JP2740828B2 - Method for producing N, N-diisopropylethylamine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to N, N-diisopropylethylamine (hereinafter referred to as D
In particular, the method for producing IPEA) uses ethylamine and acetone as starting materials, a method for producing DIPEA by a catalytic reduction reaction in the presence of a noble metal catalyst, and diisopropylamine (hereinafter referred to as DIPA) and acetaldehyde as starting materials. DI by performing catalytic reduction reaction while supplying acetaldehyde into the reaction system in the presence of a noble metal catalyst
It relates to the manufacturing method of PEA. DIPEA is a useful compound as a raw material for medical and agricultural chemicals.

(Prior Art and Problems to be Solved by the Invention) Conventionally, as a method for producing DIPEA, a method of ethylating DIPA with diethyl sulfate is known (Chem. Ber., 91 , 380-39).
2 (1958)). According to this method, DIPA as a raw material and DIPEA as a target substance are charged in equimolar amounts to a reactor, and diethyl sulfuric acid is added thereto, and the mixture is reacted at 140 ° C. for 3.5 hours to obtain DIPEA with a yield of 90%. However, although this method has a high yield, it is hard to say that it is an industrially advantageous method such as adding a target substance to promote the reaction. As another production method, DIPA is ethylated with ethyl iodide (JOC, 16 , 1911).
(1951)), but the yield is as low as about 50%, which is not a preferable method.

It is an object of the present invention to use DIPE using inexpensive raw materials.
An object of the present invention is to provide a method for obtaining A in good yield.

(Means for Solving the Problems) The first invention of the present invention is characterized in that ethylamine and acetone are subjected to a catalytic reduction reaction in the presence of a noble metal catalyst.
It is a manufacturing method of DIPEA.

Further, a second invention of the present invention is a method for producing DIPEA, wherein DIPA and acetaldehyde are subjected to catalytic reduction reaction in the presence of a noble metal catalyst to perform DIPEA, while reacting while supplying acetaldehyde into the reaction system. .

Conventionally, the method of the first invention has not been known surprisingly. The reason is that when an isopropyl group is introduced into ethylamine by catalytic reduction with acetone, the introduction of one isopropyl group is relatively easy, but the introduction of another isopropyl group is based on the intermediate N-isopropyl. It is presumed that this was thought to be difficult due to a decrease in the activity of the nitrogen atom caused by steric hindrance by the alkyl group of ethylamine (hereinafter referred to as MIPEA).

Therefore, the present inventor tried a catalytic reduction reaction of ethylamine and acetone using a Raney Ni catalyst which is extremely widely used as a hydrogenation catalyst, but the main product is isopropyl alcohol, which is a reduced form of acetone, and DIPEA Almost no formation was observed. The inventor has
As a result of further studies, it was surprisingly found that the use of a noble metal catalyst significantly improved the yield of DIPEA, and completed the first invention of the present invention.

In the production of a tertiary amine by a catalytic reduction reaction of a secondary amine and an aldehyde as in the second invention of the present invention,
Generally, a method is employed in which all of the secondary amine and the aldehyde are charged in an autoclave and a catalytic reduction reaction is carried out in the presence of a hydrogenation catalyst. However, DIPE by the catalytic reduction reaction of diisopropylamine and acetaldehyde
In the production of A, in such a general method, acetaldehyde causes a reaction other than the object of the present invention in any of the noble metal catalyst and Raney Ni catalyst, and the yield of DIPEA is extremely low or the generation of DIPEA is hardly recognized. .
As described above, in the conventional method, DIPE
A cannot be obtained in good yield.

Therefore, the present inventor has conducted intensive studies and, as a result, surprisingly, by performing the catalytic reduction reaction of DIPA and acetaldehyde while supplying the raw material acetaldehyde in the presence of a noble metal catalyst, the yield of DIPEA was improved. Was found to be significantly improved, and the second invention of the present invention was completed. By the way, even if the catalytic reduction reaction of DIPA and acetaldehyde is performed while supplying the raw material acetaldehyde to the reaction system in the presence of the Raney Ni catalyst, the main product is ethyl alcohol, a reduced form of acetaldehyde, and DIPEA
Can hardly be recognized.

In the second invention, it is important to use a noble metal catalyst as the hydrogenation catalyst and to perform the catalytic reduction reaction while supplying acetaldehyde into the reaction system.

Examples of the noble metal catalyst used in the method of the present invention include commonly used noble metal catalysts for hydrogenation, and specific examples thereof include palladium-carbon, ruthenium-carbon, rhodium-carbon, platinum-carbon and the like. The amount of the noble metal catalyst used is preferably in the range of 1 to 20% by weight based on ethylamine or diisopropylamine from the viewpoint of reaction efficiency and catalyst efficiency.

 The method of the first invention of the present invention will be further described.

The amount of acetone used is usually twice that of ethylamine.
The reaction proceeds suitably when used in an excess of 30 moles, preferably 4 to 16 moles. If the amount of acetone used is less than twice the amount of ethylamine, the production rate of MIPEA is higher than that of DIPEA.

Ethylamine can be subjected to the reaction as an aqueous solution. Industrially available as ethylamine aqueous solution
70% products are used.

The reaction of the first invention of the present invention can be produced at a relatively low temperature.
DIPEA is generated via MIPEA. According to one preferred embodiment of the first invention of the present invention, ethylamine, acetone and a noble metal catalyst are charged into an autoclave, and while introducing hydrogen, 100 to 180 ° C, preferably 130 to 160 ° C.
C., and the introduction of hydrogen may be continued at a normal pressure or higher, preferably 5 to 60 atm while maintaining the temperature. After 3 to 10 hours from the start of hydrogen introduction, absorption of hydrogen ends, and ethylamine is almost consumed. In another preferred embodiment, MIPEA is produced and isolated by performing a catalytic reduction reaction of ethylamine and acetone at room temperature to about 90 ° C in the presence of a noble metal catalyst,
Then, isolated MIPEA and acetone were added in the presence of a noble metal catalyst.
A catalytic reduction reaction at 00 to 180 ° C, preferably 130 to 160 ° C,
There are two-step methods such as manufacturing IPEA.

Further, in the method of the first invention of the present invention, MIPEA contained in the reaction solution can be induced to DIPEA by isolating from the reaction solution and subjecting it to a catalytic reduction reaction with acetone in the presence of a noble metal catalyst.

Next, the method of the second invention of the present invention will be further described.

The acetaldehyde to be supplied into the reaction system is preferably used in a theoretical amount or an excess of 1 to 2.0 times mol of DIPA. Since acetaldehyde has a low boiling point, it is easier to operate when diluted with a solvent and supplied. As the solvent, water or an organic solvent inert to amine and acetaldehyde can be used, but water having good operability in post-treatment is preferable. The amount of the solvent is not particularly limited, but is preferably 0.5 to 3 times the weight of acetaldehyde in consideration of production efficiency.

The reaction temperature is usually from room temperature to 200 ° C, preferably from 70 to 150 ° C. The reaction pressure is not lower than normal pressure and preferably 5 to 60 atm. A feed time of acetaldehyde of 1 to 6 hours is sufficient and DIPA is almost consumed.

DIPEA produced by the method of the present invention can be obtained very easily and in high purity by a common isolation and purification means, for example, by removing the catalyst from the reaction solution by filtration and distilling the filtrate.

The method of the present invention will be described with reference to Examples and Comparative Examples,
The present invention is not limited to these examples.

(Example) Example 1 A 70% ethylamine aqueous solution 64 g (1.0 mol), acetone 464 g (8.0 mol) and palladium-carbon 6.4 g were charged into a 1-volume electromagnetic stirring type autoclave, and hydrogen was introduced into this and heated. The temperature was raised to 160 ° C. and 50 atm, and the catalytic reduction reaction was performed. Next, while maintaining the temperature and the pressure, introduction of hydrogen was continued to perform a catalytic reduction reaction. Hydrogen absorption was completed 7 hours after the start of hydrogen introduction. After cooling the reaction solution, filtration was performed to remove the catalyst, and the filtrate was distilled to obtain DIPEA 82.
8 g (64.2% yield) and 20.3 g (23.3% yield) of MIPEA were obtained.

Example 2 The reaction and post-treatment were carried out in the same manner as in Example 1 except that the reaction temperature was changed to 180 ° C., and 57.7 g of DIPEA (44.7% yield) was obtained.
And 29.6 g of MIPEA (34.0% yield).

Example 3 The reaction and post-treatment were carried out in the same manner as in Example 1 except that the 70% ethylamine aqueous solution was replaced by 45 g (0.7 mol) and the acetone by 487 g (8.4 mol), and 60.8 g of DIPEA (yield: 67.3).
%) And 12.0 g of MIPEA (19.7% yield).

Example 4 The reaction and post-treatment were performed in the same manner as in Example 1 except that the reaction temperature was changed to 70 ° C except that the reaction temperature was changed to 70 ° C, and 257 g (4 mol) of a 70% ethylamine aqueous solution, 232 g (4 mol) of acetone, and 3.5 g of palladium-carbon were used. This gave 334.4 g of MIPEA (96.1% yield).
The hydrogen absorption was completed 4 hours after the start of hydrogen introduction.

Then, 100 g (1.15 mol) of the obtained MIPEA, acetone 3
33 g (5.75 mol) and 7.4 g of palladium-carbon were charged into a magnetic stirring autoclave having a capacity of 1 and subjected to a catalytic reduction reaction at 160 ° C. and 40 atm for 5 hours while introducing hydrogen into the autoclave. After cooling the reaction solution, the mixture was filtered to remove the catalyst, and
The filtrate was distilled and 105.9 g of DIPEA (71.4% yield) was obtained.
8.4 g of IPEA (8.4% recovery) was obtained.

Example 5 202 g of DIPA in a magnetic stirring autoclave having a capacity of 1
(2.0 mol) and 12.9 g of palladium-carbon,
Hydrogen was introduced into this and heated to 120 ° C. and 25 atm. Then, a catalytic reduction reaction was performed while supplying 184 g (2.1 mol) of a 50% acetaldehyde aqueous solution to the autoclave over 3 hours by using a high-pressure metering pump and maintaining hydrogen at 25 atm. After cooling the reaction solution, filtration was performed to separate the catalyst, and the oil layer of the filtrate separated into two layers was distilled to obtain 210.0 g of DIPEA.
(Yield 81.4%) and 17.8g of unreacted DIPA (8.8% recovery)
Obtained. In addition, 10.4 g (10.8% yield) of ethanol was produced as a by-product.

Example 6 Palladium-carbon was reacted and worked up in the same manner as in Example 5 except that 7.7 g of palladium and 228 g (2.6 mol) of 50% acetaldehyde aqueous solution were used, and 236.1 g of DIPEA was used.
(Yield 91.5%), 0.6g unreacted DIPA (recovery 0.3%)
And there were few left. 10.5g of other ethanol
(8.8% yield).

Comparative Example 1 DIPA202g in a magnetic stirring autoclave with a capacity of 1
(2.0 mol), 184 g (2.1 mol) of a 50% aqueous solution of acetaldehyde and 7.7 g of palladium-carbon were subjected to a catalytic reduction reaction at 120 ° C. and 25 atm while introducing hydrogen thereinto. Was stopped and the reaction was completed. After cooling the reaction solution, filtration was performed to separate the catalyst, and the oil layer of the filtrate separated into two layers was distilled to obtain 23.5 g of DIPEA (yield 9.1%) and 68.3 g of unreacted DIPA (recovery rate of 33.8%). %)Obtained. In addition, many high-boiling substances were by-produced.

Comparative Example 2 The reaction and post-treatment were carried out in the same manner as in Example 6, except that 52 g of Raney Ni was used instead of palladium-carbon. DIPEA
Was a trace, and 194.9 g of unreacted DIPA (recovery rate 96.5%) and 118 g of ethanol (yield 98.7%) were obtained.

(Effects of the Invention) According to the first and second inventions of the present invention, DIPEA can be obtained at a good yield with less expensive raw materials than the conventional method.

Claims (1)

(57) [Claims] 1. A process for producing N, N-diisopropylethylamine, comprising subjecting ethylamine and acetone to a catalytic reduction reaction in the presence of a noble metal catalyst.