A kind of production method of LC grade diethyltoluenediamine

Abstract

The present invention provides a method for producing LC-grade diethyltoluenediamine, belonging to the technical field of organic chemistry. Under inert gas protection, toluenediamine and a catalyst are mixed, heated and stirred, ethylene and a composite gas are introduced simultaneously, the mixture is kept warm and pressurized for reaction, the temperature is lowered, the pressure is released, the product is discharged, and the liquid is refined to produce LC-grade diethyltoluenediamine. The method for producing LC-grade diethyltoluenediamine is simple, exhibits few side reactions, produces a high product yield and purity, is readily industrially applicable, has a wide range of raw material sources, operates under mild reaction conditions, and the catalyst is easily separable and can be reused multiple times, thus having broad application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of organic chemistry, and in particular to a production method of LC-grade diethyltoluenediamine. Background Art

[0002] Diethyltoluenediamine, abbreviated as DETDA, is a low-viscosity, non-toxic, odorless, light yellow liquid. It is mainly used in the fields of chain extenders for polyurethane and polyurea elastomers, polyurethane and epoxy resin curing agents, coatings, lubricants, industrial oil antioxidants, chemical synthesis intermediates, etc. Commercialized DETDA is a mixture of 3,5-diethyl-2,4-toluenediamine (about 80%) and 3,5-diethyl-2,6-toluenediamine (about 20%).

[0003] DETDA is usually prepared from toluenediamine (TDA) and ethylene in the presence of a catalyst, and undergoes a Friedel-Crafts alkylation reaction under high temperature and high pressure to obtain crude DETDA. The catalyst is then separated and removed, and pure DETDA is obtained through distillation. The reaction is as follows:

[0004] .

[0005] The key to this reaction lies in the catalyst, which must provide a certain Lewis acidity to promote the alkylation of the benzene ring. Considering factors such as production cost, operational stability, and especially reaction efficiency, current large-scale DETDA production processes generally use aluminum powder, zinc powder, and / or AlCl3 as catalysts. However, these process conditions are extremely harsh, with reaction temperatures typically reaching 200-300°C and reaction pressures reaching as high as 50 MPa. While these harsh conditions favor the polarization of ethylene, allowing it to undergo an alkylation reaction with toluenediamine to produce DETDA, they also increase the likelihood that DETDA will further react with ethylene to form triethyltoluenediamine (ETDA). Furthermore, excessively high temperatures and pressures can promote numerous side reactions, such as demethylation and deamination of toluenediamine. These demethylation and deamination products can further react with ethylene to produce a large number of ethylated byproducts. Furthermore, Lewis acids can also promote N-alkylation of the benzene ring, resulting in a large number of N-alkylated substituted byproducts of toluenediamine. Therefore, avoiding these side reactions and promoting the reaction toward DETDA is key to improving the efficiency of the toluenediamine alkylation reaction.

[0006] Chinese invention patent CN106083605B discloses a method for synthesizing diethyltoluenediamine. Under certain conditions, the diethyltoluenediamine forms an "aromatic amine-aluminum" catalyst system with diaminotoluene. The system then undergoes an alkylation reaction with ethylene in an autoclave. After the reaction, the diethyltoluenediamine is directly distilled in a still. The intercepted front fraction and the remaining catalyst system are returned to the autoclave, where the raw diaminotoluene is added and the alkylation reaction with ethylene continues. This single-use "aromatic amine-aluminum" catalyst system can be reused. However, the catalytic efficiency of this catalyst system is low. Summary of the Invention

[0007] The present invention aims to provide a method for producing LC-grade diethyltoluenediamine. The method is simple, has few side reactions, high product yield, high purity, is easy to industrialize, has a wide source of raw materials, mild reaction conditions, and a catalyst that is easy to separate and can be reused multiple times, thus having broad application prospects.

[0008] The technical solution of the present invention is achieved as follows:

[0009] The invention provides a production method of LC-grade diethyltoluenediamine, comprising the following steps: under the protection of an inert gas, mixing toluenediamine and a catalyst, heating and stirring, simultaneously introducing ethylene and a composite gas, maintaining the temperature and pressurizing for reaction, cooling, releasing the pressure, discharging the material, and refining the liquid material to obtain the LC-grade diethyltoluenediamine.

[0010] As a further improvement of the present invention, the temperature is raised to 160-180°C, the pressure of the heat preservation and pressurization reaction is 6-7 MPa, and the time is 2-4 hours. The composite gas includes an inert gas, a protonic acid gas, and an ammonia gas in a volume ratio of 7-10:3-5:1-3. The protonic acid gas is selected from at least one of hydrogen fluoride, hydrogen chloride, hydrogen bromide, hydrogen iodide, hydrogen sulfide, and fluosilicic acid gas. The ammonia gas is selected from at least one of ammonia, monomethylamine, dimethylamine, trimethylamine, and triethylamine gas.

[0011] As a further improvement of the present invention, the added amount of the catalyst is 0.5-10wt% of toluenediamine, preferably 0.5-1.5wt%. The preparation method of the catalyst is as follows:

[0012] S1. Zirconium tetrachloride was added to a mixed solvent of N,N-dimethylformamide and acetic acid, 2-aminoterephthalic acid was added, hydrothermal reaction was performed, centrifuged, washed, and dried to obtain UiO-66-NH2;

[0013] S2. Piperazine and dibromo-p-xylene were mixed in acetonitrile, heated under reflux under inert gas protection, centrifuged, washed, and dried to obtain compound 1;

[0014] S3. Compound 1 was added to a solvent, 1,3-propane sultone was added, the temperature was raised, the reaction was centrifuged, washed, and dried to obtain compound 2;

[0015] S4. Compound 2 was added to water, methanesulfonic acid was added, the reaction was heated with stirring, the solvent was removed under reduced pressure, washed with ether, and dried to obtain an ionic liquid;

[0016] S5. The ionic liquid and UiO-66-NH2 were mixed, ground, heated for polymerization reaction, the product was extracted with acetonitrile, washed with methanol, centrifuged, and dried to obtain a composite;

[0017] S6. The complex was added to an aqueous solution of aluminum salt and zinc salt, the reaction was stirred, centrifuged, washed, and dried to obtain an Al / Zn complex;

[0018] S7. Adding the loaded Al / Zn composite to an aqueous solution of a cerium salt, impregnating, centrifuging, washing, and drying to obtain a catalyst.

[0019] As a further improvement of the present invention, the volume ratio of N,N-dimethylformamide and acetic acid in the mixed solvent of N,N-dimethylformamide and acetic acid in step S1 is 35:2-4, the mass ratio of zirconium tetrachloride and 2-aminoterephthalic acid is 14-17:12-14, and the temperature of the hydrothermal reaction is 120-130° C. and the time is 20-24 h.

[0020] As a further improvement of the present invention, the molar ratio of piperazine to dibromo-p-xylene in step S2 is 1:1-1.1, and the heating reflux reaction time is 24-30 hours.

[0021] As a further improvement of the present invention, in step S3, the mass ratio of compound 1 to 1,3-propane sultone is 20-22:24-26, the temperature of the temperature-raising reaction is 55-65° C., and the time is 2-4 h.

[0022] As a further improvement of the present invention, in step S4, the mass ratio of compound 2 to methanesulfonic acid is 45-47:20-22, the temperature of the heating and stirring reaction is 75-85° C., and the time is 7-10 h.

[0023] As a further improvement of the present invention, the mass ratio of the ionic liquid and UiO-66-NH2 in step S5 is 7-10:12-15, the grinding time is 1-3 hours, and the temperature of the heating polymerization reaction is 65-75°C and the time is 24-30 hours.

[0024] As a further improvement of the present invention, the mass ratio of the complex, aluminum salt and zinc salt in step S6 is 10:3-5:1-2, the aluminum salt is selected from at least one of aluminum sulfate and aluminum nitrate, the zinc salt is selected from at least one of zinc chloride, zinc sulfate and zinc nitrate, and the stirring reaction time is 30-50 min; the mass ratio of the Al / Zn-loaded complex and cerium salt in step S7 is 100:3-5, the impregnation time is 10-12 h, and the cerium salt is cerium chloride or cerium nitrate.

[0025] The present invention further protects a catalyst, the preparation method of which comprises the following steps:

[0026] S1. 1.4-1.7 parts by weight of zirconium tetrachloride was added to a mixed solvent of N,N-dimethylformamide and acetic acid, 1.2-1.4 parts by weight of 2-aminoterephthalic acid was added, and the reaction was hydrothermally reacted at 120-130°C for 20-24h, centrifuged, washed, and dried to obtain UiO-66-NH2;

[0027] The volume ratio of N,N-dimethylformamide to acetic acid in the mixed solvent of N,N-dimethylformamide and acetic acid is 35:2-4;

[0028] S2. A mixture of 10 mmol piperazine and 10-11 mmol dibromo-p-xylene was added to acetonitrile, and the mixture was heated under reflux under inert gas for 24-30 h, centrifuged, washed, and dried to obtain compound 1;

[0029] S3. 2-2.2 parts by weight of compound 1 were added to ethanol, 2.4-2.6 parts by weight of 1,3-propane sultone were added, the temperature was raised to 55-65°C, the reaction was stirred for 2-4h, centrifuged, washed, and dried to obtain compound 2;

[0030] S4. 4.5-4.7 parts by weight of compound 2 was added to water, 2-2.2 parts by weight of methanesulfonic acid was added, heated to 75-85 ° C, stirred for 7-10h, the solvent was removed under reduced pressure, washed with ether, and dried to obtain an ionic liquid;

[0031] S5. 0.7-1 parts by weight of the ionic liquid and 1.2-1.5 parts by weight of UiO-66-NH2 were mixed, ground for 1-3 hours, heated to 65-75°C, and polymerized for 24-30 hours. The product was extracted with acetonitrile, washed with methanol, centrifuged, and dried to obtain a composite;

[0032] S6. 1 part by weight of the complex was added to an aqueous solution containing 0.3-0.5 parts by weight of an aluminum salt and 0.1-0.2 parts by weight of a zinc salt, and the reaction was stirred for 30-50min, centrifuged, washed, and dried to obtain an Al / Zn complex;

[0033] S7. Add 1 part by weight of the loaded Al / Zn composite to an aqueous solution containing 0.03-0.05 parts by weight of a cerium salt, immerse for 10-12 hours, centrifuge, wash, and dry to obtain a catalyst.

[0034] The present invention has the following beneficial effects:

[0035] This invention prepares an immobilized ionic liquid Lewis acid catalyst. Piperazine and dibromo-p-xylene are first reacted, followed by reaction with 1,3-propane sultone to produce a polyionic liquid precursor. This precursor is then reacted with methanesulfonic acid to produce the polyionic liquid. This sulfonic acid group (-SO3H)-functionalized acidic ionic liquid is an emerging catalyst, combining the high activity of liquid acids with the separability of solid acids. Compared to traditional acids (sulfuric acid or hydrochloric acid), it offers advantages such as high acidity, high catalytic activity, environmental friendliness, and recyclability. Ionic liquids possess physical and chemical properties such as high adsorption capacity, high activity, good thermodynamic stability, and high solubility. The anions and cations of ionic liquids are designable and easily functionalized. However, they are difficult to separate from homogeneous catalytic reaction systems, making them difficult to reuse. Low molecular weight ionic liquids also present challenges such as difficulty in separation during preparation and low catalytic activity. Therefore, the present invention prepares a polyionic liquid and carries out in-situ polymerization with the polyionic liquid and the MOFs material (UiO-66-NH2). The MOFs material has the characteristics of high specific surface area, adjustable structural pore size, easy functionalization, etc., and the polyionic liquid prepared by the present invention with high acidity is loaded on the surface of the alkaline MOFs material. On the one hand, the two can be loaded through reaction with a high loading amount, and on the other hand, the acidity can be controlled to achieve appropriate acid-catalyzed neutral activity, thereby greatly improving the catalytic activity, and easily realizing the directional reaction of TDA and ethylene to produce diethyltoluenediamine, greatly reducing the occurrence of side reactions, and improving the yield of diethyltoluenediamine, thereby greatly improving the economic value of the reaction.

[0036] The reaction is as follows:

[0037] ;

[0038] The prepared composite is loaded with copper and zinc, which greatly improves the catalytic activity and has a synergistic catalytic effect. It is further impregnated with cerium ions. Rare earth cerium ions have an unfilled 4f electron layer structure, producing a very rich electronic energy level and a relatively large ion radius, just like adding "industrial MSG". It will produce more new catalytic active centers, thereby greatly improving the catalytic activity.

[0039] The production method of LC-grade diethyltoluenediamine is simple, has few side reactions, high product yield and high purity, is easy to implement industrial application, has a wide source of raw materials, mild reaction conditions, and the catalyst is easy to separate and can be reused multiple times, thus having broad application prospects. DETAILED DESCRIPTION

[0040] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0041] Preparation Example 1 Preparation of catalyst

[0042] Here’s how:

[0043] S1. 1.4 g of zirconium tetrachloride was added to 300 mL of a mixed solvent of N,N-dimethylformamide and acetic acid, along with 1.2 g of 2-aminoterephthalic acid. The mixture was hydrothermally reacted at 120°C for 20 h. The mixture was centrifuged, washed, and dried to produce UiO-66-NH2. The volume ratio of N,N-dimethylformamide to acetic acid in the mixed solvent was 35:2.

[0044] S2. A mixture of 10 mmol piperazine and 10 mmol dibromo-p-xylene was added to 50 mL of acetonitrile and heated under reflux under nitrogen for 24 h. The mixture was centrifuged, washed, and dried to obtain compound 1.

[0045] S3. 2 g of compound 1 was added to 200 mL of ethanol, and 2.4 g of 1,3-propane sultone was added. The temperature was raised to 55°C, and the reaction was stirred for 2 h. The mixture was centrifuged, washed, and dried to obtain compound 2.

[0046] S4. 4.5 g of compound 2 was added to 200 mL of water, and 2 g of methanesulfonic acid was added. The mixture was heated to 75°C and stirred for 7 h. The solvent was removed under reduced pressure, the mixture was washed with ether, and dried to obtain an ionic liquid.

[0047] S5. 0.7 g of the ionic liquid and 1.2 g of UiO-66-NH2 were mixed, ground for 1 h, heated to 65°C, and polymerized for 24 h. The product was extracted with acetonitrile, washed with methanol, centrifuged, and dried to obtain a composite.

[0048] S6. 1 g of the complex was added to 50 mL of an aqueous solution containing 0.3 g of aluminum sulfate and 0.1 g of zinc chloride, and the reaction was stirred for 30 min, centrifuged, washed, and dried to obtain an Al / Zn complex;

[0049] S7. Add 1 g of the loaded Al / Zn composite to 50 mL of an aqueous solution containing 0.03 g of cerium chloride, soak for 10 h, centrifuge, wash, and dry to obtain a catalyst.

[0050] Preparation Example 2 Preparation of catalyst

[0051] Here’s how:

[0052] S1. 1.7 g of zirconium tetrachloride was added to 300 mL of a mixed solvent of N,N-dimethylformamide and acetic acid, along with 1.4 g of 2-aminoterephthalic acid. The mixture was hydrothermally reacted at 130°C for 24 hours, followed by centrifugation, washing, and drying to produce UiO-66-NH2. The volume ratio of N,N-dimethylformamide to acetic acid in the mixed solvent was 35:4.

[0053] S2. 10 mmol of piperazine and 11 mmol of dibromo-p-xylene were mixed and added to 50 mL of acetonitrile. The mixture was heated under reflux under nitrogen for 30 h, centrifuged, washed, and dried to obtain compound 1.

[0054] S3. 2.2 g of compound 1 was added to 200 mL of ethanol, and 2.6 g of 1,3-propane sultone was added. The temperature was raised to 65°C, and the reaction was stirred for 4 h. The mixture was centrifuged, washed, and dried to obtain compound 2.

[0055] S4. Add 4.7 g of compound 2 to 200 mL of water, add 2.2 g of methanesulfonic acid, heat to 85°C, stir and react for 10 h, remove the solvent under reduced pressure, wash with ether, and dry to obtain an ionic liquid;

[0056] S5. 1 g of the ionic liquid and 1.5 g of UiO-66-NH2 were mixed, ground for 3 h, heated to 75°C, and polymerized for 30 h. The product was extracted with acetonitrile, washed with methanol, centrifuged, and dried to obtain a composite.

[0057] S6. 1 g of the complex was added to 50 mL of an aqueous solution containing 0.5 g of aluminum sulfate and 0.2 g of zinc sulfate, and the reaction was stirred for 50 min, centrifuged, washed, and dried to obtain an Al / Zn-loaded complex;

[0058] S7. Add 1 g of the loaded Al / Zn composite to 50 mL of an aqueous solution containing 0.05 g of cerium chloride, soak for 12 h, centrifuge, wash, and dry to obtain a catalyst.

[0059] Preparation Example 3 Preparation of catalyst

[0060] Here’s how:

[0061] S1. 1.55 g of zirconium tetrachloride was added to 300 mL of a mixed solvent of N,N-dimethylformamide and acetic acid, along with 1.3 g of 2-aminoterephthalic acid. The mixture was hydrothermally reacted at 125°C for 22 hours, followed by centrifugation, washing, and drying to produce UiO-66-NH2. The volume ratio of N,N-dimethylformamide to acetic acid in the mixed solvent was 35:3.

[0062] S2. A mixture of 10 mmol piperazine and 10.5 mmol dibromo-p-xylene was added to 50 mL of acetonitrile and heated under reflux under nitrogen for 27 h. The mixture was centrifuged, washed, and dried to obtain compound 1.

[0063] S3. 2.1 g of compound 1 was added to 200 mL of ethanol, and 2.5 g of 1,3-propane sultone was added. The temperature was raised to 60°C, and the reaction was stirred for 3 h. The mixture was centrifuged, washed, and dried to obtain compound 2.

[0064] S4. Add 4.6 g of compound 2 to 200 mL of water, add 2.1 g of methanesulfonic acid, heat to 80°C, stir and react for 8 h, remove the solvent under reduced pressure, wash with ether, and dry to obtain an ionic liquid;

[0065] The results of infrared spectrum analysis are as follows: -1 These peaks are related to the stretching vibration of -CH and -CN on the piperazine ring, 1188 and 1022 cm -1 The characteristic peaks are attributed to the S=O and SO stretching vibrations of the -SO3H group.

[0066] S5. 0.85 g of the ionic liquid and 1.35 g of UiO-66-NH2 were mixed, ground for 2 h, heated to 70°C, and polymerized for 27 h. The product was extracted with acetonitrile, washed with methanol, centrifuged, and dried to obtain a composite.

[0067] S6. 1 g of the complex was added to 50 mL of an aqueous solution containing 0.4 g of aluminum nitrate and 0.15 g of zinc nitrate, stirred for 40 min, centrifuged, washed, and dried to obtain an Al / Zn-loaded complex;

[0068] S7. 1 g of the Al / Zn composite was added to 50 mL of an aqueous solution containing 0.04 g of cerium nitrate, and the mixture was immersed for 11 h. The mixture was centrifuged, washed, and dried to obtain a catalyst.

[0069] Comparative Preparation Example 1

[0070] Compared with Preparation Example 3, the difference is that the ionic liquid in step S4 is replaced by 1-butyl-3-(4-sulfobutyl)imidazolium trifluoromethanesulfonic acid.

[0071] The preparation method is as follows:

[0072] (1) 0.85 g of 1-butyl-3-(4-sulfobutyl)imidazolium trifluoromethanesulfonic acid and 1.35 g of UiO-66-NH2 were mixed, ground for 2 h, heated to 70 °C, and polymerized for 27 h. The product was extracted with acetonitrile, washed with methanol, centrifuged, and dried to obtain a composite.

[0073] (2) Add 1 g of the complex to 50 mL of an aqueous solution containing 0.4 g of aluminum nitrate and 0.15 g of zinc nitrate, stir and react for 40 min, centrifuge, wash, and dry to obtain an Al / Zn-loaded complex;

[0074] (3) 1 g of the Al / Zn composite was added to 50 mL of an aqueous solution containing 0.04 g of cerium nitrate, immersed for 11 h, centrifuged, washed, and dried to obtain a catalyst.

[0075] Comparative Preparation Example 2

[0076] Compared with Preparation Example 3, the difference is that UiO-66-NH2 is replaced by nano-silica (average particle size of 500 nm).

[0077] The preparation method is as follows:

[0078] (1) 10 mmol of piperazine and 10.5 mmol of dibromo-p-xylene were mixed and added to 50 mL of acetonitrile. Under nitrogen protection, the mixture was heated under reflux for 27 h, centrifuged, washed, and dried to obtain compound 1.

[0079] (2) Add 2.1 g of compound 1 to 200 mL of ethanol, add 2.5 g of 1,3-propane sultone, heat to 60°C, stir and react for 3 h, centrifuge, wash, and dry to obtain compound 2;

[0080] (3) Add 4.6 g of compound 2 to 200 mL of water, add 2.1 g of methanesulfonic acid, heat to 80 °C, stir and react for 8 h, remove the solvent under reduced pressure, wash with ether, and dry to obtain an ionic liquid;

[0081] (4) 0.85 g of ionic liquid and 1.35 g of nano-silica were mixed, ground for 2 h, heated to 70 °C, and polymerized for 27 h. The product was extracted with acetonitrile, washed with methanol, centrifuged, and dried to obtain a composite.

[0082] (5) Add 1 g of the complex to 50 mL of an aqueous solution containing 0.4 g of aluminum nitrate and 0.15 g of zinc nitrate, stir and react for 40 min, centrifuge, wash, and dry to obtain an Al / Zn-loaded complex;

[0083] (6) 1 g of the loaded Al / Zn composite was added to 50 mL of an aqueous solution containing 0.04 g of cerium nitrate, immersed for 11 h, centrifuged, washed, and dried to obtain a catalyst.

[0084] Comparative Preparation Example 3

[0085] Compared with Preparation Example 3, the difference is that aluminum nitrate is not added in step S6.

[0086] The details are as follows:

[0087] S6. Add 1 g of the complex to 50 mL of an aqueous solution containing 0.55 g of zinc nitrate, stir and react for 40 min, centrifuge, wash, and dry to obtain a Zn-loaded complex.

[0088] Comparative Preparation Example 4

[0089] Compared with Preparation Example 3, the difference is that zinc nitrate is not added in step S6.

[0090] The details are as follows:

[0091] S6. Add 1 g of the complex to 50 mL of an aqueous solution containing 0.55 g of aluminum nitrate, stir and react for 40 min, centrifuge, wash, and dry to obtain an Al-loaded complex.

[0092] Comparative Preparation Example 5

[0093] Compared with Preparation Example 3, the difference is that step S6 is not performed.

[0094] The details are as follows:

[0095] S1. 1.55 g of zirconium tetrachloride was added to 300 mL of a mixed solvent of N,N-dimethylformamide and acetic acid, along with 1.3 g of 2-aminoterephthalic acid. The mixture was hydrothermally reacted at 125°C for 22 hours, followed by centrifugation, washing, and drying to produce UiO-66-NH2. The volume ratio of N,N-dimethylformamide to acetic acid in the mixed solvent was 35:3.

[0096] S2. A mixture of 10 mmol piperazine and 10.5 mmol dibromo-p-xylene was added to 50 mL of acetonitrile and heated under reflux under nitrogen for 27 h. The mixture was centrifuged, washed, and dried to obtain compound 1.

[0097] S3. 2.1 g of compound 1 was added to 200 mL of ethanol, and 2.5 g of 1,3-propane sultone was added. The temperature was raised to 60°C, and the reaction was stirred for 3 h. The mixture was centrifuged, washed, and dried to obtain compound 2.

[0098] S4. Add 4.6 g of compound 2 to 200 mL of water, add 2.1 g of methanesulfonic acid, heat to 80°C, stir and react for 8 h, remove the solvent under reduced pressure, wash with ether, and dry to obtain an ionic liquid;

[0099] S5. 0.85 g of the ionic liquid and 1.35 g of UiO-66-NH2 were mixed, ground for 2 h, heated to 70°C, and polymerized for 27 h. The product was extracted with acetonitrile, washed with methanol, centrifuged, and dried to obtain a composite.

[0100] S6. 1 g of the complex was added to 50 mL of an aqueous solution containing 0.04 g of cerium nitrate, and the mixture was immersed for 11 h. The mixture was centrifuged, washed, and dried to obtain a catalyst.

[0101] Comparative Preparation Example 6

[0102] Compared with Preparation Example 3, the difference is that step S7 is not performed.

[0103] The details are as follows:

[0104] S1. 1.55 g of zirconium tetrachloride was added to 300 mL of a mixed solvent of N,N-dimethylformamide and acetic acid, along with 1.3 g of 2-aminoterephthalic acid. The mixture was hydrothermally reacted at 125°C for 22 hours, followed by centrifugation, washing, and drying to produce UiO-66-NH2. The volume ratio of N,N-dimethylformamide to acetic acid in the mixed solvent was 35:3.

[0105] S2. A mixture of 10 mmol piperazine and 10.5 mmol dibromo-p-xylene was added to 50 mL of acetonitrile and heated under reflux under nitrogen for 27 h. The mixture was centrifuged, washed, and dried to obtain compound 1.

[0106] S3. 2.1 g of compound 1 was added to 200 mL of ethanol, and 2.5 g of 1,3-propane sultone was added. The temperature was raised to 60°C, and the reaction was stirred for 3 h. The mixture was centrifuged, washed, and dried to obtain compound 2.

[0107] S4. Add 4.6 g of compound 2 to 200 mL of water, add 2.1 g of methanesulfonic acid, heat to 80°C, stir and react for 8 h, remove the solvent under reduced pressure, wash with ether, and dry to obtain an ionic liquid;

[0108] S5. 0.85 g of the ionic liquid and 1.35 g of UiO-66-NH2 were mixed, ground for 2 h, heated to 70°C, and polymerized for 27 h. The product was extracted with acetonitrile, washed with methanol, centrifuged, and dried to obtain a composite.

[0109] S6. Add 1 g of the complex to 50 mL of an aqueous solution containing 0.4 g of aluminum nitrate and 0.15 g of zinc nitrate. Stir and react for 40 min. Centrifuge, wash, and dry to obtain the Al / Zn-loaded complex, which is the catalyst.

[0110] Comparative Preparation Example 7

[0111] Compared with Preparation Example 3, the difference is that steps S6 and S7 are not performed.

[0112] The details are as follows:

[0113] S1. 1.55 g of zirconium tetrachloride was added to 300 mL of a mixed solvent of N,N-dimethylformamide and acetic acid, along with 1.3 g of 2-aminoterephthalic acid. The mixture was hydrothermally reacted at 125°C for 22 hours, followed by centrifugation, washing, and drying to produce UiO-66-NH2. The volume ratio of N,N-dimethylformamide to acetic acid in the mixed solvent was 35:3.

[0114] S2. A mixture of 10 mmol piperazine and 10.5 mmol dibromo-p-xylene was added to 50 mL of acetonitrile and heated under reflux under nitrogen for 27 h. The mixture was centrifuged, washed, and dried to obtain compound 1.

[0115] S3. 2.1 g of compound 1 was added to 200 mL of ethanol, and 2.5 g of 1,3-propane sultone was added. The temperature was raised to 60°C, and the reaction was stirred for 3 h. The mixture was centrifuged, washed, and dried to obtain compound 2.

[0116] S4. Add 4.6 g of compound 2 to 200 mL of water, add 2.1 g of methanesulfonic acid, heat to 80°C, stir and react for 8 h, remove the solvent under reduced pressure, wash with ether, and dry to obtain an ionic liquid;

[0117] S5. Mix 0.85 g of the ionic liquid and 1.35 g of UiO-66-NH2, grind for 2 h, heat to 70°C, and polymerize for 27 h. Extract the product with acetonitrile, wash with methanol, centrifuge, and dry to obtain a composite catalyst.

[0118] Test Example 1

[0119] The performance of the catalysts prepared in Preparation Examples 1-3 and Comparative Preparation Examples 1-7 was tested. The results are shown in Table 1.

[0120] The specific surface area and total pore volume of the catalyst were determined using a 3-FLEX 3500 multi-station high-throughput gas adsorption instrument.

[0121] Prepare a 2 mmol / L 4-nitroaniline indicator solution. Weigh 1 g of the catalyst into a 10 mL volumetric flask. Use a disposable syringe to draw 2 mL of the indicator solution into the flask. Add deionized water to the volume to prepare the test solution. Use a UV spectrophotometer to scan the test solution at all wavelengths and calculate its Hammett acidity function to obtain the acidity ( H 0) value.

[0122] Table 1 ;

[0123] It can be seen from the above table that the catalysts prepared in Preparation Examples 1-3 of the present invention have larger specific surface area, total pore volume and appropriate acidity. Example 1

[0124] This embodiment provides a method for producing LC-grade diethyltoluenediamine, comprising the following steps:

[0125] Under nitrogen protection, toluenediamine and the catalyst prepared in Preparation Example 1 were mixed in an amount of 0.5 wt % of toluenediamine. The mixture was heated to 160° C. and stirred. Ethylene and composite gas were introduced simultaneously in a volume ratio of 1:1. The pressure was kept at 6 MPa and the reaction was carried out under heat and pressure for 2 h. The mixture was cooled, depressurized, discharged, and the liquid was refined to obtain LC-grade diethyltoluenediamine.

[0126] The composite gas includes nitrogen, hydrogen chloride and trimethylamine in a volume ratio of 7:3:1. Example 2

[0127] This embodiment provides a method for producing LC-grade diethyltoluenediamine, comprising the following steps:

[0128] Under nitrogen protection, toluenediamine and the catalyst prepared in Preparation Example 2 were mixed in an amount of 1.5 wt % of toluenediamine. The mixture was heated to 180° C. and stirred. Ethylene and composite gas were introduced simultaneously in a volume ratio of 1:1. The pressure was kept at 7 MPa and the reaction was carried out under heat and pressure for 4 h. The mixture was cooled, depressurized, discharged, and the liquid was refined to obtain LC-grade diethyltoluenediamine.

[0129] The composite gas includes nitrogen, hydrogen chloride and trimethylamine in a volume ratio of 10:5:3. Example 3

[0130] This embodiment provides a method for producing LC-grade diethyltoluenediamine, comprising the following steps:

[0131] Under nitrogen protection, toluenediamine and the catalyst prepared in Preparation Example 3 were mixed, the catalyst addition amount being 1 wt % of toluenediamine, and the temperature was raised to 170°C with stirring. Ethylene and composite gas were introduced simultaneously, the volume ratio of ethylene to composite gas being 1:1, and the pressure was kept at 6.5 MPa for 3 h. The temperature was lowered, the pressure was released, the material was discharged, and the liquid was refined to obtain LC-grade diethyltoluenediamine.

[0132] The composite gas includes nitrogen, hydrogen chloride and trimethylamine in a volume ratio of 8:4:2.

[0133] Comparative Examples 1-7

[0134] Compared with Example 3, the difference is that the catalysts are prepared in sequence from Comparative Preparation Examples 1-7.

[0135] Test Example 2

[0136] The reactions in Examples 1-3 and Comparative Examples 1-7 were evaluated, and the results are shown in Table 2.

[0137] Table 2 ;

[0138] As can be seen from the above table, the conversion rate of toluenediamine in the reaction of Examples 1-3 of the present invention is high, and the yield of diethyltoluenediamine is high.

[0139] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for producing LC-grade diethyltoluenediamine, characterized in that: The following steps are involved: Under the protection of inert gas, toluenediamine and a catalyst are mixed, heated and stirred, and ethylene and a composite gas are introduced at the same time, wherein the volume ratio of ethylene to the composite gas is 1:1, the reaction is carried out under heat preservation and pressure, and the pressure of the heat preservation and pressure reaction is 6-7 MPa. The temperature is reduced, the pressure is released, the material is discharged, and the liquid is refined to obtain LC-grade diethyltoluenediamine; the temperature is raised to 160-180° C. for 2-4 hours, and the composite gas is composed of an inert gas, a protonic acid gas, and an ammonia gas in a volume ratio of 7-10:3-5:1-3, the protonic acid gas is selected from at least one of hydrogen fluoride, hydrogen chloride, hydrogen bromide, hydrogen iodide, hydrogen sulfide, and fluorosilicic acid gas, and the ammonia gas is selected from at least one of ammonia, monomethylamine, dimethylamine, trimethylamine, and triethylamine gas; The preparation method of the catalyst is as follows: S1. Zirconium tetrachloride was added to a mixed solvent of N,N-dimethylformamide and acetic acid, 2-aminoterephthalic acid was added, hydrothermal reaction was performed, centrifuged, washed, and dried to obtain UiO-66-NH2; S2. Piperazine and dibromo-p-xylene were mixed in acetonitrile, heated under reflux under inert gas protection, centrifuged, washed, and dried to obtain compound 1; S3. Compound 1 was added to a solvent, 1,3-propane sultone was added, the temperature was raised, the reaction was centrifuged, washed, and dried to obtain compound 2; S4. Compound 2 was added to water, methanesulfonic acid was added, the reaction was heated with stirring, the solvent was removed under reduced pressure, washed with ether, and dried to obtain an ionic liquid; The ionic liquid has a structure as shown in Formula I: Formula I; S5. The ionic liquid and UiO-66-NH2 were mixed, ground, heated for polymerization reaction, the product was extracted with acetonitrile, washed with methanol, centrifuged, and dried to obtain a composite; S6. The complex was added to an aqueous solution of aluminum salt and zinc salt, the reaction was stirred, centrifuged, washed, and dried to obtain an Al / Zn complex; S7. Adding the loaded Al / Zn composite to an aqueous solution of a cerium salt, impregnating, centrifuging, washing, and drying to obtain a catalyst.

2. The production method according to claim 1, characterized in that The added amount of the catalyst is 0.5-1.5 wt % of toluenediamine.

3. The production method according to claim 1, characterized in that In step S1, the volume ratio of N,N-dimethylformamide to acetic acid in the mixed solvent of N,N-dimethylformamide and acetic acid is 35:2-4, the mass ratio of zirconium tetrachloride to 2-aminoterephthalic acid is 14-17:12-14, the temperature of the hydrothermal reaction is 120-130° C., and the time is 20-24 hours.

4. The production method according to claim 1, characterized in that In step S2, the molar ratio of piperazine to dibromo-p-xylene is 1:1-1.1, and the heating reflux reaction time is 24-30 hours.

5. The production method according to claim 1, characterized in that In step S3, the mass ratio of compound 1 to 1,3-propane sultone is 20-22:24-26, the temperature of the temperature-raising reaction is 55-65° C., and the time is 2-4 hours.

6. The production method according to claim 1, characterized in that In step S4, the mass ratio of compound 2 to methanesulfonic acid is 45-47:20-22, and the temperature of the heating and stirring reaction is 75-85° C. for 7-10 hours.

7. The production method according to claim 1, characterized in that In step S5, the mass ratio of the ionic liquid to UiO-66-NH2 is 7-10:12-15, the grinding time is 1-3 hours, and the temperature of the heating polymerization reaction is 65-75° C. and the time is 24-30 hours.

8. The production method according to claim 1, characterized in that In step S6, the mass ratio of the complex, aluminum salt, and zinc salt is 10:3-5:1-2, the aluminum salt is selected from at least one of aluminum sulfate and aluminum nitrate, the zinc salt is selected from at least one of zinc chloride, zinc sulfate, and zinc nitrate, and the stirring reaction time is 30-50 minutes; in step S7, the mass ratio of the Al / Zn-loaded complex and the cerium salt is 100:3-5, the impregnation time is 10-12 hours, and the cerium salt is cerium chloride or cerium nitrate.

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