KR870002017B1 - Process for preparation of amino benzylamine - Google Patents

Abstract

Amino benzylamine is prepd. by catalytic redn. of nitro benzylamine isomers (ortho, meta and para-, obtd. by nitration of benzylamine) in the presence of Pt gp. metal. Add O-nitro benzylamine 13.6g, MeOH 50 ml and 5% pd/c catalyst 0.3g into glassware and cover tightly, vigorously stir for 3 hrs at 30-40 deg.C with inject H2 into rxn. container, filter and vacuum distillate to give 10.1g of aminobenzylamine (yield=82.7 %).

Description

Method for preparing aminobenzylamine

The present invention relates to a method for producing aminobenzylamine, and in particular, to provide a production method useful as an industrial scale production method.

More specifically, the present invention relates to a method for producing aminobenzylamine by reducing nitrobenzylamine represented by the following general formula (I) using a catalyst.

Wherein the nitro group is at the O-position, the m-position, or the p-position.

As a preferred embodiment of the present invention, a method of reducing with a catalyst in the presence of an acid and using an inorganic acid salt of a nitrobenzyl amine mixture obtained by nitrating benzylamine to use nitrobenzylamine as a raw material are proposed. . Aminobenzylamine is a very important compound as a curing agent for epoxy resins, as a raw material for polyamides and polyimides, and as an intermediate raw material for pesticides and medicines. Processes for preparing aminobenzylamine using nitrobenzelaldehyde or nitrobenzelnitrile as starting materials have been known. As an example, the following method is known as a manufacturing method using nitrobenzyl aldehyde as a starting material.

(1) Nitrobenzyl aldehyde is made from nitrobenzylbromide and reacted with potassium phthalimide to prepare N-nitrobenzyl phthalimide, which is then reduced and hydrolyzed to prepare m- and p-aminobenzylamine (yield) Is about 20%). (N. Kornblum et al. J. Am. Chem. Soc 71,2137 (1949))

(2) Reducing the resulting hydrazone compound by reacting m-nitrobenzaldehyde with phenylhydrazine in the presence of a catalyst to give m-aminobenzylamine in a yield of 60% (A Siddiqui et al, Synth. Commn, 7, 71 -78 (1977).

(3) m-nitrobenzaldehyde is prepared from m-nitrobenzaldehyde and reduced under high pressure in the presence of Raney nickel catalyst to give p-aminobenzylamine in 52% yield (JR Griffith et al, NRL Report). 6439).

Alternatively, there are several methods for preparing nitrobenzonitrile as starting materials.

(4) Reduction of p-nitrobenzonitrile with aluminum lithium hydride yields p-aminobenzylamine in 37% yield (N.C. Brown et al, J. Medicinal Chem 20, 1189 (1977)).

(5) m-nitrobenzonitrile is subjected to high pressure reduction in the presence of a Raney nickel catalyst to give m-aminobenzylamine in 49% yield (J.R. Griffith et al, NRL Report 6439).

As another manufacturing method, there is a method of preparing aminobenzylamine by using nitrobenzylamine as a starting material and reducing it.

(6) m-nitrobenzylamine is reduced with tin and hydrochloric acid to prepare m-aminobenzylamine (S. Gabriel et al, Ber., 20, 2869-2870 (1887)).

(7) O-aminobenzylamine is reduced to red and a large amount of hydroiodic acid to prepare O-aminobenzylamine (S. Gabriel et al, Ber, 37, 3643-3645 (1904)).

As described above, the known methods (1) and (2) should use an expensive compound at an equivalent or more by using nitrobenzaldehyde or nitrobenzonitrile as starting materials, and once made an intermediate, the reduced aminobenzyl The manufacturing method of the amine, which has the drawback that the reduction process is complicated and requires the expense and manpower to recover by-products and the like.

In addition, the manufacturing method (4) has the disadvantage that the reducing agent is expensive and difficult to handle. In the production methods (3) and (5), the catalytic reduction reaction is carried out in a high pressure reactor at high pressure in the presence of a Raney nickel catalyst, and thus, the apparatus is expensive and its volumetric efficiency is low.

Meanwhile, in the known production method (6), nitrobenzylamine is used as a starting material and reduced using a large amount of tin and hydrochloric acid to separate the target product in the form of tin salt, and then metathesized to liberate the target product. It is necessary to separate the used metal compounds and to be careful not to leave even a small amount of metal in the product, so the manufacturing method is complicated. It also requires significant costs and manpower to prevent environmental pollution caused by large amounts of heavy metals and waste acid and to recover these hazardous substances.

In the preparation method (7), reduction reaction was carried out using red and iodide hydrochloric acid in order to improve the above production method. However, large amounts of expensive hydroiodic acid are needed, and the risk of ignition is low.

Therefore, the known method for preparing aminobenzylamine has problems with a multistage process, a complicated post-treatment process, or an apparatus.

It is an object of the present invention to provide a method for preparing aminobenzylamine on an industrial scale by reducing nitrobenzyl amine with a catalyst.

It is another object of the present invention to provide a method for producing aminobenzylamine in high yield by reducing nitrobenzylamine with a catalyst in the presence of an acid to prevent side reactions or decomposition.

It is still another object of the present invention to provide a method for preparing an aminobenzylamine isomer mixture using an inorganic acid salt of the nitrobenzylamine isomer mixture obtained by nitrating benzylamine in order to use nitrobenzylamine as a raw material.

Starting materials used in the present invention are O-nitrobenzylamine, m-nitrobenzylamine and p-nitrobenzylamine. These O-, m-, and p-isomers are prepared in high yield by reacting the corresponding nitrobenzyl chloride with ammonia or phthalimide (S. Gabriel et al, Ber., 2869 (1887): EL Holmes et al. J. Chem Soc 1800-1821 (1925): HL Ing et al, J. Chem Soc, 2348-2351 (1926).

In addition, nitrobenzylamine used as a raw material is a mixture of nitrates and / or sulfates of nitrobenzylamine obtained by nitrating benzylamine. Nitrates and / or sulfates of this kind of nitrobenzylamine can be obtained by nitrating benzylamine with a nitrating agent. The nitrating agents that can be used in the process are mixed acids, fuming nitric acid, nitric acid / acetic acid mixtures and the like.

Usually, mixed acid or fuming nitric acid is preferable. The following reaction is carried out using a nitrating agent. When nitrifying with fuming nitric acid, 80 to 90% concentration of nitric acid is used 8 to 12 times the number of moles of benzylamine. When nitrified with mixed acid, the mixed acid consists of concentrated sulfuric acid and nitric acid or nitrate, such as sodium nitrate, potassium nitrate, etc., and the molar ratio of benzylamine, nitric acid or nitrate and concentrated sulfuric acid is from 1: 1.2 to 5: 1 to 1 5

If necessary, the nitration reaction can be carried out in an organic solvent. Preferred organic solvents are halogenated hydrocarbon solvents such as methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, chloroform, carbon tetrachloride, 1,1,2,2-tetrachloroethane, Trichloroethylene and the like.

The reaction can be carried out by dropwise addition of benzylamine in the nitrating agent or vice versa. When using a mixed acid, the reaction may be performed by using an acid mixture prepared in advance or by mixing one component of the mixed acid and benzylamine before dropping the other components.

The reaction temperature is -10 ° C to 80 ° C, preferably -5 ° C to 30 ° C. The reaction time is preferably in the range of 2 to 10 hours.

After completion of the reaction, the resulting mixture is poured into a certain amount of ice water. Inorganic acid salts of nitrobenzylamine mixtures can be obtained by filtering off the precipitate. By pouring the reaction product mixture into ice water, mainly m-nitrobenzylamine and p-nitrobenzylamine are precipitated, and most O-nitrobenzylamine is removed by the filtrate. The content of O-nitrobenzylamine in the nitrobenzylamine mixture is 10 to 15% by weight at the end of the nitration reaction. Since the solubility of O-isomers in water is greater than that of other isomers, the content of O-isomers in the separated mixture is reduced to 5% by weight or less.

Inorganic acid salts of the nitrobenzylamine mixtures mentioned herein are, as described above, phosphates, nitrates, or mixed salts of O-, m- or p-substituted nitrobenzylamine mixtures obtained when nitrating benzylamine. . The ratio of m-, p- and O-isomers of the nitrobenzyl amine mixture thus obtained is in the range of 30 to 70:30 to 70: 0.2 to 10, and the content of O-isomer usually does not exceed 5% by weight. If the nitrating agent is only nitric acid or a mixed acid containing excess nitric acid and up to 2 moles of sulfuric acid, nitrobenzylamine is obtained as the nitrate. In other nitration conditions it is obtained as a product sulfate or a mixture of sulfates and nitrates. The mixture of nitrobenzylamine isomers thus obtained can be used in the catalytic reduction process as it is, in particular in the presence of nitrates, in the presence of moisture-containing water without dehydration in terms of stability and operation. The catalytic reduction according to the invention can be carried out in the absence of acid. In the present invention, however, it is preferred to carry out the catalytic reduction in the presence of an acid.

Acids that can be used in the present invention are inorganic acids, organic acids, or carbonic acid. At least one of the inorganic acids should be selected from hydrochloric acid, sulfuric acid, nitric acid, boric acid, phosphoric acid, boric anhydride, and phosphoric anhydride. Thus, the desired product can be obtained by selecting and reacting the inorganic acid.

Inorganic acids have been found to be relatively inexpensive and have a facilitating effect in the reduction reaction. Therefore, it is also one of the characteristics of the present production method that the desired product can be produced effectively and economically. In addition, the inorganic acid anhydride absorbs water present in the reaction system and water generated from reduction of the nitro group. Thus, the reduction reaction can be carried out in anhydrous and ideal conditions, that is, unwanted reactions such as decomposition or side reactions for water are suppressed, and the reduction reaction can proceed with good ring selectivity.

Organic acids also include aliphatic mono or dicarboxylic acids such as formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, maleic acid, aromatic carboxylic acids, such as benzoic acid, phthalic acid, sulfone and sulfinic acid, such as p-toluenesulfonic acid and benzenesulfinic acid. This includes. Some of these carboxylic acids may be used as the acid anhydride. On an industrial scale acetic acid is preferably used in organic acids. Some organic acids can also be used as solvents. When organic acids are used, the reaction proceeds rapidly even under mild reaction conditions because they have excellent compatibility with the raw materials of organic acids and other solvents. In addition, since the homogeneous solution is generated by the present reaction, a post-treatment process such as a catalyst and a solvent recovery can be easily performed. The fact that the activity of the recovered catalyst hardly decreases is that the catalyst can be reused so that the manufacturing process is very economical. Further, in some cases, the aminobenzylamine can be separated from its organic acid salts and then the organic acid can be recovered by distillation or other methods. This gave even better results for mass production.

Satisfactory results can be obtained when carbon dioxide is used as the carbonic acid. That is, carbon dioxide reacts with water generated in the reduction of the nitro group or water in the reaction system and is converted to carbonic acid. Carbon dioxide can be used in the form of gases, liquids and solids. The use of carbon dioxide has the advantage that the post-treatment process can be relatively simple. Excess carbon dioxide is discharged out of the system after the reaction, the catalyst is removed and distillation is performed after adding a base. This allows the solvent to be recovered at a high rate and to obtain the desired aminobenzylamine in high yield.

The present production method is also characterized in that the activity of the recovered catalyst is not lowered, it is possible to reuse it can be an economical production method. The amount of acid used is in the range of at least 0.5 equivalents, preferably 1 to 3 equivalents of nitrobenzylamine. Such acids may be used alone or as a mixture of two or more acids.

The solvent is also used in the catalytic reduction reaction in the process of the invention. Solvents that can be used in the process include water, alcohols, glycols and ethers, for example methanol, ethanol, isopropyl alcohol, n-butyl alcohol, secondary butyl alcohol, methyl-cellosolve, ethyl cellosolve, ethylene glycol, Propylene glycol, diglyme, tetraglyme, dioxane, tetrahydrofuran and the like. In some cases, they are aliphatic hydrocarbons, aromatic hydrocarbons, esters and halogenated hydrocarbons such as hexane, cyclohexane, benzene, toluene, ethyl acetate, butyl acetate, dichloromethane, chloroform, 1,1,2-trichloroethane and the like. . These solvents may be used alone or in a mixture of two or more. Although the usage-amount of a solvent is not specifically limited, Usually, 1 to 15 times by weight is enough based on the quantity of a raw material.

Reduction catalysts that can be used in the process of the invention are conventional and are, for example, nickel, palladium, platinum, rhodium, ruthenium, cobalt, copper and the like. These catalysts can be used in the form of metals, but can also be used in supported forms on a carrier such as carbon, barium sulfate, silica gel, alumina, and the like. Nickel, cobalt, copper, and the like may also be used as the Rainy deposit. The amount of the catalyst used is 0.01 to 30% by weight as a metal component based on nitrobenzylamine. Usually, 2 to 20% by weight is preferred when a Raney catalyst is used, and 0.05 to 5% by weight is preferable when using a noble metal catalyst supported on a carrier.

Although reaction temperature is not specifically limited, Usually, 0-150 degreeC, Preferably it is the range of 10-80 degreeC.

The reaction pressure is usually in the range of atmospheric pressure to 50 kg / cm 2 G.

As a general embodiment of the present invention, the catalyst is added to the raw material in a dissolved or suspended state in a solvent and hydrogen is injected until the absorption of hydrogen is stopped at a specific temperature. After completion of the reaction, the reaction mixture is filtered to remove the catalyst and then distilled to yield the desired product.

When using an inorganic acid or an organic acid, a raw material and an acid are dissolved or suspended in a solvent, a catalyst is added, and a reduction reaction is performed. When using carbon dioxide, the catalyst may be added to a starting material dissolved or suspended in a solvent, and the total amount of carbon dioxide may be added in advance or may be continuously or intermittently added in small amounts to carry out a reduction reaction. In either case, the catalytic reduction reaction is carried out until the absorption of hydrogen is complete. When the catalytic reduction reaction is carried out in the absence of acid, the reaction product is dissolved after the reaction. The resulting mixture is then filtered to remove the catalyst and distilled to yield the desired product. If a reaction mixture dissolved by catalytic reduction in the presence of an acid is produced, then the catalyst is removed by filtration. When the reaction mixture is obtained in a precipitated state, it is heated or added with water to dissolve the precipitate and treated in the same manner. In either case, the filtrate is neutralized with sodium hydroxide, potassium hydroxide, ammonia, triethylamine and the like to separate and distill the aminobenzylamine to obtain the final product.

As another method of treating the precipitated reaction mixture, the precipitate is filtered off and the neutralized acid salt is purified to give the desired product.

Therefore, the production method of the present invention is basically a method for catalytically reducing nitrobenzylamine using a catalyst in a solvent. The reaction proceeds smoothly at low temperatures to produce aminobenzylamine in high yield. If the reaction is carried out in the presence of an inorganic acid, organic acid or carbonic acid, the intermediate is present in the stable form of the acid salt of aminobenzylamine. That is, the aminomethyl group of the nitrobenzyl amine during the reduction reaction is stabilized in the form of an inorganic acid salt, an organic acid salt or a carbonic acid salt. By the stabilization phenomenon, decomposition reactions and side reactions are suppressed, so that the nitro group is rapidly reduced to the amino group, thereby selectively preparing aminobenzylamine. The aminobenzyl amine can be easily separated by distillation and purification after the reduction reaction in the form of an inorganic acid salt, an organic acid salt or a carbonate salt, or after a simple neutralization process. As such, the production method of the present invention is commercially very advantageous.

In addition, when the nitrobenzylamine mixture obtained by nitrating benzylamine is used as a raw material for the reduction reaction, the mixture is obtained in the form of inorganic acid salts of O-, m-, and p- isomers. If such a mixture is used in a reduction reaction as it is, it can be obtained as an aminobenzylamine mixture since it remains in a stable form during the reduction reaction. The contents of O-, m- and p-aminobenzylamine in the mixture range from 0 to 5, 30 to 70, and 30 to 70% by weight, respectively.

In the process of the present invention, the catalyst activity is not reduced, so that the catalyst can be reused and thus economically very advantageous. In addition, since the solvent recovery and separation of the product can be carried out simply by distillation after the production method reduction reaction, it is very commercially advantageous.

The invention has been described in detail by the following examples, in which% represents by weight.

Example 1

Into the glass reactor, 13.6 g (0.1 mol) of O-nitrobenzylamine, 50 ml of methanol, and 0.3 g of 5% Pd / c catalyst were sealed, and hydrogen was injected with vigorous stirring. When the reaction temperature is maintained at 30 to 40 ° C. for 3 hours, hydrogen of 6.9 ι is absorbed. After the absorption of hydrogen is complete, the reaction mixture is filtered for catalyst removal and vaporized in vacuo to yield 10.1 g (82.7% yield) of O-aminobenzylamine product.

The boiling point of the product was 91 to 93 ° C / mmHg, the melting point was 58 to 61 ° C, and the purity was 99.8% as a result of gas chromatography. Elemental analysis values are as follows.

Elemental Analysis (C ₇ H ₁₀ N ₂ )

Example 2

13.6 g (0.1 mol) of m-nitrobenzylamine, 70 ml of tetrahydrofuran and 2 g of Raney nickel catalyst are added to a high pressure reactor. Hydrogen is injected with vigorous stirring and the pressure is maintained at 30-35 kg / cm 2 G. The reaction is carried out at 40-50 ° C. for 2 hours. After the reaction was completed, the method of Example 1 was repeated to yield 10.7 g of m-amino benzylamine (yield 87.6%). The product had a boiling point of 130 to 132 DEG C / 6 mmHg, a melting point of 41 to 42 DEG C, and a purity of 99.9% as a result of gas chromatography. The results of elemental analysis are as follows.

Elemental Analysis (C ₇ H ₁₀ N ₂ )

Example 3

The reaction was carried out in the same manner as described in Example 1 except that 13.6 g (0.1 mol) of p-nitrobenzylamine as raw material, 50 ml of dioxane and 0.4 g of 5% Pt / c catalyst as solvent were used. 10.5 g is obtained (yield 85.9%). The product is a clear liquid having a boiling point of 129-130 ° C./5 mmHg and a purity of 99.4% based on gas chromatography. The results of the elemental analysis are as follows.

Elemental Analysis (C ₇ H ₁₀ N ₂ )

Example 4

In a glass reactor, 13.6 g (0.1 mole) of m-nitrobenzylamine, 90% isopropane, 200 ml of aqueous solution, 21 g (0.2 mole) of 35% hydrochloric acid, and 0.4 g of 5% Pd / c catalyst were injected, and hydrogen was injected with vigorous stirring. . The reaction temperature is maintained at 23-35 ° C. and reacted for 3 hours to absorb 6.68 6. of hydrogen. After the absorption of hydrogen has ended, the reaction mixture is heated to 70 ° C. and filtered to remove the catalyst. When the filtrate is left to cool, m-aminobenzylamine hydrochloride precipitates out as white needles and crystals. The crystals are filtered off, washed with isopropanol and dried to give 15.8 g of product having a melting point of 274-277 ° C. (yield 81%). The results of the elemental analysis are as follows.

Elemental Analysis (C ₇ H ₁₂ N ₂ Cl ₂ )

Example 5

13.6 g (0.1 mol) of m-nitrobenzylamine, 100 ml of water, 20 g (0.2 mol) of phosphoric acid and 0.4 g of 5% Pd / c catalyst were added to the glass reactor, followed by the procedure described in Example 4, followed by hydrogen injection. . After completion of the reaction, the Pd / c catalyst is removed by filtration, the filtrate is concentrated to one third of the volume and left to cool to precipitate m-aminobenzylamine phosphate as white needle crystals. The crystals were filtered off, washed with methanol and dried to yield 20.4 g of product having a melting point of 209-213 ° C. (yield 77.3%).

The results of the elemental analysis are as follows.

Elemental Analysis (C ₇ H ₁₀ N ₂ )

Example 6

The method described in Example 4 was repeated except that 50 ml of methanol, 3.5 g (0.05 mol) of boric anhydride and 0.27 g of 5% Pd / c catalyst were used. After completion of the reaction, the reaction mixture is filtered for catalyst removal and methanol is distilled under reduced pressure to give a yellow viscous liquid. Neutralize this liquid with 35% aqueous sodium hydroxide solution and impure m-aminobenzylamine separates from the conflict as a brown oil. The oil was vacuum distilled at 6 mmHg to obtain 11.6 g of a stroke having a boiling point of 131 to 132 DEG C (yield 94.9%). If the fraction is left overnight, crystals are precipitated. The obtained product has a melting point of 40 to 41 ° C.

The results of the elemental analysis are as follows.

Elemental Analysis (C ₇ H ₁₀ N ₂ )

Example 7

The reaction conditions and post-treatment described in Example 6 were the same except that 13.6 g (0.1 mol) of p-nitrobenzylamine, 50 ml of methanol, 14.2 g (0.1 mol) of phosphorus pentoxide and 0.27 g of 5% Pd / c catalyst were used. Do it. Distillation under vacuum afforded 11.4 g of a colorless transparent oil having a boiling point of 129.5 to 130 ° C / 5 to 6 mmHg (yield 93.9%). The results of the elemental analysis are as follows.

Elemental Analysis (C ₇ H ₁₀ N ₂ )

Example 8

Into the glass reactor, 13.6 g (0.1 mol) of p-nitrobenzylamine, 75 ml of water, 10.5 g (0.1 mol) of 60% nitric acid, and 0.27 g of 5% Pd / c catalyst are injected with vigorous stirring. The reaction is continued for 3 hours at 20-30 ° C. The reaction mixture is then warmed to 60 ° C. and filtered to remove the catalyst. The filtrate was neutralized with 32 g (0.8 mole) of sodium hydroxide to separate the p-aminobenzylamines that separated in the conflict as a brown oil. The brown oil was distilled under vacuum to afford 10.4 g of p-aminobenzylamine (yield 85.1%).

Example 9

Into a high pressure reactor, 13.6 g (0.1 mol) of O-nitrobenzylamine, 50 ml of methanol, 6.2 g (0.1 mol) of boric acid, and 1 g of Raney nickel were added, and hydrogen was injected with vigorous stirring to give a pressure of 20 to 30 kg / cm 2 G. The reaction is conducted at 90 ° C. for 90 minutes. After completion of the reaction, the resulting mixture was cooled and worked up as described in Example 6 to give 9.8 g of O-aminobenzylamine having a boiling point of 91 to 93 ° C / 1 mmHg and a melting point of 59 to 61 ° C. Yield 80.2%).

The results of the elemental analysis are as follows.

Elemental Analysis (C ₇ H ₁₀ N ₂ )

Example 10

13.6 g (0.1 mol) of m-nitrobenzylamine, 6 g (0.1 mol) of glacial acetic acid, 0.3 g of 5% Pd / c catalyst and 50 ml of isopropanol were added to the glass reactor, and hydrogen was injected with vigorous stirring. The reaction is carried out at 30 to 40 ° C. for 5 hours to absorb 6.9ι hydrogen and complete the absorption. After completion of the reaction, the resulting mixture is filtered to remove the catalyst and vacuum distilled most of the isopropanol to give a concentrated yellow viscous liquid. The liquid is left to crystallize. The resulting crystals are filtered, washed with isopropanol and dried to give 13.3 g of white crystals (73.2% yield). The melting point of m-aminobenzylamine acetate thus obtained is 129-131 ° C.

The results of the elemental analysis are as follows.

Elemental Analysis (C ₉ H ₁₄ N ₂ O ₂ )

Example 11

13.6 g (0.1 mole) of p-nitrobenzylamine, 7.4 g (0.1 mole) propionic acid, 0.4 g of 5% Pt / c catalyst and 50 ml of methanol were added to the glass lamp and the reaction conditions described in Example 10 were repeated. After completion of the reaction, the catalyst is filtered off to recover most of the methanol. 35 g of 35% aqueous sodium hydroxide solution was added to the fish residue, stirred, and left to separate into two layers. The lower layer was removed and the upper layer was distilled to give 11.3 g of p-aminobenzylamine as a colorless transparent oil having a boiling point of 129 to 131 DEG C / 6 mmHg (yield 92.5%).

Example 12

The procedure described in Example 11 was repeated except that 13.6 g (0.1 mol) of O-nitrobenzylamine, 0.6 g of 5% Pd / c catalyst and 50 ml of acetic acid were used as the acid and solvent, and the melting point was 60-61 DEG C. 10.6 g of O-aminobenzylamine at 91 to 93 ° C / 1 mmHg are obtained (yield 86.7%).

Example 13

13.2 g (0.1 mol) of p-nitrobenzylamine, 13.2 g (0.3 mol) of dry ice, 1 g of Raney nickel catalyst, and 75 ml of methanol were added to a high-pressure reactor, and hydrogen was injected to maintain a pressure of 30 to 35 k / cm 2 G. The reaction is carried out with stirring at 20-40 ° C. for 5 hours. The resulting reaction mixture was filtered to restrain the catalyst, and then 4 g of sodium hydroxide was added and distilled to give 11.0 g of p-aminobenzylamine having a purity of 99.9% by gas chromatography (yield 90%).

The results of elemental analysis are as follows.

Elemental Analysis (C ₇ H ₁₀ N ₂ )

Example 14

The same procedure as in Example 13 was carried out except that 13.6 g (0.1 mol) of O-nitrobenzylamine as a raw material and tetrahydrofuran were used as the solvent. After completion of the reaction, the separated crystals are filtered and recrystallized from isopropanol to separate white needle crystals. The pure m-aminobenzylamine carbonate obtained was 6.7 g (yield 43.1%), and melting | fusing point was 115-117 degreeC.

Elemental analysis results are as follows.

Elemental Analysis (C ₁₅ H ₂₂ N ₄ O ₃ )

Example 15

107 g (1 mole) of benzylamine is added dropwise to 643 g (1 mole) of 98% nitric acid over 5 hours at a temperature not higher than 0 ° C. After completion of the dropwise addition, the mixture was reacted at a temperature of 20 to 25 ° C. for 3 hours while stirring. The reaction mixture is poured into 750 g of ice water and the precipitated crystals are filtered and washed with saturated sodium chloride solution to give nitro benzylamine nitrate. The crystal obtained was 254 g and the solid content was 61% (yield 72.1%).

The results of elemental analysis after recrystallization with water are as follows.

Elemental Analysis (C ₇ H ₉ N ₃ O ₅ )

35.3 g (0.1 mol) of wet nitrobenzylamine nitrate crystals, 0.2 g of 5% Pd / c catalyst and 50 g of water are placed in a glass reactor. Hydrogen is injected with vigorous stirring. The reaction is continued for 7 hours at 25-30 ° C. After the reaction, the reaction mixture is warmed to 50-60 ° C. and filtered to remove the catalyst. The filtrate is neutralized by adding 32 g of granular sodium hydroxide and left to stand until separated into two layers. The lower layer was removed and the upper layer was distilled under reduced pressure to yield 11 g of a colorless transparent oily fraction. It has a boiling point of 130 to 140 ° C / 5 to 7 mmHg (total yield calculated from benzylamine is 65%). The product is a mixture of aminobenzylamines. Analysis by gas chromatography contained 41.3% m-aminobenzylamine, 57.6% p-aminobenzylamine and 1.1% O-aminobenzylamine.

Example 16

107 g (1 mole) of benzylamine is added dropwise over 5 hours to a mixed acid consisting of 77 g (1.2 mole) of 98% nitric acid and 300 g (3 mole) of 98% sulfuric acid at a temperature not higher than 0 ° C. After completion of the dropwise addition, the reaction was continued with stirring at 20-25 ° C. for 3 hours. The reaction mixture was poured into 750 g of cold water, and the precipitated crystals were filtered and washed with saturated sodium chloride solution to obtain 8 g of wet crystals having a solid content of 60%. The result of elemental analysis is as follows and the crystal obtained is nitrobenzylamine sulfate (yield 65%).

Elemental Analysis (C ₁₄ H ₁₈ N ₄ O ₈ S)

21.8 g of wet crystals of nitrobenzylamine sulfate, 0.5 g of 5% Pd / c catalyst and 45 ml of water were added to the glass reactor, hydrogen was injected with vigorous stirring, and reacted at a temperature of 25 to 30 ° C. for 7 hours. After completion of the reaction, the fished reaction mixture is warmed to 50-60 ° C. and then filtered for catalyst removal. 22.5 g of an aqueous 45% sodium hydroxide solution and 14.0 g of sodium sulfate (dehydrate) were added to the filtrate, neutralized and allowed to separate into two layers. The lower layer was removed and the upper layer was distilled under reduced pressure to yield 7.1 g of a colorless transparent oily fraction. It has a boiling point of 130 to 140 ° C./5 to 7 mmHg (total yield calculated based on benzylamine is 58.0%). The product was a mixture of aminobenzyl amines, and gas chromatography analysis showed 48.5% m-aminobenzylamine, 50.2% p-aminobenzylamine, and 1.3% O-aminobenzylamine.

Example 17

107 g (1 mole) of benzylamine is added dropwise over 5 hours to a mixed acid consisting of 257 g (4 moles) of 98% nitric acid and 200 g (2 moles) of 98% sulfuric acid at a temperature not higher than 0 ° C. After completion of the dropwise addition, the reaction is continued for 3 hours at a temperature of 20-25 ° C. under vigorous stirring. The resulting reaction mixture was poured into 750 g of ice water, and the precipitated crystals were filtered and washed with a saturated aqueous sodium chloride solution to give 284 g of wet crystals having a solid content of 64.3%. The elemental analysis results are as follows and the crystal is nitrobenzylamine nitrate (yield 85%).

Elemental Analysis (C ₇ H ₉ N ₃ O ₅ )

The wet crystals of nitrobenzylamine nitrate are reduced and worked up as described in Example 16 to give a mixture of aminobenzylamines (total yield calculated on the basis of benzylamine 74.5%).

Analysis by gas chromatography showed that the mixture contained 47.4% m-aminobenzylamine, 51.1% p-aminobenzylamine and 1.5% O-aminobenzylamine.

Example 18

107 g (1 mole) of benzylamine are nitrated by a method described in Example 17 with a mixed acid consisting of 128 g (2 moles) of 98% nitric acid and 200 g (2 moles) of sulfuric acid to give 272 g of wet crystals. The results of the elemental analysis were as follows and the product was a mixture of nitrate and sulfate of aminobenzylamine and the ratio was estimated to be generally one to one.

Elemental analysis

The inorganic acid salt of the nitrobenzylamine obtained is reduced and worked up by the method described in Example 16 to obtain an aminobenzylamine mixture (total yield based on benzyl amine is 68.7%). Gas chromatography showed that the mixture contained 47.2% m-aminobenzylamine, 51.0% p-aminobenzylamine, and 1.8% O-aminobenzylamine.

Example 19

At a temperature not higher than 0 ° C., 107 g (1 mole) of benzylamine was added to a mixed acid solution consisting of 121 g (1.2 moles) of potassium nitrate, 300 g (3 moles) of 98% sulfuric acid and 400 ml of 1,2-dichloroethane. Drop over time. After completion of the dropwise addition, the reaction was continued with stirring for 3 hours at a temperature of 20-25 DEG C and then stopped to separate the resulting mixture into two layers. The lower layer was poured into 750 g of ice water, filtered to obtain crystals, and then washed with saturated sodium chloride solution to obtain 230 g of wet crystals of nitrobenzylamine inorganic acid salt. 230 g of wet crystals, 1.5 g of 5% Pd / c catalyst, and 450 g of water were added to the glass reactor and reduced and worked up as described in Example 16 to obtain an aminobenzylamine mixture (the total yield calculated from benzylamine was 58.9%). Gas chromatography showed that the mixture contained 59.5% m-aminobenzylamine, 35.0% p-aminobenzylamine and 5.5% O-aminobenzylamine.

Example 20

Into the glass reactor, 35.3 g of wet crystals of nitrobenzylamine nitrate obtained in Example 15, 0.1 g of 5% Pd / c catalyst and 45 ml of methanol were added and hydrogen was injected while stirring. The reaction is continued for 8 hours at 25-30 占 폚. After the reaction is completed, the resulting reaction mixture is warmed to 60-65 ° C. to remove the catalyst. The filtrate is distilled under reduced pressure to remove most of the methanol and give a yellow viscous liquid. 130 g of 30% aqueous sodium hydroxide solution was added thereto, stirred, and left to stand to form two layers. The lower layer was removed and the upper layer was distilled under reduced pressure to give 11.1 g of a fraction having a boiling point of 130 to 140 ° C / 5 to 7 mmHg (total yield calculated from benzylamine 65.5%).

Example 20

Into the glass reactor, 35.3 g of wet crystals of nitrobenzylamine nitrate obtained in Example 15, 0.1 g of 5% Pd / c catalyst, and 45 ml of methanol were added thereto, and hydrogen was directly injected with vigorous stirring. The reaction is counted at 25-30 ° C. for 8 hours. After completion of the reaction, the resulting reaction mixture is warmed to 60-65 ° C. to remove the catalyst. The filtrate is distilled under vacuum to distill off methanol to yield a yellow viscous liquid. 130 g of 30% aqueous sodium hydroxide solution was added thereto, stirred, and left to separate into two layers. The lower layer was removed and the upper layer was distilled under reduced pressure to obtain 11.1 g of a fraction having a boiling point of 130 to 140 ° C./5 to 7 mmHg (total yield calculated from benzylamine is 65.5%).

Claims (5)

A process for preparing an amino benzylamine mixture, comprising catalytically reducing the photoacid salt of the nitro benzylamine isomer mixture obtained by nitrating benzylamine in the presence of a platinum group metal. The mixture of aminobenzyl amines according to claim 1 wherein the mineral acid salt is a mixture of mineral salts containing 0-, m- and p-isomers of nitrobenzylamine in the range of 0.2 to 10,30 to 70 and 30 to 70% by weight, respectively. Manufacturing method. The process for preparing the amino benzylamine mixture according to claim 1, wherein the photo acid salt of the nitrobenzylamine mixture is nitrate. The process for producing a benzylamine mixture according to claim 1, wherein the photo acid salt of the nitrobenzylamine mixture is sulfate. The process for preparing the amino benzylamine mixture according to claim 1, wherein the photo acid salt of the nitrobenzylamine mixture is a mixture of nitrate and sulfate.