CA1256452A - Process for preparing aminobenzylamine - Google Patents
Process for preparing aminobenzylamineInfo
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- CA1256452A CA1256452A CA000483423A CA483423A CA1256452A CA 1256452 A CA1256452 A CA 1256452A CA 000483423 A CA000483423 A CA 000483423A CA 483423 A CA483423 A CA 483423A CA 1256452 A CA1256452 A CA 1256452A
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- Prior art keywords
- mixture
- aminobenzylamine
- acid
- nitrobenzylamine
- reaction
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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
-
- 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
-
- 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
-
- 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
-
- 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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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
This invention relates to a process for preparing an aminobenzylamine mixture which comprises catalytically reducing, in the presence of a metal of platinum group, mineral acid salts of a nitrobenzylamine isomer mixture, obtained by nitrating ben-zylamine. The aminobenzylamine isomer mixture obtained in the process of this invention is liquid at the room temperature and gives excellent physical properties to the cold cure epoxy resin.
This invention relates to a process for preparing an aminobenzylamine mixture which comprises catalytically reducing, in the presence of a metal of platinum group, mineral acid salts of a nitrobenzylamine isomer mixture, obtained by nitrating ben-zylamine. The aminobenzylamine isomer mixture obtained in the process of this invention is liquid at the room temperature and gives excellent physical properties to the cold cure epoxy resin.
Description
s~
The present invention relates to a process for prepar-ing an aminobenzylamine mixture. The aminobenzylamlne isomer mixture obtained in the process of this invention is liquid at the room temperature and gives excellent physical properties to the cold cure epoxy resin.
Aminobenzylamine is an importan-t cornpound as a curing agent for epoxy resin, a raw material for polyamides and poly-imides, and a raw material for intermediates of agricultural chemicals and medicines. Processes for preparing aminobenzyl-amine by using nitrobenzaldehyde or nitrobenzonitrile as starting material have so far been known. For example, as for the process using the former as starting material-, there are known the fol-lowing processes: (i) Nitrobenzylbromide is derived from nitrobenzaldehyde, which is then reacted with potassium phthal-imide to obtain N-nitrobenzylphthalimide, and m- and p-amino-benzylamines is produced with an ~5~S~
yield of about 20% by reduced and hydrolyzed. (N. Kornblum et al7 J. Am. Chem. Soc , 71,2137 (1949)).
(ii) m-Nitrobenzaldehyde ls reacted with phenylhydrazlne and A the resulting hydrazone compound ls catalytically reduced wherebym-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 derlved 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, m-aminobenzylamine 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 e~ample, (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)).
~s mentioned above,according to the known processes(i) and (ii) which prepare aminobenzylamine by using nitrobenzaldehyde or ~s~
nitrobenzonitrile as the starting materlals, a more than equivalent quantity of relatively expensive compound i5 used to prepare inter-mediates which are reduced to obtaln intended products. llowever, in these processes there are disadvantages that reduction steps are complicated or expense and labor are required for recovering by-pro-ducts and the like.
Also in the process(iv), there are the disadvan~ages 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 ls 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 requlred :Ln large quantities and red phosphorus is in a great danger of ignition.
Therefore the known processes for preparing aminobenzylamine have many steps, complicated after-treatments, or equipmental problems.
The present invention provides a process for prepariny an aminobenzylamine isomer mixture by using rnineral acid salts of a nitrobenzylamine isomer mixture obtained by nitratiny benzyl-amine for use as nitrobenzylamine raw materials.
~ ccording to the present invention there is provided a process for preparing an aminobenzylamine mixture which comprises catalytically reducing, in the presence of a me-tal of platinum group, mineral acid salts of a nitrobenzylamine isomer mixture, obtained by nitrating benzylamine.
The aminobenzylamine isomer mixture obtained in the process of this invention is li~uid at the room temperature and gives excellent physical properties to the cold cure epoxy resin.
The starting materials used in this invention are the mineral acid salts of a mixture of o-nitrobenzylamine, m-nitrobenzylamine and p-nitrobenzylamine. These o-, m-, and p-isomers are prepared with a high yield by reacting a correspond-ing nitrobenzylchloride with ammonia or phthalimide (S. Gabrielet al, ser., 286g (1887); E.L. Holmes et al, J. Chem. Soc., 1800-1821 (1925); H.L. Ing et at, J. Chem. Soc., 2348-2351 (1926)).
In particular mineral acid salts of nitrobenzylamine which are used for the raw materials is nitrate and/or sulfate of nitrobenzylamine 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 acidtacetic acid mixture, and the like. Normally, the mixed acid or fuming nitric acid is pre-ferred. 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 : 1.2 - 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 -10C to 80C, preferably -5C to 30C. 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 nitrobenæylamine mixture may be obtained by filtering the precipi-tate. 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 lO 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 weigllt and less.
The mineral ac:Ld salts of nitrobenzylamlne mixture herein mentioned are sulfate, nitrate or mixtures thereof of the o-, m-, or p-substituted nitrobenzylamine mixture obtalned by nitrating benzyl-amine as described above. The m-, p-, and o-isomer ratlo in thé
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 nitrlc 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 acidl sulfuric acid, nitric acid, boric acid, phosphoric acld, boric acid anhydride and phosphoric acid anhydride. The use of these mlneral 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 5~4~5Z
prepared efficiently and economically. In addition, mlneral acid anhydrides absorb water existed in the reaction system and generated from the reduction of nitro group. Thus reducing reactlon may be carried out in anhydrous and ideal conditions, that is, undesired actiori such as decomposition or side reaction by water ls 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 benæoic acid, phthalic acid, sulfonic and sulfinic acids such as p-toluenesulfonic acid and benzenesulfinic 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 acid, 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 ~:25~
generates from the reductlon of nitro groups. Carbon dioxlde 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 ~ lso solvents are used for catalytic reduction in the process of 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 cel-losolve, 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, ~2~
platinum, rhodium, ruthenium, cobalt, copper and the llke. Although these catalysts may be used in the form of metal, they may be used in form supported on a carrier such as carbon, bariurn sulEate, sillca gel, alumlna,and the like. Nickel, coba]t, copper, and the llke may also be used as Raney catalysts. The amount of catalysts used is in the range of 0.01 to 30% by weight ln term of metal based on nltro-e ~ered~
benzylamine. Usually, a range of 2 to 20~ by weight is ~4~r~
ln the case where Raney catalysts are used, while a range of 0,05 to 5% by welght in the case where noble metals supported on a carrler are used.
The reaction temperature ls not particularly limlted, though it is usually ln the range of 0 to 150C, preferably lO to 80C.
The reaction pressure may be usually ln the range of atmo-spheric pressure to 50 Kg/cm G.
As for general embodiments of this invention, a catalyst may be added to the raw materials in a state where it ls dissolved or suspended ln a solvent, followed by lntroduclng hydrogen to carry out at the specified temperature untll lts absorption stops. After the completion of the reaction, the reaction mixture is filtered to remove the catalysts and dlstilled to obtain the intended product.
When using mineral or organic acids, a catalyst may be added to a solution or suspension of the raw materlals and the aclds in the solvents, and reducing reaction ls carriecl out. When applying carbon dioxide, a catalyst may be added to a solution or suspension of the raw materials in a solvent and then reduclng reactlon is carried out either by previously adding whole amount of carbon dioxide or by continuously or lntermlttently addlng. In any case, catalytic reduction is carried out untll absorption of hydrogen stops. When catalytic reductlon is conducted in the absence of 6~5~
acids, the reaction product is dissolved after the reaction. Then resultant mixture is filtered to remove the cata1ysts and distilled to obtain the intended product, When a dissolved r~action mixture is resulted from catalytic reduction in the presence of the acids, it is filtered to remove the catalysts, When a preclpitated 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 precip:Ltated reaction mlxture 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-benzylamlne 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 aminobenzylamine. 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 ~ 10 ` `` ~Z5~;~5:~
neutralization. Thus, the process of this invention is commer-cially 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 aminobenzyl-amine mixture with a high yield. The contents of o-, m-, and p-aminobenæylamines 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 reduc-tion in catalyst activity, enables recycled use of the catalysts and is economically very favorable. The process is also commer-cially advantageous, because solvent recovery and product isola-tion may easily be carrled out by distillation after the reac-tion.
This invention will now be desribed in detail by fol-lowing Examples in which % represent percent by weight.
Example 1 At a temperature of not hlyher -than 0C, 107 grams (l mol) of benzylamine were dropped into ~3 grams (1 mol) of 9~%
nitric acid over a period of 5 hours. After the end o~ dropping, reaction was continued with stirring at 20-Z5C 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 nitrobPnzyl-amine 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 Hg N3 05) ___________________ ___________________________________________ C H N
_______________________________________________________________ Calculated (%) 39.07 4.19 19.53 Found (~) 38091 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 -- 1~ --~Z5~L5;i~
gram of 5% Pd/C catalyst and 50 grams of water. Hydrogen wasimmediately introduced with a vigorou~ stlrrlng. Reaction was continued at 25-30C for 7 hrs. After the end of the reactlon, the resultant mixture was warmed to 50-60C and flltered 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 130-140C /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-aminobenzylamlne.
Example ~
At a temperature of not higher than 0C, 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 20-25C for 3 hours. The resultant reaction mixture was then poured into 750 grams of ice water, fol-lowed by filtering separated crystals which were washed wlth satu-rated 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) .
f ~ 3 ~5~a~5~
. ~
Elemental Analysls ( C14 lll8 ~4 8 C ll N 0 ~. .
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 25-30C for 7 hours.
After the end of the reaction, the resultant reactlon mixture was warmed to 50-60C and filtered to remove the catalyst. The filtrate was neutralized by addlng 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 oily fraction having a boiling point 130-140C/
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 ~
At a temperature of not higher than 0C, 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 20-25C for 3 hours. The resultant reaction mixture was then poured into 750 grams of ice water, !, followed by filtering separated crygtals which were washed with satu-rated sodium chloride solution to obtain 284 grarns of wet crystals having a solid content oE 64.3%.
The results of elemental ana:lysis were as follows and the crystais obtained were nitrobenzylamine nitrate (85% yield).
E].emental Analysis ( C7 Hg N3 O5 ) C H N
. .
Calculated (%) 39.07 4.19 19.53 Eound (%) 38.35 4.21 19.86 The wet nitrobenzylamine nitrate crystals were then reduced . ~ and aftertreated by the same procedure as described in Example ~r, and a mixture of aminobenzylamine was obtained. (The total yield calculated from benzylamine was 74.5%.) According to gas chromato-graphy, the mixture contains 47.4% of m-aminobenzylamine, 51.1% of p-aminobenzylamine and 1.5~ of o-aminobenzylamine.
Example ~r One hundred and seven grams (1 mol) of benzylamine was nit-rated with a mixed acid containing 128 grams (2 mols) of 98% nitric acid and 200 grams (2 mols) of 98% sulEuric acid by the same proce-dure as described in Example ~r 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 1/1.
~t,~ ~/S
~2~
Elemental Analysis C ll N S
Caiculated (%) 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 descrlbed in Example ~ to obtain a mixture of aminobenzylamine. (The total yield calculated from benzylamine was 68.7%.) According to gas chromato-graphy, the mixture contains 47.2% of m-aminobenzylamine, 51.0% of p-aminobenzylamine and 1.8% of o-aminobenzylamine.
Example ~
At a temperature of not higher than 0C, 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-dichloro-ethane.
After the end of dropping, reaction was continued with stirring at 20-25C 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 oE nitrobenzylamine mineral acid salts. A sealed glass reaction vessel was then charged with 230 grams of the wet crystals h~
56a~5æ
of nitrobenzylamine mlnera] acid saltg, 1.5 grams of 5% Pd/C catalyst ~_ and ~50 grams of water. The charge was reduced and aftertreated by ~3~-~the same procedure as descrlbed ln Example ~ and a mixture of aminobenzylamine was obtained. (The total yield calculated from benzylamine was 58.9%.) According to gae chromatography, the mixture contains 59.5% of m-aminobenzylamine, 35.0% of p-aminobenzyl-amine and 5.5% of o-aminobenzylamine.
Example ~
A sealed glass reaction vessel was charged with 35.3 grams of the wet crystals of nltrobenzylamine nitrate obtained in Example ~
0.1 grams of 5% Pd/C catalyst and 45 ml of methanol. Ilydrogen was immediately introduced with a vigorous stirring. Reaction was continued at 25-30C for 8 hours. After the end of the reaction, the resulted reaction mixture was warmed to 60-65C 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 130~140C/ 5-7 mmHg, (The total yield calculated from benzylamine was 65.5%.)
The present invention relates to a process for prepar-ing an aminobenzylamine mixture. The aminobenzylamlne isomer mixture obtained in the process of this invention is liquid at the room temperature and gives excellent physical properties to the cold cure epoxy resin.
Aminobenzylamine is an importan-t cornpound as a curing agent for epoxy resin, a raw material for polyamides and poly-imides, and a raw material for intermediates of agricultural chemicals and medicines. Processes for preparing aminobenzyl-amine by using nitrobenzaldehyde or nitrobenzonitrile as starting material have so far been known. For example, as for the process using the former as starting material-, there are known the fol-lowing processes: (i) Nitrobenzylbromide is derived from nitrobenzaldehyde, which is then reacted with potassium phthal-imide to obtain N-nitrobenzylphthalimide, and m- and p-amino-benzylamines is produced with an ~5~S~
yield of about 20% by reduced and hydrolyzed. (N. Kornblum et al7 J. Am. Chem. Soc , 71,2137 (1949)).
(ii) m-Nitrobenzaldehyde ls reacted with phenylhydrazlne and A the resulting hydrazone compound ls catalytically reduced wherebym-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 derlved 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, m-aminobenzylamine 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 e~ample, (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)).
~s mentioned above,according to the known processes(i) and (ii) which prepare aminobenzylamine by using nitrobenzaldehyde or ~s~
nitrobenzonitrile as the starting materlals, a more than equivalent quantity of relatively expensive compound i5 used to prepare inter-mediates which are reduced to obtaln intended products. llowever, in these processes there are disadvantages that reduction steps are complicated or expense and labor are required for recovering by-pro-ducts and the like.
Also in the process(iv), there are the disadvan~ages 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 ls 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 requlred :Ln large quantities and red phosphorus is in a great danger of ignition.
Therefore the known processes for preparing aminobenzylamine have many steps, complicated after-treatments, or equipmental problems.
The present invention provides a process for prepariny an aminobenzylamine isomer mixture by using rnineral acid salts of a nitrobenzylamine isomer mixture obtained by nitratiny benzyl-amine for use as nitrobenzylamine raw materials.
~ ccording to the present invention there is provided a process for preparing an aminobenzylamine mixture which comprises catalytically reducing, in the presence of a me-tal of platinum group, mineral acid salts of a nitrobenzylamine isomer mixture, obtained by nitrating benzylamine.
The aminobenzylamine isomer mixture obtained in the process of this invention is li~uid at the room temperature and gives excellent physical properties to the cold cure epoxy resin.
The starting materials used in this invention are the mineral acid salts of a mixture of o-nitrobenzylamine, m-nitrobenzylamine and p-nitrobenzylamine. These o-, m-, and p-isomers are prepared with a high yield by reacting a correspond-ing nitrobenzylchloride with ammonia or phthalimide (S. Gabrielet al, ser., 286g (1887); E.L. Holmes et al, J. Chem. Soc., 1800-1821 (1925); H.L. Ing et at, J. Chem. Soc., 2348-2351 (1926)).
In particular mineral acid salts of nitrobenzylamine which are used for the raw materials is nitrate and/or sulfate of nitrobenzylamine 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 acidtacetic acid mixture, and the like. Normally, the mixed acid or fuming nitric acid is pre-ferred. 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 : 1.2 - 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 -10C to 80C, preferably -5C to 30C. 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 nitrobenæylamine mixture may be obtained by filtering the precipi-tate. 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 lO 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 weigllt and less.
The mineral ac:Ld salts of nitrobenzylamlne mixture herein mentioned are sulfate, nitrate or mixtures thereof of the o-, m-, or p-substituted nitrobenzylamine mixture obtalned by nitrating benzyl-amine as described above. The m-, p-, and o-isomer ratlo in thé
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 nitrlc 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 acidl sulfuric acid, nitric acid, boric acid, phosphoric acld, boric acid anhydride and phosphoric acid anhydride. The use of these mlneral 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 5~4~5Z
prepared efficiently and economically. In addition, mlneral acid anhydrides absorb water existed in the reaction system and generated from the reduction of nitro group. Thus reducing reactlon may be carried out in anhydrous and ideal conditions, that is, undesired actiori such as decomposition or side reaction by water ls 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 benæoic acid, phthalic acid, sulfonic and sulfinic acids such as p-toluenesulfonic acid and benzenesulfinic 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 acid, 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 ~:25~
generates from the reductlon of nitro groups. Carbon dioxlde 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 ~ lso solvents are used for catalytic reduction in the process of 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 cel-losolve, 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, ~2~
platinum, rhodium, ruthenium, cobalt, copper and the llke. Although these catalysts may be used in the form of metal, they may be used in form supported on a carrier such as carbon, bariurn sulEate, sillca gel, alumlna,and the like. Nickel, coba]t, copper, and the llke may also be used as Raney catalysts. The amount of catalysts used is in the range of 0.01 to 30% by weight ln term of metal based on nltro-e ~ered~
benzylamine. Usually, a range of 2 to 20~ by weight is ~4~r~
ln the case where Raney catalysts are used, while a range of 0,05 to 5% by welght in the case where noble metals supported on a carrler are used.
The reaction temperature ls not particularly limlted, though it is usually ln the range of 0 to 150C, preferably lO to 80C.
The reaction pressure may be usually ln the range of atmo-spheric pressure to 50 Kg/cm G.
As for general embodiments of this invention, a catalyst may be added to the raw materials in a state where it ls dissolved or suspended ln a solvent, followed by lntroduclng hydrogen to carry out at the specified temperature untll lts absorption stops. After the completion of the reaction, the reaction mixture is filtered to remove the catalysts and dlstilled to obtain the intended product.
When using mineral or organic acids, a catalyst may be added to a solution or suspension of the raw materlals and the aclds in the solvents, and reducing reaction ls carriecl out. When applying carbon dioxide, a catalyst may be added to a solution or suspension of the raw materials in a solvent and then reduclng reactlon is carried out either by previously adding whole amount of carbon dioxide or by continuously or lntermlttently addlng. In any case, catalytic reduction is carried out untll absorption of hydrogen stops. When catalytic reductlon is conducted in the absence of 6~5~
acids, the reaction product is dissolved after the reaction. Then resultant mixture is filtered to remove the cata1ysts and distilled to obtain the intended product, When a dissolved r~action mixture is resulted from catalytic reduction in the presence of the acids, it is filtered to remove the catalysts, When a preclpitated 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 precip:Ltated reaction mlxture 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-benzylamlne 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 aminobenzylamine. 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 ~ 10 ` `` ~Z5~;~5:~
neutralization. Thus, the process of this invention is commer-cially 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 aminobenzyl-amine mixture with a high yield. The contents of o-, m-, and p-aminobenæylamines 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 reduc-tion in catalyst activity, enables recycled use of the catalysts and is economically very favorable. The process is also commer-cially advantageous, because solvent recovery and product isola-tion may easily be carrled out by distillation after the reac-tion.
This invention will now be desribed in detail by fol-lowing Examples in which % represent percent by weight.
Example 1 At a temperature of not hlyher -than 0C, 107 grams (l mol) of benzylamine were dropped into ~3 grams (1 mol) of 9~%
nitric acid over a period of 5 hours. After the end o~ dropping, reaction was continued with stirring at 20-Z5C 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 nitrobPnzyl-amine 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 Hg N3 05) ___________________ ___________________________________________ C H N
_______________________________________________________________ Calculated (%) 39.07 4.19 19.53 Found (~) 38091 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 -- 1~ --~Z5~L5;i~
gram of 5% Pd/C catalyst and 50 grams of water. Hydrogen wasimmediately introduced with a vigorou~ stlrrlng. Reaction was continued at 25-30C for 7 hrs. After the end of the reactlon, the resultant mixture was warmed to 50-60C and flltered 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 130-140C /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-aminobenzylamlne.
Example ~
At a temperature of not higher than 0C, 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 20-25C for 3 hours. The resultant reaction mixture was then poured into 750 grams of ice water, fol-lowed by filtering separated crystals which were washed wlth satu-rated 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) .
f ~ 3 ~5~a~5~
. ~
Elemental Analysls ( C14 lll8 ~4 8 C ll N 0 ~. .
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 25-30C for 7 hours.
After the end of the reaction, the resultant reactlon mixture was warmed to 50-60C and filtered to remove the catalyst. The filtrate was neutralized by addlng 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 oily fraction having a boiling point 130-140C/
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 ~
At a temperature of not higher than 0C, 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 20-25C for 3 hours. The resultant reaction mixture was then poured into 750 grams of ice water, !, followed by filtering separated crygtals which were washed with satu-rated sodium chloride solution to obtain 284 grarns of wet crystals having a solid content oE 64.3%.
The results of elemental ana:lysis were as follows and the crystais obtained were nitrobenzylamine nitrate (85% yield).
E].emental Analysis ( C7 Hg N3 O5 ) C H N
. .
Calculated (%) 39.07 4.19 19.53 Eound (%) 38.35 4.21 19.86 The wet nitrobenzylamine nitrate crystals were then reduced . ~ and aftertreated by the same procedure as described in Example ~r, and a mixture of aminobenzylamine was obtained. (The total yield calculated from benzylamine was 74.5%.) According to gas chromato-graphy, the mixture contains 47.4% of m-aminobenzylamine, 51.1% of p-aminobenzylamine and 1.5~ of o-aminobenzylamine.
Example ~r One hundred and seven grams (1 mol) of benzylamine was nit-rated with a mixed acid containing 128 grams (2 mols) of 98% nitric acid and 200 grams (2 mols) of 98% sulEuric acid by the same proce-dure as described in Example ~r 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 1/1.
~t,~ ~/S
~2~
Elemental Analysis C ll N S
Caiculated (%) 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 descrlbed in Example ~ to obtain a mixture of aminobenzylamine. (The total yield calculated from benzylamine was 68.7%.) According to gas chromato-graphy, the mixture contains 47.2% of m-aminobenzylamine, 51.0% of p-aminobenzylamine and 1.8% of o-aminobenzylamine.
Example ~
At a temperature of not higher than 0C, 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-dichloro-ethane.
After the end of dropping, reaction was continued with stirring at 20-25C 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 oE nitrobenzylamine mineral acid salts. A sealed glass reaction vessel was then charged with 230 grams of the wet crystals h~
56a~5æ
of nitrobenzylamine mlnera] acid saltg, 1.5 grams of 5% Pd/C catalyst ~_ and ~50 grams of water. The charge was reduced and aftertreated by ~3~-~the same procedure as descrlbed ln Example ~ and a mixture of aminobenzylamine was obtained. (The total yield calculated from benzylamine was 58.9%.) According to gae chromatography, the mixture contains 59.5% of m-aminobenzylamine, 35.0% of p-aminobenzyl-amine and 5.5% of o-aminobenzylamine.
Example ~
A sealed glass reaction vessel was charged with 35.3 grams of the wet crystals of nltrobenzylamine nitrate obtained in Example ~
0.1 grams of 5% Pd/C catalyst and 45 ml of methanol. Ilydrogen was immediately introduced with a vigorous stirring. Reaction was continued at 25-30C for 8 hours. After the end of the reaction, the resulted reaction mixture was warmed to 60-65C 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 130~140C/ 5-7 mmHg, (The total yield calculated from benzylamine was 65.5%.)
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for preparing an aminobenzylamine mixture which comprises catalytically reducing, in the presence of a metal of platinum group, mineral acid salts selected from nitrates, sulfates and mixtures thereof of a nitrobenzylamine isomer mixture, obtained by nitrating benzylamine.
2. A process according to claim 1 wherein said mineral acid salts are a mixture of mineral acid salts containing o-, m-and p-isomers of nitrobenzylamine in the range of 0.2-10, 30-70 and 30-70% by weight, respectively.
3. A process according to claim 1 wherein said mineral acid salts of said nitrobenzylamine mixture are nitrates.
4. A process according to claim 1 wherein said mineral acid salts of said nitrobenzylamine mixture are sulfates.
5. A process according to claim 1 wherein said mineral acid salts of said nitrobenzylamine mixture are a mixture of nitrates and sulfates.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59-123817 | 1984-06-18 | ||
| JP59123817A JPS615055A (en) | 1984-06-18 | 1984-06-18 | Preparation of aminobenzylamine |
| JP59-127533 | 1984-06-22 | ||
| JP59127533A JPH0655697B2 (en) | 1984-06-22 | 1984-06-22 | Method for producing aminobenzylamine |
| JP59-129982 | 1984-06-26 | ||
| JP59129982A JPH0655698B2 (en) | 1984-06-26 | 1984-06-26 | Process for producing aminobenzylamine mixture |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1256452A true CA1256452A (en) | 1989-06-27 |
Family
ID=27314801
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000483423A Expired CA1256452A (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) |
Families Citing this family (2)
| 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 |
| DE3611677A1 (en) * | 1986-04-08 | 1987-10-15 | Bayer Ag | METHOD FOR PRODUCING AROMATIC DIAMONDS |
-
1985
- 1985-06-07 GB GB08514417A patent/GB2162839B/en not_active Expired
- 1985-06-07 CA CA000483423A patent/CA1256452A/en not_active Expired
- 1985-06-13 NL NL8501705A patent/NL8501705A/en not_active Application Discontinuation
- 1985-06-13 DE DE19853521271 patent/DE3521271A1/en active Granted
- 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
Also Published As
| Publication number | Publication date |
|---|---|
| FR2565970A1 (en) | 1985-12-20 |
| DE3521271C2 (en) | 1991-05-29 |
| FR2565970B1 (en) | 1989-02-03 |
| DE3521271A1 (en) | 1985-12-19 |
| GB2162839B (en) | 1987-11-04 |
| KR870002017B1 (en) | 1987-11-30 |
| GB8514417D0 (en) | 1985-07-10 |
| CH670635A5 (en) | 1989-06-30 |
| KR860000244A (en) | 1986-01-27 |
| GB2162839A (en) | 1986-02-12 |
| NL8501705A (en) | 1986-01-16 |
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