Process for hydrogenating 4,4′-methylenedianiline

Abstract

The present invention relates to a process for hydrogenating 4,4-methylenedianiline and/or polymeric MDA with hydrogen in the presence of a catalyst comprising ruthenium on a zirconium oxide support material, and also to the use of a catalyst comprising ruthenium on a zirconium oxide support material for hydrogenating 4,4-methylenedianiline and/or polymeric MDA.

Claims

1. A process for hydrogenating at least one of 4,4-methylenedianiline and polymeric methylenedianiline, the process comprising: hydrogenating at least one of 4,4-methylenedianiline and polymeric methylenedianiline with hydrogen in the presence of a catalyst, wherein the catalyst comprises ruthenium on a zirconium oxide support material, and the zirconium oxide support material has a BET surface area of from 73 to 300 m.sup.2/g.

2. The process according to claim 1, which is carried out in suspension or in a fixed bed.

3. The process according to claim 2, wherein the zirconium oxide support material of the catalyst, present as a fixed bed catalyst, has a pore size distribution where more than 50% of the pores present are formed by mesopores having a diameter of from 2 nm to 50 nm and the remainder to 100% are formed by macropores having a diameter of >50 nm.

4. The process according to claim 2, wherein the catalyst, present as a fixed bed catalyst, has a pore size distribution where more than 50% of the pores present are formed by mesopores having a diameter of from 2 nm to 50 nm and the remainder to 100% are formed by macropores having a diameter of >50 nm.

5. The process according to claim 2, wherein the zirconium oxide support material of the catalyst, present as a suspension catalyst, has a pore size distribution where more than 40% of the pores present are macropores having a diameter of >50 nm and the remainder to 100% are formed by mesopores having a diameter of from 2 nm to 50 nm.

6. The process according to claim 2, wherein the catalyst, present as a suspension catalyst, has a pore size distribution where more than 40% of the pores present are formed by macropores having a diameter of >50 nm and the remainder to 100% are formed by mesopores having a diameter of from 2 nm to 50 nm.

7. The process according to claim 1, which is carried out as a continuous operation or batchwise.

8. The process according to claim 2, which is carried out in a fixed bed at a temperature of from 50 to 190? C.

9. The process according to claim 2, which is carried out in suspension at a temperature of from 50 to 190? C.

10. The process according to claim 1, which is carried out at a pressure of from 60 to 300 bar.

11. The process according to claim 1, wherein the catalyst comprises ruthenium in an amount of from 0.05 to 20 wt % based on the whole catalyst.

12. The process according to claim 1, wherein the zirconium oxide support material is present in at least one of a monoclinic phase, a tetragonal phase, a cubic phase and an amorphous phase.

13. The process according to claim 1, wherein the zirconium oxide support material is present in at least one of a monoclinic phase and a tetragonal phase.

14. The process according to claim 1, wherein the zirconium oxide support material has a pore volume of from 0.1 to 1 cm.sup.3/g, and a tamped density of from 500 to 2000 kg/m.sup.3.

15. The process according to claim 1, wherein the catalyst has a BET surface area of from 78 to 300 m.sup.2/g, a pore volume of from 0.1 to 1 cm.sup.3/g, and a tamped density of from 500 to 2000 kg/m.sup.3.

16. The process according to claim 1, wherein the reaction time of said hydrogenating is from 10 to 400 min.

17. The process according to claim 1, wherein said hydrogenating is carried out in an organic solvent.

18. The process according to claim 1, wherein a mixture is obtained from said hydrogenating and comprises isomers of 4,4-diaminodicyclohexylmethane when 4,4-methylenedianiline is hydrogenated, and oligomeric or polymeric ring-hydrogenated compounds when the polymeric methylenedianiline is hydrogenated; wherein the isomers of 4,4-diaminodicyclohexylmethane comprise trans, trans isomer of 4,4-diaminodicyclohexylmethane in an amount of from 10 to 30 wt %, cis, trans isomer of 4,4-diaminodicyclohexylmethane in an amount of from 30 to 55 wt %, and cis, cis isomer of 4,4-diaminodicyclohexylmethane in an amount of from 10 to 50 wt %, based on a total amount of all isomers present; and wherein the oligomeric or polymeric ring-hydrogenated compounds comprise trans, trans isomeric unit of 4,4-diaminodicyclohexylmethane in an amount of from 10 to 30 wt %, cis, trans isomeric unit of 4,4-diaminodicyclohexylmethane in an amount of from 30 to 55 wt %, and cis, cis isomeric unit of 4,4-diaminodicyclohexylmethane in an amount of from 10 to 50 wt %, based on a total amount of all isomeric repeating units.

19. The process according to claim 1, wherein a mixture obtained from said hydrogenating comprises isomers of 4,4-diaminodicyclohexylmethane when 4,4-methylenedianiline is hydrogenated and oligomeric or polymeric ring-hydrogenated compounds when the polymeric methylenedianiline is hydrogenated, and has a melting point of less than 40? C.

20. A method of making a compound, the method comprising reacting a mixture obtained by the process of claim 18 to obtain the compound, which is a surfactant, a medicament, a crop protection agent, a stabilizer, a polymer, a polyimide, an isocyanate, a hardener for an epoxy resin, a catalyst for polyurethane synthesis, an intermediate for preparing a quaternary ammonium compound, a plasticizer, a corrosion inhibitor, a synthetic resin, an ion exchanger, a textile auxiliary, a dye, a vulcanization accelerant, an emulsifier, or a starter for urea or polyurea synthesis.

Description

EXAMPLES

Preparation of the Catalysts According to the Invention

(1) 1. Preparation of Fixed-Bed Catalyst 1% Ru on ZrO.sub.2

(2) 238 g of ZrO.sub.2 extrudates (diameter 3 mm, SZ 31108 from NorPro, BET surface area: 73 m.sup.2/g, pore volume 0.30 ml/g, pore size distribution: 6% macropores, 94% mesopores) are sprayed with 19.81 g of Ru(III) nitrosyl nitrate (15.95 wt % Ru(III) nitrosyl nitrate (from Heraeus) in dilute nitric acid) diluted with 35 ml DM water, in an impregnation drum. The extrudates are then dried in a circulating air drying cabinet at 120? C. for 16 h and subsequently calcined in a muffle furnace at 180? C. for 2 h. The catalyst is then first reduced at 200? C. for 2 h (4 l/h H.sub.2; 40 l/h N.sub.2) and passivated at room temperature for 1 h with a mixture of 10 vol % air and 90 vol % N.sub.2. The active material thus prepared contains 1 wt % Ru and 99 wt % zirconium oxide.

(3) The catalyst thus prepared has the following characteristics: a BET surface area of 81 m.sup.2/g, a tamped density of 1.2 kg/I, a pore volume of 0.24 ml/g (determined by Hg porosimetry).

(4) 2. Preparation of Suspension Catalyst 10% Ru on ZrO.sub.2

(5) 30.51 g of Ru(III) nitrosyl nitrate solution (15.95 wt % Ru(III) nitrosyl nitrate (from Heraeus) in dilute nitric acid) are added to a measuring cylinder and made up to a total volume of 37.5 ml with DM water. 50 g of zirconium oxide powder (D9-89, BASF, BET surface area: 78 m.sup.2/g, pore volume: 0.84 ml/g, pore volume distribution: 68% macropores, 32% mesopores) are then added to a ceramic dish, the solution is added and mixed to homogeneity. The powder is subsequently dried in a circulating air drying cabinet at 120? C. for 16 h and calcined in air at 200? C. for 2 h. The powder is then first purged with 40 l/h of N.sub.2 for 20 min in a rotary tube oven and then reduced over a period of 90 min (3 l/h hydrogen and 53 l/h nitrogen). Once the powder has cooled down to room temperature, the hydrogen is switched off and the powder is purged with about 60 l/h of nitrogen. In order to passivate the powder, 60 l/h of nitrogen and 1 l/h of air are initially introduced and the amount of air is then slowly raised to 10 l/h (0 l/h of nitrogen). Care must be taken to ensure the temperature of the catalyst does not exceed 35? C. The active material thus prepared contains 10 wt % Ru and 90 wt % ZrO.sub.2. The catalyst thus prepared has the following characteristics: tamped density is 1.13 kg/I, the pore volume (Hg porosimetry) is 0.32 ml/g, the BET surface area 75 m.sup.2/g; the pore distribution is as follows: 0% mesopores (2-50 mm), 100% macropores (>50 nm).

Example 1: Suspension Mode, Testing of Different Catalysts

(6) A defined amount of the catalyst (150 mg) was added to a 10 ml autoclave along with 7 ml of a 9 wt % solution of 4,4-methylenedianiline (MDA) in dioxane. The reaction mixture is subsequently heated to the appropriate reaction temperature under 140 bar of hydrogen pressure, with stirring, and held for 180 minutes. The solution is then cooled down to room temperature and the autoclave is decompressed to atmospheric pressure. The analysis of the reaction mixture is carried out by GC chromatography; the method is shown below. The results are shown in table 1.

(7) The preparation of the catalysts was carried out analogously to the preparation of the catalyst according to the invention using appropriate metal salts/supports.

(8) TABLE-US-00001 TABLE 1 Metal content Temp. Conversion Select. Isomer ratio [%] Metal [%] Support [? C.] [%] [%] trans/trans cis/trans cis/cis Ru 10 ZrO.sub.2 (mixture of 120 91 85 16 49 35 monoclinic, tetragonal) Pt 1% ZrO.sub.2 (mixture of 120 0 0 monoclinic, tetragonal) Ru 9.4 ?-Al.sub.2O.sub.3 (CT19, 120 35 61 9 40 51 Almatis) Ru 10 Norit-SX Plus 120 25 58 7 37 56 (Cabot Norit Activated Carbon) Ru 10 TiO.sub.2 120 98 55 12 44 44 (FINNTI S150, Kemira) Ru 9.4 ?-Al.sub.2O.sub.3 140 49 81 11 43 46 (CT19, Almatis) Ru 10 Norit-SX Plus 140 63 86 10 43 47 (Cabot Norit Activated Carbon) Ru 75 No support 120 98 63 12 46 42 oxihydrate

(9) These examples show that the Ru/ZrO.sub.2 catalyst according to the invention combines excellent reactivity with high selectivity.

Example 2: Suspension Mode, Testing of Different ZrO2 Support Materials

(10) A defined amount of the catalyst (10% Ru on ZrO.sub.2, 150 mg) was added to a 10 ml autoclave along with 7 ml of a 9 wt % solution of 4,4-methylenedianiline (MDA) in dioxane. The reaction mixture is subsequently heated to 120? C. under 140 bar of hydrogen pressure, with stirring, and held for 180 minutes. The solution is then cooled down to room temperature and the autoclave is decompressed to atmospheric pressure. The analysis of the reaction mixture is carried out by GC chromatography; the method is shown below. The results are shown in table 2. The preparation of the catalysts was carried out analogously to the preparation of the catalyst according to the invention using appropriate supports.

(11) TABLE-US-00002 TABLE 2 BET Pore Pore surface distribution Support volume area (mesopores: Conversion Selectivity Isomer ratio [%] description [ml/g] [m.sup.2/g] macropores) [%] [%] trans/trans cis/trans cis/cis D9-89 0.84 75 32:68 91 85 16 49 35 D9-89 0.48 17 2:98 23 68 11 44 45 (1000? C.)

(12) The Examples show that a low BET surface area results in a decline in selectivity and conversion and that a high BET surface area is advantageous.

Example 3: Suspension Mode, Optimization of the Reaction Conditions

(13) A defined amount of the catalyst according to the invention (10 wt % Ru on ZrO.sub.2) was added to a 10 ml autoclave along with 7 ml of a 9 wt % solution of 4,4-methylenedianiline (MDA) in dioxane. The reaction mixture is subsequently heated to the appropriate reaction temperature under 140 bar of hydrogen pressure, with stirring, and held for a defined period of time. The solution is then cooled down to room temperature and the autoclave is decompressed to atmospheric pressure. The analysis of the reaction mixture is carried out by GC chromatography; the method is shown below. The results are shown in tables 3 and 4:

(14) TABLE-US-00003 TABLE 3 Reaction Amount of PACM T time catalyst Conversion selectivity Isomer ratio [%] No. [? C.] [min] [mg] [%] [%] trans/trans cis/trans cis/cis 1.1 100 120 75 67 14 10 44 46 1.2 100 300 37.5 56 9 9 42 49 1.3 120 240 150 100 49 29 50 21 1.4 120 240 75 100 95 19 49 32 1.5 120 240 37.5 100 91 14 47 39 1.6 140 240 150 100 48 57 36 7 1.7 140 240 75 100 93 49 41 10 1.8 140 240 37.5 100 94 38 47 15 PACM denotes 4,4-diaminodicyclohexylmethane

(15) The results of table 3 show that, with the aid of the catalyst according to the invention, the product PACM is obtained in an isomer ratio according to the invention at a reaction temperature of 120? C. Above 140? C., the isomer ratio changes so that the proportion of the trans,trans isomer increases significantly.

(16) TABLE-US-00004 TABLE 4 Reaction Amount of PACM T time catalyst Conversion selectivity Isomer ratio [%] No. [? C.] [min] [mg] [%] [%] trans/trans cis/trans cis/cis 1.9 120 120 75 99 85 14 46 40 1.10 120 180 75 91 85 16 49 35 1.11 120 240 75 100 95 19 49 32 1.12 140 120 75 100 93 35 48 17 1.13 140 180 75 100 94 45 44 11 1.14 140 240 75 100 93 49 41 10 PACM denotes 4,4-diaminodicyclohexylmethane

(17) The results of table 4 show that the proportion of trans,trans isomer in the product increases with increasing reaction time.

Example 4: Fixed-Bed Mode

(18) 120 ml of the passivated supported ruthenium catalyst according to the invention (1 wt % Ru on ZrO.sub.2) were packed into a tubular reactor heated with an outer jacket (height: 1.4 m, interior diameter: 12 mm). Once initially flooded with hydrogen, the reactor was subsequently charged with a solution of 10 wt % of 4,4-methylenedianiline (MDA). Hydrogenation was carried out at varying temperatures at a pressure of 140 bar, and the space velocity over the catalyst was 0.04 kg MDA/kg cat*h, the reactor being operated with circulation, i.e., part of the discharge is recycled into the reactor. The reaction discharges were analyzed by gas chromatography and the isomer distribution was determined. The method is shown below. The results are shown in table 5 and show that, using the catalyst according to the invention, a particularly low proportion of the trans,trans isomer, namely 19%, is attained at 80? C.

(19) TABLE-US-00005 TABLE 5 PACM T Conversion selectivity Isomer ratio No. [? C.] [%] [%] trans/trans cis/trans cis/cis 2.1 140 96 95 51 40 9 2.2 130 94 96 47 41 12 2.3 100 84 86 28 49 23 2.4 80 67 60 19 49 32 PACM denotes 4,4-diaminodicyclohexylmethane

Example 5: Fixed-Bed Mode

(20) Further reactions according to the invention are carried out. The results are shown in table 6.

(21) 120 ml of the passivated supported ruthenium catalyst (1 wt % Ru on ZrO.sub.2) were packed into a tubular reactor heated with an outer jacket (height: 1.4 m, interior diameter: 12 mm). Once initially flooded with hydrogen, the reactor was subsequently charged with a solution of 10 wt % of 4,4-methylenedianiline (MDA). Hydrogenation was carried out at varying temperatures, with varying space velocities over the catalyst and also at a pressure of 140 bar, the reactor being operated with circulation, i.e., part of the discharge is recycled into the reactor. The reaction discharges were analyzed by gas chromatography and the isomer distribution was determined. The method is shown below. The results are shown in table 6 and show that the isomer ratio can be advantageously influenced by selection of the space velocity over the catalyst and the temperature.

(22) TABLE-US-00006 TABLE 6 Reaction Space velocity PACM time over the catalyst T Conversion selectivity Isomer ratio No. [h] [kg/(kg*h)] [? C.] [%] [%] trans/trans cis/trans cis/cis 3.1 1-149 0.04 140 95 95 51 40 9 3.2 364-477 0.04 80 67 60 19 49 33 3.3 1369-1377 0.02 77 78 73 20 49 31 3.4 1393-1424 0.02 60 47 32 18 48 34 3.5 1473-1539 0.02 90 85 86 22 49 29 3.6 1539-1561 0.04 90 72 74 21 49 30 3.7 1639 0.08 90 54 64 19 49 32 PACM denotes 4,4-diaminodicyclohexylmethane
Analysis by Gas Chromatography:

(23) TABLE-US-00007 Column: 30 m RTX5 amine; 0.25 mm; 0.5 ?m Temperature Program: 80? C. - 0 min - 20? C./min - 200? C. - 0 min - 4? C./min - 260? C. - 5 min => 26 min total run time Retention times [min]: trans, trans 18.39 cis, trans 18.58 cis, cis 18.75 MDA (reactant) 25.00