JPS60178848A - Prduction of aminobenzylamine - Google Patents

Abstract

PURPOSE:To produce the titled compound useful as a raw material of the intermediate of agricultural chemicals and pharmaceuticals, etc., in high yield, economically in an industrial scale, by the catalytic reduction of nitrobenzaldoxime in the presence of an organic acid. CONSTITUTION:The objective compound can be produced by the catalytic reduction of the nitrobenzaldoxime of formula (nitro group is substituted to o-, m- or p-position) in the presence of an organic acid such as formic acid, using a reduction catalyst such as nickel. EFFECT:Since the activity of the catalyst can be maintained, the catalyst can be used repeatedly after recovery, and the process is extremely economical. Various intermediates such as amine, etc. produced in the reduction can be stabilized in the form of organic acid salts, and the basicity of the amino group of the organic acid salt is lowered. Accordingly, the decomposition of the product and the side reactions are suppressed, and the reduction is carried out rapidly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing aminobenzylamine, and in particular provides a method that is extremely advantageous for industrial implementation.

More specifically, the nitrobenzaldoxime represented by the general formula (1) (in which the nitro group is at the ○-position, m-position or p-position) is catalytically reduced in the presence of an organic acid. The present invention relates to a method for producing aminobenzylamine.

Aminobenzylamine is an important substance that serves as a raw material for epoxy resin curing agents, polyamides, polyimides, and agricultural and pharmaceutical intermediates.

Conventionally, aminobenzylamine is produced by a method using dil-obenzaldehyde or nitrobenzonitrile as a starting material. For example, as a method using the former as a starting material, there are the following methods.

(a) Deriving nitrobenzyl bromide from nitrobenzaldehyde, then reacting with potash 7-talimide,
N-(m-nitrobenzyl)-phthalimide was obtained, followed by a two-step reduction method to obtain 1]]-aminobenzylamine in approximately 20% yield (N, Kornbl
um et al., J, Am, Chem, Soc,, 71213
7 (1949)).

(A, 5iddiqui et al., 5ynth Co.
nnnn 7.71-78 (1977)).

(c)m-=)lovenzaldehyde)", J: Rim-nido.

Benzaldoxime was obtained, which was subjected to high-pressure catalytic reduction using a Raney nickel catalyst to give m-aminobenzylamine 5
obtained in a yield of 2% (J, L Griffith et al.
NRL Report 6439).

On the other hand, as a method using the latter as a starting material, there are the following methods.

(to)■]-i derived from nitrobenzonitrile]
-aminobenzonitrile hydride lithium aluminum dic
inal Chem, 20 1189 (1977)
).

111-Aminobenzylamine was obtained in a yield of 49% by high-pressure catalytic reduction of (7I→n]-nitropenzonitrile using a Wolaney Nickel catalyst (J, RGriff).
ith et al., NRL Report 6439).

As described above, in the production of aminobenzylamine by the known method, as in (a) and (b), an intermediate is produced using an equivalent or more of a relatively expensive compound such as potassium phthalimide and phenylhydrazine, The target product is obtained by reducing this, but these methods are not economical because the reaction steps are long and recovery of by-products requires expense and labor.

The method (2) also has the disadvantage that the reducing agent is expensive and it is difficult to handle.

(/→, (as in (1), using Raney Nisokel catalyst
It is clear that the method of high-pressure catalytic reduction in an autoclave is disadvantageous in that it is expensive to load and has low volumetric efficiency.

Generally, the method for producing benzylamine by a conventional reduction method of benzonitrile or benzaldoxime is
The yield of benzylamine is low because it produces secondary amines and ammonia as by-products.

For example, when benzonitrile is catalytically reduced in ethanol under a Ni catalyst, the benzylamine yield is 40-50%,
The dibenzylamine yield is 20% (edited by the Chemical Society of Japan, Experimental Chemistry Course, Vol. 17 (1), Maruzen, 313 Sada (1956).
) ).

Furthermore, when benzaldoxime is catalytically reduced in water-alcohol under a Pd colloid catalyst, the yield of benzylamine is 47%.
, the dibenzylamine yield was 41% (Wl, Gul
ewitsch, Ber, 57.1645 (1
924)).

This is because benzalimine is initially formed during the reduction of benzonitrile and benzaldoxime, and as a by-product of benzaldehyde accompanying the hydrolysis reaction of benzalimine and condensation of benzalimine with benzaldehyde, intermediates in the reduction reaction system occur. This is due to the low yield of benzylamine due to the formation of by-products due to various reactions in the body.

Therefore, in order to suppress the production of such by-products and improve the yield of benzylamine, a method using acetic anhydride or dry hydrogen chloride during reduction has been proposed.

For example, in a method using acetic anhydride, when benzonitrile is reduced with 2.65 times the mole of acetic anhydride,
Benzylamine was obtained with a yield of 69%, and 12.
When carried out at 7 times the molar ratio, benzylamine equivalent to 91% was obtained (W, T1. Carotllcrs et al., J.
Am,Chem,Soc,, 47 3051-3057
(1925), F.E., Gould et al., J., Org., C.
hcm,.

25 1658-1660 (1960)').

Furthermore, after isolating benzaldoxime acetate from benzaldoxime and acetic anhydride, it was reduced to 91
Benzylamine was obtained with a yield of % (K, W
, Rosenrnund et al., Ber, 5622
58-2262 (1923)).

These methods of reducing benzonitrile and benzaldoxime in an acetic anhydride solvent all involve isolating N-acetylbenzylamine and hydrolyzing it to produce benzylamine.

On the other hand, in the method using hydrogen chloride, when the amount of dry hydrogen chloride gas used is 1 equivalent or more in the case of benzonitrile and 3 equivalents or more in the case of benzaldoxime, high yields of benzylamine can be obtained. obtained (W, I-1
, Il-1artun, J., Aw., Chem.
Soc.

50 3370-3374 (1928)).

When producing benzylamine by reducing benzonitrile or benzaldoxime, the method using acetic anhydride or dry hydrogen chloride is effective in terms of yield, but acetic anhydride and dry hydrogen chloride are It is thought that benzaldoxime has the effect of stabilizing the intermediate during reduction as mentioned above, and the effect of suppressing the decomposition reaction by capturing the water produced, but this acetic anhydride or dry hydrogen chloride The method used is not economical because it requires the use of a large amount of relatively expensive acetic anhydride, and when dry hydrogen chloride is used, the solvent must be used in an anhydrous state. There are serious drawbacks, such as slow hydrogen absorption, which requires a dilute solution, and extremely significant catalyst deterioration.

Furthermore, there are also problems with the material of the device.

When reducing nitrobenzaldehyde using this method, in addition to the above-mentioned problems, a more complicated reaction is expected due to the presence of a nitro group.

That is, 2) Reaction with the amino group generated by the reduction of the o group, hydrolysis accompanied by by-produced water, side reactions of aminobenzaldehyde generated by this hydrolysis, etc. can be considered, and these side reactions are suppressed. For this purpose, it is necessary to use a large amount of acetic anhydride or dry hydrogen chloride.

Therefore, it must be said that it is extremely difficult to industrially produce aminobenzylamine using such a technical background and known method.

The present inventors have intensively studied a method for producing aminobenzylamine that does not have the above drawbacks.

As a result, aminobenzylamine can be produced in high yield by using nitrobenzaldoxime, which can be easily produced from nitrobenzaldehyde, as a raw material and catalytically reducing it using a reduction catalyst in the presence of a relatively inexpensive organic acid. and completed the method of the present invention.

An aminobenzylamine characterized by catalytically reducing a nitrobenzaldoxime represented by (in the formula, 21. is at the ○-position, m-position or p-position) in the presence of an organic acid. This is a manufacturing method.

In the method of the present invention, reduction is carried out in an organic solvent in the presence of an organic acid. Therefore, the intermediate product exists in a stable form as an organic acid salt of aminobenzylamine.

That is, by stabilizing various intermediates such as amines and imines generated during reduction as organic acid salts, and reducing the basicity of the amine groups and imino groups of the organic acid salts,
Decomposition and side reactions are suppressed, and as a result, the reduction of 21. occlusion to the amino group and the reduction of the aldoxime group to the amine methyl group proceed rapidly, and the target product, aminobenzylamine, is selectively produced. can.

Furthermore, the method of the present invention has the great advantage that the activity of the catalyst does not decrease. Therefore, after recovery, it can be used repeatedly, which is extremely advantageous economically.

After the reaction is completed, aminobenzylamine can be easily isolated by separating and purifying it as an organic acid salt, or by distilling and purifying it by simple neutralization, which is extremely advantageous industrially.

The raw material used in the method of the present invention is O-nitrobenzaldoxime, m-nitrobenzaldoxime or p-nitrobenzaldoxime.

These can be easily produced by reacting the corresponding nitrobenzaldehyde with an industrially inexpensive hydroxyamine.

Next, the organic acids used in the present invention include formic acid, acetic acid,
Flopionic acid, oxalic acid, malonic acid, aliphatic mono- and dicarboxylic acids such as hydroxylic acid and maleic acid, aromatic carboxylic acids such as benzoic acid and phthalic acid, sulfonic acids such as p-toluenesulfonic acid and benzenesulfinic acid and sulfinic acids.

Industrially, acetic acid is preferably used.

Note that among the organic acids listed above, some of the carboxylic acids are also used as anhydrides.

It is appropriate to use these organic acids in an amount of 0.2 equivalent or more, preferably in a range of 1 to 3 equivalents, relative to the raw material nitropenzaldoxime. The organic acid is used in a state where it is dissolved or suspended in a solvent together with the raw materials. In this case, there is no problem in using it alone or in combination of two or more. Examples of this solvent include methanol, ethanol, isopropyl alcohol, n-butyl alcohol/L'
, 5ec-butyl alcohol, methyl cellosolve, ethyl cellosolve, ethylene glycone, propylene glycol, diglyme, tetraglyme, dioxane, tetrahydrofuran, and other alcohols, glycols, and ethers are preferably used, and in some cases, hexane, cyclohexane, and benzene. , toluene, ethyl acetate,
Butyl acetate, dichloromethane, chloroporm, 1.1
．． Aliphatic hydrocarbons such as 2-trichloroethane, aromatic hydrocarbons, esters, . . . logenated hydrocarbons can also be used. Even if these solvents are used alone, 2
A mixture of two or more types may be used, and a water-containing solvent may also be used. The amount of the solvent to be used is not particularly limited, but usually 1 to 15 times the weight of the raw material is sufficient.

In the method of the present invention, the catalytic reduction comprises as a reduction catalyst:
Commonly used reduction catalysts such as nickel, palladium, platinum, rhodium, ruthenium, cobalt, copper, etc. can be used.

Industrially it is preferred to use Raney nickel catalysts and palladium catalysts.

Although these catalysts can be used in the metallic state, they are usually applied individually on the surface of a support such as carbon, barium sulfate, silica gel, or alumina.Also, nickel, cobalt, copper, etc. It is also used as a catalyst.The amount of catalyst used is in the range of 0.01 to 30% by weight as a metal based on the raw material nitrobenzaldoxime,
Usually, when used as a Raney catalyst, 2 to 20% by weight,
When individually added to a carrier, the amount is in the range of 0.05 to 5% by weight.

The reaction temperature is not particularly limited and is generally 0 to 150°C.
A range of 10 to 80°C is particularly preferable, and the reaction pressure may generally be from normal pressure to 50 kg/cd-G.

In a general embodiment of the method of the present invention, a catalyst is added to a raw material and an organic acid dissolved or suspended in a solvent, and hydrogen is introduced at a predetermined temperature. After neutralization, the desired product can be obtained by distillation.

If it is in a precipitated state, the organic acid salt can be isolated and purified by filtration, and then neutralized to obtain the desired product.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 m-nitrobenzaldehyde 151 in 70°C hot water 11
(1 mol) was added thereto, and then 50% aqueous hydroxylamine solution (manufactured by Nippon Kogyo Co., Ltd.) (1.1 mol) was added thereto while stirring.

After stirring at the same temperature for 1 hour, the mixture was cooled to room temperature, and the precipitated crystals were filtered and dried to obtain m-nitrobenzaldoxime 160F (yield 96%). Melting point 1
18-121℃ This m-nitrobenzaldoxime 16.61 (0,
1 mo/l/ ) tofropionic acid 7.4 f (0,1
mol), Raney Nisokel 1y, and methanol 50- are charged into an autoclave, and hydrogen is introduced to increase the pressure to 20~
30 and /ai-Q. The reaction was completed by stirring vigorously for 4 hours at a reaction temperature of 20-25°C.

Next, the reaction solution was filtered to remove the face medium, and then caustic soda-4F (0.1 mol) was added and distilled. 79.4%). The boiling point is 1
29-130℃ 75 as Hf, melting point is 39-42℃
The results of elemental analysis are as follows: Example 2 In-nitrobenzaldoxime 1 obtained in Example 1
6.69 (0.1 mol), glacial acetic acid 7.2F (0.12
mol), ethyl acetate 50. n! , and 0.5 f of a 5% Pd-C catalyst were placed in a closed glass container and vigorously stirred while introducing hydrogen.

The reaction was completed at a temperature of 25° C. for 12 hours.

After the reaction was completed, the catalyst was removed by filtration, 9.19 (0.1.5 moles) of concentrated ammonia water was added, and the mixture was thoroughly stirred and allowed to stand to separate into two layers. When the lower layer is removed and the upper layer is distilled, the purity is 99.6% as determined by gas chromatography.
9.4.9 kg of 111-aminobenzylamine was obtained (yield 77%). Melting point: 39-42°C Example 3 The reaction was carried out in the same manner as in Example 2, except that Improper Tool was used as the solvent. After the reaction is complete, filter to remove the catalyst.
When most of the isopropanol was distilled off by concentration under reduced pressure, a yellow viscous liquid was obtained. When this was allowed to stand, it crystallized, so it was filtered, washed with isopropanol, and dried to obtain m-aminobenzylamine acetate in the form of white needles.

Yield 11.7f (yield 64.3%), melting point 127-13
The results of elemental analysis at 0°C are as follows.

Example 4 m-nitrobenzaldoxime 16 obtained in Example 1
．． 69 (0.1 mol), l]-toluenesulfonic acid 9
．． 51 (0.05 mol), 10% pt-c catalyst 0.5
f and dioxane 75- were placed in a closed glass container and vigorously stirred while introducing hydrogen. Temperature 30-40
The reaction was completed after 8 hours at °C. Then, the catalyst was removed by filtration, and 35f (0.3 mol) of a 35% aqueous solution of caustic soda was added.

After stirring, when left to stand, it separated into two layers, so the lower layer was removed and the upper layer was distilled to obtain 8.9y of m-aminobenzylamine with a purity of 99.3% by gas chromatography (yield 72.9 %) Example 5 A reduction reaction was carried out in exactly the same manner as in Example 1 except that oxalic acid was used as the organic acid, and n]-aminobenzylamine was obtained in a yield of 82%.

Example 6 Methanol 350rn1. 151 g (1 mol) of p-nitrobenzaldehyde is dissolved in the solution. Next, increase the temperature to 30℃
80.3 g of hydroxyamine hydrochloride (1,
An aqueous solution of 1 mol) and 100 mol of water was added dropwise over 30 minutes. After stirring continuously at the same temperature for 2 hours, water 100%
Diluted with 0-.

The precipitated white crystals were filtered, washed with water and dried 7)
161! p-nitrobenzaldoxime was obtained.

Yield 97%, melting point 128-131°C.

This p-nitrobenzaldoxime 16.6f (0,1
mol), benzoic acid 14.7 g (0.12 mol), 5% P
0.21 ml of dC catalyst and 150 ml of methanol were placed in a closed glass container, and the mixture was vigorously stirred while introducing hydrogen. The reaction was completed at a temperature of 30 to 40°C for 10 hours.

After the reaction was completed, the catalyst was removed by filtration, and most of the methanol was distilled off by concentration under reduced pressure. A 25% caustic soda aqueous solution 32f (0.2 mol) was added to the obtained yellow viscous liquid, and after stirring at a temperature of 80 to 90°C, the mixture was allowed to stand and was separated into two layers. The colorless and transparent liquid in the lower layer was an aqueous solution of sodium benzoate, and when this was extracted, a reddish-brown transparent oily liquid was obtained.

Vacuum distill this material to 129-130℃15-6m
A fraction 9.7f of l-19 was obtained.

This is I]-aminobenzylamine, yield 79.
5% and a purity of 99% by gas chromatography.

The results of elemental analysis are as follows.

Example 7 The same procedure as Example 6 was carried out except that 7.11 (0.06 mol) of succinic acid was used instead of benzoic acid to obtain 10.1y of p-aminobenzylamine (yield: 82.7 %)
.

Example 8 5 0-nitrobenzaldehyde in 150 ml of methanol
2,9 (0,35 mol) was dissolved, then the temperature was increased to 3
27.8g of hydroxyamine hydrochloride (0°C) while keeping at 0℃.
, 38 mol) and water 3541 were added dropwise over 30 minutes. After continuing to stir at the same temperature for 2 hours, add 30% water
0. n! diluted with The precipitated white crystals were filtered, washed with water, and dried to obtain 53 g of 0-nitrobenzaldoxime. Yield 91%, melting point 95-98°C This 0-nitrobenzaldoxime 16.69 (0,
1 mol) to 5% I) d -C catalyst 0.831, glacial acetic acid 12! (0,2 mol) and tetrahydrofuran 100
m1. It was then placed in a sealed glass container.

Next, hydrogen was introduced with vigorous stirring, and the temperature was 25~25°C.
The reaction was carried out at 35°C for 7 hours.

After the reaction was completed, the contents were filtered to remove the catalyst, and caustic Sogu 89 (0.2 mol) was added and distilled to obtain 9.7 g of O-aminobenzylamine with a purity of 99.4% as determined by gas chromatography. Ta.

Yield 794%, boiling point 91-b, melting point 58-61°C, and the results of elemental analysis are as follows.

patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1) Catalytic reduction of nitrobenzaldoxime represented by general formula (I) (wherein the nitro group is at the ○-position, m-position or p-position) in the presence of an organic acid. A method for producing aminobenzylamine characterized by: