GB2162839A - Process for preparing aminobenzylamine - Google Patents
Process for preparing aminobenzylamine Download PDFInfo
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- GB2162839A GB2162839A GB08514417A GB8514417A GB2162839A GB 2162839 A GB2162839 A GB 2162839A GB 08514417 A GB08514417 A GB 08514417A GB 8514417 A GB8514417 A GB 8514417A GB 2162839 A GB2162839 A GB 2162839A
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/30—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds
- C07C209/32—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds by reduction of nitro groups
- C07C209/36—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds by reduction of nitro groups by reduction of nitro groups bound to carbon atoms of six-membered aromatic rings in presence of hydrogen-containing gases and a catalyst
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/68—Preparation of compounds containing amino groups bound to a carbon skeleton from amines, by reactions not involving amino groups, e.g. reduction of unsaturated amines, aromatisation, or substitution of the carbon skeleton
- C07C209/76—Preparation of compounds containing amino groups bound to a carbon skeleton from amines, by reactions not involving amino groups, e.g. reduction of unsaturated amines, aromatisation, or substitution of the carbon skeleton by nitration
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/82—Purification; Separation; Stabilisation; Use of additives
- C07C209/90—Stabilisation; Use of additives
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C211/00—Compounds containing amino groups bound to a carbon skeleton
- C07C211/01—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to acyclic carbon atoms
- C07C211/26—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to acyclic carbon atoms of an unsaturated carbon skeleton containing at least one six-membered aromatic ring
- C07C211/29—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to acyclic carbon atoms of an unsaturated carbon skeleton containing at least one six-membered aromatic ring the carbon skeleton being further substituted by halogen atoms or by nitro or nitroso groups
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C211/00—Compounds containing amino groups bound to a carbon skeleton
- C07C211/43—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton
- C07C211/44—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton having amino groups bound to only one six-membered aromatic ring
- C07C211/49—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton having amino groups bound to only one six-membered aromatic ring having at least two amino groups bound to the carbon skeleton
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Abstract
A process for preparing an aminobenzylamine comprises catalytically reducing a nitrobenzylamine of the general formula (I): <IMAGE> wherein the nitro-group is located at the o-position, m-position, or p-position. As preferred embodiments of this process, there is disclosed a method for catalytically reducing in the presence of acids, and a method of using mineral acid salts of a nitrobenzylamine mixture obtained by nitrating benzylamine.
Description
SPECIFICATION
Process for preparing aminobenzylamine
This invention relates to a process for preparing aminobenzylamine, and particularly provides a very advantageous process for industrial practices
Aminobenzylamine is an important compound as a curing agent for epoxy resin, a raw material for polyamides and polyimides, and a raw material for intermediates of agricultrual chemicals and medicines. Processes for preparing aminobenzylamine by using nitrobenzaldehyde or nitro-benzonitrile as starting material have so far been known
For example, as for the process using the former as starting material, there are known the following processes:
(i) Nitrobenzylbromide is derived from nitrobenzaldehyde which is then reacted with potassium phthalimide to obtain N- nitro-benzylphthalimide, and m- and p-aminobenzylamines is produced with an yield of about 20% by reduced and hydrolyzed. (N.Kornblum et al, J. Am. Chem. Soc., 71,2137 (1949)).
(ii) m-Nitrobenzaldehyde is reacted with phenylhydrazine and the resulting hydrazone compound is catalytically reduced whereby m-aminobenzylamine is obtained in 60% yield. (A. Siddiqui et al, Synth.
Commn., 7, 71-78 (1977)).
(iii) m-Nitrobenzaldoxime is derived from m-nitrobenzaldehyde and catalytically reduced on a Raney nickel catalyst under a high pressure whereby p-aminobenzylamine is obtained in 52% yield. (J.R. Griffith et al, N R L report 6439).
On the other hand, processes starting the latter are as follows:
(iv) p-Aminobenzonitrile derived from p-nitrobenzonitrile is reduced by aluminum lithium hydride and thus, p-aminobenzylamine is obtained in 37% yield (N. C. Brown et al, J. Medicinal Chem., 20,1189 (1977)).
(v) By catalytically reducing m-nitrobenzonitrile under a high pressure on the Raney nickel catalyst, maminobenzylamine is obtained in 49% yield. (J. R. Griffith et al, N R L Report 6439).
In other processes, aminobenzylamine is prepared by reducing nitrobenzylamine as the starting materials. For example,
(vi) m-Aminobenzylamine is prepared by reducing m-nitrobenzyl-amine with tin and hydrochloric acid.
(S. Gabriel et al, Ber., 20,2869-2870 (1887)).
(vii) o-Aminobenzylamine is prepared by reducing o-nitro-benzylamine with red phosphorus and large quantities of hydroiodic acid (S. Gabriel et al, Ber., 37, 3643-3645 (1904)).
As mentioned above, according to the known processes(i) and (ii) which prepare aminobenzylamine by using nitrobenzaldehyde or nitrobenzonitrile as the starting materials, a more than equivalent quantity of relatively expensive compound is used to prepare intermediates which are reduced to obtain intended products. However, in these processes there are disadvantages that reduction steps are complicated or expense and labor are required for recovering by-products and the like.
Also in the process(iv), there are the disadvantages that the reducing agent is expensive and difficult in handling. In the processes (iii) and (v), wherein the catalytic reduction on the Raney nickel catalyst is carried out in an autoclave under a high pressure, equipment apparatus is expensive and volume efficiency is low.
On the other hand, in the known process (vi), nitrobenzylamine as the starting materials, is reduced by large quantities of tin and hydrochloric acid to isolate a tin salt of the intended product before its liberation by double decomposition. The process is complicated because of separating procedure on resultant metallic compounds and care is needed not to leave a trace of the metal. In addition, considerable expense and labor are needed to prevent environmental problems caused by large amount of heavy metals and waste acids, as well as to recover these hazardous materials.
As a means of improving above mentioned processes, the product is obtained in the process (vii) by reducing with red phosphorus and hydroiodic acid. And yet expensive hydroiodic acid is required in large quantities and red phosphorus is in a great danger of ignition.
Therefore the known processes for preparing-aminobenzylamine have many steps, complicated aftertreatments, or equipmental problems.
It is an object of this invention to provide a process for industrially preparing aminobenzylamine by catalytically reducing nitrobenzylamine.
It is an another object of this invention to provide a process for preparing aminobenzylamine with a high yield, which comprises catalytically reducing nitrobenzylamine in the presence of acids to prevent decomposition or side reaction. It is a still further object of this invention to provide a process for preparing an aminobenzylamine isomer mixture by using mineral acid salts of a nitrobenzylamine isomer mixture obtained by nitrating benzylamine to use as nitrobenzylamine raw materials.
The starting materials used in this invention is o-nitro-benzylamine, m-nitrobenzylamine and p-nitrobenzylamine. These o-, m-, and p-isomers are prepared with a high yield by reacting a corresponding nitrobenzylchloride with ammonia or phthalimide (S. Gabriel et al, Ber., 2869 (1887); E. L. Holmes et al, J.
Chem. Soc., 1800-1821 (1925); H. L. Ing et al, J. Chem.Soc., 2348-2351 (1926)).
In addition, nitrobenzylamine which are used for the raw materials is nitrate and/or sulfate of nitroben zylamine mixture obtained by nitrating benzylamine. This kind of nitrate and/or sulfate of nitrobenzylamine may be obtained by nitrating benzylamine with a nitrating agent. The nitrating agent which may be used in the process includes a mixed acid, fuming nitric acid, a nitric acid / acetic acid mixture, and the like. Normally, the mixed acid or fuming nitric acid is preferred. By using the nitrating agent, reaction is carried out as follows. When nitrating with fuming nitric acid, nitric acid having a concentration of 80 to 98% is used 8 to 12 times the mol of benzylamine. When nitrating with the mixed acid, it is composed of concentrated sulfuric acid and nitric acid or nitrate such as sodium nitrate, potassium nitrate, and the like.The mol ratio among benzylamine, nitric acid or nitrate, and concentrated sulfuric acid is in a range of 1 1:1.2-5:1-5 If necessary, nitration may be carried out in organic solvents. Preferred organic solvents include halogenated hydrocarbon solvents such as methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, chloroform, carbon tetrachloride, 1,1,2, 2-tet-rachloroethane, trichloroethylene, and the like.
The reaction can proceed either by dropping benzylamine into the nitrating agent or by a reverse method. When applying the mixed acid, the reaction can be carried out either by using the previously prepared acid mixture, or by mixing benzylamine with one component of the mixed acid before dropping the other component.
The reaction temperature is in the range of -10 C to 800C, preferably -BC to 30"C. The reaction time is preferably in the range of 2 to 10 hours
After completion of reaction, the resultant mixture is poured into a specified amount of ice water. Mineral acid salts of the nitrobenzylamine mixture may be obtained by filtering the precipitate. By pouring the reaction mixture into ice water, m- nitro-benzylamine and p-nitrobenzylamine are mainly settled, and most of o-nitrobenzylamine is removed to the filtrate. o-Nitrobenzylamine content in the nitrobenzylamine mixture is 10 to 15% by weight at the end of nitrating reaction. Solubility of o-isomer in water is large as compared with other isomers and thus, as stated above, o-isomer content of the separated mixture reduces to 5% by weight and less.
The mineral acid salts of nitrobenzylamine mixture herein mentioned are sulfate, nitrate or mixtures thereof of the o-, m-, or p-substituted nitrobenzylamine mixture obtained by nitrating benzylamine as described above. The m-, p-, and o-isomer ratio in the nitrobenzylamine mixture thus obtained is in the range of 30-70 : 30-70 : 0.2-10, and o-isomer content is normally not more than 5% by weight. When the nitrating agent is composed of nitric acid alone or the mixed acid containing not more than 2 mol ratio of sulfuric acid and excess nitric acid, nitrobenzylamine is obtained as nitrate. In other nitrating conditions, the product is sulfate or the mixture of sulfate and nitrate.The mixture of nitrobenzylamine isomers thus obtained, particularly in the presence of nitrate, is not desiccated from safety and operation view point.
The wet mixture may be applied as it is to the catalytic reduction from safety and operation viewpoint.
The catalytic reduction in this invention may be carried out in the absence of acid. In this invention, however, the catalytic reduction may preferably be conducted in the presence of acids.
The acid which may be used in this invention is mineral acid, organic acid or carbonic acid. As to mineral acid is at least one member of selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, boric acid, phosphoric acid, boric acid anhydride and phosphoric acid anhydride. The use of these mineral acids selectively proceeds the reaction to obtain desired products.
The mineral acids are relatively low priced and accelerating effect is found in the reducing reaction.
Thus it is also a characteristic of this process that the intended product may be prepared efficiently and economically. In addition, mineral acid anhydrides absorb water existed in the reaction system and generated from the reduction of nitro group Thus reducing reaction may be carried out in anhydrous and ideal conditions, that is, undesired action such as decomposition or side reaction by water is prohibited and the reducing reaction may be proceeded with excellent selectivity.
Also, as to organic acid is aliphatic mono- or di-carboxylic 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, sulfonic and sulfinic acid such as p-toluenesulfonic acid and benzenesul- finic acid. A part of these carboxylic acids may also be used as acid anhydrides. Acetic acid is used preferably among the organic acids in commercial scale. Some organic acids may also be used as solvents. When using the organic acids, the reaction proceeds quickly under mild conditions due to the good compatibility of organic acids with raw materials and other solvents. Since a homogeneous solution is resulted from the reaction, aftertreatment such as catalyst and solvent recovery etc. may easily be carried out.
The fact that almost no reduction is found on the activity of recovered catalysts, is a great advantage of this process, enables recycled use of the catalysts and makes the process economical. Further in some cases, it is possible to recover organic acids by distillation or other means after amino-benzylamine is isolated from its organic acid salts, which permits better results on the commercial scale application.
As carbonic acids, satisfactory results may be obtained by use of carbon dioxide. That is, carbon dioxide converts to carbonic acid by reacting with water which exists in the reaction system or generates from the reduction of nitro groups. Carbon dioxide may be used in gas, liquid and solid states. Relatively simple after-treatment is a great merit of reactions using carbon dioxide. Excess carbon dioxide is discharged after the reaction, the catalysts are removed and distillation is carried out after adding base.
Thus solvents are recovered at a high rate and desired product of aminobenzylamine may be obtained in high yield. The process has also a characteristic of no reduction on the activity of recovered catalysts, which enables their recycled use and makes the process economical.
The amount of acid used is not less than 0.5 equivalent of nitrobenzylamine, preferably in the range of 1 to 3 equivalent. These acids may be used alone or in mixture of two or more.
Also solvents are used for catalytic reduction in the process 6f this invention. The solvent which may be used in this process is water, alcohols, goycols and ethers, e.g. methanol, ethanol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, methyl cellosolve, ethyl cellosolve, ethylene glycol, propylene glycol, diglyme, tetraglyme, dioxane, tetrahydrofuran, and the like. In some cases, there are used aliphatic hydrocarbons, aromatic hydrocarbons, esters and halogenated hydrocarbons e.g. hexane, cyclohexane, benzene, toluene, ethyl acetate, butyl acetate, dichloromethane, chloroform, 1,1 ,2-trichloroethane, and these like. These solvents may be used alone or in mixture of two or more.
The amount of solvent used is not particularly limited, but normally sufficient at 1 to 15 times by weight based on the amount of raw materials.
The reducing catalysts which may be used in the process of this invention may be conventional one, e.g. nickel, palladium, platinum, rhodium, ruthenium, cobalt, copper and the like. Although these catalysts may be used in the form of metal, they may be used in form supported 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
Raney catalysts. The amount of catalysts used is in the range of 0.01 to 30% by weight in term of metal based on nitro-benzylamine. Usually, a range of 2 to 20% by weight is preffered in the case where Raney catalysts are used, while a range of 0.05 to 5% by weight in the case where noble metals supported on a carrier are used.
The reaction temperature is not particularly limited, though it is usually in the range of 0 to 150"C, preferably 10 to 80"C.
The reaction pressure may be usually in the range of atmo- spheric pressure to 50 Kg/cm2G.
As for general embodiments of this invention, a catalyst may be added to the raw materials in a state where it is dissolved or suspended in a solvent, followed by introducing hydrogen to carry out at the specified temperature until its absorption stops. After the completion of the reaction, the reaction mixture is filtered to remove the catalysts and distilled to obtain the intended product.
When using mineral or organic acids, a catalyst may be added to a solution or suspension of the raw materials and the acids in the solvents, and reducing reaction is carried out. When applying carbon dioxide, a catalyst may be added to a solution or suspension of the raw materials in a solvent and then reducing reaction is carried out either by previously adding whole amount of carbon dioxide or by continuously or intermittently adding. In any case, catalytic reduction is carried out until absorption of hydrogen stops. When catalytic reduction is conducted in the absence of acids, the reaction product is dissolved after the reaction. Then resultant mixture is filtered to remove the catalysts and distilled to obtain the intended product.When a dissolved reaction mixture is resulted from catalytic reduction in the presence of the acids, it is filtered to remove the catalysts. When a precipitated reaction mixture is obtained, the same procedure is carried out after the precipitate is dissolved by warming or by addition of water and the like. In either case, the filtrate is neutralized with sodium hydroxide, potassium hydroxide, ammonia, triethylamine, or the like to liberate aminobenzylamine and distilled to obtain the end product.
Another method of treating the precipitated reaction mixture is that the precipitate is filtered to isolate and purify the acid salts which are neutralized to obtain the intended product.
Accordingly the process of this invention is basically the catalytic reduction of nitrobenzylamine in solvents and by use of catalysts. The reaction proceeds smoothly at low temperature to obtain aminobenzylamine in high yields. When the reduction is carried out in the presence of mineral acids, organic acids or carbonic acid, the intermediates exist in a stable state of acid salts of aminobenzylamine. That is, aminomethyl group of nitro-benzylamine is stabilized during the reduction in the form of mineral acid salts, organic acid salts or carbonate. The stabilization suppress decomposition and side reactions and results in a quick reduction of nitro group to amino group, which enables selective production of aminobenzyamine.Aminobenzylamine may easily be isolated after the reducing reaction either by separation and purification in the form of mineral acid salts, organic acid salts or carbonate, or by distillation and refining after a simple neutralization. Thus the process of this invention is commercially very advantageous.
Further, when nitrobenzylamine mixture resulted from nitration of benzylamine is used as raw materials for reduction, the mixture is obtained as mineral acid salts of o-, m-, and p- isomers. On applying the mixture as it is to the reduction, it stays in a stable form during the reaction to obtain aminobenzylamine mixture with a high yield. The contents of o-, m-, and p-aminobenzylamines in the mixture are in the range of 0-5, 30-70, and 30-70% by weight respectively.
The process of this invention has a merit of no reduction in catalyst activity, enables recycled use of the catalysts and is economically very favorable. The process is also commercially advantageous, because solvent recovery and product isolation may easily be carried out by distillation after the reaction.
This invention will now be described in detail by following examples in which % represent percent by weight.
Example 1
A sealed glass reaction vessel was charged with 13.6 grams (0.1 mol) of o-nitrobenzylamine, 50 ml of methanol and 0.3 gram of 5 % Pd/C catalyst. Hydrogen was introduced with a vigorous stirring. Reaction temperature was maintained at 30-40"C for 3 hours and 6.9 1 of hydrogen was absorbed. After the absorption of hydrogen was stopped, the reaction mixture was filtered to remove the catalyst and distilled in vacuum to obtain 10.1 grams of o-aminobenzylamine product (82.7% yield). The product has a boiling point of 91-93"C / 1 mmHg, a melting point of 58-61"C, and purity of 99.8% based on gas chromatography.
The results of elemental analysis were as follows.
Elemental Analysis (C, H10 N2)
C H N
Calculated (%) 68.8 8.25 22.9
Found ( /^) 68.7 8.4 22.3
Example 2
An autoclave was charged with 13.6 grams (0.1 mol) of m- nitro-benzylamine, 70 ml of tetrahydrofuran, and 2 grams of Raney nickel catalyst. Hydrogen was introduced with a vigorous stirring and pressure was maintained at 30-35 kg/cm2G. Reaction was carried out at 40-500C for 2 hours. After the completion of the reaction, the procedure of Example 1 was repeated to obtain 10.7 grams of m-amino-benzylamine (87.6% yield). The product had a boiling point of 130-132 C/6 mmHg, a melting point of 41-41"C, and purity of 99.9% based on gas chromatography.
The results of elemental analysis were as follows.
Elemental analysis (C, H,o N2)
C H N
Calculated (%) 68.8 8.25 22.9
Found (%) 68.6 8.4 22.7
Example 3
The reaction was carried out according to the method described in Example 1 except that 13.6 grams (0.1 mol) of p-nitrobenzyl- amine raw material, 50 ml of dioxane solvent and 0.4 gram of 5% Pt/C catalyst were employed, to obtain 10.5 grams of p-aminobenzyl- amine (85.9% yield). The product was a transparent liquid having a boiling point of 129-130"C/5 mmHg and purity of 99.4% based on gas chromatography.
The results of elemental analysis were as follows.
Elemental analysis ( C, H10 N2
C H N
Calculated (%) 68.8 8.25 22.9
Found (%) 68.4 8.7 22.8
Example 4
A sealed glass reaction vessel was charged with 13.6 grams (0.1 mol) of m-nitrobenzylamine, 200 ml of90% aqueous isopropanol solution, 21 grams (0.2 mol) of 35% hydrochloric acid and 0.4 gram of 5%-Pd/C catalyst. Hydrogen was introduced with a vigorous stirring. Reaction temperature was maintained at 23 35"C for 3 hours and 6.68 1 of hydrogen was absorbed. After the absorption of hydrogen was stopped, the reaction mixture was warmed to 700C and filtered to remove the catalyst. When the filtrate was allowed to cool, crystals of m-aminobenzylamine hydrochloride separated as while needles. The crystals were filtered, washed with isopropanol and dried to obtain 15.18 grams of the product (81% yield) having a melting point of274-277"C.
The results of elemental analysis were as follows.
Elemental Analysis ( C7 H12 N2 C12 C H N Cl
Calculated (%) 43.1 6.2 14.4 36.3
Found (%) 42.7 6.7 14.0 36.5
Example 5
A sealed glass reaction vessel was charged with 13.6 grams (0.1 mol) of m-nitrobenzylamine, 100 ml of water, 20 grams (0.2 mol) of phosphoric acid and 0.4 gram of 5% Pd/C catalyst. Hydrogen was introduced and the procedure described in Example 4 was followed. After the completion of the reaction, Pd/C catalyst was filtered off and the filtrate was concentrated to one third of its volume. Upon being allowed to cool, crystals of m-aminobenzylamine phosphate separated as while needles. The crystals were filtered, washed with methanol and dried to obtain 20.4 grams of the product (77.3% yield) having a melting point of 209-213"C.
The results of elemental analysis were as follows.
Elemental analysis ( C14 H29 N4 P2 12 C H N P
Calculated (%) 31.9 5.6 10.6 17.6
Found (%) 31.8 6.0 10.6 17.2
Example 6
The procedure described in Example 4 was repeated except that 50 ml of methanol, 3.5 grams (0.05 mol) of boric acid anhydride and 0.27 gram of 5% Pd/C were employed,
After the end of the reaction, the reaction mixture was filtered to remove the catalyst and methanol was distilled under vacuum to obtain a yellow viscous liquid. On neutralizing the liquid with 35% aqueous sodium hydroxide solution, crude m- aminobenzylamine separated in the upper layer as brown oil.The oil was vacuum distilled at 6 mmHg to obtain 11.6 grams of a fraction (94.9% yield) having a boiling point of 131-132"C. The fraction was crystallized after staying overnight. The product obtained had a melting point of 40-41"C.
The results of elemental analysis were as follows.
Elemental Analysis ( C, H10 N2)
C H N
Calculated (%) 68.8 8.3 22.9
Found (%) 68.5 8.2 22.6
Example 7
The same reaction conditions and aftertreatment were employed as described in Example 6 except 13.6 grams (0.1 mol) of p- nitrobenzylamine, 50 ml of methanol, 14.2 grams (0.1 mol) of phosphorus pentaoxide and 0.27 gram of 5% Pd/C catalyst.
Upon distillation in vacuum, 11.4 grams of colorless clear oil having a boiling point of 129.5-130"C/5-6 mmHg were obtained (93.3% yield).
The results of elemental analysis were as follows.
Elemental Analysis ( C7 H10 N2
C H N
Calculated (%) 68.8 8.3 22.9
Found (%) 69.1 8.6 22.5
Example 8
A sealed glass reaction vessel was charged with 13.6 grams (0.1 mol) of p-nitrobenzylamine, 75 ml of water, 10.5 grams (0.1 mol) of 60% nitric acid and 0.27 gram of 5% Pd/C catalyst. Hydrogen was introduced with a vigorous stirring. The reaction was continued at 20-30 C for 3 hours. The reaction mixture was then warmed to 60"C and filtered to remove the catalyst. The filtrate was neutralized with 32 grams (0.8 mol) of flaked sodium hydroxide to separate in the upper layer crude p-aminobenzyl- amine as bro.wn oil. The brown oil was distilled in vacuum to obtain 10.4 grams of p-aminobenzylamine (85.1% yield).
Example 9
An autoclave was charged with 13.6 grams (0.1 mol) of o-nitro- benzylamine, 50 mol of methanol, 6.2 grams (0.1 mol) of boric acid and 1 gram of Raney nickel. Hydrogen was introduced with a vigorous stirring to apply constant pressure of 20-30 Kg/cm7G at 70-80"C for 90 minutes. After the end ot the reaction, the resultant mixture was cooled and aftertreated as described in Example 6 to obtain 9.8 grams of o-aminobenzylamine (80.2% yield) having a boiling point of 91-93 C/1 mmHg and a melting point of 59 61vac.
Elemental analysis (C7 H10 N2
C H N
Calculated (%) 68.8 8.25 22.9
Found (%) 68.8 8.5 22.6
Example 10
A sealed glass reaction vessel is charged with 13.6 grams (0.1 mol) of m-nitrobenzylamine, 6 grams (0.1 mol) of glacial acetic acid, 0.3 gram of 5% Pd/C catalyst and 50 ml of isopropanol. Hydrogen was introduced with a vigorous stirring. After reacting at 30-40"C for 5 hours, 6.9 1 of hydrogen was absorbed and the absorption was stopped. Upon ending the reaction, the resultant mixture was filtered to remove the catalyst, concentrated in vacuum to distill off most of isopropanol, and a yellow viscous liquid was obtained. The liquid was set aside to crystallize.The resultant crystals were filtered, washed with isopropanol and dried to obtain 13.3 grams (73.2% yield) of white crystals. m-Aminobenzylamine acetate thus obtained had a melting point of 129-131"C.
The results of elemental analysis were as follows.
Elemental Analysis ( Cs H14 N2 O2
C H N
Calculated (%) 59.15 8.13 15.28
Found (%) 58.97 8.39 15.05
Example 11
A sealed glass reaction vessel was charged with 13.6 grams (0.1 mol) of p-nitrobenzylamine, 7.4 grams (0.1 mol) of propionic acid, 0.4 gram of 5% Pt/C catalyst and 50 ml of methanol. The reaction conditions as described in Example 10 were followed. After the end of the reaction, the catalyst was filtered off and most of methanol was recovered. To the resultant residue, 35 grams of 35% aqueous sodium hydroxide solution was added, stirred and allowed to stand for separating into two layers.The lower layer was removed and the upper layer was distilled to obtain 11.3 grams (92.5% yield) of p-aminobenzylamine as colorless transparent oil having a boiling point of 129-131 C /6 mmHg.
Example 12
The procedure as described in Example 11 was repeated except that 13.6 grams (0.1 mol) of o-nitrobenzylamine raw material, 0.6 gram of 5% Pd/C catalyst and 50 ml of acetic acid as acid and solvent were used to obtain 10.6 grams (86.7% yield) of o-aminobenzylamine having a melting point of 60-61"C and a boiling point of 91-93"C /1 mmHg.
Example 13
An autoclave was charged with 13.2 grams (0.1 mol) of p- nitrobenzylamine, 13.2 grams (0.3 mol) of dry ice, 1 gram of Raney nickel catalyst and 75 ml of methanol. Hydrogen was introduced to maintain the pressure at 30-35 Kg/cm7G. The reaction was continued at 20-40"C for 5 hours under vigorous stirring.
After the resultant reaction mixture was filtered to remove the catalyst, 4 grams of sodium hydroxide was added, followed by distillation to obtain 11.0 grams (90% yield) of p-aminobenzylamine having purity of 99.9% based on gas chromatography.
The results of elemental analysis are as follows.
Elemental Analysis ( C, H15 N7 C H N
Calculated (%) 68.8 8.25 22.9
Found (%) 68.7 8.3 23.0
Example 14
The same procedure was employed as in Example 13 except that 13.6 grams (0.1 mol) of o-nitrobenzylamine raw material and 50 ml of tetrahydrofuran solvent were used. After the end of the redaction, separated crystals were filtered and recrystallized from isopropanol to separate while needles. Pure maminobenzy- lamine carbonate thus obtained was 6.7 grams (43.1% yield) having a melting point of 115 117 C.
The results of elemental analysis were as follows.
Elemental Analysis ( C15 H22 N4 03 ) C H N
Calculated (%) 58.8 7.24 18.3
Found (%) 58.6 7.53 18.1
Example 15
At a temperature of not higher than 0 c, 107 grams (1 mol) of benzylamine were dropped into 643 grams (1 mol) of 98% nitric acid over a period of 5 hours. After the end of dropping, reaction was continued with stirring at 20-25"C for 3 hours. The resultant reaction mixture was poured into 750 grams of ice water, followed by filtering separated crystals which were washed with saturated sodium chloride solution to obtain nitrobenzylamine nitrate. The wet crystals thus obtained were 254 grams having a solid content of 61% (72.1% yield).
The results of elemental analysis after recrystallizing from water were as follows.
Elemental Analysis ( C7 H5 N7 05 ) C H N
Calculated (%) 39.07 4.19 19.53
Found (%) 38.91 4.07 19.33
A sealed glass reaction vessel was then charged with 35.3 grams (0.1 mol) of the wet nitrobenzylamine nitrate crystals, 0.2 gram of 5% Pd/C catalyst and 50 grams of water. Hydrogen was immediately introduced with a vigorous stirring. Reaction was continued at 25-30"C for 7 hours. After the end of the reaction, the resultant mixture was warmed to 50-60"C and filtered to remove the catalyst. The filtrate was neutralized by adding 32 grams of granular sodium hydroxide and allowed to stand for separating into two layers. The lower layer was removed and the upper layer was distiled in vacuum to obtain 11 grams of a colorless transparent oily fraction having a boiling point of 130-140 C /5-7 mmHg. (The total yield calculated from benzylamine was 65%.) The product was a mixture of aminobenzylamine. According to gas chromatography, it contains 41.3% m-aminobenzylamine, 57.6% of p-aminobenzylamine and 1.1% of o-aminobenzylamine.
Example 16
At a temperature of not higher than 0 C, 107 grams (1 mol) of benzylamine were dropped over a period of 5 hours into a mixed acid containing 77 grams (1.2 mols) of 98% nitric acid and 300 grams (3 mols) of 98% sulfuric acid. After the end of dropping. reaction was continued with stirring at 20-25"C for 3 hours.
The resultant reaction mixture was then poured into 750 grams of ice water, followed by filtering separated crystals which were washed with saturated sodium chloride solution to obtain 218 grams of wet crystals having a solid content of 60%. The results of elemental analysis were as follows and the crystals obtained were nitrobenzylamine sulfate (65% yield).
Elemental Analysis ( C14 H,8 N4 O, S
C H N O
Calculated (%) 41.79 4.48 13.93 7.96
Found (%) 39.9 4.14 13.67 8.45
A sealed glass reaction vessel was then charged with 21.8 grams of the wet nitrobenzylamine sulfate crystals, 0.5 gram of 5% Pd/C catalyst and 45 ml of water, and hydrogen was introduced with a vigorous stirring. Reaction was continued at 25-30"C for 7 hours. After the end of the reaction, the resultant reaction mixture was warmed to 50-60"C and filtered to remove the catalyst. The filtrate was neutralized by adding 22.5 grams of 45% sodium hydroxide solution and 14.0 grams of sodium sulfate (ten hydrate), and allowed to stand for separating into two layers.The lower layer was removed and the upper layer was distilled in vacuum to obtain 7.1 grams of a colorless transparent oil fraction having a boiling point 130-1400C/5-7 mmHg. (The total yield calculated from benzylamine was 58.0%.) The product was a mixture of aminobenzylamine. According to gas chromatography, it contains 48.5% of m-aminobenzylamine, 50.2% of p-aminobenzylamine and 1.3% of o-aminobenzylamine.
Example 17
At a temperature of not higher than 0 C, 107 grams (1 mol) of benzylamine were dropped over a period of 5 hours into a mixed acid containing 257 grams (4 mols) of 98% nitric acid and 200 grams (2 mols) of 98% sulfuric acid. After the end of dropping, reaction was continued with stirring at 20-25"C for 3 hours.
The resultant reaction mixture was then poured into 750 grams of ice water, followed by filtering separated crystals which were washed with saturated sodium chloride solution to obtain 284 grams of wet crystals having a solid content of 64.3%.
The results of elemental analysis were as follows and the crystals obtained were nitrobenzylamine nitrate (85% yield).
Elemental Analysis ( C2 Hg N3 0,
-C H N
Calculated (%) 39.07 4.19 19.53
Found (%) 38.35 4.21 19.86
The wet nitrobenzylamine nitrate crystals were then reduced and aftertreated by the same procedure as described in Example 16, and a mixture of aminobenzylamine was obtained. (The total yield calculated from benzylamine was 74.5%). According to gas chromatography, the mixture contains 47.4% of m-aminobenzylamine, 51.1% of p-aminobenzylamine and 1.5% of o-aminobenzylamine.
Example 18
One hundred and seven grams (1 mol) of benzylamine was nitrated with a mixed acid containing 128 grams (2 mols) of 98% nitric acid and 200 grams (2 mols) of 98% sulfuric acid by the same procedure as described in Example 17 and 272 grams of wet crystals were obtained. The results of elemental analysis were as follows and the product was a mixture of nitrate and sulfate of aminobenzylamine, the ratio of which were assumed to be approximately 111.
Elemental Analysis
C H N S
Calculated (%) sulfate 41.79 4.48 13.93 7.96
nitrate 39.07 4.19 19.53
Found (%) 40.52 4.25 16.82 3.81
The mineral acid salts of nitrobenzylamine thus obtained were reduced and aftertreated by the same procedure as described in Example 16 to obtain a mixture of aminobenzylamine. (The total yield calculated from benzylamine was 68.7%). According to gas chromatography, the mixture contains 47.2% of maminobenzylamine, 51.0% of p-aminobenzylamine and 1.8% of o-aminobenzylamine.
Example 19
At a temperature of not higher than 0 C, 107 grams (1 mol) of benzylamine were dropped over a period of 5 hours into a solution of mixed acid which contains 121 grams (1.2 mols) of potassium nitrate, 300 grams (3 mols) of 98% sulfuric acid and 400 ml of 1,2-dichloroethane.
After the end of dropping, reaction was continued with stirring at 20-25"C for 3 hours. When allowed to stand, the resultant mixture was separated into two layers. The lower layer of the mixed acid solution was poured into 750 grams of ice water, followed by filtering separated crystals which were washed with saturated sodium chloride solution to obtain 230 grams of wet crystals of nitrobenzylamine mineral acid salts. A sealed glass reaction vessel was then charged with 230 grams of the wet crystals of nitrobenzylamine mineral acid salts, 1.5 grams of 5% Pd/C catalyst and 450 grams of water.The charge was reduced and aftertreated by the same procedure as described in Example 16, and a mixture of aminobenzylamine was obtained. (The total yield calculated from benzylamine was 58.9%.) According to gas chromatography, the mixture contains 59.5% of m-aminobenzylamine, 35.0% of p-aminobenzylamine and 5.5% of o-aminobenzylamine.
Example 20
A sealed glass reaction vessel was charged with 35.3 grams of the wet crystals of nitrobenzylamine nitrate obtained in Example 15, 0.1 grams of 5% Pd/C catalyst and 45 ml of methanol. Hydrogen was immediately introduced with a vigorous stirring. Reaction was continued at 25-30"C for 8 hours. After the end of the reaction, the resulted reaction mixture was warmed to 60- 65"C to remove the catalyst. The filtrate was concentrated in vacuum to distill off most of methanol to obtain a yellow viscous liquid, wherein 130 grams of 30% aqueous sodium hydroxide solution were added, mixed and allowed to stand for separating into two layers. The lower layer was removed and the upper layer was distilled in vacuum to obtain 11.1 grams of a fraction having a boiling point of 130-140"C/ 5-7 mmHg. (The total yield calculated from benzylamine was 65.5%.)
Claims (13)
1. A process for preparing aminobenzylamine, which comprises catalytically reducing nitrobenzylamine represented by the general formula(l):
wherein nitro group is located at o-, m-, or p-, position, in solvents.
2. A process according to claim 1 wherein said catalytic reduction is carried out in the presence of acids.
3. A process according to claim 2 wherein said acids are at least one mineral acid selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, boric acid, phosphoric acid, boric acid anhydride and phosphoric acid anhydride.
4, A process according to claim 2 wherein said acids are organic acids.
5. A process according to claim 4 wherein said organic acids are aliphatic monocarboxylic acids.
6. A process according to claim 4 wherein said organic acids are acetic acid.
7. A process according to claim 2 wherein carbon dioxide exists on the form of said acids.
8. A process according to claim 1 wherein nitrobenzylamine is mineral acid salts of a nitrobenzylamine mixture obtained by nitrating benzylamine.
9. A process according to claim 8 wherein said mineral acid salts are mixture of mineral acid salts containing o-, m-, and p-isomers of nitrobenzylamine in the range of 0.2-10, 30- 70% by weight respectively.
10. A process according to claim 8 wherein said mineral acid salts of a nitrobenzylamine mixture are nitrate.
11. A process according to claim 8 wherein said mineral -acid salts of a nitrobenzylamine mixture are sulfate.
12. A process according to claim 8 wherein said mineral acid salts of a nitrobenzylamine mixture are a mixture of nitrate and sulfate.
13. A process for preparing aminobenzylamine substantially as described in any of the Examples herein.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59123817A JPS615055A (en) | 1984-06-18 | 1984-06-18 | Preparation of aminobenzylamine |
| JP59127533A JPH0655697B2 (en) | 1984-06-22 | 1984-06-22 | Method for producing aminobenzylamine |
| JP59129982A JPH0655698B2 (en) | 1984-06-26 | 1984-06-26 | Process for producing aminobenzylamine mixture |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8514417D0 GB8514417D0 (en) | 1985-07-10 |
| GB2162839A true GB2162839A (en) | 1986-02-12 |
| GB2162839B GB2162839B (en) | 1987-11-04 |
Family
ID=27314801
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08514417A Expired GB2162839B (en) | 1984-06-18 | 1985-06-07 | Process for preparing aminobenzylamine |
Country Status (7)
| Country | Link |
|---|---|
| KR (1) | KR870002017B1 (en) |
| CA (1) | CA1256452A (en) |
| CH (1) | CH670635A5 (en) |
| DE (1) | DE3521271A1 (en) |
| FR (1) | FR2565970B1 (en) |
| GB (1) | GB2162839B (en) |
| NL (1) | NL8501705A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2176190B (en) * | 1985-06-17 | 1989-11-08 | Mitsui Toatsu Chemicals | Aminobenzylamine composition suitable for use in curing epoxy resins |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3611677A1 (en) * | 1986-04-08 | 1987-10-15 | Bayer Ag | METHOD FOR PRODUCING AROMATIC DIAMONDS |
-
1985
- 1985-06-07 CA CA000483423A patent/CA1256452A/en not_active Expired
- 1985-06-07 GB GB08514417A patent/GB2162839B/en not_active Expired
- 1985-06-13 DE DE19853521271 patent/DE3521271A1/en active Granted
- 1985-06-13 NL NL8501705A patent/NL8501705A/en not_active Application Discontinuation
- 1985-06-14 KR KR1019850004212A patent/KR870002017B1/en not_active IP Right Cessation
- 1985-06-17 CH CH2546/85A patent/CH670635A5/de not_active IP Right Cessation
- 1985-06-17 FR FR858509141A patent/FR2565970B1/en not_active Expired
Non-Patent Citations (2)
| Title |
|---|
| BER 20 2869-2870 (1887) * |
| BER 37 3643-3645 (1904) * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2176190B (en) * | 1985-06-17 | 1989-11-08 | Mitsui Toatsu Chemicals | Aminobenzylamine composition suitable for use in curing epoxy resins |
Also Published As
| Publication number | Publication date |
|---|---|
| CA1256452A (en) | 1989-06-27 |
| DE3521271A1 (en) | 1985-12-19 |
| KR860000244A (en) | 1986-01-27 |
| GB2162839B (en) | 1987-11-04 |
| GB8514417D0 (en) | 1985-07-10 |
| NL8501705A (en) | 1986-01-16 |
| FR2565970B1 (en) | 1989-02-03 |
| KR870002017B1 (en) | 1987-11-30 |
| DE3521271C2 (en) | 1991-05-29 |
| CH670635A5 (en) | 1989-06-30 |
| FR2565970A1 (en) | 1985-12-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20030607 |