CN113893866A

CN113893866A - H12Method for regenerating catalyst in MDA production process and H12Method for producing MDA

Info

Publication number: CN113893866A
Application number: CN202111312235.0A
Authority: CN
Inventors: 李鑫; 孙家家; 张聪颖; 初长坤; 魏运恒; 智丁未
Original assignee: Wanhua Chemical Group Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd
Priority date: 2021-11-08
Filing date: 2021-11-08
Publication date: 2022-01-07
Anticipated expiration: 2041-11-08
Also published as: CN113893866B

Abstract

The invention relates to a method for producing H₁₂Regeneration method of catalyst in MDA production process and H₁₂A method for the production of MDA, said regeneration method comprising the steps of: using diaminodiphenylmethane as raw materialThe method comprises the steps of preparing diaminodicyclohexylmethane by hydrogenation, treating a catalyst at a certain temperature and pressure by using water as a solvent and a small amount of acid liquor as an accelerator when the activity of the catalyst is reduced so as to reduce the alkalinity of tar attached to the catalyst, thereby realizing the separation of the catalyst and the tar, and then regenerating and activating the catalyst by using an organic solvent. The regeneration method of the invention can obviously prolong the service life of the catalyst, effectively keep the stability of the anti-reverse isomer and greatly reduce the production cost.

Description

H12Method for regenerating catalyst in MDA production process and H12Method for producing MDA

Technical Field

The invention relates to the technical field of benzene ring hydrogenation, in particular to a regeneration method of a catalyst in a diaminodicyclohexyl methane production process and H with a content of a trans-product of 15-25%₁₂A method for producing MDA.

Background

Diaminodicyclohexylmethane (H)₁₂MDA) is an important cycloaliphatic diamine, primarily used to prepare cycloaliphatic dicyclohexylmethane diisocyanate (H)₁₂MDI) or directly as an epoxy resin curing agent. H₁₂The MDI can be used for processing various environment-friendly polyurethane coatings, adhesives and other surface materials with good transparency and yellowing resistance. From H₁₂The epoxy resin cured by MDA has excellent heat resistance, dielectric property, solvent resistance, mechanical property, optical property and weather resistance, and can be used in the fields of damping materials, optical materials, coatings, engineering plastics, adhesives and the like.

Preparation H₁₂MDA mainly adopts a noble metal-loaded catalyst to carry out the reaction of diaminodiphenylmethane (MDA) catalytic hydrogenation in a fixed bed or an autoclave reactor so as to meet the requirements of higher product yield and lower trans-anti-isomer ratio. Because the cost of the noble metal catalyst is high, the catalyst needs to be continuously recycled and reused so as to reduce the production cost. However, as the number of times of catalyst application increases, the channels and active sites on the surface of the catalyst are covered by the increasing amount of high-boiling-point tar, so that the activity and selectivity of the catalyst are gradually weakened, further more secondary amine tar is generated, and the proportion of anti-isomer is continuously increased. Meanwhile, as the catalyst is wrapped by viscous tar, catalyst particles are more viscous, the filtering time of the product liquid is prolonged by times, and even the catalyst is taken out in advance and retired, so that the production efficiency is reduced, and the operation cost is increased.

In order to increase the catalyst life, the prior art generally has two categories; the method reduces the generation amount of tar in the reaction process by optimizing the reaction process, thereby relieving the adhesion and the wrapping of the catalyst by the tar and prolonging the service life of the catalyst. For example, US4754070A discloses a novel process by which a trans-trans isomer ratio of 17-24% can be obtained. In the method, 0.1-15 wt% of alkali modified catalyst is added before catalytic reaction to modify the supported rhodium-ruthenium double-component catalyst. US6075167A provides a ruthenium-catalyzed aromatic diamine compound reduction process using metal nitrite as a promoter, which improves the reaction rate and reduces the production of high-boiling by-product tar. US3697449A modifies the supported ruthenium catalyst with 1-35% aqueous alkali metal alkoxide or hydroxide solution, followed by hydrogenation reduction of MDA. However, this method requires the addition of an alkali metal salt or nitrite as an accelerator. The activity of the catalytic system is reduced by the reaction of alkali metal salt or nitrite and the supported noble metal catalyst, thereby reducing the tar which is a byproduct with high boiling point. In order to ensure the continuity, new promoters need to be added continuously in the subsequent catalyst application, so that alkali metal in the catalytic system is continuously remained and accumulated, the performance of the noble metal-loaded catalyst is irreversibly damaged, the reaction time is continuously prolonged, and the proportion of the anti-inverse isomer in the product is continuously increased and exceeds the index.

The other method adopts a technical means to regenerate the deactivated catalyst, thereby prolonging the service life of the catalyst. For example, US3071551A describes a means for regenerating rhodium catalysts by heating, but this solution requires removal of the catalyst and the addition of corresponding equipment, which is difficult to achieve either in batch or continuous mode. US3856862A describes a solution for regenerating a catalyst using a separate regeneration system by high temperature heat regeneration in a special tubular reactor with oxygen as the oxidant, again requiring removal and special equipment to effect regeneration of the catalyst. CN103265438A discloses a preparation method of PACM20 by diaminodiphenylmethane hydrogenation, when the activity of the catalyst is reduced, 5-15 wt% of 2, 4'-MDA is added into 4,4' -MDA raw material, and the activity regeneration of the catalyst is achieved by reducing the hydrogen consumption rate of the catalyst. Due to the fact thatIn the regeneration process of the agent, 2, 4' -H is introduced into the product₁₂MDA, therefore, requires the addition of a work-up procedure to make 2, 4' -H₁₂MDA and 4,4' -H₁₂And (5) separating the MDA. CN108840801A provides a regeneration process of a catalyst in the continuous production process of 4,4' -diaminodicyclohexyl methane with the content of trans-products of 45-55%. When the activity of the catalyst is reduced, the method switches the raw material from MDA-100 to PACM20, simultaneously adds water with certain concentration, recovers the activity of the catalyst while producing PACM50 through isomerization reaction, and then carries out hydrogenation reaction of MDA-100 again. In this method, the basicity of the reaction system is enhanced by introducing an appropriate amount of water, and PACM20 reacts with the carrier that exhibits amphoteric oxide in the catalyst, so that although the catalyst activity can be temporarily improved, the catalyst carrier cannot withstand long-term attack by the base.

Accordingly, there is a need in the art to develop a diaminodiphenylmethane catalyst regeneration process that overcomes the above-mentioned deficiencies of the prior art processes.

Disclosure of Invention

The invention aims to provide a regeneration process of a catalyst in a diaminodicyclohexyl methane production process, which realizes the separation of the catalyst and tar by treatment and then adopts an organic solvent to regenerate and activate the catalyst. The treatment process can obviously prolong the service life of the catalyst, effectively keep the stability of the anti-reverse isomer and greatly reduce the production cost.

Another object of the present invention is to provide a process for producing 4,4' -diaminodicyclohexylmethane having a trans-product content of 15 to 25%.

In order to achieve the above purpose, the invention adopts the following technical scheme:

h₁₂The regeneration method of the catalyst in the MDA production process takes diaminodiphenylmethane as a raw material, and prepares diaminodicyclohexylmethane by hydrogenation under the action of a metal supported catalyst, wherein when the yield of 4,4' -diaminodicyclohexylmethane is reduced to below 90 percent, the catalyst is regenerated by adopting the following steps:

1) treating the catalyst with water as solvent and a small amount of acid solution as promoter at certain temperature and pressure in inert atmosphere;

2) the catalyst is subjected to regeneration and activation reaction by adopting an organic solvent.

In a particular embodiment, the treatment pressure in step 1) is from 0.1 to 5MPa, preferably from 0.5 to 1 MPa; the treatment temperature is 80-150 ℃, and preferably 100-120 ℃; the treatment time is 1-10h, preferably 5-7 h; the addition amount of water is 50-500 times of the mass of the metal supported catalyst, preferably 100-200 times;

preferably, the inert atmosphere is any one of nitrogen, hydrogen, argon, helium or carbon dioxide, and more preferably nitrogen;

preferably, the acid solution is any one of formic acid, acetic acid, hydrochloric acid, sulfuric acid and phosphoric acid, and more preferably phosphoric acid;

preferably, the amount of the acid solution added is 0.1 to 10 times, more preferably 0.2 to 0.5 times, the mass of the metal supported catalyst.

In a specific embodiment, the regeneration activation reaction in step 2) is carried out in the presence of a solvent;

preferably, the addition amount of the solvent is 50 to 500 times of the mass of the metal supported catalyst, and more preferably 100-200 times;

preferably, the solvent is selected from at least any one of cyclohexane, dioxane, tetrahydrofuran, cyclohexylamine, dicyclohexylamine, methanol, ethanol, isopropanol, n-butanol, 2-butanol or methylcyclohexane, and more preferably tetrahydrofuran.

In a specific embodiment, the hydrogen pressure of the regeneration activation reaction in step 2) is 2 to 10MPa, preferably 6 to 8 MPa; the regeneration activation reaction temperature is 200-250 ℃, preferably 210-220 ℃; the activation time is 1-10h, preferably 5-7 h.

In a specific embodiment, the diaminodiphenylmethane feedstock comprises from 96 to 100 wt% of 4,4' -diaminodiphenylmethane, from 0 to 2 wt% of 2, 4' -diaminodiphenylmethane and from 0 to 2 wt% of N-methyl-4, 4' -diaminodiphenylmethane, based on the weight of the diaminodiphenylmethane feedstock; preferably comprising 99 to 100 wt% of 4,4' -diaminodiphenylmethane, 0 to 0.5 wt% of 2, 4' -diaminodiphenylmethane and 0 to 0.5 wt% of N-methyl-4, 4' -diaminodiphenylmethane, based on the weight of the diaminodiphenylmethane feedstock.

In a specific embodiment, the metal supported catalyst comprises a combination of a metal and a support;

preferably, the metal comprises any one or a combination of at least two of the group VIIIB metals; more preferably, the metal comprises any one or a combination of at least two of Pt, Rh, Ru, Ir or Pd, further preferably Rh;

preferably, the support comprises any one or a combination of at least two of rare earth, diatomaceous earth, alumina, activated carbon, lithium aluminate, spinel, silica or silica alumina, more preferably alumina;

more preferably, the metal supported catalyst is Rh/Al₂O₃；

More preferably, the metal is present in an amount of 3 to 6 wt%, preferably 4 to 5 wt%, based on the weight of the metal supported catalyst

In a specific embodiment, the metal supported catalyst is added in an amount of 0.5 to 5 wt%, preferably 1 to 3 wt%, and more preferably 1.5 to 2 wt% based on the total weight of the diaminodiphenylmethane feedstock.

In a particular embodiment, the hydrogenation reaction is carried out in the presence of a solvent; preferably, the concentration of the solvent is in the range of from 30 to 60 wt%, preferably from 40 to 50 wt%, based on the total weight of the diaminodiphenylmethane feedstock and solvent.

In a specific embodiment, the hydrogenation reaction temperature is 100-250 ℃, preferably 150-200 ℃, and more preferably 170-190 ℃;

preferably, the absolute pressure of the hydrogenation reaction is 3-15MPa, preferably 5-10MPa, and more preferably 6-8 MPa;

preferably, the reactor comprises a batch autoclave reactor with a catalyst filtration unit;

preferably, the catalyst filtering device is an internal filter or an external filter, and preferably an autoclave internal filter.

In another aspect, a₁₂MDA production method, especially a method for producing H with 15-25% of trans-isomer content₁₂A process for the production of MDA, comprising a process for the regeneration of the aforementioned catalyst.

Compared with the prior art, the invention has the advantages that:

the method adopts an acidic aqueous solution, and under a certain temperature and pressure, the amine tar adsorbed on the catalyst is reacted to generate hydroxyl substituted tar so as to eliminate the alkalinity of the tar, and further an organic solvent is used for washing, regenerating and activating, so that the tar and the catalyst are desorbed and separated. The invention changes the chemical structure of tar through chemical reaction, eliminates the strong adsorption effect of amine tar on the catalyst from the molecular layer surface, and further realizes the activation and regeneration of the catalyst.

The production method of the 4,4' -diaminodicyclohexyl methane with the content of the trans-isomer of 15-25 percent, which comprises the catalyst regeneration method, can obviously prolong the service life of the catalyst, effectively keep the stability of the trans-isomer and greatly reduce the production cost.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

The starting materials used in the following examples or comparative examples, unless otherwise specified, are commercially available technical grade conventional materials, and the main materials and test equipment information are as follows:

5wt％Rh/Al₂O₃and 4 wt% Rh/Al₂O₃Purchased from Zhuangxinwan corporation, wt% refers to the metal content.

Phosphoric acid was obtained from the alatin reagent with a purity of 85%.

Tetrahydrofuran was purchased from Kemi Europe and was analytically pure.

MDA-100 is from Wanhua WANAMINE MDA-100. Wherein the content of 4,4'-MDA is 99.5 wt%, the content of N-methyl-4, 4' -MDA is 0.35 wt%, and the content of monoaminodiphenylmethane is 0.15 wt%.

The gas chromatography is 7890 series of Agilent, DB-5 capillary chromatographic column, FID detector temperature is 300 deg.C, initial column temperature is 160 deg.C, 10 deg.C/min is increased to 300 deg.C, and the time is 20 min.

Example 1

In a 2L autoclave with built-in filter, 3g of Rh/Al with a metal content of 5 wt.% were charged₂O₃The catalyst, with the addition of 200g of MDA-100 and 200g of tetrahydrofuran, was stirred with 1MPa (absolute) of N₂After three times of replacement, 1MPa (absolute pressure) of H is added₂Three times of replacement, then H₂The pressure is supplemented to 5MPa (absolute pressure). Raising the temperature to 180 ℃, and continuously introducing H into the reaction kettle through a hydrogen flow controller in the reaction process₂The reaction pressure is maintained at 6MPa (absolute pressure), and when the hydrogen flow indication number passing through the hydrogen flow controller is lower than 100sccm, the introduction of H is stopped₂And when the pressure drop of the reaction kettle is less than 0.01MPa/min, stopping the reaction, and cooling and decompressing the reaction kettle. When the temperature of the reaction kettle is reduced to 50 ℃, N not more than 0.6MPa (absolute pressure) is adopted₂And filtering and separating the product liquid and the catalyst through a built-in filter, and carrying out gas chromatography analysis on the product liquid. And after the product liquid is filtered, continuously adding 200g of MDA-100 and 200g of tetrahydrofuran, and repeating the steps to recycle the catalyst. When H is in the product liquid₁₂When the MDA yield is lower than 90%, the catalyst is temporarily used circularly, 600g of water and 1.5g of phosphoric acid are added, the mixture is pretreated at 120 ℃ under 1MPa of nitrogen for 5 hours, and then the reaction mother liquor is filtered completely. 600g of THF are again added and after 5h of activation at 210 ℃ and 8MPa of hydrogen, the THF is filtered off. 200g of MDA-100 and 200g of tetrahydrofuran are added continuously, the steps are repeated, and the catalyst is recycled. The reaction results are shown in Table 1.

Table 1 results of the catalyst application reaction of example 1

In Table 1, the contents of the respective substances are mass contents based on the total mass of the product, i.e., based on H₁₂The total mass of MDA and other products is 100%, and the content of trans-isomer is that the trans-isomer accounts for H₁₂The percentage of MDA content, the same as the following data, is not repeated herein.

As can be seen from Table 1, after Run23 batches, the catalyst was reactivated by regeneration as described above to give H₁₂The MDA yield rises from 89.8% to 95.9%, while the trans-isomer content remains below 20%.

Example 2

6g of Rh/Al with a metal content of 4% by weight were introduced into a 2L autoclave with built-in filter₂O₃The catalyst, with the addition of 300g of MDA-100 and 200g of tetrahydrofuran, was stirred with 1MPa (absolute) of N₂After three times of replacement, 1MPa (absolute pressure) of H is added₂Three times of replacement, then H₂The pressure is supplemented to 5MPa (absolute pressure). Raising the temperature to 170 ℃, and continuously introducing H into the reaction kettle through a hydrogen flow controller in the reaction process₂The reaction pressure was maintained at 8MPa (absolute pressure), and when the hydrogen flow rate indicated by the hydrogen flow rate controller was less than 100sccm, the introduction of H was stopped₂And when the pressure drop of the reaction kettle is less than 0.01MPa/min, stopping the reaction, and cooling and decompressing the reaction kettle. When the temperature of the reaction kettle is reduced to 50 ℃, N not more than 0.6MPa (absolute pressure) is adopted₂And filtering and separating the product liquid and the catalyst through a built-in filter, and carrying out gas chromatography analysis on the product liquid. And after the product liquid is filtered, continuously adding 300g of MDA-100 and 200g of tetrahydrofuran, and repeating the steps to recycle the catalyst. When H is in the product liquid₁₂When the MDA yield is lower than 90%, the catalyst is temporarily used, 600g of water and 1.2g of phosphoric acid are added, the mixture is pretreated at 100 ℃ and under 0.5MPa of hydrogen for 7 hours, and then the reaction mother liquor is filtered. 600g of THF are again added and after activation at 220 ℃ and 6MPa of hydrogen for 7h, the THF is filtered off. 300g of MDA-100 and 200g of tetrahydrofuran are added in succession and the process is repeatedAnd (3) recycling the catalyst. The reaction results are shown in Table 2.

Table 2 results of the catalyst application reaction of example 2

As can be seen from Table 2, after Run25 batch, the catalyst was reactivated by regeneration as described above to give H₁₂The MDA yield rises from 89.7% to 94.9%, while the trans-isomer content remains below 20%.

Example 3

1.5g of Rh/Al with a metal content of 5% by weight are introduced into a 2L autoclave with an internal filter₂O₃The catalyst, with the addition of 150g of MDA-100 and 225g of tetrahydrofuran, was stirred with 1MPa (absolute) of N₂After three times of replacement, 1MPa (absolute pressure) of H is added₂Three times of replacement, then H₂The pressure is supplemented to 6MPa (absolute pressure). Raising the temperature to 160 ℃, and continuously introducing H into the reaction kettle through a hydrogen flow controller in the reaction process₂The reaction pressure is maintained at 10MPa (absolute pressure), and when the hydrogen flow indication number passing through the hydrogen flow controller is lower than 100sccm, the introduction of H is stopped₂And when the pressure drop of the reaction kettle is less than 0.01MPa/min, stopping the reaction, and cooling and decompressing the reaction kettle. When the temperature of the reaction kettle is reduced to 50 ℃, N not more than 0.6MPa (absolute pressure) is adopted₂And filtering and separating the product liquid and the catalyst through a built-in filter, and carrying out gas chromatography analysis on the product liquid. And after the product liquid is filtered, continuously adding 150g of MDA-100 and 225g of tetrahydrofuran, and repeating the steps to recycle the catalyst. When H is in the product liquid₁₂When the MDA yield is lower than 90%, the catalyst is temporarily used circularly, 750g of water and 15g of formic acid are added, the mixture is pretreated and reacted for 2 hours at 80 ℃ under 0.12MPa of nitrogen, and then the reaction mother liquor is filtered completely. 750g of THF are again added and, after activation at 250 ℃ and 3MPa under hydrogen for 1h, the THF is filtered off. 150g of MDA-100 and 225g of tetrahydrofuran are added continuously, and the steps are repeated to recycle the catalyst. The reaction results are shown in Table 3.

Table 3 results of the catalyst application reaction of example 3

As can be seen from Table 3, after Run25 batch, the catalyst was reactivated by regeneration as described above to produce H₁₂The MDA yield increased from 89.5% to 93.2% while the trans-isomer content remained below 20%.

Example 4

In a 2L autoclave with built-in filter, 10.5g of Rh/Al with a metal content of 4 wt.% were charged₂O₃The catalyst, 350g of MDA-100 and 150g of tetrahydrofuran are added simultaneously, using 1MPa (absolute pressure) of N₂After three times of replacement, 1MPa (absolute pressure) of H is added₂Three times of replacement, then H₂The pressure is supplemented to 3MPa (absolute pressure). Raising the temperature to 200 ℃, and continuously introducing H into the reaction kettle through a hydrogen flow controller in the reaction process₂The reaction pressure is maintained at 5MPa (absolute pressure), and when the hydrogen flow indication number passing through the hydrogen flow controller is lower than 100sccm, the introduction of H is stopped₂And when the pressure drop of the reaction kettle is less than 0.01MPa/min, stopping the reaction, and cooling and decompressing the reaction kettle. When the temperature of the reaction kettle is reduced to 50 ℃, N not more than 0.6MPa (absolute pressure) is adopted₂And filtering and separating the product liquid and the catalyst through a built-in filter, and carrying out gas chromatography analysis on the product liquid. And after the product liquid is filtered, continuously adding 350g of MDA-100 and 150g of tetrahydrofuran, and repeating the steps to recycle the catalyst. When H is in the product liquid₁₂When the MDA yield is lower than 90%, the catalyst is temporarily used circularly, 525g of water and 1.1g of acetic acid are added, the pretreatment reaction is carried out at 150 ℃ under 5MPa of nitrogen for 10 hours, and then the reaction mother liquor is filtered completely. 525g of THF are again added and after 10h of activation at 200 ℃ and 10MPa of hydrogen, the THF is filtered off. 350g of MDA-1 are further added00 and 150g of tetrahydrofuran, and repeating the steps to recycle the catalyst. The reaction results are shown in Table 4.

Table 4 results of the catalyst application reaction of example 4

As can be seen from Table 4, after Run20 batch, the catalyst was reactivated by regeneration as described above to produce H₁₂The MDA yield rises from 89.6% to 94.2%, while the trans-isomer content remains below 20%.

Comparative example 1

When H is present₁₂When the MDA yield drops below 90%, regeneration activation is carried out without using water and phosphoric acid and THF, and the rest of the conditions are the same as in example 1. The reaction results are shown in Table 3.

Table 3 results of the reaction for using the catalyst of comparative example 1

From Table 3, Run25 to Run40 batches, H₁₂The MDA yield continued to drop to 79.1%.

Comparative example 2

When H is present₁₂When the MDA yield is reduced to below 90%, the conditions are the same as in example 1 except that phosphoric acid is not added during the pretreatment. The reaction results are shown in Table 4.

Table 4 results of the catalyst application reaction of comparative example 2

As can be seen from Table 4, when no phosphoric acid is added, the substitution reaction rate of the secondary amine hydroxyl groups is low, the reaction effect of tar on the surface of the catalyst and water is not good, and the catalyst cannot achieve the expected regeneration effect.

Comparative example 3

When H is present₁₂The same procedure as in example 2 was followed except that the pretreatment reaction temperature was 160 ℃ when the MDA yield was reduced to 90% or less. The reaction results are shown in Table 5.

TABLE 5 results of the reaction for using the catalyst of comparative example 3

As can be seen from Table 5, when the pretreatment reaction temperature was increased to 160 ℃, the catalyst activity was greatly decreased after the regeneration treatment. This is because phosphoric acid, which is a pretreatment reaction accelerator, can react with the generated ammonia gas to generate monoammonium phosphate, thereby accelerating the rapid progress of the hydroxyl substitution reaction. When the pretreatment temperature exceeds 130 ℃, the monoammonium phosphate reaches the decomposition temperature, ammonia gas is released, and thus the reaction acceleration effect cannot be achieved. Meanwhile, the acidity of the phosphoric acid is enhanced at high temperature, and the phosphoric acid has an erosion effect on a catalyst carrier, so that the framework structure of the catalyst is damaged, and the activity of the catalyst is greatly reduced.

Comparative example 4

When H is present₁₂When the MDA yield decreased to 90% or less, the procedure was the same as in example 2 except that no THF activation was used after the pretreatment reaction. The reaction results are shown in Table 6.

Table 6 results of the catalyst application reaction of comparative example 4

As can be seen from Table 6, the catalyst activity did not achieve the expected regeneration effect if only the pretreatment reaction was used, but not the THF regeneration activation. This is because the produced hydroxy tar cannot be desorbed by washing with THF at a high temperature, and remains partially on the catalyst surface, thereby affecting the recovery of the catalyst activity.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. It will be appreciated by those skilled in the art that modifications or adaptations to the invention may be made in light of the teachings of the present specification. Such modifications or adaptations are intended to be within the scope of the present invention as defined in the claims.

Claims

1. H₁₂The regeneration method of the catalyst in the MDA production process takes diaminodiphenylmethane as a raw material, prepares diaminodicyclohexylmethane by hydrogenation under the action of a metal supported catalyst, and is characterized in that when the yield of 4,4' -diaminodicyclohexylmethane is reduced to below 90 percent, the catalyst is regenerated by adopting the following steps:

2. The process for regenerating the catalyst according to claim 1, characterized in that the treatment pressure in step 1) is comprised between 0.1 and 5MPa, preferably between 0.5 and 1 MPa; the treatment temperature is 80-150 ℃, and preferably 100-120 ℃; the treatment time is 1-10h, preferably 5-7 h; the addition amount of water is 50-500 times of the mass of the metal supported catalyst, preferably 100-200 times;

3. The method for regenerating a catalyst according to claim 1 or 2, wherein the regeneration activation reaction in the step 2) is carried out in the presence of a solvent;

4. The process for regenerating the catalyst according to claim 3, characterized in that the hydrogen pressure of the regeneration activation reaction in step 2) is 2 to 10MPa, preferably 6 to 8 MPa; the regeneration activation reaction temperature is 200-250 ℃, preferably 210-220 ℃; the activation time is 1-10h, preferably 5-7 h.

5. The process for regenerating the catalyst according to any of claims 1 to 4, characterized in that the diaminodiphenylmethane feedstock comprises from 96 to 100% by weight of 4,4' -diaminodiphenylmethane, from 0 to 2% by weight of 2, 4' -diaminodiphenylmethane and from 0 to 2% by weight of N-methyl-4, 4' -diaminodiphenylmethane, based on the weight of the diaminodiphenylmethane feedstock; preferably comprising 99 to 100 wt% of 4,4' -diaminodiphenylmethane, 0 to 0.5 wt% of 2, 4' -diaminodiphenylmethane and 0 to 0.5 wt% of N-methyl-4, 4' -diaminodiphenylmethane, based on the weight of the diaminodiphenylmethane feedstock.

6. The method for regenerating a catalyst according to any one of claims 1 to 4, characterized in that the metal-supported catalyst comprises a combination of a metal and a support;

more preferably, the metal supported catalyst is Rh/Al₂O₃；

7. Process for regenerating a catalyst according to any of claims 1-4, characterized in that the metal supported catalyst is added in an amount of 0.5-5 wt-%, preferably 1-3 wt-%, more preferably 1.5-2 wt-%, based on the total weight of the diaminodiphenylmethane feedstock.

8. The process for regenerating the catalyst according to any one of claims 1 to 4, characterized in that the hydrogenation reaction is carried out in the presence of a solvent; preferably, the concentration of the solvent is in the range of from 30 to 60 wt%, preferably from 40 to 50 wt%, based on the total weight of the diaminodiphenylmethane feedstock and solvent.

9. The method for regenerating a catalyst according to claim 8, wherein the hydrogenation reaction temperature is 100-250 ℃, preferably 150-200 ℃, and more preferably 170-190 ℃;

10. H₁₂Process for the production of MDA, characterized in that it comprises a process for the regeneration of the catalyst according to any one of claims 1 to 9.