JPS60178847A - Production 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 carbon dioxide gas. 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 an organic solvent in the presence of carbon dioxide gas, 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 carbonates only by introducing carbon dioxide gas into the reaction system, and the basicity of the amino group of the carbonate 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 particularly provides a method that is extremely advantageous for industrial implementation.

More specifically, catalytic reduction of nitrobenzaldoxime represented by general formula (I) oi (wherein the nitro group is at the ○-position, m-position or p-position) in the presence of carbon dioxide gas is described. The present invention relates to a method for producing characteristic aminobenzylamine.

Aminobenzylamine is an epoxy resin curing agent, polyamide 1. It is an important material that is a raw material for polyimide and agricultural and pharmaceutical intermediates.

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

(a) Nitrobenzyl bromide is derived from nitrobenzaldehyde, then reacted with potash phthalimide, and N
-(m-nitrobenzyl)-phthalimide was obtained, followed by a two-step reduction method to obtain m-aminohensylamine in about 20% yield (N, Kornblum et al.
J,Am,Chem,Soc,,712137(19
49) ).

(0)+71-Nitrobenzaldehyde was reacted with phenylhydrazine to obtain a hydrazone compound, which was catalytically reduced to obtain nl-aminobenzylamine in a yield of 60% (A, 5iddiqui et al., SynthC
ommn 7, 71-78 (1977)).

(c)■-nitropenzaldehy)”J: ') m
−= ) o Benzaldoxime was obtained, and this was subjected to high-pressure catalytic reduction using a Raney nickel catalyst to obtain 1η-aminobenzylamine in a yield of 52 ( J , I (
,, Qri 110h et N RL ratio (! p 0 +
“t 6439).

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

) derived from p-nitrobenzonitrile) −
Aminobenzonitrile was reduced with lithium aluminum hydride to obtain l)-aminobenzylamine in a yield of 37% (N, C, Brown et al., J, 'We-
dicinal Chem, 201189 (1977
) ).

(e) 1n-aminobenzylamine was obtained in a yield of 49% by high-pressure catalytic reduction using Il+-nitrobenzonitrile as a Raney nickel catalyst (J, Li, GriHit
h et al., N ILL IL Report 6439).

As described above, in the production of aminobenzylamine by the known method, as in 0) and (b), an intermediate is produced using an equivalent or more of a relatively expensive compound such as potash phthalimide and tunylhydrazine, The target product is obtained by reducing this, but these methods require long reaction steps,
It is not economical because it requires expense and labor to recover by-products.

The method (2) also has the disadvantage that the reducing agent is expensive and the handling is clumsy.

Using Raney nickel catalyst as in (c) and (e),
It is clear that the method of high-pressure catalytic reduction in an autoclave is disadvantageous in that the equipment is expensive and the volumetric efficiency is low.

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

For example, when benzonitrile is catalytically reduced in ethanol under Ni solvent, the benzylamine yield is 40-50%.
, the yield of dibenzylamine is 20% (1. ``Jikken Chemistry Course'' edited by the Chemical Society of Japan, Vol. 17 (G), Maruzen, p. 313 (19
56)).

Furthermore, when benzaldoxime is catalytically reduced in water-alcohol under PD Raffroid catalyst, the yield of benzylamine is 47% and the yield of dibenzylamine is 41% (Wl, Gu
lcwi tsch, Ber, , 57.1645 (1
924)).

This is due to the fact that benzalimine is initially formed when benzonitrile and benzaldoxime are formed, and as a by-product of benzaldehyde accompanying the hydrolysis reaction of benzalimine, and as an intermediate in the reduction reaction system, such as the condensation of benzalimine and benzaldehyde. 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 in a yield of 69 qb, and similarly 12
, if carried out at 7 times the molar ratio, benzylamine equivalent to 91 units is obtained (W, II, Carothers I:)
.

J', Am, Che+n, Soc,, 47 3051
~3057 (1925).

Ir, IU, Gould et al., J., Org, Chern.
, , 251658-1660 (1960)).

Additionally, benzaldoxime acetate was prepared from benzaldoxime and acetic anhydride, and then reduced to give benzylamine in 91% yield (K,
W. Rosenmund et al., Ber, 562258~
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, if the amount of dry hydrogen chloride gas used is 1 equivalent or more for benzonitrile and 3 equivalents or more for benzaldoxime, benzylamine can be produced in high yield. Obtained (W, I-I,
f-1artung, J., Aw., Chcm, Soc.

503370-3374 (1928)).

When producing benzylamine by reducing benzonitrile or benzaldoxime in this way, the method of using acetic anhydride or dry hydrogen chloride is effective for improving the yield, but acetic anhydride and dry hydrogen chloride However, it is thought that benzaldoxime has the effect of stabilizing the intermediate during reduction as described above, and the effect of capturing the water produced and suppressing the decomposition reaction, but this acetic anhydride or dry hydrogen chloride The method using acetic anhydride, which is relatively expensive, is not economical because it requires the use of large quantities, and when dry hydrogen chloride is used, it is necessary to use the solvent in an anhydrous state. However, since hydrogen absorption is delayed, it is necessary to use a dilute solution, and there are serious drawbacks in that the deterioration of the catalyst is extremely significant.

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.

In other words, reactions with amino groups generated by reduction of nitro groups, hydrolysis accompanied by by-product water, side reactions of aminobenzaldehyde generated by this hydrolysis, etc. can be considered, and in order to suppress these side reactions, In addition, 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, it was discovered that aminobenzylamine could 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 carbon dioxide gas. The method of the present invention has been completed.

That is, the method of the present invention involves contacting nitrobenzaldoxime represented by the general formula (I)02 (in the formula, the nitro group is at the 0-position, the 1-position, or the p-position) in the presence of carbon dioxide gas. This is a method for producing aminobenzylamine, which is characterized by reduction.

In the method of the present invention, 4
do the original. Since this carbon dioxide gas becomes carbonic acid in the presence of water, the intermediate product exists in a stable form as a carbonate of aminobenzylamine.

In other words, in the reduction of nitrobenzaldoxime by the method of the present invention, carbon dioxide gas becomes carbonic acid with water generated by reduction of nitro groups, etc., so that simply introducing carbon dioxide gas into the reaction system will reduce the amount of coagulation during condensation. By stabilizing the generated various intermediates such as amines and imines as carbonates and reducing the basicity of the amino and imino groups of the carbonates, decomposition and side reactions are suppressed, and as a result, nitro The reduction of the group to the amine group and the reduction of the aldoxime group to the aminomethyl group proceed rapidly, and the desired product, aminobenzylamine, can be selectively produced.

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

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

The raw materials used in the method of the present invention include O-nitrobenzaldoxime, In-nitrobenzaldoxime or p-nitrobenzaldoxime.
Nitrobenzaldoximes, which can be easily prepared by reacting the corresponding nitrobenzaldehydes with industrially inexpensive hydroxyamines.

Next, the carbon dioxide gas used in the present invention may be used in any form of gas, liquid, or solid.

The amount of carbon dioxide gas used is 0.5 equivalent or more relative to the raw material nitrobenzaldoxime, preferably 1 to 10 equivalents.
It is appropriate to carry out the treatment within an equivalent range.

Carbon dioxide gas may be charged in advance with the raw materials or may be added as appropriate during the reaction. Examples of solvents used in the method of the present invention include methanol, ethanol, isopropyl alcohol, n-fluoric alcohol, sec-70 methyl alcohol methyl cellosol, ethyl cellosol, ethylene glycol,
Alcohols such as propylene glycol, schifraime, tetraglyme, dioxane, and tetrahydrofuran,
Krykol, ethers are preferably used, and in some cases hexane, cyclohexane, benzene, toluene, ethyl acetate, vinegar, dichloromethane, chloromethane, 1, 1, 2-1 chloroethane, etc. fatty monolateral hydrocarbons, aromatic hydrocarbons, esters, etc.
Logenated hydrocarbons can also be used.

These solvents may be used alone or in combination of two or more, and water-containing solvents may also be used.

The number of solvents to be used is not particularly limited; usually, 1 to 15 times the weight of the raw material is sufficient.

In the method of the present invention, the catalytic reduction 4 and the reducing catalytic agents commonly used as reducing insect media include the reduction catalyst a, fPIJ,
-X, nickel, palladium, platinum, rhodium) rethenium, cobalt, copper, etc. can be used.

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

Although these catalysts can be used in the metallic state, they are usually used by being attached to the surface of a carrier such as carbon, barium sulfate, silica gel, alumina, etc. The number of catalysts used is 0.01 to 301 to 30% by weight as metal based on the raw material nitrobenzaldoxime,
Usually, when used as a Raney catalyst, 2 to 20% by weight,
When attached to a carrier, the amount is in the range of 0.05 to 5 weight.

The reaction temperature is generally 0 to 15, without any particular limitation.
A range of 0°C, particularly 10 to 80°C is preferred.

In addition, the reaction pressure may be ``usually normal pressure to 5 kg,'' = .G.

In a general embodiment of the method of the present invention, a catalyst is added to the raw materials dissolved or suspended in a solvent, and then,
Pour the entire predetermined amount of carbon dioxide gas in advance. Add or 7shi]
Rui: i'/1 If introduced, the predetermined i! ! Introduce hydrogen at a different temperature and continue until absorption stops.

After completion of the reaction, if the reaction mixture is in a soluble state, the catalyst can be removed by filtration, neutralized with caustic soda, caustic potash, ammonia, triethylamine, etc., and then distilled to obtain the desired product.

If it is in a precipitated state, the desired product can be obtained by filtering and purifying the charcoal salt using a single 111r method, and then neutralizing it.

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

Example 1 15 m-nitrobenzaldehyde was added to 11 hot water at 70°C.
Add 19 (1 mol) and then add 50 with stirring.
Hydroxylamine water soluble kg. (Nichiken 2 [company product]
72.69 (1.1 mol) was added dropwise.

After stirring at the same temperature for 1 hour, the precipitated crystals were cooled to room temperature and filtered, washed with water, and dried.
Nitrobenzaldoxime 160.5 9 f. =
(Yield 9G.6).

Melting point 118-121℃ This ■1-nitrobenzaldoki/mu1G,Ci'/
(0.1 mol), 22 liters of solid carbon dioxide (0.5 mol), 1 g of borosilicate nickel and 150 rn1 methanol.
．． was charged into an autoclave, hydrogen was introduced, and the pressure was increased to 20
It was maintained at ~30 ky/cwt-G. Reaction temperature 2
The reaction was terminated by vigorous stirring at 0 to 25°C for 8 hours.

Next, after filtering the reaction solution to remove the catalyst, caustic soda-6! 7 (OJ5 mono0 was added and distilled to obtain 10.6 g of m-aminobenzylamine with a purity of 99 as determined by gas chromatography. is 39-42
The results of elemental analysis at °C are as follows.

Example 2 The reaction was carried out in the same manner as in Example 1 except that methylene chloride was used as the solvent.

After the reaction was completed, the precipitated crystals were filtered together with the catalyst. Yield: 10 g (yield! 58.8%) The crystals were 111-aminobenzylamine carbonate, and were recrystallized with isopropanol to obtain pure white needle crystals. The melting point is 113-116°C, and the results of elemental analysis are as follows.

Excellent calculated value) 58.8 7,24 18.3 Example 3 Methanol 100- to p-nitrobenzaldehyde 52
．． 97 (0.35 mol) and then lowered the temperature to 30°C.
Hydroxyamine hydrochloride 27.8'7 (0,
A solution of 38 moles) and 35 moles of water was added dropwise over 30 minutes.

After stirring continuously at the same temperature for 2 hours, water 300%
Diluted in ml. The precipitated white crystals were filtered and dried to give 55 g of p-nitrobenzaldoxime, with a yield of 94.7% and a melting point of 128-131°C.

This p-nitropenzaldoxime 16.6!7 (0
, 1 mol) of 5% Pd-C catalyst and 100 m/! of isopropyl alcohol! At the same time, the glass reactor is charged with carbon dioxide gas at a rate of 30 rnl per minute! Hydrogen was introduced by stirring vigorously while aerating at intervals of .

The reaction was completed at a temperature of 25 to 35°C for 8 hours.

After the reaction was completed, the catalyst was removed by filtration, and most of the isopropyl alcohol was distilled off by concentration under reduced pressure.

Add 25% caustic soda aqueous solution 3 to the obtained yellow viscous liquid.
217 (0.2 mol) was added, stirred, and then left to stand to separate into two layers. When the colorless and transparent aqueous solution in the lower layer was removed, a reddish-brown transparent oily liquid was obtained. This product was vacuum distilled to 129-130℃ 15-6 yimf-Ig fraction 9
．． I got 9 points. This was p-aminobenzylamine, with a yield of 81.1% and a purity of 99.3% by gas chromatography.

The results of elemental analysis are as follows.

Elemental analysis C7H76Nz Calculated value (chi) 68.8 8.25 22.9 Measured value (
Li 68.4 8,3 22.7 Example 4 O-nitrobenzaldehyde 52 in methanol 150-
．． 99 (0.35 mol) and then lowered the temperature to 3
27.8g of hydroxyamine hydrochloride (0°C) while keeping at 0℃.
, 38 mol) and water were added dropwise over 30 minutes. After continuing to stir at the same temperature for 2 hours, add 300% water
- diluted with The precipitated white crystals were filtered once, washed with water and dried to obtain 539 0-nitropenzaldoxime.

Yield 91%, melting point 95-98°G This O-nitrobenzaldoxime 16.69 (0,
1 mol) was charged into an autoclave having an internal volume of 250 mm along with 0.83 mm of 5% Pd-C catalyst and 100 mm of tetrahydrofuran, and carbon dioxide gas was introduced until the pressure reached 5 kg/f-.G.

Next, hydrogen was introduced with vigorous stirring and the pressure was increased to 20
The reaction was carried out at a temperature of 25 to 35°C for 7 hours while maintaining the weight at ~30 kg/-J-G.

After the reaction was completed, the contents were filtered to remove the catalyst, and 6 g (0.15 mol) of caustic soda was added thereto and distilled.
9.7 g of aminobenzylamine was obtained.

Yield 79.4%, boiling point 91-93°C 71mutl
g, the melting point is 58-61°C, and the results of elemental analysis are as follows.

Calculated value (%) 68,8 8.2!5 22,9 Measured value excellent) 68,7 8,3 22.1 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 carbon dioxide gas A method for producing aminobenzylamine, characterized in that: