CH628611A5 - METHOD FOR PRODUCING CYCLOALIPHATIC AMINES BY CATALYTIC HYDRATION. - Google Patents

Description

The invention relates to a process for the preparation of cycloaliphatic amines by catalytic hydrogenation of corresponding aromatic amines in the presence of a supported ruthenium catalyst and to novel cycloaliphatic amines which can be prepared according to the invention.

The use of a ruthenium catalyst for the hydrogenation of nuclei of 4,4'-diamino-diphenyl-methane is already known from DE-AS 1 542 392 and DE-OS 1 909 342. In this known process, however, large amounts of catalyst, based on the starting material used, are required and activity and selectivity of the catalyst are limited. There is therefore a need for a better and generally applicable process for the preparation of cycloaliphatic amines by catalytic hydrogenation of the corresponding aromatic amines.

It has now been found that, in good yield, cy-30 cloaliphatic amines can be obtained by catalytic hydrogenation of the corresponding aromatic amines at elevated pressure and temperature in the presence of a ruthenium catalyst if a supported ruthenium catalyst is used, the catalyst support of which is made from hydroxides and / or 3s oxide hydrates of chromium and manganese and / or their dehydration products or contains them.

The ruthenium content of the catalyst used in the process according to the invention, calculated as ruthenium, is generally 0.1 to 10% by weight, preferably 0.5 to 5 40% by weight, based on the supported catalyst.

In general, the weight ratio of the elements manganese and chromium to one another is generally 0.2: 1 to 5: 1, preferably 0.5: 1 to 3: 1, in particular 0.8: 1 to 2: 1.

The catalyst used in the process according to the invention can be produced by methods known per se. It is expediently carried out in two stages, the catalyst support being prepared in the first stage and the ruthenium being applied to the catalyst support in the second stage. so

The catalyst support can be prepared by methods known per se, e.g. by co-precipitating a chromium-manganese hydroxide mixture from a solution containing chromium and manganese salts with alkali metal hydroxide solution or ammonia and then washing out the 55 soluble fractions with water (Journal American Chemical Society, Volume 63, pages 1385, 1386 (1941)). It can also be carried out in such a way that manganese carbonate is precipitated from a manganese salt solution using alkali or ammonium carbonate, which is washed with water without anions and then reacted in an aqueous suspension with ammonium bichromate at elevated temperature, preferably 70 to 100 ° C (cf. DOS 1 443 901). Another possibility is the production according to DE-AS 1 542 370 by reacting manganese carbonate with chromium trioxide. ös

The catalyst support used in the process according to the invention can also be mixed in a known manner with other known catalyst supports, such as Al 2 O 3, SiO 2, diatomaceous earth, pumice stone, iron oxide, e.g. by adding these carrier materials to the manganese salt solution before the manganese carbonate is precipitated. Likewise, instead of these carrier materials, their water-soluble precursors, such as iron and aluminum salts, can also be added. In general, the proportion of this carrier material will not exceed 50% by weight. The amount to be selected expediently can easily be determined by a few experiments.

The catalyst support used in the process according to the invention can be used in the second stage either directly after its preparation in water-moist form or after drying at an elevated temperature up to about 120 ° C. and, if appropriate, after further temperature treatment.

The drying can be carried out both under normal pressure and under reduced pressure, the drying temperature then being able to be selected to be lower.

The further temperature treatment is expediently carried out at temperatures above 200 ° to about 450 ° C., preferably in the temperature range from 250 to 350 ° C. This temperature treatment can be particularly advantageous in the case of catalyst supports which are produced using chromium (VI) compounds.

After drying or further temperature treatment, the catalyst support used in the process according to the invention can furthermore be ground, homogenized and shaped to give moldings in a manner known per se.

The second step in the preparation of the catalyst, the application of the ruthenium to the catalyst support, can also be carried out according to methods known per se, expediently starting from water-soluble ruthenium compounds, such as ruthenium trichloride hydrate.

For the production of powdered catalysts it may be advantageous to deposit the ruthenium on the catalyst support from aqueous solution e.g. by precipitation with alkali lyes or alkali carbonate solutions.

In the production of lumpy catalysts, one can proceed, for example, by soaking the catalyst support in succession with the ruthenium salt solution and the precipitating solution described above in any order after it has been deformed, for example by tableting the powdered support, and intermediate drying and impregnation after the impregnation the resulting alkali salt is washed out with water. However, both solutions can also be sprayed onto the deformed catalyst support in succession in a heated coating drum and then washed. The single or multiple impregnation or coating is usually based on the amount of ruthenium to be applied.

The catalyst used in the process according to the invention can be used directly after drying. However, it may also be advantageous to subject it to hydrogen treatment at temperatures from about 20 to about 200 ° C before use.

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Aniline and substituted anilines are preferably suitable as starting compounds for the process according to the invention.

The process according to the invention is therefore preferably used for the catalytic core hydrogenation of aromatic amines of the formula ## STR1 ## in the

R1, R2 and R3 are the same or different and represent hydrogen or an alkyl radical,

R4 and R5 are the same or different and represent an optionally substituted alkyl, cycloalkyl, aralkyl or aryl radical and m, n and p each represent one of the numbers 0 or 1.

Straight-chain and branched alkyl radicals with 1 to 10 carbon atoms, preferably with up to 6 and in particular up to 4 carbon atoms, may be mentioned as alkyl radicals, for example methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert. Butyl, the isomeric pentyl and hexyl radicals.

Optionally substituted cycloalkyl radicals with up to 10 carbon atoms may be mentioned as cycloalkyl radicals, preferably cyclopentyl and cyclohexyl.

Aralkyl radicals which may be mentioned are those having up to 30 carbon atoms, preferably having up to 6 carbon atoms in the chain and 12 carbon atoms in the aromatic part, for example benzyl, benzhydryl, phenylethyl, phenylpropyl, phenylisopropyl, phenylbutyl, phenylisobutyl , Phenyltrimethylpropyl, preferably benzyl and phenylisopropyl.

Aromatic radicals which may be mentioned are those with up to 14 carbon atoms, preferably phenyl and naphthyl, in particular phenyl.

Examples of substituents for the optionally substituted radicals R4 and R5 are lower alkyl radicals, the hydroxyl group and preferably the amino group and the alkylamino group.

A particularly preferred group of the compounds of general formula I thus corresponds to formula II

in the

R1, R2, m, n and p have the meaning given above and

R6 and R7 are the same or different and represent an alkyl radical.

Examples of compounds of the general formula II are:

Aniline, alkylanilines such as o-, m-, and p-toluidine, xylidines such as 1,2,3-, 1,2,4- and 1,3,4- and 1,3,5-xylidine, ethyl, propyl -, Isopropyl, butyl, isobutyl, tert. Butyl and anilines substituted by higher alkyl radicals; furthermore N-alkylanilines such as N-methylaniline, N-ethylaniline, N-propylaniline, N-isopropylaniline, the isomers N-butyl-, N-pentyl- and N-hexylaniline;

o-, m-, and p-phenylenediamine, 2,4-diaminotoluene.

The following may also be mentioned as compounds of the general formula I:

4,4'-diaminodiphenyl, bis (4-aminophenyl) methane, bis (4-methylaminophenyl) methane, 2,2 ', 6,6'-tetramethyl-4,4'-diaminodiphenyl methane, 2, 2 ', 6,6'-tetraethyl-4,4'-diamino-phenyl-methane, 2,2-bis (4-aminophenyl) propane, 1,1-bis (4-aminophenyl) cyclohexane, 4 , 4 ', 4 "-Triaminotriphenyl-methane, 1,3-bis- (4-aminophenyI) -1,1,3-trimethyl-propane.

Particularly preferred groups of substituted anilines of the formula I correspond to the general formulas

(III)

A

(IV)

in which l

R1, R2, R3 have the meaning given above.

3rd

Zen,

R8, Ry and R10 are the same or different and represent hydrogen or an alkyl radical and

A represents an optionally substituted alkylene radical, preferably having 1 to 6 carbon atoms.

Another preferred group of starting compounds corresponds to the general formula

(v)

in the

R1, R2, R3, R8, Ry and R10 have the meaning given above.

Preferred compounds of the formula V are a, a'-bis- (4-aminophenyl) -m-diisopropylbenzene, a, a-bis- (4-aminophenyl) -p-diisopropylbenzene, a, a'-bis- (4 -methylamino-nophenyl) -p-diisopropylbenzene, a, a'-bis- (4-methylaminophenyl) -m-diisopropylbenzene and mixtures of the aforementioned isomeric compounds.

In general, the process according to the invention is carried out at an elevated temperature above 150 to approximately 350 ° C., preferably in the temperature range between approximately 180 and 280 ° C.

Likewise, the process according to the invention is carried out at elevated pressure, preferably at a pressure above 100 bar, in particular above 180 bar to about 1000 bar. The reaction rate generally increases with higher pressure, so that an upper limit of the pressure is only given from the apparatus side.

In general, the process according to the invention is carried out without using a solvent; however, the presence of a solvent is not detrimental, but generally has no advantage.

In general, the catalyst used in the process according to the invention is used in an amount whose Ru5

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thenium content is about 0.005 to 0.5 g, preferably about 0.01 to 0.2 g and in particular 0.02 to 0.1 g per kg of the starting material to be hydrogenated.

In general, the process according to the invention can be carried out batchwise or continuously in a conventional manner, e.g. in a stirred autoclave or a reaction tube; the apparatuses required to carry out the process according to the invention are state of the art. It is possible to use the method according to the invention, for. B. as a sump phase or trickle phase process.

The process according to the invention is carried out batchwise in a customary manner as a bottom phase process in an autoclave in the presence of powdered catalyst. 15

The process according to the invention can particularly advantageously be carried out continuously. This is done in the usual way either with powdered catalyst e.g.

according to the bubble column principle in such a way that the liquid starting product in which the catalyst is suspended is passed through a reaction tube cascade together with hydrogen in cocurrent, or with lumpy catalyst e.g. according to the trickle phase principle in such a way that the starting product trickles liquid over the stationary catalyst located in the reaction tube, while the hydrogen is passed through the reaction tube in cocurrent or countercurrent. Excess hydrogen is advantageously circulated.

In the case of multinuclear aromatic amines, it is generally possible to direct the reaction in such a way that all or only some of the aromatic nuclei are hydrogenated. For example, a, a-bis- (4-aminocyclohexyl) -p-diisopropylbenzene can be obtained in almost quantitative yield if a, a-bis- (4-aminophenyl) -p-diisopropylbenzene is obtained at 250 ° C and hydrogen pressure from about 200 to 300 bar in the presence of a percent by weight of the catalyst used in the process according to the invention with a ruthenium content of 1% by weight until the stoichiometrically necessary amount of hydrogen of 6 moles per mole of starting compound is taken up.

If the hydrogenation is continued under the stated conditions until 9 mol of hydrogen are absorbed per mol of starting compound, a, a '~ bis- (4-aminocyclohexyl) -1,4-diisopropylcyclohexane is normally obtained.

The reaction rate of the hydrogenation of the middle core is usually much lower than that of the outer core under the same conditions, so that a pronounced kink occurs in the reaction rate-time diagram. For the hydrogenation of the middle core, it is therefore generally advisable to choose higher temperatures, higher hydrogen pressures and lower catalyst loads.

In general, preferred compounds of the formulas can be obtained from compounds of the formula V by the process of the invention

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6

in which R1 and R2 have the meaning given above, obtained. The most convenient reaction conditions, e.g. With regard to temperature, hydrogen pressure, catalyst concentration or catalyst load, it can easily be determined in individual cases by a few preliminary tests.

Compounds of the formulas VI and VII were hitherto unknown. For example, they are valuable intermediates for the production of polycondensation plastics and lacquers such as polyureas, polyimides and especially polyamides and polyurethanes. For example, the polyamides made from the corresponding primary diamines are usually characterized by improved hardness and elasticity (modulus of elasticity), transparency, high freezing temperature, low water absorption, improved solubility in common solvents and improved electrical behavior, i.e. low dielectric loss factor (tgó) and high tracking resistance. The polyurethanes produced from the primary and secondary diamines generally also have similar improved properties. Because of their light color and high resistance to yellowing, they are normally particularly suitable for use in the paint sector. Furthermore, their resistance to degradation by exposure to aggressive chemicals should be emphasized in general.

The particular advantages of the process according to the invention compared to known hydrogenation processes generally consist in the fact that it is possible to work in the absence of an inert solvent and of ammonia, the presence of which has previously been advantageous in order to avoid side reactions (DE-OS 1 909 342). Furthermore, a much smaller amount of ruthenium, based on the starting material, can be used in the process according to the invention than corresponds to the prior art (DE-OS 2 132 547). Furthermore, the method according to the invention can be carried out at a higher temperature than corresponds to the prior art. By avoiding the dilution with an inert solvent or ammonia, elevated temperature and thus a higher reaction rate, the process according to the invention usually results in a significantly higher space-time yield while saving ruthenium.

example 1

A solution of 3000 g of MnS04H20 in 151 water is mixed with a solution of 2500 g of sodium carbonate in 10 l of water over the course of about 10 minutes. The precipitate is washed sulfate-free, suspended in 10 l of water and heated to 85 ° C. with stirring. A solution of 5350 g of ammonium bichromate in 7000 ml of water is run into this suspension at 85 ° C. and stirring is continued at 85 ° C. for 3 hours. After cooling, the dark precipitate is filtered off, washed with a little water and dried at 120 ° C. 3510 g of a brown-black powder (carrier (la)) are obtained.

Analysis:

27.3% Mn 25.3% Cr.

300 g of the carrier (la) are heated to 250 to 260 ° C for about 30 minutes. 246 g of a brown-black powder (carrier (lb)) are obtained.

Analysis:

33.2% Mn 30.8% Cr.

100 g of the homogenized carrier (Ia) are slurried in 500 ml of water and a solution of 2.48 g of ruthenium chloride hydrate (Ru content: 40.3%) in 200 ml of 0.05N HCl is added at room temperature while stirring . Then about 140 minutes of sodium hydroxide solution are added dropwise over a period of about 5 minutes to a pH of 9 to 10. After stirring for five hours, the catalyst is separated off, washed free of chloride and dried at 110 ° C. for 3 hours. 93 g of a brown-black powder (catalyst (la)) are obtained.

Analysis:

28.7% Mn 20.6% Cr 1.1% Ru.

50 g of the homogenized carrier (lb) are slurried in 250 ml of water and, as described above, a solution of 1.24 g of ruthenium trichloride hydrate in 100 ml of 0.05N HCl and 85 ml of n-NaOH are added in succession. After stirring for five hours, the product is filtered off with suction, washed free of chloride and dried in a vacuum desiccator. 50.5 g of a black-brown powder (catalyst (lb)) are obtained.

Analysis:

32.9% Mn 23.8% Cr 1.0% Ru.

Example 2

A solution of 338 g MnS04.H20 and 50 g A1 (N03) 3.9H20 in 1600 ml water is mixed in 5 minutes with stirring with a solution of 281 g Na2C03 in 1200 ml water. The precipitate is washed free of sulfate and nitrate and heated to 85 ° C. as a suspension in 1000 ml of water. A solution of 550 g (NH4) 2Cr207 in 750 ml of water is then added in 5 minutes and the mixture is stirred at 85 ° C. for a further 90 minutes. After cooling, the dark precipitate is separated off, washed with about 1000 ml of water and dried at 120 ° C. for 12 hours. 353 g of a brown-black powder (carrier (2a)) are obtained.

Analysis:

25.0% Mn 19.2% Cr 1.8% AI.

100.0 g of the carrier (2a) are heated to 250 ° C. for about 30 minutes. 78.0 g of a brown-black powder (carrier (2b)) are obtained.

Analysis:

32.0% Mn 23.7% Cr 2.3% AI.

10.0 g of the homogenized carrier (2b) are slurried in 50 ml of water and a solution of 0.248 g of ruthenium trichloride hydrate (Ru content: 40.3%) in 20 ml of 0.05N HCl is added with stirring at room temperature . Then about 15 ml of n-NaOH are added dropwise in the course of 5 minutes until the pH has reached the value of about 9 to 10. After stirring for five hours, the catalyst is separated off, washed free of chloride and dried in a vacuum desiccator. 10.0 g of a brown-black powder (catalyst (2)) are obtained.

Example 3

A solution of 338 g of MnS04.H20 and 500 g of A1 (N03) 3.9H20 in 1800 ml of water is mixed with a solution of 530 g of ammonium carbonate in 1200 ml of water with stirring at room temperature over the course of 10 minutes. The mixture is stirred for about 30 minutes, washed free of sulfate and nitrate and then reacted in aqueous suspension in 1000 ml of water by heating to 85 ° C. for 2.5 hours with a solution of 530 g of ammonium bichromate in 750 ml of water. After cooling, the dark-colored precipitate is separated off, washed with about 500 ml of water and dried for 3 hours at 120 ° C. 455 g of a brown-black mass are obtained (analysis: 22.8% Mn, 21.0% Cr, 9.3% Al), which is heated to 250 ° C. for 20 minutes; This gives 390 g of a brown-black powder (carrier (3)).

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Analysis:

26.6% Mn 24.5% Cr 10.8% AI.

10.0 g of the carrier 3 are suspended in 50 ml of water, at room temperature with a solution of 0.248 g of ruthenium trichloride hydrate in 20 ml of 0.05 n-HCl and then in about 10 minutes with about 14 ml of n-NaOH a pH of 9 to 10 was added. After stirring for five hours, the catalyst is separated off, washed free of chloride and dried in a vacuum desiccator. 9.8 g of a brown-black powder (catalyst (3)) are obtained.

Example 4

A solution of 590 g of ammonium carbonate in 1350 ml of water is allowed to flow into a solution of 338 g of MnS04.H20, 500 g of A1 (N03) 3.9H20 and 70 g of FeS04.7H20 in 2000 ml of water at 25 ° C. with stirring in 5 minutes with stirring for 5 minutes . The mixture is stirred for about 30 minutes, washed free of sulfate and nitrate, then heated in suspension in 1000 ml of water to 85 ° C and at this temperature a solution of 550 g (NH4) 2Cr207 in 750 ml of water flows in. The mixture is stirred at 85 ° C. for about 2 hours, the dark precipitate is separated off after cooling, washed with 500 ml of water and dried at 120 ° C. for 3 hours. 480 g of a brown-black powder are obtained; Analysis: 21.7% Mn, 20.0% Cr, 8.9% AI, 2.5% Fe. This powder is heated to 250 ° C for about 30 minutes. This gives 392 g of a brown-black powder (carrier (4)).

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10.0 g of the powdery carrier 4 are suspended in 50 ml of water and a solution of 0.248 g of ruthenium trichloride hydrate (ruthenium content: 40.3% by weight) in 20 ml of 0.05N HCl is added. About 17 ml of n-NaOH are then added dropwise to a pH of about 8 to 10. After 5 hours, the dark precipitate is separated off, washed free of chloride and dried at 120 ° C. for 2 hours. 9.6 g of a brown-black powder (catalyst (4)) are obtained.

Example 5 (comparative example)

In each case 10.0 g of finely powdered Cr203, Mn02 and MnC03 are suspended in 50 ml of water and, analogously to Examples 2 to 4, first with a solution of 0.248 g of RuCl3 hydrate in 20 ml of 0.05N-HCl and then with n-NaOH treated up to a pH of 9 to 10. After washing and drying you get:

Catalyst (5a): Ru (1%) / Cr203; 10.1 g catalyst (5b): Ru (1%) / Mn02; 9.7 g catalyst (5c): Ru (1%) / MnC03; 10.0 g

Example 6 (Use)

Each 100 g of 4,4'-diamino-diphenyl-methane are hydrogenated in a shaking autoclave at 250 ° C. in the pressure range from 200 to 280 bar with the catalysts listed in Table I below until the water has ended. The amount of ruthenium applied is 0.05 g per kg of substance to be hydrogenated in all cases. The results of Table I are obtained

Table I

catalyst

No.

composition

Quantity (g)

Hydrogenation time (min)

Yield (9c)

Next-

prod.

Dest. Residue

(la)

Ru (1%) - Mn-Cr

0.5

80

0.8

97.4

1.8

(lb)

Ru (1%) - Mn-Cr

0.5

70

0.7

98.5

0.8

(lb)

Ru (1%) - Mn-Cr1

0.5

100

1.0

98.2

0.8

(2)

Ru (1%) - Mn-Cr-Al

0.5

90

1.0

98.2

0.8

(3)

Ru (1%) - Mn-Cr-Al

0.5

70

0.8

97.7

1.5

(4)

Ru (1%) - Mn-Cr-Al-Fe

0.5

100

0.7

97.3

. 2.0

This catalyst was treated with hydrogen at 100 ° C for 1 hour before use.

Example 7 (comparative example)

For comparison with the catalysts according to the invention, under otherwise identical conditions as mentioned in Example 6, catalysts are used which are commercially available or contain only individual constituents of the catalyst supports according to the invention. The amounts of ruthenium applied here are in all cases about 0.05 g per kg of substance to be hydrogenated. The results are shown in Table II.

Table II

Catalyst hydrogenation yield (%)

No. Composition quantity time incidental

(g) (min) prod.

/ hV-WW, / ~ Vw, Dest.-

A- 'A *' residue chl ch,

Xä> Wx

Ru (5%) - Al203 0.1 (commercially available)

(5a) Ru (1%) -Cr203 0.5

(5b) Ru (1%) - Mn02 0.5

(5c) Ru (1%) - MnC03 0.5

925

185

890

465

Hydr.

remains incomplete. Hydr.

remains incomplete

250-270 ° C hydr.

does not end

2.2

1.2

1.7

1.1

33.2 37.6

74.1

5.1

0.4 22.7

2.3 33.6 54.9

7.6

46.6 36.2

3.0

16.0

11.0

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The example shows that the comparative catalysts in the low use concentration, in which the catalysts according to the invention are still highly effective, have only unsatisfactory activity and selectivity. The hydrogenations cannot be completed quantitatively. 5

Example 8

2000 g of 4,4'-diamino-diphenyl-methane are stirred in a stirred autoclave together with 4.0 g of catalyst 2 at 250 ° C. under a hydrogen pressure of 280 bar until the hydrogen uptake has ended; Duration about 150 minutes. After cooling, the reaction product is taken up in methanol, filtered and distilled. 2100 g of distillate, bp: 128 to 130 ° C./0.05 torr, consisting of 99.2% 4,4'-diaminodicyclohexylmethane and 0.8% 4-amino-15 dicyclohexylmethane, corresponds to a yield of 98 % of theory. The freezing point of the distillate is 42 ° C.

Example 9

1500 g of 2,4-diaminotoluene are stirred in the presence of 7.5 g of catalyst 2 with a ruthenium content of about 1% by weight under a hydrogen pressure of about 280 bar in the temperature range from 235 to 250 ° C. until hydrogen uptake has ceased; Duration 9 hours. After cooling, the catalyst is separated off by filtration and the filtrate is fractionally distilled. You get:

23 g hexahydrotoluidine 1525 g 2,4-diamino-methylcyclohexane (= 96.8% of theory) 21 g distillation residue.

Comparison test

If the hydrogenation is carried out under the same conditions in the presence of 1.5 g of a commercially available Ru (5%) - Al203 catalyst, the hydrogenation stops after 5.5 hours of hydrogen absorption of about 25% of theory. If a further 6.0 g of the Ru (5%) - Al203 catalyst are added to the hydrogenation mixture, a reaction mixture is obtained after a further 6.5 hours, which consists of 49.1% from hexahydrotoluidine and 46.7% from 2. 4-diamino-methylcyclohexane.

Example 10

100 g of 4,4'-diamino-3,3 ', 5,5'-tetraethyl-diphenylmethane are in the presence of 0.5 g of the catalyst la in a shaking autoclave at 250 ° C under a hydrogen pressure of 200 to 280 bar to Termination of hydrogen uptake shaken; Hydrogenation time: 5 hours. The hydrogenation product is worked up by distillation in a conventional manner after removal of the catalyst. This gives 102 g of a colorless, viscous distillate, bp02: 157 to 163 ° C, which consists of practically pure 4,4'-diamino-3,3 ', 5,5'-tetraethyl-dicyclohexyl-methane. Yield: 98% of theory. The titration gives 9.9% strongly basic primary amino groups. The gas chromatographic analysis shows a degree of purity of 100%.

The hydrogenation of the following bisaniline derivatives also gives good results:

20th

Starting product

catalyst

Hydrogenation conditions Temp. Water time (° C) Fabric pressure (h) (bar)

Result

Yield (° C)

Diamine (% of theory)

1,1-bis (4-aminophenyl) cyclohexane

2,2-bis (4-aminophenyl) propane

(lb) 1.0 (lb) 1.0

250-270 200-280 4

250 200-280 3

92

95

Kp0ii: 152-155 Mp: 55-71

Kp0.3: 133-136

Example 11

100 g of N.N'-dimethyl-4,4'-diaminophenylmethane are hydrogenated in the presence of 0.5 g of catalyst 1 a under a hydrogen pressure of 180 to 280 bar until the hydrogen uptake has ended. The hydrogenation temperature is increased from 165 to 210 ° C. in the course of the 3-hour hydrogenation.

When the hydrogenation product freed from the catalyst is worked up by distillation, the N.N'-dimethyl-4,4'-diaminodicyclohexylmethane is obtained as a colorless, viscous liquid,

Boiling point: 120 to 122 ° C / 0.1 Torr

Quantity: 104.5 g = 99% of theory,

Analysis:

total strong bas. Nitrogen, found 11.7%

sec. strong bas. Nitrogen, found 11.6% calc. 11.73%.

Example 12

100 g "." '- Bis- (4-aminophenyl) -p-diisopropylbenzene are in the presence of 1.0 g of catalyst 2 (approx. 1% ruthenium) at 240 to 250 ° C under a hydrogen pressure of 170 to 290 bar Hydrogen until the rate of hydrogen absorption drops very sharply. Hydrogenation time about 100 minutes. After cooling, the reaction product is taken up in methanol, filtered and, after the solvent has been stripped off, distilled in vacuo.

101 ga.a'-bis- (4-aminocycIohexyl) -p-diisopropylbenzene are obtained, corresponding to 97.6% of theory,

45 Boiling point: 203 to 205 ° C / 0.1 Torr; Freezing point: 97 to 105 ° C,

Comparative experiment If the hydrogenation is carried out in the presence of 0.2 g of a commercial Ru (5%) - Al 2 O 3 catalyst, a hydrogenation product is obtained after a hydrogenation time of 590 minutes, from which 59 g of 95 5% a. A '- bis (4-aminocyclohexyl) -p-diisopropylbenzene are obtained (= 54.4% of theory) and 42 g of distillation residue are obtained.

Example 13

100 ga.a'-bis- (4-methylamino-phenyl) -p-diisopropyl-benzyl are in the presence of 1.0 g of the catalyst lb (about 1% ruthenium at 180 to 200 ° C and 200 to 280 bar hydrogen pressure ) hydrogenated until the hydrogen absorption is complete. Duration about 160 minutes. After cooling, the hydrogenation product is taken up in methanol, filtered, concentrated and distilled under reduced pressure. You get 103

Analysis:

strong bas. Nitrogen: found 7.75%, calc. 7.85%.

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g <<. r /.'- bis- (4-methylaminocyclohexyl) -p-diisopropylbenzene, corresponding to 100% of theory,

Boiling range: 203 to 206 ° C / 0.2 Torr freezing point: 84 to 86 ° C,

Analysis:

total strong bas. Nitrogen: found 7.22%

sec. strong bas. Nitrogen: found 7.19%, calc. 7.28%.

Comparative experiment If, instead of 1.0 g of the lb catalyst, 0.2 g of a commercial Ru (5%) - Al203 catalyst is used, 98.5 g of hydrogenation product are obtained after hydrogenation at 210 ° C. for 6 hours;

Boiling range: 205 to 210 ° C / 0.2 Torr freezing point: 107 to 108 ° C,

Analysis:

total strong bas. Nitrogen: found 7.07%

aromatically bound nitrogen: found 0.20%

sec. strong bas. Nitrogen: found 6.60%, calc. 7.28%.

The comparison experiment shows that the hydrogenation with the Ru (5%) - Al203 catalyst is associated with a considerable elimination of the methyl group. In addition, the hydrogenation is not quantitative, as the proportion of aromatically bound nitrogen shows.

Example 14

100 g of 4,4'-triamino-triphenyl-methane are shaken in the presence of 2.0 g of the catalyst 1b at 260 to 265 ° C. under a hydrogen pressure of 240 to 300 bar until the hydrogen absorption has ended ; Duration about 19 hours. After cooling, the reaction mixture is taken up in methanol, filtered and, after concentration, distilled under the pressure used. 60.5 g of a colorless, viscous distillate which slowly crystallizes; io boiling range: 188 to 193 ° C / 0.2 Torr,

Analysis:

bas. Nitrogen: found 13.0%, calc. 13.66%.

Colorless crystals are obtained by recrystallization from three times the amount of methylcyclohexane:

15 melting point: 132 to 136 ° C,

Analysis:

strong bas. Nitrogen: found 13.5%, calc. 13.66%.

If the hydrogenation is carried out in the presence of 4.0 g of the same catalyst at 250 ° C. under a hydrogen pressure 20 of 250 to 300 bar, 82.0 g of colorless distillate, which slowly crystallizes, is obtained after a reaction time of 7 hours in the subsequent distillation;

Boiling range: 145 to 200 ° C / 0.3 Torr,

Analysis:

25 strong bas. Nitrogen: found 13.2%, calc. 13.66%.

Claims (14)

628 611 2nd PATENT CLAIMS 1. A process for the preparation of cycloaliphatic amines by catalytic hydrogenation of the corresponding aromatic amines at elevated pressure and temperature in the presence of a ruthenium catalyst, characterized in that a supported ruthenium catalyst is used, the catalyst support of which consists of hydroxides and / or oxide hydrates of chromium and Manganese and / or their dehydration products exist or contain them. 2. The method according to claim 1, characterized in that the catalyst support is mixed with other catalyst supports. 3. The method according to claim 1 and 2, characterized in that the ruthenium supported catalyst contains 0.1 to 10 wt .-% ruthenium, based on the supported catalyst. 4. The method according to claims 1 to 3, characterized in that the weight ratio of the elements manganese and chromium to each other is 0.2: 1 to 5: 1. 5. Process according to Claims 1 to 4, characterized in that aniline and substituted anilines are used as starting compounds. 6. Process according to Claims 1 to 5, characterized in that aromatic amines of the formula are used as starting compounds 1 CLOCK CLOCK2). (I) used in the R \ R2 and R3 are the same or different and represent hydrogen or an alkyl radical, R4 and Rs are identical or different and represent an optionally substituted alkyl, cycloalkyl, aralkyl or aryl radical and m, n and p each represent one of the numbers 0 or 1. 7. Process according to Claims 1 to 6, characterized in that compounds of the general formula are used as starting compounds - 5th 10th EHE1 NHR2). (II) 20th 25th 30th used in the R1 and R2 are the same or different and represent hydrogen or an alkyl radical, R6 and R7 are the same or different and represent an alkyl radical and m, n and p each represent one of the numbers 0 or 1. 8. Process according to Claims 1 to 6, characterized in that compounds of the general formula are used as starting compounds R2KK 10th P- R R8 i (IV) 40 used in the R1, R2, R3, R8, R9 and R10 are the same or different and represent hydrogen or an alkyl radical and A represents an optionally substituted alkylene radical, preferably having 1 to 6 carbon atoms. 9. Process according to Claims 1 to 6, characterized in that compounds of the general formula are used as starting compounds in which R1, R2, R3, R8, R'J and R10 are the same or different and represent hydrogen or an alkyl radical. 10. The method according to claims 1 to 9, characterized in that one works in the temperature range between 150 and 350 ° C. • NÏÏR (V) 11. The method according to claims 1 to 10, characterized in that one works at a hydrogen pressure above 100 bar. 12. The method according to claim 1, characterized in that compounds of the formula mr in the R1 and R2 are the same or different and represent hydrogen or an alkyl radical. 13. The method according to claim 1, characterized in 65 that a, a'-bis- (4-aminocyclohexyl) -p-diisopropylbenzene is prepared. 14. The method according to claim 1, characterized in that compounds of the formula 3rd 628 611 R1HN, ö- in the R1 and R2 are the same or different and represent hydrogen or an alkyl radical. NHR 15. The method according to claim 1, characterized in that 4,4 ', 4 "-triamino-tricyclohexylmethane is prepared.