CH654295A5 - PROCESS FOR THE PREPARATION OF 3,3'- OR 3,4'-DIAMINODIPHENYLMETHANE. - Google Patents

Description

The present invention relates to a new process for the preparation of 3,3'- or 3,4'-diaminodiphenylmethane.

3,3'-diaminodiphenylmethane and 3,4'-diaminodiphenylmé-thane are useful as monomers in the production of high molecular weight compounds, intermediates for the production of chemicals used in agriculture, pharmacological compounds and dyes, and particularly useful as starting materials in the production of polyamides and polyimides having an excellent heat resistance.

Until now, 3,3'-diaminodiphenylmethane was prepared by condensing 3-nitrobenzyl alcohol with nitrobenzene or by condensing nitrobenzene with formaldehyde to prepare 3,3'-dinitrodiphenylmethane which was then reduced in the presence of chloride stannic or iron [L. Gattermann et al., "Ber.", 27, 2295 (1894); L. Thorp et al., "J. Am. Chem. Soc. ”, 37, 373 (1915); M. Schöpff et al., "Ber.", 27, 2322 (1894)].

3,4'-diaminodiphenylmethane was prepared by condensing 4-nitrobenzyl alcohol with nitrobenzene to prepare 3,4'-dinitrodiphenylmethane which was then reduced [L. Gattermann et al. *, "Ber.", 27, 2293 (1894)].

However, even if the condensation reaction between benzyl alcohol and nitrobenzene or between nitrobenzene and forma-line is carried out for a long period of time using a large amount of concentrated sulfuric acid, these methods give yields of dinitrodiphenylmethane as low as 20 to 30%. In addition, dinitrodiphenylmethane must be reduced in the presence of a tin or iron compound to obtain diaminodi-phenylmethane. However, it is tedious to separate the metal compound used for reduction from the product and care must be taken to ensure that as few traces of the metal as possible remain in the product.

Thus, the conventional processes for the preparation of dinitrophenylmé-thane by the known condensation reaction and its reduction to obtain diaminodiphenylmethane have drawbacks in that they require a great deal of cost and effort for the elimination of a large quantity. various wastes in order to prevent them from polluting the environment or for their recovery, and, moreover, the desired product is obtained in low yield. Consequently, these processes are uninteresting from the industrial point of view for reasons of economy and environmental protection.

The present invention proposes to provide an advantageous and economical process from the industrial point of view for the preparation of 3,3'- or 3,4'-diaminodiphenylmethane.

The present invention also proposes to provide a process for the preparation of 3,3'- or 3,4'-diaminodiphenylmethane in high yield.

The present invention finally proposes to provide a process which does not require much cost or effort compared to conventional processes for the elimination of a large quantity of various wastes, formed as by-products during the manufacturing processes. , in order to prevent them from polluting the environment, and which gives excellent performance from the point of view of environmental protection.

According to the present invention, it is possible to prepare 3,3'- or 3,4'-diaminodiphenylmethane by catalytic reduction and dechlorination, in the presence of a reduction catalyst, of a dinitrobenzophenone of formula:

in which X is chlorine and is fixed in position 4 or 6 on the benzene nucleus, Y is hydrogen or chlorine, provided that. when Y is hydrogen, the nitro group is fixed in position 3 'or 4' and that when Y is chlorine, Y is fixed in position 4 'and the nitro group is fixed in position 3'.

The process of the present invention has advantages in that it does not require much cost or effort for the disposal of a large amount of various wastes in order to prevent them from polluting the environment. or for their recovery and, moreover, the desired product can be obtained in a high yield, whereas the conventional processes for the preparation of 3,3'- or 3,4'-dinitrodiphenyl-methane by the known reaction of condensation and reduction require a lot of expense and effort.

The process of the present invention, which includes dechlorination of a dinitrochlorobenzophenone, reduction of its nitro groups and, in addition, conversion of its carbonyl group to a methylene group, is not known to those skilled in the art. Consequently, the present invention provides a new process for the preparation of 3,3'- or 3,4'-diaminodiphenylmethane which can be advantageously prepared from the industrial point of view.

The present invention relates to a process for the preparation of 3,3'- or 3,4'-diaminodiphenylmethane by catalytic reduction and dechlorination, in the presence of a reduction catalyst, of dinitrobenzophenone represented by the above formula to obtain the hydrochloride of 3,3'- or 3,4'-diaminodiphenylmethane, followed by neutralization with ammonia or an amine.

Examples of dinitrobenzophenones which can be used as starting materials in the implementation of this in5

10

15

20

25

30

35

40

45

50

55

60

65

3

654,295

vention include 3,3'-dinitro-4,4'-dichlorobenzophenone, 3,3'-dinitro-6,4'-dichlorobenzophenone, 3,3'-dinitro-6-chloroben-zophenone, 3,3 '-dinitro-4-chlorobenzophenone, 3,4'-dinitro-6-chlorobenzophenone and 3,4'-dinitro-4-chlorobenzophenone.

These dinitrobenzophenones can easily be obtained by nitration of the corresponding halobenzophenones, such as 4,4'-dichlorobenzophenone, 4-chlorobenzophenone, 4-nitro-6'-chlorobenzophenone, 4-chloro-4'-nitrobenzophenone and 2, 4'-dichlorobenzophenone. •

For example, 3,3'-dinitro-4,4'-dichlorobenzophenone can be prepared in 95-98% yield by nitration of 4,4'-dichlo-robenzophenone [E.R. Kofanov et al., "J. Org. Chem. USSR ", 15, 98-100 (1979)]. 5,3'-dinitro-2,4'-dichlorobenzophénone can be prepared in high yield by nitration of 2,4'-dichlorobenzo-phenone [E.H. Faith et al., "J. Am. Chem. Soc. ”, 77, 543 (1955)]. 3,3'-dinitro-4-chlorobenzophenone can be prepared in high yield by nitration of 4-chlorobenzophenone [G.S. Mi-ronov et al., "J. Org. Chem. USSR ", 8, 1538 (1972)]. 3,4'-dini-tro-4-chlorobenzophenone can be prepared by nitration of 4-ha-logeno-4'-nitrobenzophenone obtained by the condensation reaction between p-nitrobenzoyl chloride and chlorobenzene [P.T. Montagne et al., "Ber.", 49, 2267-2270 (1916); G.S. Mironov et al., “J. Org. Chem. USSR ", 8, 1538-1543 (1972)]. 3,3'-dinitro-6,4'-dichlorobenzophenone can be prepared in high yield by nitration of 2,4'-dichlorobenzophenone obtained by the condensation reaction between 2-chlorobenzoyl chloride and chlorobenzene [H.F. Faith et al., "J. Am. Chem. Soc. ”, 77, 543 (1955)].

As reduction catalysts suitable for practicing the present invention, there may be used metal catalysts which are commonly used in catalytic reduction. Examples of the metals are nickel, palladium, platinum, rhodium, ruthenium, cobalt and iron. From an industrial point of view, the palladium catalyst is preferred. These catalysts can be used in metallic form, but they are generally fixed on a support such as carbon, barium sulphate, silica gel or alumina. Nickel, cobalt and copper can be used in the form of a Raney catalyst.

The catalyst is used in an amount of 0.05 to 10% by weight, relative to the starting dinitrobenzophenone. When the catalyst is used in metallic form, its amount is generally between 2 and 10% by weight. When fixed on a support, its amount is between 0.1 and 5% by weight.

In general, the reaction of the present invention is carried out in an organic solvent. Any organic solvent which is inert with respect to the reaction of the present invention can be used, without particular limitation. Examples of such organic solvents include alcohols such as methanol, ethanol and isopropyl alcohol; glycols such as ethylene glycol and propylene glycol; ethers such as ether itself, dioxane, tetrahydrofuran and methylcellosolve; aliphatic hydrocarbons such as hexane and cyclohexane; aromatic hydrocarbons such as benzene, toluene and xylene; esters such as ethyl acetate and butyl acetate; halogenated hydrocarbons such as dichlo-romethane, chloroform, carbon tetrachloride, 1,2-di-chlorethane, 1,1,2-trichlorethane and tetrachlorethane; N, N-dimethylformamide and dimethylsulfoxide. Hydrogen chloride or hydrochloric acid may be added to these solvents beforehand in a molar ratio of 1 to 2 to effect the reduction of the present invention. When an organic solvent immiscible with water is used and the reaction proceeds too slowly, this reaction can be accelerated by adding a conventional phase transfer catalyst such as a quaternary ammonium salt or a quaternary phosphonium salt. . The solvent is used in an amount sufficient to suspend the starting dinitrobenzophenones or to completely dissolve them. There is no particular upper limit on the amount of solvent to be

use, but this is generally used in an amount of 0.5 to 10 times the weight of the starting material.

The reaction temperature is generally between 20 and 200 ° C, preferably between 50 and 150 ° C.

5 The reaction pressure is generally between atmospheric pressure and 4.9 MPa on the pressure gauge.

In the implementation of the present invention, the dinitrobenzophenone is suspended or dissolved in a solvent and a reduction catalyst is added thereto. Hydrogen is introduced into the mixture while stirring at a predetermined temperature in order to transform the nitro groups into amino groups and the carbonyl group into methylene group and to effect dechlorination, so as to obtain the hydrochloride of 3.3′- or 3,4'-diaminodiphenyl-methane.

The reaction mixture is filtered to collect a mixture of the desired hydrochloride and the catalyst. Then, the mixture is dissolved in a 70-90% aqueous solution of isopropyl alcohol while heating, then filtered. The filtrate is cooled to precipitate the pure 3,3'- or 3,4'-diaminodiphenylmethane hydrochloride which is then separated by filtration. The separated hydrochloride is dissolved in water, then neutralized to obtain the free 3,3'- or 3,4'-diaminodi-phenylmethane.

The progress of the reaction can be followed by the absorption of a theoretical amount of hydrogen or by thin layer chromatography.

The following examples illustrate the present invention in more detail.

Example 1:

30 34.1 g (0.1 mol) of 3.3'-dinitro-4,4'-di-chlorobenzophenone, 3.4 g are introduced into a closed glass container equipped with a thermometer and a stirrer. of catalyst with 5% Pd on carbon (a product of Nippon Engelhardt KK) and 100 ml of dioxane. While stirring the mixture at a temperature of 80 to 85 ° C, hydrogen is introduced into it and 21.8 1 (0.97 mol) of hydrogen is absorbed over 10 h. Because no more hydrogen absorption is noticed, the reaction is complete at this time.

The reaction mixture is cooled to room temperature. A precipitate is filtered off and washed with 10 ml of dioxane to obtain a black filter cake. This cake is dissolved in 100 ml of an 80% aqueous solution of isopropyl alcohol while heating. The solution is filtered with heating to remove the catalyst. The filtrate is cooled to precipitate the 3,3'-diaminodiphenylmethane dihydrochloride in the form of white crystal needles. This product is separated by filtration, washed with 10 ml of a 90% aqueous solution of isopropyl alcohol, and dried to obtain 20.3 g (75% yield) of 3.3'-di dihydrochloride -aminodiphenylmethane in the form of white crystalline needles melting above 260 ° C.

50

Elementary analysis for C13H16N2C12:

Calculated: C57.6 H 6.0 N 10.3 Cl 26.1%

Found: C 57.4 H 6.1 N 10.3 Cl 25.9%

55

Example 2:

Is introduced into a closed glass container equipped with a thermometer and a stirrer 34.1 g (0.1 mol) of 3.3'-dinitro-4,4'-di-chlorobenzophenone, 1.5 g of catalyst at 5% Pd on carbon and 60 100 ml of ethanol. While stirring the mixture at a temperature of 50 to 60 ° C, hydrogen is introduced therein and 22.91 (1.02 mol) of hydrogen is made to absorb over 7.5 h. Since no more absorption of hydrogen is noticed, the reaction is complete at this time. The reaction solution is neutralized with 13.4 g (0.22 mol) 65 of 28% aqueous ammonia and filtered to remove the catalyst. The filtrate is concentrated to obtain 3,3'-diaminodiphenylmethane in the form of a brown oil. High performance liquid chromatography reveals a purity of 93.8%.

654,295

4

This brown oil is distilled under vacuum to obtain 16.8 g (85% yield) of a fraction having a boiling point of 228 at 229 ° C / 666.5 Pa. The purity is 99.9%.

This fraction is recrystallized from benzene to obtain a pure product in the form of white prismatic crystals melting at 84.5-85 ° C.

Elementary analysis for C13H14N2:

Calculated: C78.7 H 7.1 N14, l%

Found: C78.7 H 7.2 N 14.1%

Example 3:

34.1 g (0.1 mol) of 3.3'-dinitro-6,4-dichloro-benzophenone, 1 g of catalyst are introduced into a closed glass container equipped with a thermometer and a stirrer. with palladium black and 100 ml of ethylcellosolve. While stirring the mixture at a temperature of 75 to 80 ° C, hydrogen is introduced therein and 22.3 1 (1.0 mol) of hydrogen is made to absorb over 5 hours. Since no more absorption of hydrogen is noticed, the reaction is complete at this time. The reaction solution is neutralized with 42 g (0.21 mol) of a 20% aqueous solution of caustic soda, and filtered to remove the catalyst. The filtrate is concentrated and distilled under vacuum to obtain 15.6 g (78.7% yield) of a fraction boiling at 228-229 ° C / 666.5 Pa. Purity: greater than 99.9%.

Example 4:

15.3 g (0.05 mol) of 3.3′-dinitro-4-chlorobenzophenone, 1.5 g of 10% Pt catalyst on charcoal and 50 ml of diethylene glycol dimethyl ether are introduced into an autoclave. While stirring the mixture at a temperature of 100 to 110 ° C, hydrogen is introduced. The reaction is carried out for 2 h while maintaining the gauge pressure at 0.99 MPa. At the end of the reaction, the reaction mixture is cooled and neutralized with 3.7 g (0.06 mol) of 28% aqueous ammonia. The catalyst is removed by filtration. The filtrate is concentrated and distilled under vacuum to obtain 7.9 g (79.8% yield) of a fraction boiling at 228-229 ° C / 666.5 Pa.

Example 5:

Is introduced into a closed glass container equipped with a thermometer and a stirrer 30.7 g (0.1 mol) of 3.3'-dinitro-4-chloroben-io zophenone, 1.5 g of catalyst 5% Pd on carbon and 100 ml of ethanol. While stirring the mixture at a temperature of 65 to 70 ° C, hydrogen is introduced therein and 20.11 (0.9 mol) of hydrogen is made to absorb over 6 h. Since no more absorption of hydrogen is observed, the reaction is terminated at this time. The reaction mixture is cooled to room temperature and filtered to obtain a black filter cake. This cake is dissolved in 100 ml of a 90% aqueous solution of isopropyl alcohol while heating. The catalyst is removed by filtration with heating. The filtrate is cooled to precipitate the 3,3'-diaminodiphenylmethane hydrochloride in the form of crystals. The crystals are separated by filtration, washed with 10 ml of isopropanol and neutralized with dilute aqueous ammonia to precipitate white crystals. These crystals are separated by filtration and dried under vacuum to obtain 16.3 g (yield 82.2%) of 3,3'-diaminodi-phenylmethane.

Examples 6 to 9:

The experiment of Example 2 is repeated with the difference that the catalysts, the solvents, the reaction temperatures and the reaction pressures indicated in the table are used to obtain the desired product.

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Board

Example No.

Catalyst (g)

Solvent (ml)

Reaction

Yield (%)

Temperature / Time (° C / h)

Manometric pressure (MPa)

6

Raney nickel 3.5

Ethylene glycol 150

100-110 / 5

0.19-0.29

72

7

Palladium black 1

Ethyl acetate 100

70-75 / 12

Atmospheric pressure

77

8

10% Pt / C 7

Ethanol 100

70-75 / 10

Atmospheric pressure

71

9

5% Pd / C 5

Benzene 100

70-75 / 28

0.99-1.09

62

Example 10:

Is introduced into a closed glass container equipped with a thermometer and a stirrer 15.3 g (0.05 mol) of 3,4'-dinitro-4-chloroben-zophenone, 0.75 g of 5% catalyst % Pd on carbon and 50 ml of ethylcellosolve. While stirring the mixture at a temperature of 75 to 80 ° C, hydrogen is introduced therein and 10.3 1 (0.46 mol) of hydrogen is made to absorb over 13 h. Since no more absorption of hydrogen is observed, the reaction is terminated at this time. The reaction solution is neutralized with 3.6 g (0.06 mol) of 28% aqueous ammonia. The catalyst is removed by filtration. The filtrate is concentrated to obtain 3,4'-diaminodiphenylmethane in the form of a brown oil. High performance liquid chromatography reveals that the purity is 88.2%.

This brime oil is distilled in vacuo to obtain 7.9 g (yield 79.7%) of 3,4'-diaminodiphenylmethane with a purity of 99.7% according to high performance liquid chromatography.

This product is recrystallized from water to obtain a pure product in the form of white crystalline needles, melting at 85-87 ° C.

50 Elementary analysis for C13H14N2:

Calculated: C78.7 H 7.1 N 14.1%

Found: C78.5 H 7.1 N 14.0%

Example 11:

The reduction of 15.3 g (0.05 mol) of 3,4'-dinitro-4-55 chlorobenzophenone is carried out in a manner analogous to that of Example 10. At the end of the reaction, it is immediately eliminated the catalyst by filtration while heating. 5.2 g (0.05 mol) of concentrated hydrochloric acid are added to the filtrate. After cooling, light brown crystalline needles precipitate. The crystals are separated by filtration, 60 is washed with isopropanol, and dried to obtain 8.9 g (yield 66%) of 3,4'-diaminodiphenylmethane hydrochloride. These crude crystals are recrystallized from an aqueous isopropanol solution to obtain pure 3,4'-diaminodiphenylmethane hydrochloride in the form of white crystals, melting above 210 ° C. (slow de-65 composition).

Elementary analysis for C13HlfiN2Cl2:

Calculated: C 57.6 H 6.0 N 10.3 Cl 26.1%

Found: C 57.3 H 6.2 N 10.2 Cl 25.9%

R

Claims (9)

654,295 1. Process for the preparation of 3,3'- or 3,4'-diaminodiphenylmé-thane, characterized in that it comprises catalytic reduction and dechlorination, in the presence of a reduction catalyst, of a dini-trobenzophenone of formula: ^ ö'iK ^ NO / O 2 no2 wherein X is chlorine and is attached in position 4 or 6 of the benzene ring, and Y is hydrogen or chlorine, provided that when Y is hydrogen, the nitro group is attached in position 3 'or 4 ', and that when Y is chlorine, Y is fixed in position 4' and the nitro group is fixed in position 3 '. 2. Method according to claim 1, characterized in that the reduction catalyst is a metal catalyst intended to be used in catalytic reduction. 2 3. Method according to claim 1, characterized in that the catalyst is used in an amount of 0.05 to 10% by weight relative to the amount of dinitrobenzophenone. 4. Method according to claim 1, characterized in that the reaction temperature is between 20 and 200 ° C. 5. Method according to claim 1, characterized in that the reaction is carried out in an organic solvent. 6. Method according to claim 2, characterized in that the metal catalyst consists of nickel, palladium, platinum, rhodium, ruthenium or cobalt. 7. Method according to claim 6, characterized in that the metal catalyst is fixed on a support. 8. Method according to claim 6, characterized in that the metal catalyst is a Raney catalyst. 9. Method according to claim 5, characterized in that the organic solvent is chosen from the group comprising alcohols, glycols, ethers, aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, N, N-dimethyl-formamide and dimethyl sulfoxide.