CA2038126A1 - Method of improving the quality of crude diaminodiphenylmethanes - Google Patents
Method of improving the quality of crude diaminodiphenylmethanesInfo
- Publication number
- CA2038126A1 CA2038126A1 CA 2038126 CA2038126A CA2038126A1 CA 2038126 A1 CA2038126 A1 CA 2038126A1 CA 2038126 CA2038126 CA 2038126 CA 2038126 A CA2038126 A CA 2038126A CA 2038126 A1 CA2038126 A1 CA 2038126A1
- Authority
- CA
- Canada
- Prior art keywords
- crude
- diaminodiphenylmethanes
- mda
- treatment
- bar
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 24
- ZZTCPWRAHWXWCH-UHFFFAOYSA-N diphenylmethanediamine Chemical class C=1C=CC=CC=1C(N)(N)C1=CC=CC=C1 ZZTCPWRAHWXWCH-UHFFFAOYSA-N 0.000 title claims abstract description 14
- 238000005984 hydrogenation reaction Methods 0.000 claims abstract description 19
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 17
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 17
- 239000001257 hydrogen Substances 0.000 claims abstract description 17
- 239000003054 catalyst Substances 0.000 claims abstract description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 14
- 238000002360 preparation method Methods 0.000 claims description 3
- 238000010924 continuous production Methods 0.000 claims 1
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N Aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 description 18
- UPMLOUAZCHDJJD-UHFFFAOYSA-N 4,4'-Diphenylmethane Diisocyanate Chemical compound C1=CC(N=C=O)=CC=C1CC1=CC=C(N=C=O)C=C1 UPMLOUAZCHDJJD-UHFFFAOYSA-N 0.000 description 11
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 9
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 8
- 239000000203 mixture Substances 0.000 description 8
- YGYAWVDWMABLBF-UHFFFAOYSA-N Phosgene Chemical compound ClC(Cl)=O YGYAWVDWMABLBF-UHFFFAOYSA-N 0.000 description 7
- 150000001875 compounds Chemical class 0.000 description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- MVPPADPHJFYWMZ-UHFFFAOYSA-N chlorobenzene Chemical compound ClC1=CC=CC=C1 MVPPADPHJFYWMZ-UHFFFAOYSA-N 0.000 description 4
- 238000002845 discoloration Methods 0.000 description 4
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 4
- 229910052763 palladium Inorganic materials 0.000 description 4
- OHKOAJUTRVTYSW-UHFFFAOYSA-N 2-[(2-aminophenyl)methyl]aniline Chemical compound NC1=CC=CC=C1CC1=CC=CC=C1N OHKOAJUTRVTYSW-UHFFFAOYSA-N 0.000 description 3
- UTNMPUFESIRPQP-UHFFFAOYSA-N 2-[(4-aminophenyl)methyl]aniline Chemical compound C1=CC(N)=CC=C1CC1=CC=CC=C1N UTNMPUFESIRPQP-UHFFFAOYSA-N 0.000 description 3
- YBRVSVVVWCFQMG-UHFFFAOYSA-N 4,4'-diaminodiphenylmethane Chemical compound C1=CC(N)=CC=C1CC1=CC=C(N)C=C1 YBRVSVVVWCFQMG-UHFFFAOYSA-N 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 3
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 description 3
- 229910052750 molybdenum Inorganic materials 0.000 description 3
- 239000011733 molybdenum Substances 0.000 description 3
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 3
- 229920002635 polyurethane Polymers 0.000 description 3
- 239000004814 polyurethane Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- 239000011149 active material Substances 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- RYHBNJHYFVUHQT-UHFFFAOYSA-N 1,4-Dioxane Chemical compound C1COCCO1 RYHBNJHYFVUHQT-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 239000007868 Raney catalyst Substances 0.000 description 1
- 229910000564 Raney nickel Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- HIFVAOIJYDXIJG-UHFFFAOYSA-N benzylbenzene;isocyanic acid Chemical class N=C=O.N=C=O.C=1C=CC=CC=1CC1=CC=CC=C1 HIFVAOIJYDXIJG-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 238000005282 brightening Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000009903 catalytic hydrogenation reaction Methods 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 1
- 239000000543 intermediate Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- -1 methanol and ethanol Chemical compound 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000000741 silica gel Substances 0.000 description 1
- 229910002027 silica gel Inorganic materials 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- 239000011949 solid catalyst Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 238000010626 work up procedure Methods 0.000 description 1
- 239000010457 zeolite Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/82—Purification; Separation; Stabilisation; Use of additives
- C07C209/84—Purification
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Catalysts (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A method of improving the quality of crude diaminodiphenylmethanes comprising the treatment thereof with hydrogen in the presence of a hydrogenation catalyst.
A method of improving the quality of crude diaminodiphenylmethanes comprising the treatment thereof with hydrogen in the presence of a hydrogenation catalyst.
Description
2038~2~
O.Z. 41479 METHOD OF IMPROVING THE QUALITY
OF CRUDE DIAMINODIPHENYLMETHANES
The present invention relates to a method of improving the quality of crude diaminodiphenylmethanes.
The industrial mixture coming from the acid-catalyzed reaction of aniline with formaldehyde and containing various condensates (diaminodiphenylmethanes, normally referred to as 'MDA') mainly consists of the binuclear p,p'-isomer H2N~CH2 ~NH2 MDA is chiefly used for the synthesis of corresponding diphenylmethane diisocyanates ('MDI') by reacting it with phosgene. MDI itself is one of the most important intermediates in the preparation of polyurethanes.
It is well known, e.g. from DE-A 3,329,124 and US-A
3,479,384, that phosgenation of MDA leads to highly undesirable discoloration of the product, which discoloration remains when the MDI is processed to polyurethanes.
The proposals of the above patents involve subjecting the crude MDI to certain purifying extraction processes. These processes, however, suffer from the drawback that the production of undesirable components causing discoloration is not avoided, so that such components have to be removed in an additional process step and collected for disposal.
US-A 4,465,639 proposes a method of brightening MDI
O.Z. 41479 METHOD OF IMPROVING THE QUALITY
OF CRUDE DIAMINODIPHENYLMETHANES
The present invention relates to a method of improving the quality of crude diaminodiphenylmethanes.
The industrial mixture coming from the acid-catalyzed reaction of aniline with formaldehyde and containing various condensates (diaminodiphenylmethanes, normally referred to as 'MDA') mainly consists of the binuclear p,p'-isomer H2N~CH2 ~NH2 MDA is chiefly used for the synthesis of corresponding diphenylmethane diisocyanates ('MDI') by reacting it with phosgene. MDI itself is one of the most important intermediates in the preparation of polyurethanes.
It is well known, e.g. from DE-A 3,329,124 and US-A
3,479,384, that phosgenation of MDA leads to highly undesirable discoloration of the product, which discoloration remains when the MDI is processed to polyurethanes.
The proposals of the above patents involve subjecting the crude MDI to certain purifying extraction processes. These processes, however, suffer from the drawback that the production of undesirable components causing discoloration is not avoided, so that such components have to be removed in an additional process step and collected for disposal.
US-A 4,465,639 proposes a method of brightening MDI
2~8126 comprising treating the reaction solution with a little water immediately after the MDA has been reacted with phosgene but before the excess phosgene has been removed. It is then not necessary to work up the solution by extraction, but the hydrogen chloride formed leads to corrosion problems.
It is thus an object of the present invention to avoid, from the outset, any discoloration of the product obtained when MDA is treated with phosgene and thus to make any further, expensive purification of the crude MDI unnecessary.
Accordingly, we have found a method of improving the quality of crude diaminodiphenylmethanes comprising the treatment thereof with hydrogen in the presence of a hydrogenation catalyst.
The aqueous reaction mixture produced by the reaction of aniline and formaldehyde to form MDA can be immediately subjected to the hydrogenation treatment, and the excess aniline, water and other low-boiling components can then be distilled off.
However, we recommend that the treatment be effected on crude MDA
from which aniline and water have been removed. Such MDA usually has the following composition:
50-95% w/w of 4,4'-diaminodiphenylmethane, 1-40% w/w of 2,4'-diaminodiphenylmethane, 0.1-10% w/w of 2,2'-diaminodiphenylmethane, 10-40% w/w of tri- or quadri-nuclear MDA homologues and 1-10% wow of higher molecular weight MDA homologues and unidentified substances.
The conditions used during the hydrogenation treatment are not critical, although it is obvious that severe conditions causing damage to the aromatic ring are to be avoided.
In general, a hydrogen pressure of from 1 to 300 bar, preferably from 10 to 200 bar and more preferably from 20 to 60 bar, and a temperature of from 20 to 400C, preferably from 700 to 320C, are to be recommended, so that the crude MDA remains liquid even at atmospheric pressure.
Suitable hydrogenation catalysts are any of those conventionally used for catalytic hydrogenation, in the form of solid catalysts or supported catalysts.
A particularly suitable active material is a platinum metal, especially platinum and palladium. In addition, all conventional hydrogenation catalysts are suitable, for example Raney nickel, a metal, an oxide of tungsten or molybdenum, or a mixture of metals such as a mixture of nickel and molybdenum.
Suitable supports are, for example, aluminum oxide, silica gel, silicates, active carbon and zeolites.
The amount of catalyst used is advantageously from 0.001 to 10% w/w of active material, based on the weight of crude MDA.
The process may be carried out continuously or batchwise. In the latter case, the time required until no more hydrogen is absorbed is usually from 10 minutes to 2 hours.
The reaction is advantageously carried out without the addition of solvent, but it is possible to use additional 2~3~126 solvent, for example a hydrocarbon such as n-heptane and cyclohexane, an alcohol such as methanol and ethanol, or an ether such as tetrahydrofuran and 1,4-dioxane, in a concentration of from 0.05 to 5 kg per kg of MDA. Particularly good results are obtained when the hydrogenation treatment is effected in the presence of from 0.5 to 20% w/w of water.
MDI prepared from MDA which has been treated by hydrogenation is pale to dark yellow and can be used in the preparation of polyurethanes without further purification.
example 1 Batchwise treatment of crude MDA by hydrogenation 500 g of crude MDA, which had been prepared by condensation of aniline and formaldehyde under acid conditions and from which water and excess aniline had been removed, and which contained 55% w/w of 4,4'-diaminodiphenylmethane, 3% w/w of 2,4'-diaminodiphenylmethane, 1% w/w of 2,2'-diaminodiphenylmethane, 25% w/w of tri-nuclear MDA compounds, 10 w/w quadri-nuclear MDA compounds and 6% w/w of MDA compounds having a higher number of nuclei and unidentified substances, were subjected to hydrogenation treatment for 2 hours at 80~C
under a hydrogen pressure of 50 bar and in the presence of 5 g of a powdered supported catalyst consisting of 5% wjw of palladium and 95~ w/w of aluminum oxide, after which the catalyst was separated off.
E~pl~ 2 Batchwise treatment of crude MDA
203~:L26 To an anhydrous and aniline-free MDA mixture of the composition stated in Example 1 there were added 25 g of water.
This mixture was subjected to hydrogenation treatment for 2 hours at 100C under a hydrogen pressure of 50 bar and in the presence of 5 g of a powdered supported catalyst consisting of 5% w/w of palladium and 95% w/w of aluminum oxide, after which the catalyst was separated off.
example 3 Continuous treatment of crude MDA by hydrogenation 50 g/h of crude MDA as used in Example 1 were passed continuously through 50 g of a fixed bed catalysts consisting of 3% w/w of palladium on aluminum oxide while hydrogenation was effected under a hydrogen pressure of 50 bar at 150C.
Example Continuous treatment of crude MDA by hydrogenation 50 g/h of a water-containing and aniline-containing MDA
mixture containing 42% w/w of 4,4'-diaminodiphenylmethane, 2% w/w of 2,4'-diaminodiphenylmethane, 0.5% w/w of 2,2'-diaminodiphenylmethane, 19% w/w of trinuclear MDA compounds, 8 w/w of quadrinuclear MDA compounds, 5% w/w water, 20% w/w of aniline and 3.5~ w/w of NDA compounds having more than 4 nuclei and unidentified substances were continuously passed through 50 g of a fixed bed catalyst consisting of 5% w/w of nickel and 12.7%
w/w of molybdenum on alumina while hydrogenation was effected under a hydrogen pressure of 30 bar at 300C.
2038:126 Example 5 Quality tests on the pure MDA obtained in Examples 1 to 4 The MDA obtained in Examples 1 to 4 was distilled to remove any water and~or aniline present and then treated with chlorobenzene saturated with phosgene under a phosgene pressure of 2 bar to produce MDI by reaction with phosgene. Samples of the MDI were diluted with 5 times their volume of chlorobenzene, and the color indices of the resulting solutions were determined as specified by DIN 6162.
For control purposes, the color index was determined on an MDI prepared by anhydrous, aniline-free crude MDA which had not been subjected to hydrogenation treatment. The results of these tests are given in the Table below.
TABLE
MDI prepared Color Color Index from MDA (determined visually) (determined by DIN 6162) of the invention:
Example 1 pale yellow 40 Example 2 pale yellow 20 Example 3 pale yellow 20 Example 4 pale yellow 50 for comparison:
with no hydrogena-tion treatment dark brown 180
It is thus an object of the present invention to avoid, from the outset, any discoloration of the product obtained when MDA is treated with phosgene and thus to make any further, expensive purification of the crude MDI unnecessary.
Accordingly, we have found a method of improving the quality of crude diaminodiphenylmethanes comprising the treatment thereof with hydrogen in the presence of a hydrogenation catalyst.
The aqueous reaction mixture produced by the reaction of aniline and formaldehyde to form MDA can be immediately subjected to the hydrogenation treatment, and the excess aniline, water and other low-boiling components can then be distilled off.
However, we recommend that the treatment be effected on crude MDA
from which aniline and water have been removed. Such MDA usually has the following composition:
50-95% w/w of 4,4'-diaminodiphenylmethane, 1-40% w/w of 2,4'-diaminodiphenylmethane, 0.1-10% w/w of 2,2'-diaminodiphenylmethane, 10-40% w/w of tri- or quadri-nuclear MDA homologues and 1-10% wow of higher molecular weight MDA homologues and unidentified substances.
The conditions used during the hydrogenation treatment are not critical, although it is obvious that severe conditions causing damage to the aromatic ring are to be avoided.
In general, a hydrogen pressure of from 1 to 300 bar, preferably from 10 to 200 bar and more preferably from 20 to 60 bar, and a temperature of from 20 to 400C, preferably from 700 to 320C, are to be recommended, so that the crude MDA remains liquid even at atmospheric pressure.
Suitable hydrogenation catalysts are any of those conventionally used for catalytic hydrogenation, in the form of solid catalysts or supported catalysts.
A particularly suitable active material is a platinum metal, especially platinum and palladium. In addition, all conventional hydrogenation catalysts are suitable, for example Raney nickel, a metal, an oxide of tungsten or molybdenum, or a mixture of metals such as a mixture of nickel and molybdenum.
Suitable supports are, for example, aluminum oxide, silica gel, silicates, active carbon and zeolites.
The amount of catalyst used is advantageously from 0.001 to 10% w/w of active material, based on the weight of crude MDA.
The process may be carried out continuously or batchwise. In the latter case, the time required until no more hydrogen is absorbed is usually from 10 minutes to 2 hours.
The reaction is advantageously carried out without the addition of solvent, but it is possible to use additional 2~3~126 solvent, for example a hydrocarbon such as n-heptane and cyclohexane, an alcohol such as methanol and ethanol, or an ether such as tetrahydrofuran and 1,4-dioxane, in a concentration of from 0.05 to 5 kg per kg of MDA. Particularly good results are obtained when the hydrogenation treatment is effected in the presence of from 0.5 to 20% w/w of water.
MDI prepared from MDA which has been treated by hydrogenation is pale to dark yellow and can be used in the preparation of polyurethanes without further purification.
example 1 Batchwise treatment of crude MDA by hydrogenation 500 g of crude MDA, which had been prepared by condensation of aniline and formaldehyde under acid conditions and from which water and excess aniline had been removed, and which contained 55% w/w of 4,4'-diaminodiphenylmethane, 3% w/w of 2,4'-diaminodiphenylmethane, 1% w/w of 2,2'-diaminodiphenylmethane, 25% w/w of tri-nuclear MDA compounds, 10 w/w quadri-nuclear MDA compounds and 6% w/w of MDA compounds having a higher number of nuclei and unidentified substances, were subjected to hydrogenation treatment for 2 hours at 80~C
under a hydrogen pressure of 50 bar and in the presence of 5 g of a powdered supported catalyst consisting of 5% wjw of palladium and 95~ w/w of aluminum oxide, after which the catalyst was separated off.
E~pl~ 2 Batchwise treatment of crude MDA
203~:L26 To an anhydrous and aniline-free MDA mixture of the composition stated in Example 1 there were added 25 g of water.
This mixture was subjected to hydrogenation treatment for 2 hours at 100C under a hydrogen pressure of 50 bar and in the presence of 5 g of a powdered supported catalyst consisting of 5% w/w of palladium and 95% w/w of aluminum oxide, after which the catalyst was separated off.
example 3 Continuous treatment of crude MDA by hydrogenation 50 g/h of crude MDA as used in Example 1 were passed continuously through 50 g of a fixed bed catalysts consisting of 3% w/w of palladium on aluminum oxide while hydrogenation was effected under a hydrogen pressure of 50 bar at 150C.
Example Continuous treatment of crude MDA by hydrogenation 50 g/h of a water-containing and aniline-containing MDA
mixture containing 42% w/w of 4,4'-diaminodiphenylmethane, 2% w/w of 2,4'-diaminodiphenylmethane, 0.5% w/w of 2,2'-diaminodiphenylmethane, 19% w/w of trinuclear MDA compounds, 8 w/w of quadrinuclear MDA compounds, 5% w/w water, 20% w/w of aniline and 3.5~ w/w of NDA compounds having more than 4 nuclei and unidentified substances were continuously passed through 50 g of a fixed bed catalyst consisting of 5% w/w of nickel and 12.7%
w/w of molybdenum on alumina while hydrogenation was effected under a hydrogen pressure of 30 bar at 300C.
2038:126 Example 5 Quality tests on the pure MDA obtained in Examples 1 to 4 The MDA obtained in Examples 1 to 4 was distilled to remove any water and~or aniline present and then treated with chlorobenzene saturated with phosgene under a phosgene pressure of 2 bar to produce MDI by reaction with phosgene. Samples of the MDI were diluted with 5 times their volume of chlorobenzene, and the color indices of the resulting solutions were determined as specified by DIN 6162.
For control purposes, the color index was determined on an MDI prepared by anhydrous, aniline-free crude MDA which had not been subjected to hydrogenation treatment. The results of these tests are given in the Table below.
TABLE
MDI prepared Color Color Index from MDA (determined visually) (determined by DIN 6162) of the invention:
Example 1 pale yellow 40 Example 2 pale yellow 20 Example 3 pale yellow 20 Example 4 pale yellow 50 for comparison:
with no hydrogena-tion treatment dark brown 180
Claims (16)
1. A method of improving the quality of crude diaminodiphenylmethanes comprising the treatment thereof with hydrogen in the presence of a hydrogenation catalyst.
2. A method as claimed in claim 1, wherein the hydrogen pressure is from 1 to 300 bar.
3. The method of claim 1 wherein said treatment is carried out at from 20° to 400°C.
4. The method of claim 2 wherein said treatment is carried out at from 20° to 400°.
5. The method of claim 1 wherein the treatment is carried out in the presence of 0.5 to 20 weight percent of water, based on the weight of crude MDA.
6. The method of claim 2 wherein the treatment is carried out in the presence of 0.5 to 20 weight percent of water, based on the weight of crude MDA.
7. The method of claim 3 wherein the treatment is carried out in the presence of 0.5 to 20 weight percent of water, based on the weight of crude MDA.
8. The method of claim 4 wherein the treatment is carried out in the presence of 0.5 to 20 weight percent of water, based on the weight of crude MDA.
9. A continuous process for the preparation of light color crude diaminodiphenylmethanes, comprising a. contacting crude diaminodiphenylmethanes with an effective amount of a hydrogenation catalyst in the presence of hydrogen at a pressure of from 1 to 300 bar and a temperature of from 20° to about 400°C to form light color diaminodiphenylmethanes;
and b. removing said light color diaminodiphenylmethanes from said catalyst;
such that said light color diaminodiphenylmethanes are lighter in color than said crude diaminodiphenylmethanes prior to performing step a).
and b. removing said light color diaminodiphenylmethanes from said catalyst;
such that said light color diaminodiphenylmethanes are lighter in color than said crude diaminodiphenylmethanes prior to performing step a).
10. The process of claim 9 wherein said crude diaminodiphenylmethanes contain water in an amount of from about 0.5 to about 20 weight percent based on the amount of diaminodiphenylmethanes.
11. The process of claim 9 wherein said hydrogen pressure is from about 10 to about 200 bar and the temperature is from 70° to about 320°C.
12. The process of claim 10 wherein said hydrogen pressure is from about 10 to about 200 bar and the temperature is from 70° to about 320°C.
13. The process of claim 9 wherein said hydrogen is from about 20 to about 60 bar.
14. The process of claim 10 wherein said hydrogen is from about 20 to about 60 bar.
15. The process of claim 11 wherein said hydrogen is from about 20 to about 60 bar.
16. The process of claim 12 wherein said hydrogen is from about 20 to about 60 bar.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19904008074 DE4008074A1 (en) | 1990-03-14 | 1990-03-14 | METHOD FOR IMPROVING THE QUALITY OF RAW DIAMINODIPHENYLMETHANES |
| DEP4008074.9 | 1990-03-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2038126A1 true CA2038126A1 (en) | 1991-09-15 |
Family
ID=6402141
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2038126 Abandoned CA2038126A1 (en) | 1990-03-14 | 1991-03-11 | Method of improving the quality of crude diaminodiphenylmethanes |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0446781A1 (en) |
| CA (1) | CA2038126A1 (en) |
| DE (1) | DE4008074A1 (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5583251A (en) * | 1994-04-07 | 1996-12-10 | Bayer Aktiengesellschaft | Process for the production of isocyanates and for the production of light-colored foams therefrom |
| US5889070A (en) * | 1991-12-10 | 1999-03-30 | Bayer Corporation | Process for preparing polyamines and polysocyanates |
| US6140382A (en) * | 1992-03-16 | 2000-10-31 | Bayer Aktiengesellschaft | Process for the preparation of isocyanates or isocyanate mixtures useful for the preparation of polyurethane foams |
| US6900348B1 (en) | 1999-06-23 | 2005-05-31 | Basf Aktiengesellschaft | Light isocyanates, method for producing them and use thereof |
| US7368595B2 (en) | 2006-01-17 | 2008-05-06 | Bayer Materialscience Ag | Process for the production of light-colored isocyanates |
| CN102282127A (en) * | 2008-11-19 | 2011-12-14 | 巴斯夫欧洲公司 | Method for producing an isocyanate |
| US9279029B2 (en) | 2011-10-21 | 2016-03-08 | Bayer Intellectual Property Gmbh | Method for producing light-coloured polyisocyanates |
| US9382198B2 (en) | 2007-11-14 | 2016-07-05 | Covestro Deutschland Ag | Preparation of light-colored isocyanates |
| CN109761855A (en) * | 2018-12-20 | 2019-05-17 | 万华化学集团股份有限公司 | A method of preparing isophorone diisocyanate |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19711447A1 (en) * | 1997-03-19 | 1998-09-24 | Basf Ag | Process for the preparation of light colored isocyanates |
| EP2370400B2 (en) | 2008-11-26 | 2019-10-16 | Huntsman International LLC | Process for manufacturing isocyanates |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3068289A (en) * | 1960-03-08 | 1962-12-11 | Atlantic Refining Co | Stabilization of aromatic diamines |
| US3154583A (en) * | 1962-02-14 | 1964-10-27 | Nopco Chem Co | Stabilization of aromatic amines |
| DE3231911A1 (en) * | 1982-08-27 | 1984-03-01 | Bayer Ag, 5090 Leverkusen | DIAMINES OR DIAMINE MIXTURES, AND A METHOD FOR THE PRODUCTION THEREOF |
| US4754070A (en) * | 1986-01-23 | 1988-06-28 | Air Products And Chemicals, Inc. | Hydrogenation of methylenedianiline to produce bis(para-aminocyclohexyl)methane |
| US4766247A (en) * | 1986-09-26 | 1988-08-23 | Air Products And Chemicals, Inc. | Color reduction of polyamines by mild catalytic hydrogenation |
-
1990
- 1990-03-14 DE DE19904008074 patent/DE4008074A1/en not_active Withdrawn
-
1991
- 1991-03-07 EP EP91103473A patent/EP0446781A1/en not_active Withdrawn
- 1991-03-11 CA CA 2038126 patent/CA2038126A1/en not_active Abandoned
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5889070A (en) * | 1991-12-10 | 1999-03-30 | Bayer Corporation | Process for preparing polyamines and polysocyanates |
| US6140382A (en) * | 1992-03-16 | 2000-10-31 | Bayer Aktiengesellschaft | Process for the preparation of isocyanates or isocyanate mixtures useful for the preparation of polyurethane foams |
| US5583251A (en) * | 1994-04-07 | 1996-12-10 | Bayer Aktiengesellschaft | Process for the production of isocyanates and for the production of light-colored foams therefrom |
| US6900348B1 (en) | 1999-06-23 | 2005-05-31 | Basf Aktiengesellschaft | Light isocyanates, method for producing them and use thereof |
| US7368595B2 (en) | 2006-01-17 | 2008-05-06 | Bayer Materialscience Ag | Process for the production of light-colored isocyanates |
| US9382198B2 (en) | 2007-11-14 | 2016-07-05 | Covestro Deutschland Ag | Preparation of light-colored isocyanates |
| CN102282127A (en) * | 2008-11-19 | 2011-12-14 | 巴斯夫欧洲公司 | Method for producing an isocyanate |
| CN102282127B (en) * | 2008-11-19 | 2015-02-11 | 巴斯夫欧洲公司 | Method for producing an isocyanate |
| US9279029B2 (en) | 2011-10-21 | 2016-03-08 | Bayer Intellectual Property Gmbh | Method for producing light-coloured polyisocyanates |
| CN109761855A (en) * | 2018-12-20 | 2019-05-17 | 万华化学集团股份有限公司 | A method of preparing isophorone diisocyanate |
| US11939280B2 (en) | 2018-12-20 | 2024-03-26 | Wanhua Chemical Group Co., Ltd. | Method for preparing isophorone diisocyanate |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0446781A1 (en) | 1991-09-18 |
| DE4008074A1 (en) | 1991-09-19 |
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| EEER | Examination request | ||
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