JPS60104044A - Production of n-alkyl-1,2-dimethylpropylamine - Google Patents

Abstract

PURPOSE:To produce the titled compound useful as a raw material of pharmaceuticals and pesticides, easily, by the catalytic reduction of methyl isopropyl ketone and a primary amine with hydrogen in the presence of a Pd catalyst. CONSTITUTION:The objective compound of formula I can be produced by the catalytic reduction of methyl isopropyl ketone (MIPK) and a primary amine of formula R-NH2 (R is 1-4C alkyl) with hydrogen in the presence of a Pd catalyst at 50-150 deg.C. The hydrogen partial pressure of the reaction system is >=1atm, preferably 5-100atm. EFFECT:The objective compound can be produced in high selectivity, yield and purity by the use of the Pd catalyst. There occurs little side reactions, and the production of the aldol condensation product of MIPK is negligible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing N-alkyl-1,2-dimethylproylamine represented by the general formula CI) (wherein R represents an alkyl group having 1 to 4 carbon atoms) . More specifically, methyl impropyl ketone (hereinafter abbreviated as MIPK) and a primary amine represented by the general formula (II) R-NH2(II) (wherein R is the same as above) were combined in the presence of a palladium catalyst. The present invention relates to a method for producing a compound of general formula (I) by catalytic hydrogen reduction.

The compound of general formula (I) is useful as a raw material for medicines and agricultural chemicals. A conventionally known method for producing the compound of general formula (I) is 2-alkylamino-2-methylbutane-3-
The only method using ol as a starting material (G, H
enn1on chopsticks J, O, C, 302G50 (lae5
)). According to this method, the starting material is J1! The resulting N-
It is not an industrially advantageous production method because it requires a long process of hydrogenating alkyl-1,2-dimethylallylamine to produce the compound of general formula (I).

The inventors conducted extensive research on a method for catalytic hydrogen reduction of MIPK, which is generally easily available, and the primary amine of general formula (II), and found that Raney nickel, which is the most commonly used reduction catalyst, When using Raney Kobal I, the product is a complex mixture, with the general formula (I) of the desired product
The selectivity to the compound was extremely low. After further intensive study, we discovered that by using palladium as a catalyst, we were able to achieve high selectivity, high yield, and high purity with the general formula (
It was discovered that the compound I) could be obtained, and the present invention was completed.

The primary amine of general formula (II) used in the present invention is, for example, methylamine, ethylamine, propylamine, or butylamine, and the early use thereof is MI
The ratio is 0.8 to 28 moles to PK. Palladium catalysts are palladium 111 supported on a support such as alumina, silica, clay, or activated carbon.

The palladium star contained in this catalyst is traditionally 0.2 ~
It is selected within the range of l O ton - hi%. The catalyst is MI
It is used at a ratio of 0.1 to 20% by nail amount based on PK.

Next, as for the reaction conditions, the reaction pressure is preferably atmospheric pressure air -11, preferably hydrogen partial pressure of 5 to 100 atmospheres. The reaction temperature is suitably carried out at room temperature or lower, preferably within the range of 50 to 150°C. This reaction does not particularly require a solvent, or can be carried out in the presence of a solvent.

As the solvent, an inert liquid is selected under the reaction conditions, but
Typical examples include saturated hydrocarbons such as n-hexane, saturated alcohols such as methanol, cyclic ethers such as dioxane, and water.

According to the present invention, the reaction is completed in 1 to 5 hours, almost no side reactions occur, and catalytic hydrogen reduction is achieved in high yield. That is, it is an extremely advantageous production method in which a highly purified compound of general formula (I) can be obtained in a yield of 96% or more based on MI PK, and an aldol condensate of MI PK is not substantially produced. be.

Next, the present invention will be explained by giving examples. However, the present invention is not limited to this.

Example 1 MIPK258 in a 1-liter capacity electromagnetic stirring autoclave
g, 193 g of 70% ethylamine aqueous solution, and 5% P
2.6 g of d-carphone was charged, hydrogen was introduced thereto to make the pressure 20 atm, and catalytic hydrogen reduction was carried out at 60°C. As the reaction progressed, the hydrogen pressure decreased, so hydrogen was added sequentially. After 2 hours, hydrogen absorption stopped and the reaction was completed. The resulting reaction solution was filtered to remove the catalyst, separated, and the oil layer was distilled to obtain N-ethyl-1 with a purity of 99.8% (by gas chromatography, 1+t1).
, 2-dimethylpropylamine 338g (yield 98.
0%) was obtained.

Example 2 MIPK25 in a 1-liter electromagnetic stirring autoclave
8g, 40% methylamine aqueous solution 233g, 5%P
2.6 g of d-carbon was charged, hydrogen was introduced thereto to make the pressure 20 atm, and catalytic hydrogen reduction was carried out at 50°C. As the reaction progressed, the hydrogen pressure decreased, so hydrogen was added sequentially. After 1.5 hours, hydrogen absorption stopped and the reaction was completed. The mixture was then treated in the same manner as in Example 1 and 1i11 to obtain 29 g of N-methyl-1,2=nidimethylpropylamine with a purity of 99.5% (yield: -9&!36, 7%).

Distributor: Koei Chemical Industry Co., Ltd. 1

Claims (1)

[Claims] 1. General formula (1): N-alkyl-1,2-dimethylpropylamine represented by the formula % (in the formula, R represents an alkyl group having 1 to 4 carbon atoms) In producing , methyl isopropyl ketone and a primary amine represented by the general formula (II): RNH2(II) (wherein R is the same as above) are subjected to catalytic hydrogen reduction in the presence of a palladium catalyst. N-furkyl-1,
Method for producing 2-dimethylpropylamine. 2. Using the primary amine of general formula (II) in a molar ratio of 0.8 to 2 times to methyl isopropyl ketone, 50 to 1
The method according to claim 1, wherein the catalytic hydrogen quantification is carried out at a reaction temperature of 50°C. 3. The method according to claim 1, wherein the primary amine of general formula (IT) is ethylamine.