JPH0469626B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing hydroxylamine represented by the following formula. A: or B: RNHOH In compound A, groups R ₁ , R ₂ , R ₃ , R ₄ and
R ₅ is a hydrogen atom, a hydroxy group, a halogen atom, a straight or branched alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, and a phenyl group, respectively. an alkyl or alkylphenyl group (the alkyl group having 1 to 6 carbon atoms) or a group R ₁ , R ₂ , R ₃ , R ₄ or R ₅ attached to adjacent carbon atoms of the benzene ring; The two together with the two carbon atoms of the benzene ring to which they are engaged form a second benzene ring that is ortho-fused to this benzene ring. In compound B, the group R represents a linear or branched and/or cyclic alkyl group having 1 to 24 carbon atoms. In case the radicals R ₁ to R ₅ or R are hydrocarbon-containing radicals, they can have unsaturated bonds and can also be amino, hydroxylamino, amido,
It can have substituents such as cyano, hydroxy, alkoxy, carboxyl, oxycarbonyl, carboxy, sulfoxide and sulfone. The groups R ₁ -R ₅ or R may be combined to form part of the polymer structure. Aromatic hydroxylamine A is obtained by hydrogenation of the corresponding nitro derivative in the presence of an inert solvent, a platinum catalyst and a nitrogenous base. This process is known from US Pat. No. 3,927,101. This patent states that in order to obtain a sufficiently high yield of hydroxylamine, the weight ratio of organic base to nitro compound should be at least 0.1:1, preferably 0.5:
It is stated that the ratio should be 1 to 5:1. Furthermore, it is stated that the use of small amounts of base makes it impossible to stop the hydrogenation reaction at the hydroxylamine stage. After the hydrogenation reaction is complete, the organic base must be removed. It has been found that there are problems in isolating hydroxylamine by using such large amounts of organic base. In the above process, the hydrogenation is carried out in the presence of a trivalent or pentavalent organophosphorus compound and the nitrogen-containing base is added to the starting reaction mixture in an amount of less than 10% by weight, calculated on the amount of nitro derivative. It has been found that equivalent or higher yields of hydroxylamine can be obtained by adding hydroxylamine to hydroxylamine. 10 for the amount of phosphorus compounds or nitro derivatives
It has been found that if only amounts less than % by weight of nitrogenous base are used, the yield of isolated hydroxylamine is significantly reduced compared to that obtained by the process of the invention. It should be added that JP-A-57-30096 describes the use of trivalent phosphorus compounds in this type of reaction. However, this publication does not mention the combination with nitrogen-containing bases of the present invention. Additionally, U.S. Patent No.
No. 3441610 describes nitroalkanes as N-alkyl-
Catalytic hydrogenation of hydroxylamine has been described. A recovered palladium catalyst and iron, nickel or cobalt cations are used in a two-phase liquid system of aqueous sulfuric acid and an immiscible organic solvent. In such acidic media, catalyst losses are considerable and the equipment undergoes severe corrosion.
According to the invention, these drawbacks are obviated. The present invention relates to a process for the catalytic selective production of hydroxylamines of structural formula A or B by selective catalytic hydrogenation of the corresponding nitro derivatives. A problem that arises with the use of platinum-containing catalysts is to prevent the nitro derivative from being reduced to the amine in the hydrogenation step. The process of the present invention provides a process that does not exhibit the drawbacks of such known processes. As the organic phosphorus compound, a trivalent or pentavalent compound can be used. Trivalent phosphorus compounds are preferred. Examples of suitable phosphorus compounds include trivalent compounds containing aryl or aryloxy groups with or without substituents. Preferably the aryl and aryloxy groups are phenyl and phenyloxy groups.
Examples of such phosphorus compounds include triphenyl phosphite, dimethylphenyl phosphite,
Mention may be made of triphenylphosphonite, tri-p-chlorophenylsphosphonite, tri-p-nitrophenylphosphonite and tricresylphosphonite. Diphenyl phosphite, di-p-
Chlorophenyl phosphite, di-p-nitrophenyl phosphite and di-p-methylphenyl phosphite are also suitable phosphorus compounds. Very suitable phosphorus compounds are those having alkyl or alkoxy groups containing 1 to 20 carbon atoms. Particularly preferred are trialkyl phosphines and trialkyl phosphites,
The alkyl group contains 1 to 20 carbon atoms. Examples of these are trimethylphosphine,
Triethylphosphine, triisopropylphosphine, tributylphosphine, trioctylphosphine, triotadecylphosphine, trimethylphosphite, triethylphosphite, triisopropylphosphite, tributylphosphite, trihexylphosphite, triheptylphosphite , trioctyl phosphite, trinonyl phosphite, tridecyl phosphite and trilauryl phosphite. Most preferred among these are compounds in which the alkyl group contains 1 to 6 carbon atoms, and particularly preferred are triethyl phosphite, triisopropyl phosphite and tributyl phosphite. Other examples of phosphorus compounds that can be used in the present invention include phosphorus trichloride, dimethylphosphochloridite, diethylphosphochloridite and hexamethylphosphoric triamide. The last two compounds combine the functions of a nitrogenous base and a phosphorous compound. When using such compounds, the amount of other nitrogenous bases can be reduced. Of course, mixtures of the above-mentioned phosphorus compounds can also be used. Generally the reaction mixture contains 0.1 to 5% by weight of phosphorus compound, preferably 0.2 to 2.0% by weight, more preferably 0.3 to 2.0% by weight, based on the amount of nitro derivative.
Should contain 1.0% by weight. Suitable nitrogenous bases include ammonia, monoalkylamines, dialkylamines, trialkylamines, monoalkanolamines, dialkanols,
trialkanolamines, mono-, di- or tri-arylamines, (poly)alkylene polyamines, pyrrolidine and piperidine (pyrrolidine and piperidine by one or two alkyl groups having 1 to 4 carbon atoms) pyridine (optionally substituted or unsubstituted) and pyridine (optionally substituted or unsubstituted by one or more alkyl, amino, phenylalkylamine, phenylamino or pyrrolidone groups); ). Nitrogen-containing bases can include primary, secondary and tertiary alkyl and/or alkanol groups. In general, alkyl and alkanol groups not specified above may contain 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms, and most preferably 1 to 4 carbon atoms. Examples of mono-, di- and trialkylamines are methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, hebutylamine, octylamine, nonylamine, octadecylamine, dimethylamine, diethylamine, dipropylamine, dipentyl. Amine, dihexylamine, diheptylamine, dioctylamine, didecylamine, didodecylamine, dioctadecylamine, trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, tripentylamine, trihexylamine,
These include trihebutylamine, trioctylamine, tri-2-ethylhexylamine, tridecylamine and tri-octadecylamine. Suitable mono-, di- and tri-alkanolamines include those having alkanol groups containing 1 to 20, preferably 1 to 4 carbon atoms. Examples are ethanolamine, propanolamine, butanolamine, diethanolamine and triethanolamine. Suitable mono-, di- and tri-arylamines include N,N-diethyl-N-phenylamine, N-ethyl-N,N-diphenylamine,
Triphenylamine, tri-o-methylphenylamine, tri-m-methylphenylamine, tri-p-methylphenylamine, tri-benzylamine, N-benzyl-N,N-dimethylamine,
N-benzyl-N,N-diethylamine, N-benzyl-N,N-di-isopropylamine, N-
There are benzyl-N,N-di-n-butylamine and N-benzyl-N,N-di-tert.-butylamine. Suitable (poly)alkylene polyamines include ethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, pentaethylenehexamine. Pyrrodilines and piperidines and substituted pyrrolidines and piperidines containing 1 to 2 alkyl groups having 1 to 4 carbon atoms can also be used. Preferred examples of these are pyrrolidine, piperidine and mono-, di-, tri- and tetramethylpyrrolidine and piperidine. Most preferred are one or more alkyl, amino, phenyl, alkylamino, phenylamino or pyrrolidone groups (alkyl groups preferably contain 1
-6 carbon atoms) or unsubstituted pyridine. Examples include pyridine, N-methylpyridine, 2,6-dimethylpyridine, 4-methylpyridine, 4-aminopyridine, 4-dimethylaminopyridine, 4-di-ethylaminopyridine,
-dipropylaminopyridine, 4-dibutylaminopyridine and 4-diphenylaminopyridine. Dialkylaminopyridine is preferred, especially 4-dimethylaminopyridine. Of course, mixtures of the abovementioned nitrogenous bases can also be used. The reaction mixture contains less than 10% by weight of nitrogenous base based on the amount of nitro derivative, generally
It should contain 0.05-5%, preferably 0.1-2%, more preferably 0.2-1%. The starting nitro derivative is represented by the following formula. C: or D: RNO ₂ In compound C the groups R ₁ , R ₂ , R ₃ , R ₄ and R ₅
are each a hydrogen atom, a hydroxyl group, a halogen atom, a straight or branched alkyl group having 1 to 20, preferably 1 to 6 carbon atoms, 1 to 20, preferably 1 to 6 carbon atoms; an alkoxyl group, a cyclobentyl group, a cyclohexyl group,
phenyl, phenylalkyl or alkylphenyl groups (the alkyl group having 1 to 6 carbon atoms) or groups R ₁ , R ₂ , R ₃ attached to adjacent carbon atoms of the benzene ring, Two of R ₄ or R ₅ together with the two carbon atoms of the benzene ring to which they are engaged form a second benzene ring that is ortho-fused with this benzene ring. In compound D, the radical R represents a straight-chain or branched and/or cyclic alkyl group having 1 to 24 carbon atoms. When the radicals R ₁ to R ₅ or R are hydrocarbon-containing radicals, these radicals can have unsaturated bonds and can also be amino, amido, nitro, nitroso, cyano, hydroxy, alkoxy, carbonyl, oxycarbonyl. , carboxy, sulfoxide and sulfone. Such substituents may be attached to form part of the polymer structure. Examples of aromatic nitro derivatives include nitrobenzene, o-nitrotoluene, m-nitrotoluene,
p-nitrotoluene, p-isopropylnitrobenzene, m-butylnitrobenzene, 1,3-dimethyl-(2 or 4 or 5)nitrobenzene,
1,3,5-trimethyl-2-nitrobenzene,
4-nitro-biphenyl, parachloronitrobenzene and (1 or 2 or 3) nitronaphthalene. Nitrobenzene is preferred. Examples of aliphatic nitro compounds are nitroethane, nitropropane, 2-methyl-2-nitropropane, 9-nitro-9-methyl-1,6-decadiene. The catalyst should contain platinum and may be supported or unsupported. Suitable support materials are carbon blanks, alumina, silica,
These include calcium carbonate and barium sulfate. When platinum is supported on a carrier, the catalyst composition is generally
It contains 0.1-20% platinum, preferably 1-10%. These catalysts can be manufactured by methods well known in the art. Generally, the reaction mixture is 0.001 to 5% based on the amount of nitro derivative.
% by weight, preferably 0.01-1% by weight of platinum. The hydrogenation reaction is generally carried out in the presence of an inert solvent. The solvent used is not particularly limited as long as it does not react with the hydroxylamine to be formed. Suitable solvents are water, lower alcohols such as methanol, ethanol, propanol, isopropanol, aromatic and aliphatic hydrocarbons such as toluene and hexane. Lower alcohols are preferred. Mixtures of the abovementioned solvents can also be used. The reaction mixture preferably contains 5 to 80% by weight of solvent. The selective hydrogenation reaction is performed at a hydrogen pressure of 10 to 2000 kPa, preferably 100 to 500 kPa, at 0°C to 150°C,
Preferably, it can be carried out at 5°C to 50°C. The invention is illustrated by the following examples. Example 1 Nitrobenzene 24.6 dissolved in 80 ml methanol
Fill g into a 600ml autoclave. Catalyst consisting of platinum and carbon black, containing 3% platinum
Add 0.33g. Then 0.1 g of 4-dimethylaminopyridine and 0.25 g of tributyl phosphite are added to the autoclave. The autoclave is then sealed and the air removed using a vacuum pump. Hydrogenation is then carried out at 414 kPa and 10° C. for 3/4 hour. A stoichiometric amount of hydrogen is then absorbed.
After filtering the Pt/C catalyst, the filtrate is distilled under reduced pressure at 45-55°C (bath temperature) using a rotary evaporator. Next, the remaining trace amount of solvent is removed using an oil pump. 20.3 g of crude phenylhydroxylamine are obtained. The crude product is then treated with 75 ml of hexane, then the mixture is stirred and filtered. Finally, 17.7 g of purified phenylhydroxylamine is obtained (yield 81.2%, mp81℃,
IR and NMR results are also correct). Comparative Example A Hydrogenation is carried out in the absence of 4-dimethylaminopyridine using the following amounts of starting materials and conditions similar to Example 1. Nitrobenzene 12.3g Methanol 40ml Tri-ethyl phosphite 0.322g 3% Pt/C 0.400g Hydrogen pressure 414kPa Temperature 10°C Time 1 3/4 hours 9.4g of oily substance is finally obtained. This oil did not crystallize to give phenylhydroxylamine. Similar results were obtained using 0.25 g of tributyl phosphite instead of triethyl phosphite. Comparative Example B Hydrogenation is carried out in the absence of trialkylphosphite using the following amounts of starting materials and conditions similar to Example 1. Nitrobenzene 24.6g Methanol 80ml 4-dimethylaminopyridine 2g 3% Pt/C 0.4g Hydrogen pressure 414kPa Temperature 10°C Time 1 1/2 hours Finally, 21g of oily substance is obtained. This oil was treated with hexane (100 ml) and then −30
Cooling to 10 g of crystalline phenylhydroxylamine is obtained (yield 45.9%, mp 80° C.). Example 2 The effects of adding various combinations of phosphorus compounds and organic bases were evaluated as follows. The general procedure was the same as in Example 1, except that the organic base and phosphorus compound were changed as shown in the table below. In this experiment, the hydrogen pressure was maintained at 212 kPa, and the final reaction mixture was analyzed using gas-liquid chromatography.

Table: Example 3 Hydrogenation is carried out as described above using the following amounts of starting materials and the same conditions as in Example 1. 2-Nitrotoluene 27.42 g Methanol 80 ml 4-DMAP 0.1 g Tributyl phosphite 0.250 g 3% Pt/C 0.33 g Hydrogen pressure 212 kPa Temperature 32°C Time 4 hours 21.8 g of oily substance is obtained. This oil is treated with hexane (100ml) and then cooled to about -30°C to give 14.76g of N-o-tolylhydroxylamine (60% yield, mp44°C, IR
and the NMR spectra are correct). Example 4 Hydrogenation is carried out as described above using the following amounts of starting materials and the same conditions as in Example 1. 4-Nitrotoluene 27.42g Methanol 80ml 4-DMAP 0.1g Tributyl phosphite 0.25g 3% Pt/C 0.33g Hydrogen pressure 212kPa Temperature 25°C Time 1 hour 24.5g of oily substance is obtained. This is treated with hexane (100ml) and then cooled to about -30°C to give 14.2g of N-(p-tolyl)hydroxylamine (57.7% yield, mp 98°-99°C, IR
and the NMR spectra are correct). Example 5 Hydrogenation is carried out as described above using the following amounts of starting materials and the same conditions as in Example 1. p-chloronitrobenzene 31.51g methanol 80ml 4-DMAP 0.1g tributyl phosphite 0.25g 3% Pt/C 0.33g Hydrogen pressure 414kPa Temperature 25°C Time 2 hours 25.2g of oily substance is obtained. This is treated with hexane (125 ml) and then cooled to about -30°C to give 18.52 g of p-chlorophenyl-hydroxylamine (yield 64.5%, mp 83°-84°C,
IR and NMR spectra are correct). Example 6 Hydrogenation was carried out as described above using the following amounts of starting materials and the same conditions as in Example 1. 1-Nitrofuropane 17.82g Triethylamine 0.10g Triethylphosphite 0.166g 3% Pt/C 0.33g Hydrogen pressure 345kPa Temperature 40℃ Reaction time Approximately 5/6 hours Filter the crude mixture to remove Pt/C and prepare for next use I made it. The organic layer was treated with concentrated hydrochloric acid and cooled to below room temperature to obtain N-(1-propyl)hydroxylamine hydrochloride (17.84 g) in 80% yield. Example 7 Using the following amounts of starting materials and the same conditions as Example 1, 1-nitropropane, 2-nitropropane, 2-methyl-2-nitropropane and 9-
Hydrogenation of methyl-9-nitro-1,6-decadiene is carried out as described above. Aliphatic nitro compound 0.2 mol 4-dimethylaminopyridine 0.1 g Tributyl phosphite 0.25 g 3% Pt/C 0.33 g Hydrogen pressure 414 kPa Temperature 40°C Reaction time about 3/4 hour The crude product was treated with 75 ml of hexane, It was then filtered with vigorous stirring. 1-nitropropane, 2-
N-(1-propyl)hydroxylamine, N-(2-propyl)hydroxylamine, N- from nitropropane, 2-methyl-2-nitropropane and 9-methyl-9-nitro-1,6-decadiene, respectively (2-Methylpropyl)hydroxylamine and 9-hydroxyl-amino-
9-methyl-1,6-decadiene is 60 each,
Yields of 67, 67 and 60% were obtained.

Claims (1)

[Claims] Primary formula A: or B: RNHOH [In the above formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each hydrogen atom, hydroxy group, halogen atom, straight chain or branched alkyl group having 1 to 20 carbon atoms, carbon Alkoxy group having 1 to 20 atoms, cyclopentyl group,
a group representing a cyclohexyl group, phenyl group, phenylalkyl group or alkylphenyl group (the alkyl group having 1 to 6 carbon atoms), or a group attached to adjacent carbon atoms of a benzene ring
two of R ₁ , R ₂ , R ₃ , R ₄ or R ₅ together with the two carbon atoms of the benzene ring to which they are engaged form a second benzene ring that is ortho-fused with the benzene ring; R represents a linear or branched chain and/or cyclic alkyl group having 1 to 24 carbon atoms.
In the process which is obtained by hydrogenating the corresponding nitro derivative in the presence of a platinum catalyst and a trivalent or pentavalent organophosphorus compound, the nitrogen-containing base is calculated on the basis of the amount of nitro derivative. A process characterized in that it is added to the starting reaction mixture in an amount of less than 10% by weight. 2. The method according to claim 1, wherein the hydroxylamine has the structure A. 3. The method according to claim 1, wherein the hydroxylamine has the structure B. 4. The phosphorus compound according to claim 1, 2 or 3, wherein the phosphorus compound contains at least one alkyl group or at least one aryl group or aryloxy group having 1 to 20 carbon atoms. Method. 5. The method according to claim 4, wherein the phosphorus compound is triphenylphosphine and/or triphenylphosphite. 6. The method according to claim 4, wherein the phosphorus compound is trialkylphosphine and/or triphenylphosphite. 7. The method of claim 6, wherein the phosphorus compound is a trialkyl phosphite and the alkyl group contains 1 to 6 carbon atoms. 8. The method according to claim 7, wherein the phosphorus compound is triethyl phosphite, tripropyl phosphite and/or tributyl phosphite. 9. A process according to any of the preceding claims, wherein the nitrogen-containing base is a di- or tri-alkylamine and the alkyl group contains 1 to 6 carbon atoms. 10. The method of claim 9, wherein the nitrogen-containing base is triethylamine. 11 The nitrogen-containing base is pyridine or pyridine substituted by one or more alkyl, amino, phenyl, alkylamino, phenylamino or pyrrolidone groups, and the alkyl group is 1 to 6
9. A method according to any one of claims 1 to 8, wherein the method comprises 5 carbon atoms. 12. The method of claim 11, wherein the nitrogen-containing base is dialkylaminopyridine. 13. The method of claim 12, wherein the nitrogen-containing base is dimethylaminopyridine.