DE19619359A1 - Simple hydrogenation of nitro cpds. to amine(s) in high yield and selectivity - Google Patents

Abstract

Redn. of NO2 gps. to NH2 gps. comprises reacting a nitro cpd. with H2 in the presence of a water-soluble metal catalyst of formula MLnYm (I), where M is Ru, Rh, Ni or Pd; L is a water-soluble ligand(s); Y is other ligand(s) or an alkali metal or alkaline earth metal ion; n = 1, 2, 3 or 4; and m = 0, 1 or 2. Also claimed is a method of preparing Rh(CO)Cl(TPPTS)2 (IA) (TPPTS = tri-Na triphenyl phosphane bisulphonate).

Description

The invention relates to a method for reducing nitro compounds to the corresponding amines using a homogeneous palladium, Ruthenium, nickel or rhodium catalyst.

The reduction of nitro compounds, especially nitro aromatics to the Corresponding amines or anilines have been used for over a hundred years carried out industrially. Until a few years ago the reduction Has been used on an industrial scale using iron, has recently catalytic reduction with precious metal catalysts on various Backing materials found their way into industry. Although this method many In practice, there are advantages over iron reduction often problems. So are often long filtration times when separating the Catalyst required. The catalysts are usually extremely sensitive to Traces of catalyst poisons such as lower sulfur compounds Oxidation levels, which can lead to a complete standstill of the reduction. The Troubleshooting due to the nature of a failure of the reaction is one heterogeneous catalyst often problematic and sometimes only with considerable expenditure on equipment possible.

If the nitroaromatic contains halogen substituents, it often occurs Dehalogation as a side reaction. This can be done by selectively deactivating the Catalyst are suppressed, but reproducibility is difficult is.  

Reductions with homogeneous catalysts compared to heterogeneous Catalysts are often more efficient, for example, in J. Org. Chem. 1976, 41, 1200 and J. Indian Chem. Soc. 1986, 63, 901. Because of the problems with separating the catalyst from the product these reactions have so far only been carried out on a laboratory scale. Here too occurs as a side reaction in halogenated nitroaromatic dehalogenation.

The task was therefore to provide a method which the above Disadvantages at least reduced and the reduction of nitro compounds too Amines in a simple manner and in high yields.

It has now been found that the reduction of nitro compounds with Hydrogen in an aqueous system with precious metal catalysis and gentle can be carried out in high yields if the reaction in the presence of a water-soluble ligand is carried out.

EP-A-0 372 313 describes the use of noble metal catalysts Tris- (m-sulfophenyl) -phosphine is described as a complex ligand. This Catalysts are used in particular in the water gas reaction Hydrocarbonylations and hydroformulations used.

It was therefore surprising that these can also be used for the reduction of Nitroaromatics are suitable for the corresponding anilines without for example a dehalogenation or C '/ C link under Dehalogenation can be observed.

With water-soluble catalysts, nitro aromatics have so far only been able to Use of carbon monoxide or formic acid derivatives to anilines can be reduced (Tetrahedron Letters 1995, 36, 9305). For the technical Realization of these procedures is the acute toxicity of carbon monoxide and the relatively high price of formic acid derivatives a disadvantage.  

The invention therefore relates to a method for reducing Nitro groups to amino groups, characterized in that one Nitro compound with hydrogen in the presence of an aqueous solution of a implement water-soluble metal catalyst of the general formula (I),

M (L) _n (Y) _m (I)

where the symbols and indices have the following meanings:
M is ruthenium, rhodium, nickel or palladium;
L is the same or different a water-soluble ligand;
Y is the same or different, another ligand or an alkali or alkaline earth ion;
n is 1, 2, 3 or 4;
m is 0, 1 or 2.

With the method according to the invention, nitro compounds are very high Yield and selectivity reduced, being in the case of halogenated Nitro compounds only rarely lead to dehalogenation reactions. The The aqueous catalyst solution can be separated off by simple Phase separation take place.

M is preferably rhodium, ruthenium or palladium.

Water-soluble ligands suitable for the process according to the invention contain, for example, sulfonic acid salt and / or sulfonic acid residues and / or Carboxylic acid salt and / or carboxylic acid residues and / or phosphonic acid hydrochloric and / or phosphonic acid residues and / or phosphinic acid salt and / or Phosphinic acid residues, and / or phosphonium groups and / or Peralkylammonium groups and / or hydroxyl groups and / or Polyether groups with a suitable chain length, preferably with more than 10 Alkylene oxide units. Preferred are sulfonic acid salt, sulfonic acid,  Carboxylic acid salt, carboxylic acid, phosphonic acid salt and Phosphonic acid groups.

Preferred classes of water soluble ligands are with the above groups substituted phosphanes, such as trialkylphosphines, tricycloalkylphosphines, Triarylphosphane, Dialkylarylphosphane, Alkyldiarylphosphane and Heteroarylphosphane, such as tripyridylphosphine and trifurylphosphane, the three substituents on the phosphorus may be the same or different, chiral or achiral can and wherein one or more of the substituents are the phosphorus groups can link several phosphines and being part of this link can also be one or more metal atoms, phosphites, Phosphinous esters and phosphonous esters, phospholes and Dibenzophosphole. which also includes cyclic or oligo- and polycyclic compounds count.

Other suitable groups of water-soluble complex ligands include for example bipyridines, phenanthrolines, porphyrins and alizarines, which with the above groups are modified.

Preferred water-soluble phosphines are those of the general Formulas (II) to (VIII),

where the symbols and indices have the following meanings:
Aryl: a phenyl or naphthyl group which can also carry one or more substituents R;
Alkyl: a straight-chain or branched alkyl group having 1 to 8 carbon atoms;
R, R ′: alkyl, aryl or aralkyl with 1 to 18 carbon atoms;
M: alkali, alkaline earth metal or NR₄;
X: halogen, BF₄, PF₆, OSO₂CF₃, 1/2 [SO₄];
l, m: 1 to 8;
n, o, p, q: 0, 1 to 8;
s: 0, 1 to 3.

The following are examples of particularly preferred water-soluble complex ligands:
(R, unless otherwise noted, has the meanings given in the formulas (II) to (VIII))
1. Sulfonated phosphines

2. Phosphines with hydrophilic groups in the periphery

3. Phosphines with quaternized aminoalkyl and aminoaryl substituents

4. Carboxylated phosphines

5. Phosphines with hydroxyalkyl or polyether substituents

6. Phosphinoalkyl phosphonium salts

7. Phosphites

P [-OC₆H₄SO₃ {NH (i-octyl) ₃}] ₃

Particularly preferred water-soluble phosphine ligands are:

Y is preferably H, CO, CN or halogen, preferably Cl, or a Alkali or alkaline earth metal ion, preferably Na, K or Li.

If M is palladium, Y particularly preferably denotes Cl⊖, CO, Na, K, Li.

If M is rhodium, Y particularly preferably denotes Cl⊖, CO, Na, K, Li, H.

The water-soluble complex ligands used according to the invention are largely known from the literature. The syntheses of these compounds are for example described in W.A. Herrmann and C.W. Kohlpainter, Angew. Chem. Int. Ed. Engl. 32 (1993) 1524 and the literature cited therein or can be familiar to the expert according to literature or analog Methods are done. The production of BINAS is described in EP-A 0 571 819 and US-A 5,347,9045.  

Mixtures of two or more can optionally also be used various water-soluble complex ligands can be used.

The water-soluble metal catalyst of the formula (II) can be synthesized separately be or in situ by combining a ruthenium, nickel, Palladium or rhodium salt, such as rhodium chloride hydrate or Ruthenium chloride, such as rhodium chloride hydrate, ruthenium chloride, Nickel halide or palladium (II) salts and a water-soluble ligand getting produced.

If necessary, a reducing agent is added. Usually is Hydrogen is the suitable reducing agent to represent the active Catalyst species.

The metal complexes of the formula (II) used according to the invention are partial known from the literature (see, for example, EP-A-0 372 313 or J. Organomet. Chem. 1990, 389, 103).

Particularly preferred metal complexes of the formula (II) are Rh (CO) Cl (TPPTS) ₂, where TPPTS means triphenylphosphane bisulfonate tri sodium salt, Pd (TPPTS) ₂ and Ru (TPPTS) ₂Cl₂.

The invention further relates to a method for producing Rh (CO) Cl (TPPTS) ₂. The catalyst mentioned can by a new process easily from an aqueous solution of TPPTS and rhodium trichloride as well subsequently added formaldehyde with subsequent heating as described in Example 1 below. This procedure is compared to that described in EP-0 372 313 much simpler. A Isolation and chromatographic purification of the intermediate stages are eliminated. The TPPTS can be used as a technical product, as it occurs in production will. The carbon monoxide is replaced by the aqueous formaldehyde solution  replaced, so that the equipment handling is also considerably simplified here becomes.

The process according to the invention is expediently carried out in an autoclave carried out.

According to Römpps Chemie Lexikon, autoclaves are closable to a high degree Metal vessels tested for overpressure with screwed on, through bayonet lock secured or pressed on, tightly closing lid. In this Autoclave heads are, for example, connection options for a Bursting plate or a safety valve, pressure gauge, thermometer and often also for a gas-tight stirrer. In addition to stationary autoclaves Internal stirring (also magnetic stirring) is also available in shaking autoclaves and rotating autoclaves. The autoclave is heated by Labor-Au toklaves (capacity from approx. 100 ml up to several liters) mostly electrical, larger autoclaves in industrial process engineering (up to several m³) mostly by steam. Autoclaves in which reactions under Expire consumption of gases, e.g. B. pressure hydrogenation, additionally contain a Inlet for the gas-bearing raw material, usually from a compressor is promoted. In the majority of cases, the material of the autoclaves is made made of high-alloy steel (e.g. V4A), but there are also special autoclaves Copper, light and monel metal.

The catalyst, containing a metal complex of the formula (I), is aqueous Solution used, the amount of water in a wide range can vary. As the reaction takes place in the water phase, the provision of larger quantities of water dissolve more nitroaromat in the water, which accelerates the reduction. The amount of water is therefore in certain limits influence the reaction rate. Since the Catalyst itself is extremely well soluble in water, you are also here in the Water quantity not restricted. It should also be borne in mind that forms water itself during the reduction. With one mole of substrate and one  Millimoles of catalyst are generally 10-1000 ml, preferably 50-500 ml, especially 100-200 ml of water. The molar ratio The catalyst to substrate is generally 1: 100 to 1: 100,000, preferably 1: 500 to 1: 10,000, in particular 1: 500 to 1: 5000. From the circumstances There is a ratio of catalyst to substrate and catalyst to water from catalyst to water from about 1: 500 to 1: 200,000, preferred 1: 2000 to 1: 190,000, in particular 1: 5,000 to 1: 100,000.

The respective reaction speed depends on many parameters, such as Pressure, temperature, the amount of catalyst, the amount of substrate and the Amount of water. But it also depends crucially on the solubility of the Substrate in water. Nitroaromatics, e.g. B. an ethoxy or Containing methoxy group are usually more water-soluble than alkylated Links. The response time is usually depending on the Reaction conditions and the nature of the nitroaromatic 30 minutes to 10 hours. The Hydrogen absorption usually breaks sharply after complete reduction from.

The reaction temperature is generally 20 to 150 ° C, preferably 50-130 ° C, especially at 60 to 110 ° C. the hydrogen pressure can 1-150 bar, preferably 10-100 bar, particularly preferably 10-20 bar. Frequently chosen reaction conditions are 100 ° C and 20 bar Hydrogen pressure.

The reaction product is after the reduction of the aqueous Catalyst solution separated. The aqueous catalyst solution can be used for further Reductions are used. A loss of activity will result in repatriation not observed. If the catalyst is recycled several times, the aqueous catalyst solution always by the added water of reaction more diluted. For example, by membrane filters or by constricting Vacuum can restore the original concentration ratios  will.

The catalyst system is relatively insensitive to air, but the aqueous system should Solution to be treated inertly to the longest possible life and To ensure traceability of the catalyst.

In the reduction, the addition of an organic solvent for the nitro aromatics can be dispensed with. This also eliminates the elaborate and costly solvent treatment. Even those with the heterogeneous Catalytic reduction of the necessary filtration from the catalyst is eliminated. It is however, it is also possible that the nitro compound with an organic Solvents, for example with toluene, o-xylene, m-xylene, p-xylene, mixtures isomeric xylenes, ethylbenzene, mesitylene, chlorobenzene, dichlorobenzene, chlorotoluene, Cyclohexane, cumene, decalin, ethyl acetate, butyl acetate or a mixture of two or more of these solvents, diluted.

Preferred educts of the process according to the invention are aromatic Nitro compounds. Particularly preferred starting compounds are those of the formula (IX)

where the symbols and indices have the following meanings:

is an aromatic hydrocarbon, which may also contain heteroatoms, preferably -O- and / or -N- and / or -S-, with 4 to 20 carbon atoms, preferably phenyl or naphthyl;
n: depending on the aromatic base, it is 0, 1 2, 3, 4 or 0, 1, 2, 3, 4, 5, 6, preferably 0, 1 or 2;
R: is the same or different -H, -F, -Cl, -Br, -I, CN, -SCN, -OCN, -OH, -NH₂, -CHO, -NO₂, -SO₃H, R ′, OR ′, -COOR¹, -OCOR¹, -NHR¹, -NR'₂, NHCOR ';
R ': is the same or different H, a branched or unbranched alkyl, alkenyl or alkynyl group having 1 to 12, preferably 1 to 8, carbon atoms, in which one or more CH₂ groups by -O- and / or one or more H atoms can be replaced by -F, -Cl, -Br, -O -OH and / or -NH₂; or an aromatic hydrocarbon radical which may optionally also contain heteroatoms, preferably -O-, -N- and / or -S- and which may also contain further substituents R, with 4 to 20 carbon atoms, preferably phenyl or naphthyl.

Compounds in which are preferred
n is 0, 1 or 2 and
R is methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, i-pentyl, n-hexyl, n-heptyl, n-octyl -, 2-ethylhexyl- 2-ethyldecyl-, n-decyl-, n-dodecyl-, furthermore methoxy-, ethoxy-, propoxy-, isopropoxy-, butoxy-, pentyloxy-, hexyloxy-, octyloxy-, hydroxy, 2 -Ethylhexyloxy-, decyloxy-, dodecyloxy-, furthermore a carboxylic acid, methyl carboxylate, ethyl carboxylate, propyl carboxylate, butyl carboxylate, pentyl carboxylate, hexyl carboxylate, 2-ethyl carboxylic acid, phenyl amide, formyl amide, carboxylic acid -, Carbonsäurediethylamid-, Carbonsäuremethylamid-, Carbonsäureethylamid-, further an N, N-Dimethylamino- N, N-Diethylamino-, N-Methylamino-, N-Ethylamino-, N, N-Methylethylamino-, N, N-Dipropylamino-, N, N-dibutylamino, N-morpholino, finally an acetoxy, propionyloxy and butyryloxy group and / or a phenyl group which may also be substituted.

Particularly preferred products of the process according to the invention are accordingly amino compounds of the formula (X),

where the symbols and indices have the meanings given in the formula (IX) to have.

The compounds produced according to the invention are used in a variety of ways, for example as intermediates for the production of active ingredients, polymers and dyes.

The compounds prepared according to the invention preferably serve as Starting materials for the preparation of diazonium salts and benzoxazoles, such as Fenoxaprop-P-ethyl, a selective herbicide sold under the name Puma® is sold by AgrEvo, Frankfurt, Germany.

Diazonium salts serve, for example, as intermediates for the preparation of Active ingredients, polymers and dyes and especially as Diazotype precursors.

The invention is illustrated by the examples, without thereby want to restrict.  

example 1 Preparation of the catalyst Rh (CO) Cl (TPPTS)

RhCl₃ × H₂O (0.26 g, 1 mmol) became a boiling solution of TPPTS (29.2%, 19.5 g, 10 mmol). After about 15-20 seconds, one Formaldehyde solution (35%, 15 g, 175 mmol) added. The solution discolored from dark red to yellow. The mixture was then heated to approximately 80 ° C. for 10 minutes and added dropwise with ethanol until a slight clouding occurred. Upon cooling, TPPTS and the Rh-TPPTS complex crystallized from the Solution. The crystals were washed with ethanol / H₂O 80/20 largely freed from excess TPPTS. After recrystallization Ethanol / H₂O and drying in vacuo, the complex was highly enriched.

Example 2 Reduction of nitrobenzene

In a 2 l autoclave with a gassing stirrer, a two-phase system, consisting of 200 g (1.62 mol) nitrobenzene, 200 g water and 0.31 g (0.235 mmol) Rh (CO) Cl (TPPTS) ₂, hydrogenated at 20 bar and 100 ° C. After 8 hours with a conversion of 99.3%, an aniline content of 87.1% was obtained. The aqueous catalyst solution was separated in a separatory funnel.

Example 3 Reduction of nitrobenzene with recycled catalyst

200 g of nitrobenzene was among those given in Example 2 Reaction conditions in the presence of those recovered in this example Catalyst solution reduced. This time, after 3.5 h, sales of 98%. The aniline content was 95.5%.  

Example 4 Reduction of 2-chloronitrobenzene with recycled catalyst

Under the same reaction conditions as in Example 2, 200 g (1.27 mol) of 2-chloronitrobenzene were reacted with the catalyst recovered from Example 2. After 8.5 h, a solution of the following composition was obtained:
11.0% aniline (through reductive dehalogenation), 81.8% 2-chloroaniline as well
3.2% unreacted 2-chloronitrobenzene.

Example 5 Reduction of 4-ethoxynitrobenzene

Under the same reaction conditions as in Example 2, 200 g (1.31 mol) 4-ethoxynitrobenzene in 400 g of toluene with fresh rhodium catalyst Example 1 (0.23 mol in 200 ml of water) implemented. After an hour it was Reaction ended. According to GC, the solution contained after phase separation 95.5% 4-ethoxyaniline and 1.4% 4-ethoxynitrobenzene.

Example 6 Reduction of 3-nitrotoluene with recycled catalyst

With the aqueous catalyst solution recovered from Example 5 200 g (1.87 mol) of 3-nitrotoluene in 400 g of toluene under the same Reaction conditions reduced. After 3 h 40 min the connection was complete completely converted to 3-methylaniline. Educt was no longer in the solution detectable.  

Example 7 Reduction of 2,4-dimethylnitrobenzene with recycled catalyst

A mixture of 200 g (0.76 mol) of 2,4-dimethylnitrobenzene and recycled The catalyst solution was heated to 100 ° C. for 10 h at 20 bar hydrogen pressure. A GC analysis of the product solution showed a content of 97.7% 3,4-dimethylaniline.

Example 8 Reduction of 5-chloro-2-nitro-phenol

100 g (0.576 mol) of 5-chloro-2-nitro-phenol in 200 ml were placed in a 2-liter autoclave Suspended water and hydrogenated at 100 ° C / 20 bar hydrogen. At the start a catalyst solution consisting of 0.129 h (0.576 mmol) was added to the reaction Pd (ac) ₂, 2 ml DMSO and 3.9 ml TPPTS / H₂O solution (0.6 molar). After 7 hours the conversion was 99.3% and the solution contained 5-chloro-2-aminophenol of 95.53%. The catalyst phase was through Filtration of the product separated and reused.

Example 9 Reduction of 5-chloro-2-nitro-phenol with recycled catalyst

100 g (0.576 mol) of 5-chloro-2-nitro-phenol were added to a 2 l autoclave 100 ° C / 20 bar hydrogen hydrogenated. At the beginning of the reaction they were given the Catalyst solution from Example 8. After 10 hours, the conversion was 99.8% and the solution contained 96.5% 5-chloro-2-aminophenol. The Catalyst phase was separated by filtration of the product and reused.  

Example 10 Reduction of 5-chloro-2-nitro-phenol with recycled catalyst

100 g (0.576 mol) of 5-chloro-2-nitro-phenol were added to a 2 l autoclave 100 ° C / 20 bar hydrogen hydrogenated. At the beginning of the reaction they were given the Catalyst solution from Example 9. After 5.5 hours, the conversion was 99.9% and the solution contained 95.1% 5-chloro-2-aminophenol. The Catalyst phase was separated by filtration of the product and reused.

Example 11 Reduction of 5-chloro-2-nitro-phenol with recycled catalyst

100 g (0.576 mol) of 5-chloro-2-nitro-phenol were added to a 2 l autoclave 100 ° C / 20 bar hydrogen hydrogenated. At the beginning of the reaction they were given the Catalyst solution from Example 10. After 9.5 h, the conversion was 99.9% and the solution contained 95.6% 5-chloro-2-aminophenol. The The catalyst phase was separated off by filtration of the product.

Example 12 Reduction of 5-chloro-2-nitro-phenol

100 g (0.576 mol) of 5-chloro-2-nitro-phenol in 200 ml were placed in a 2 l autoclave Suspended water and hydrogenated at 100 ° C / 20 bar hydrogen at pH 7.5. At the beginning of the reaction, a catalyst solution consisting of 0.129 g was added (0.576 mmol) Pd (ac) ₂, 2 ml DMSO and 3.9 ml TPPTS / H₂O solution (0.6 molar) to. After 2.5 hours the conversion was 99.8% and the solution had one Content of 82.4% of 5-chloro-2-aminophenol. The catalyst phase was separated by filtration of the product and reused.  

Example 13 Reduction of 5-chloro-2-nitro-phenol with recycled catalyst

100 g (0.576 mol) of 5-chloro-2-nitro-phenol were added to a 2 l autoclave 100 ° C / 20 bar hydrogen hydrogenated at pH 7.5. At the beginning of the reaction there the catalyst solution from Example 12 is added. After 6.5 hours, the conversion was 99.6% and the solution contained 92.8% 5-chloro-2-amino phenol. The catalyst phase was separated off by filtration of the product.

Example 14 Reduction of 5-chloro-2-nitro-phenol with recycled catalyst

100 g (0.576 mol) of 5-chloro-2-nitro-phenol were added to a 2 l autoclave 100 ° C / 20 bar hydrogen hydrogenated at pH 7.5. At the beginning of the reaction, one gave the catalyst solution from Example 13. After 8.5 hours, the conversion was 99.6% and the solution contained 95.2% 5-chloro-2-aminophenol. The The catalyst phase was separated off by filtration of the product.

Example 15 Reduction of 5-chloro-2-nitro-phenol with recycled catalyst

100 g (0.576 mol) of 5-chloro-2-nitro-phenol were added to a 2 l autoclave 100 ° C / 20 bar hydrogen hydrogenated at pH 7.5. At the beginning of the reaction, one gave the catalyst solution from Example 14. After 9.5 h, the conversion was 99.9% and the solution contained 94.3% 5-chloro-2-aminophenol. The The catalyst phase was separated off by filtration of the product.  

Example 16 Reduction of 5-chloro-2-nitro-phenol

100 g (0.576 mol) of 5-chloro-2-nitro-phenol were added to a 2 l autoclave 200 ml of water suspended and hydrogenated at 100 ° C / 20 bar hydrogen. To At the start of the reaction, a catalyst solution consisting of (0.576 mmol) was added Ru (TPPTS) ₃Cl₂ too. After 2.5 h, the conversion was 99.8% and Solution contained 92.4% 5-chloro-2-aminophenol. The Catalyst phase was separated by filtration of the product and reused.

Claims (10)

1. Process for the reduction of nitro groups to amino groups, characterized in that a nitro compound is reacted with hydrogen in the presence of an aqueous solution of a water-soluble metal catalyst of the general formula (I), M (L) _n (Y) _m (I) where the symbols and clues have the following meanings:
M is ruthenium, rhodium, nickel or palladium;
L is the same or different a water-soluble ligand;
Y is the same or different, another ligand or an alkali or alkaline earth ion;
n is 1, 2, 3 or 4;
m is 0, 1 or 2. 2. The method according to claim 1, characterized in that the water-soluble ligand at least one substituent from the following Group contains: sulfonic acids, sulfonic acid salts, carboxylic acids, Carboxylic acid salts, phosphonic acids, phosphonic acid salts, Phosphonium salts, phosphinic acids, phosphinic acid salts, Peralkylammonium groups, hydroxy groups and polyether groups. 3. The method according to claim 2, characterized in that one Ligands from the group of phosphines, phosphites, phosphinous esters, Phosphonous acid esters, phospholes, bipyridines, phenanthrolines, porphyrins and Alizarine chooses. 4. The method according to claim 3, characterized in that a water-soluble phosphine ligand of the general formula (III) to (VIII) is used: where the symbols and indices have the following meanings:
Aryl: a phenyl or naphthyl group which can also carry one or more substituents R;
Alkyl: a straight-chain or branched alkyl group having 1 to 8 carbon atoms;
R, R ′: alkyl, aryl or aralkyl with 1 to 18 carbon atoms;
M: alkali, alkaline earth metal or NR₄;
X: halogen, BF₄, PF₆, OSO₂CF₃, 1/2 [SO₄];
l, m: 1 to 8;
n, o, p, q: 0, 1 to 8;
s: 0.1 to 3. 5. The method according to one or more of the preceding claims, characterized in that a catalyst: substrate ratio from 1: 100 to 1: 100,000. 6. The method according to one or more of the preceding claims, characterized in that at a reaction temperature of 20 works up to 150 ° C. 7. The method according to one or more of the preceding claims, characterized in that at a hydrogen pressure of 1 to 150 bar works. 8. The method according to one or more of the preceding claims, characterized in that the nitro compound with a organic solvents from the group of toluene, o-xylene, m-xylene, p-xylene, mixtures of isomeric xylenes, ethylbenzene, mesitylene, chlorobenzene, Dichlorobenzene, chlorotoluene, cyclohexane, cumene, decalin, ethyl acetate, Butyl acetate or a mixture of two or more of these Diluted solvent. 9. Use of an amino compound made by a process according to one or more of claims 1 to 9, as an intermediate to Manufacture of active ingredients, polymers and / or dyes. 10. A process for the preparation of Rh (CO) Cl (TPPTS) ₂, thereby characterized in that an aqueous solution of TPPTS and Rhodium trichloride mixed with formaldehyde and then heated.