JP3325302B2 - Method for producing diamines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for producing diamines. The diamines produced in the present invention are very useful compounds as raw materials such as polyamide and bismaleimide, and as curing agents for epoxy resins, polyurethane resins or polyurea resins. It can also be used as a raw material for diisocyanate.

[0002]

2. Description of the Related Art As a method for producing diamines, the present inventors use α- (m-aminophenyl) ethylamine (hereinafter abbreviated as APA) using m-nitroacetophenone (hereinafter abbreviated as NAP) as a starting material. ) Was previously proposed (JP-A-2-145548, JP-A-3-93749).
). However, in this method of producing APA using NAP as a starting material, in the step of catalytic reduction of a nitro group and the step of catalytic reduction-amination of a carbonyl group, α- ( There is a drawback associated with by-products of (aminophenyl) alkyl alcohol, and it is important how to suppress the by-products of the general formula (V) in order to obtain a target product in good yield.

[0003]

Embedded image (Wherein, R represents a lower alkyl group having 1 to 5 carbon atoms;
₂ groups indicate o-, m- or p- position)

In the method (1), NAP is subjected to catalytic reduction of a nitro group and catalytic reduction-amination of a carbonyl group in the same vessel to obtain APA. Although this method has the advantage of simplifying the process and obtaining APA in one step,
The raw material NAP and ammonia must be separately charged using a high-pressure pump, and when the charging ratio of NAP and ammonia fluctuates, the disadvantage that the by-products of general formula (V) and high-boiling substances increase. It was with. On the other hand, in the method, NAP is converted to m-aminoacetophenone (hereinafter, AA).
This is a method for producing APA, in which a by-product is suppressed by adding a weak acid or a weak base during the reaction of catalytically reducing and aminating the compound after producing P). However, in this method, the by-product rate of the general formula (V) could not be suppressed to only about 5%.

Since the by-product of the general formula (V) has a small difference in vapor pressure from APA, it is difficult to obtain high-quality APA by simple distillation, and in order to obtain high-purity APA, rectification with a high number of theoretical plates is required. A tower was required, which was disadvantageous for industrial implementation. In particular, when the by-product of the general formula (V) is phosgenated to APA to produce a diisocyanate, the general formula (V)
I) It becomes a chlorine derivative represented by (Chem. 6). The diisocyanate containing this by-product adversely affects the reactivity between the isocyanate group and the active hydrogen compound when producing a urethane resin using the diisocyanate as a raw material. Therefore, it is very important to use high purity APA for the phosgenation reaction.

[0006]

Embedded image (Wherein, R represents a lower alkyl group having 1 to 5 carbon atoms;
O group indicates o-, m- or p- position)

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a high-purity diamine with a high yield while suppressing the generation of by-products.

[0008]

The present invention has been intensively studied in order to solve the above-mentioned problems, and as a result, the present invention has been completed. That is, the present invention provides a method for subjecting an aminophenylalkyl ketone represented by the general formula (I) to a catalytic reduction-amination reaction with hydrogen and ammonia with an alkali or alkaline earth metal hydroxide. The present invention relates to a method for producing a diamine represented by the general formula (II) (Chem. 8).

[0009]

Embedded image (Wherein, R represents a lower alkyl group having 1 to 5 carbon atoms;
₂ groups indicate o-, m- or p- position)

[0010]

Embedded image (Wherein, R represents a lower alkyl group having 1 to 5 carbon atoms;
₂ groups indicate o-, m- or p- position)

Further, the phenylalkylketones represented by the general formula (III) (formula 9) are nitrated to form a compound represented by the general formula (IV)
After converting the nitrophenyl alkyl ketones represented by the chemical formula (10), the aminophenyl alkyl ketones obtained by catalytically reducing the nitro group are subjected to catalytic reduction with hydrogen and ammonia.
The present invention relates to a method for producing diamines, in which a hydroxide of an alkali or alkaline earth metal is added during an amination reaction.

[0012]

Embedded image (Wherein, R represents a lower alkyl group having 1 to 5 carbon atoms)

[0013]

Embedded image (Wherein, R represents a lower alkyl group having 1 to 5 carbon atoms;
₂ groups indicate o-, m- or p- position)

The present inventors have conducted intensive studies and as a result, have found that the formation of α- (aminophenyl) alkyl alcohol represented by the general formula (V) is suppressed during the catalytic reduction-amination reaction of aminophenyl ketones. For this purpose, it has been found that it is extremely effective to add an alkali or alkaline earth metal hydroxide. As a result, it is not necessary to perform purification using a rectification column having a high theoretical plate number, and it has become extremely advantageous industrially, and it has become possible to obtain high-purity diamines.

In order to produce nitrophenyl ketones represented by the general formula (IV) from phenyl alkyl ketones of the general formula (III), known methods can be employed. For example, 5
Phenylalkylketone is dropped into concentrated sulfuric acid cooled to ℃, cooled to -7 ℃, mixed acid (68%-nitric acid 40vol% / concentrated sulfuric acid 60vol%) is slowly dropped to produce nitrate. [ORGANIC SYNTHESIS Col.Vo
l.II (1943)]. The aminophenyl ketones represented by the general formula (I) can be prepared in a solvent in the presence of a noble metal catalyst such as Pt, Pd, Rh or the like, as proposed by the present inventors in JP-A-3-93749. And nitrophenyl ketones can be produced in good yield by catalytic reduction.

Aminophenylketones are obtained by nitrating phenylalkylketones, completely removing the attached acid component by recrystallization or neutralization treatment, and then performing a catalytic reduction reaction to increase the reaction rate. It can be manufactured industrially advantageously. Also, in the case of unpurified nitrophenyl ketones, if the catalytic reduction reaction is performed by adding an alkali in an amount equivalent to the neutralization of the attached acid, the same effect as in the case of purification can be obtained, so the purification step is omitted You can also.

The process for producing a diamine according to the present invention comprises the step of catalytically reducing an aminophenyl ketone represented by the general formula (I) with hydrogen and ammonia in the presence of an alkali or alkaline earth metal hydroxide. This is a method of performing an amination reaction. After the production of aminophenyl ketones, the catalyst can be filtered off from the reaction solution, replaced with a new catalyst, an alkaline substance is added, ammonia and hydrogen are injected, and catalytic reduction-amination can be employed.

Examples of the alkali or alkaline earth metal hydroxide used in the present invention include hydroxides of lithium, potassium, sodium, barium, strontium, calcium, magnesium and the like. Further, in the method of the present invention, since water is generated during the reaction, a substance such as potassium carbonate or sodium carbonate which is converted into a hydroxide upon contact with water may be used. Of these, potassium hydroxide and sodium hydroxide are most suitable in view of the yield of the target product and the price. The amount used is 0.005 to 0.2 mol, preferably 0.01 to 0.1 mol, per 1 mol of the aminophenyl alkyl ketone as a raw material. If the amount of the alkali or alkaline earth metal hydroxide used is small, the formation of by-products cannot be sufficiently suppressed, and if the amount used is large, the side reaction suppression effect reaches a limit at a certain amount. Any further use will be wasted.

In the method of the present invention, liquid ammonia is used. The amount of the liquid ammonia is 1 to 10 moles, preferably 1 to 5 moles, per mole of the aminophenyl alkyl ketone as a raw material.
Is a mole. In the method of the present invention, the reaction temperature during the catalytic reduction-amination is from 80 ° C to 120 ° C, preferably 9 ° C.
0 ° C to 100 ° C. An increase in the reaction temperature is not preferred because by-products tend to increase. The hydrogen pressure is from 20 kgf / cm ² G to 100 kgf / cm ² G, preferably
The range is from 30 kgf / cm ² G to 50 kgf / cm ² G. Also in this case, if the hydrogen pressure is too high, the amount of by-products increases, which is not preferable.

As the reaction solvent in the present invention, a solvent that dissolves ammonia and a hydroxide of an alkali or alkaline earth metal well is preferable. For example, a polar solvent such as methanol, ethanol, or isopropyl alcohol is optimal. The amount used is not particularly limited, but is 1 to 20 times, preferably 2 to 10 times, per raw material. Raney nickel, Raney cobalt, nickel-diatomaceous earth, etc. are suitable as the catalytic reduction-amination catalyst in the present invention. Nickel-diatomaceous earth is particularly preferred for ease of handling.

[0021]

The present invention will be described below in more detail with reference to examples. The present invention is not limited by this. In addition, a molar ratio shows the molar ratio with respect to aminophenyl alkyl ketones. Example 1 150 ml of concentrated sulfuric acid was charged into a 1-liter four-neck glass flask equipped with a stirrer, a cooling condenser, a thermometer, and a dropping funnel, and then cooled to 5 ° C. in an ice bath. Subsequently, 60 g (0.5 mol) of acetophenone was added dropwise over 10 minutes, and salt was added to an ice bath to cool the internal temperature to -7 ° C. Next,
After mixing 40 ml (0.65 mol) of 68% nitric acid and 60 ml of concentrated sulfuric acid while cooling to prepare a mixed acid, the mixed acid was slowly added dropwise over 2 hours while maintaining the internal temperature at 0 ° C. or lower. After aging for 30 minutes, add ice water (ice)
750 g / 1.5 l of water) was added, and the reaction solution was discharged with stirring to precipitate crystals. After stirring was continued until the ice was completely melted, the mixture was filtered to separate crystals. Next, to remove the adhering acid, the crystal was washed five times with water, taken out of the crystal, added with 120 ml of cold ethanol, sludged, and separated by filtration. 180ml of ethanol to further remove attached acid
And purified by recrystallization. 45.3g after drying
Met. The purity of m-nitroacetophenone by gas chromatography was 99.5%. After charging m-nitroacetophenone 40 g (0.24 mol), methanol 160 g, and 5% Pd-C 0.24 g (solid content 51%) obtained in the above reaction to a SUS316L autoclave with a stirrer having an inner volume of 0.5 l,
After connecting to a 3 liter pressure accumulator and purging with nitrogen and hydrogen, hydrogen was injected to 5 kgf / cm ² G. Hydrogen absorption occurred simultaneously with the stirring, and the internal temperature gradually increased from 15 ° C to 50 ° C due to the heat of the reaction. Two hours after the start of the reaction, when the theoretical amount was absorbed, the hydrogen absorption was stopped, and the reaction was terminated. After cooling to room temperature, the reaction solution was taken out, and the catalyst was separated by filtration. When the filtrate was analyzed by gas chromatography, m
99.2% aminoacetophenone production, 0.
8%. Next, the same amount of filtrate, 4.9 g of stabilized Ni catalyst and KOH flakes were placed in the same autoclave as above.
0.79 g (0.05 mol ratio) was charged, and after substitution with nitrogen and hydrogen, 14.3 g (3.5 mol ratio) of liquid ammonia was charged.
The temperature was raised to 95 ° C., and after aging for 2 hours, hydrogen was injected under pressure up to 50 kgf / cm ² G. Hydrogen absorption occurred at the same time as the stirring, and the absorption of hydrogen stopped in about 9 hours, so the reaction was terminated. After cooling to room temperature, the reaction solution was taken out and the catalyst was separated by filtration. When a part of the filtrate was analyzed by gas chromatography according to the internal standard method, α- (m-aminophenyl) ethylamine formation rate was
97.0%. After removing the solvent, simple distillation at 2-3 mmHg,
α- (m-aminophenyl) ethylamine (distillation temperature 1
30.2 g (fraction at 05-110 ° C.) was obtained (yield 92.5%). The purity by gas chromatography was 99.9%.

Example 2 An autoclave made of SUS316L with a stirrer having an inner volume of 0.5 l was
After charging the reagent m-nitroacetophenone 40 g (0.24 mol), methanol 160 g and 5% Pd-C 0.24 g (solid content 51%), the mixture was connected to a 3 liter pressure accumulator, and after hydrogen substitution and hydrogen substitution, hydrogen was removed. It was press-fitted to 5 kgf / cm ² G. Hydrogen absorption occurs simultaneously with stirring, and the internal temperature gradually rises from 15 ° C to 50 ° C due to the heat of reaction.
° C. 1.5 hours after the start of the reaction, the reaction was stopped when the theoretical amount of hydrogen had been absorbed, and the reaction was terminated. After cooling to room temperature, the reaction solution was taken out, and the catalyst was separated by filtration.
When the filtrate was analyzed by gas chromatography,
The production rate of m-aminoacetophenone is 99.7%,
0.3%. The total amount of the filtrate was charged into a 0.5-liter autoclave, and 3.2 g of stabilized Ni catalyst and 0.79 g of KOH flakes were added.
(0.05 molar ratio), and after hydrogen substitution and nitrogen substitution,
14.3 g (3.5 molar ratio) of liquid ammonia was charged. Subsequently, the temperature was raised to 95 ° C., and after aging for 2 hours, hydrogen was injected under pressure up to 50 kgf / cm ² G. At the same time as the stirring, absorption of hydrogen occurred, and after about 9 hours, the absorption of hydrogen was stopped, and the reaction was terminated. After cooling to room temperature, the reaction solution was taken out and the catalyst was separated by filtration.
When a part of the filtrate was analyzed by gas chromatography by an internal standard method, the yield of α- (m-aminophenyl) ethylamine was 98.2%. After removing the solvent, simple distillation was performed at 2-3 mmHg to obtain 30.7 g of α- (m-aminophenyl) ethylamine (a fraction having a distillation temperature of 105 to 110 ° C.) (yield 94.0%).
%). The purity by gas chromatography was 100%.

Example 3 By operating in the same manner as in Example 2, m-aminoacetophenone was synthesized. The entire amount of the filtrate was charged into a 0.5-liter autoclave, and 3.2 g of stabilized Ni catalyst and 0.49 g of NaOH flakes were prepared.
(0.05 molar ratio), and after hydrogen substitution and nitrogen substitution,
14.3 g (3.5 molar ratio) of liquid ammonia was charged. Subsequently, the temperature was raised to 95 ° C., and after aging for 2 hours, 50 kgf / cm ² G of hydrogen was added.
Press-fitted. Hydrogen absorption occurs at the same time as stirring, and about 9
At time, the reaction was terminated because the absorption of hydrogen ceased. After cooling to room temperature, the reaction solution was taken out and the catalyst was separated by filtration. When a part of the filtrate was analyzed by gas chromatography by an internal standard method, the yield of α- (m-aminophenyl) ethylamine was 97.3%. After removing the solvent, simple distillation was performed at 2-3 mmHg to obtain 30.4 g of α- (m-aminophenyl) ethylamine (a fraction having a distillation temperature of 105 to 110 ° C.) (yield 9).
3.0%). The purity by gas chromatography was 99.9%.

Comparative Example 1 m-Aminoacetophenone was synthesized in the same manner as in Example 2, the whole amount of the filtrate was charged into a 0.5-liter autoclave, 3.2 g of a stabilized Ni catalyst was charged, and hydrogen substitution and After purging with nitrogen, 14.3 g (3.5 molar ratio) of liquid ammonia was charged. Subsequently, the temperature was raised to 95 ° C, and after aging for 2 hours, 50% of hydrogen was added.
It was press-fitted to kgf / cm ² G. Hydrogen absorption occurred at the same time as the stirring, and in about 7 hours, the hydrogen absorption stopped and the reaction was terminated. After cooling to room temperature, the reaction solution was taken out and the catalyst was separated by filtration. When a part of the filtrate was analyzed by gas chromatography by an internal standard method, the yield of α- (m-aminophenyl) ethylamine was 59.6%. After removing the solvent, 2-3
Simple distillation at mmHg yielded 15.7 g of α- (m-aminophenyl) ethylamine (a fraction having a distillation temperature of 105 to 110 ° C.) (yield: 48.0%). 93.5 purity by gas chromatography
%Met.

Comparative Example 2 By operating in the same manner as in Example 2, m-aminoacetophenone was synthesized. The entire amount of the filtrate was charged into a 0.5-liter autoclave, and 3.2 g of stabilized Ni catalyst, solid carbonate (dry ice) After charging 2.6 g, and after purging with hydrogen and nitrogen, 14.3 g (3.5 molar ratio) of liquid ammonia was charged. The temperature was raised to 95 ° C., and after aging for 2 hours, hydrogen was injected under pressure up to 50 kgf / cm ² G.
At about 8 hours, absorption of hydrogen occurred at the same time as the stirring, and the absorption of hydrogen stopped, so the reaction was terminated. After cooling to room temperature, the reaction solution was taken out and the catalyst was separated by filtration. When a part of the filtrate was analyzed by gas chromatography using the internal standard method, α
-(M-aminophenyl) ethylamine formation rate is 94.0%
Met. After removal of the solvent, α-
(M-aminophenyl) ethylamine (distillation temperature 105 ~
29.5 g (fraction at 110 ° C.) was obtained (yield 90.2%). The purity by gas chromatography was 99.1%.

Example 4 The same operation as in Example 1 was carried out except that 60 g (0.5 mol) of acetophenone was changed to 67 g (0.5 mol) of propiophenone.
53.7 g of m-nitropropiophenone were obtained. The purity by gas chromatography was 99.6%. Next, in a SUS316L autoclave with a stirrer having an inner volume of 0.5 l, m-nitropropiophenone 43 g (0.
24 mol), methanol 172 g, 5% Pd-C 0.25 g (solid content 51%)
, And connected to a 3 liter pressure accumulator. After nitrogen replacement and hydrogen replacement, hydrogen was injected to 5 kgf / cm ² G. Hydrogen absorption occurred simultaneously with the stirring, and the internal temperature gradually increased from 15 ° C to 50 ° C due to the heat of the reaction. Two hours after the start of the reaction, the hydrogen absorption was stopped when the theoretical amount was absorbed, so the reaction was terminated. After cooling to room temperature, the reaction solution was taken out, and the catalyst was separated by filtration. When the filtrate was analyzed by gas chromatography, the production rate of m-aminopropiophenone was 99.4%.
% And by-products were 0.6%. Then, 0.5 l same as above
In an autoclave, the total amount of filtrate and 5.3 g of stabilized Ni catalyst,
Add 0.79 g (0.05 molar ratio) of KOH flakes as an additive, replace with nitrogen and hydrogen, and add 14.3 liquid ammonia.
g (3.5 molar ratio). Subsequently, the temperature was raised to 95 ° C., and after aging for 2 hours, hydrogen was injected under pressure up to 50 kgf / cm ² G. At about 8 hours, absorption of hydrogen occurred at the same time as the stirring, and the absorption of hydrogen stopped, so the reaction was terminated. After cooling to room temperature, the reaction solution was taken out and the catalyst was separated by filtration. After removing the solvent, simple distillation was performed at 1-2 mmHg to obtain 32.8 g of α- (m-aminophenyl) propylamine (a fraction having a distillation temperature of 110 to 125 ° C.) (yield 9).
1.0%). The purity by gas chromatography was 99.8%.

Example 5 Except that 40 g (0.24 mol) of m-nitroacetophenone of the reagent of Example 2 was changed to p-nitroacetophenone of the reagent,
The same operation was performed to synthesize p-aminoacetophenone.
The purity by gas chromatography was 99.4%.
Next, the whole amount of the filtrate was charged into a 0.5 l autoclave, and 3.2 g of stabilized Ni catalyst and 0.79 g (0.05 g) of KOH flakes were added.
, And after substitution with hydrogen and nitrogen, 14.3 g (3.5 molar ratio) of liquid ammonia was charged. Subsequently, 95 ° C
After aging for 2 hours, hydrogen was injected under pressure up to 50 kgf / cm ² G. Hydrogen absorption occurred at the same time as the stirring, and in about 12 hours, the hydrogen absorption stopped and the reaction was terminated. After cooling to room temperature, the reaction solution was taken out and the catalyst was separated by filtration. When a part of the filtrate was analyzed by gas chromatography using the internal standard method,
The production rate of α- (p-aminophenyl) ethylamine was 95.3.
% Met. After removing the solvent, simple distillation at 4-5 mmHg
(P-aminophenyl) ethylamine (distillation temperature 120 ~
30.2 g (fraction at 125 ° C.) was obtained (yield 92.5%). The purity by gas chromatography was 99.8%.

[0028]

According to the method of the present invention, a side reaction is suppressed by adding an alkaline substance at the time of catalytic reduction-amination of aminophenyl ketones, and diamines having high purity and high yield can be obtained. It makes it possible to manufacture. Accordingly, the present invention provides an industrially extremely advantageous method for producing diamines.

Continuation of the front page (56) References JP-A-3-93749 (JP, A) JP-A-61-293969 (JP, A) JP-A-60-248647 (JP, A) JP-A-5-208940 (JP) (A) JP-A-2-145548 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 211/49 C07C 209/26 CA (STN) CASREAT (STN) REGISTRY (STN)

Claims (4)

(57) [Claims] 1. An aminophenyl alkyl ketone represented by the general formula (I): ## STR1 ## (Wherein, R represents a lower alkyl group having 1 to 5 carbon atoms;
_{(The two} groups indicate o-, m- or p-positions.) Hydrogen and ammonia, which are characterized by adding an alkali or alkaline earth metal hydroxide during the catalytic reduction-amination reaction. Formula (II) (Formula 2) (Wherein, R represents a lower alkyl group having 1 to 5 carbon atoms;
_Two groups indicate the position of o-, m- or p-). 2. The method according to claim 1, wherein the aminophenylalkyl ketone is m-aminoacetophenone. 3. The aminophenylalkyl ketone is a phenylalkylketone represented by the general formula (III): (Wherein R represents a lower alkyl group having 1 to 5 carbon atoms), which is nitrated to be represented by the general formula (IV). (Wherein, R represents a lower alkyl group having 1 to 5 carbon atoms;
_The method for producing diamines according to claim 1, wherein the _two groups are obtained by subjecting nitrophenyl alkyl ketones to catalytic reduction with nitrophenyl alkyl ketones. 4. The method for producing a diamine according to claim 2, wherein the m-aminoacetophenone is obtained by catalytically reducing m-nitroacetophenone.