℃, obtain the target product N,N-dimethylacetamide.

Embodiment 5

Add in embodiment 4 containing the low boiler cut of raw material Trimethylamine 99 and the Trimethylamine 99 of embodiment 4 identical proportionings-DMAC solution, the catalyzer of embodiment 2 identical proportionings, be pressed into carbon monoxide and reacted, and operation steps is identical with embodiment 4, obtain the target product N,N-dimethylacetamide.

Embodiment 6

Add in embodiment 5 containing the low boiler cut of raw material Trimethylamine 99 and the Trimethylamine 99 of embodiment 4 identical proportionings-DMAC solution, the catalyzer of embodiment 3 identical proportionings, be pressed into carbon monoxide and reacted, and operation steps is identical with embodiment 4, obtain the target product N,N-dimethylacetamide.

GC marker method analysis for the target product N,N-dimethylacetamide that embodiment 4-6 obtains, purity all is greater than 99.5%, with the raw material Trimethylamine 99, calculates, and transformation efficiency is more than 85%.

Claims

1. the continuous production method of a N,N-dimethylacetamide, is characterized in that comprising the steps:

Trimethylamine 99-DMAC solution is added in zirconium material autoclave, add rhodium chloride under-20--10 ℃, the iridium chloride catalyzer, the methyl iodide promotor, be pressed into 25-30kg/cm ²carbon monoxide carries out oxo process at the temperature of 245-265 ℃, reacts 3.5-4.5 hours, and in reaction process, the carbon monoxide top pressure is 50-65kg/cm ², the reaction mixture obtained is in room temperature, 4-6kg/cm ²still is depressed and is pressed into the still kettle distillation, and low boiler cut returns to zirconium material autoclave recycled through transfer tank, and high boiling fraction, through rectifying, is collected the cut of 164-166 ℃, and serialization obtains the target product N,N-dimethylacetamide,

Wherein, the ratio that the mol ratio of Trimethylamine 99 and DMAC reaction solvent is 1:1.5-2.5 is formulated.

2. method according to claim 1, is characterized in that, said Trimethylamine 99 refers to the trimethylamine aqueous solution that concentration expressed in percentage by weight is 25-33%.

3. method according to claim 2, is characterized in that, the concentration expressed in percentage by weight of said Trimethylamine 99 is 30%.

4. method according to claim 1, is characterized in that, said rhodium chloride, and the iridium chloride catalyzer, the consumption of methyl iodide promotor is Trimethylamine 99: rhodium chloride: iridium chloride: methyl iodide=1000:5-15:3-6:50-100, mmol/mmol.