A solid catalyst, a method for preparing the same, and a method for synthesizing 1,2-propanediamine using the catalyst

Abstract

This invention relates to a green, environmentally friendly, and highly selective synthesis method for 1,2-propanediamine, a highly efficient solid-state catalyst for this method, its preparation, and a method for synthesizing 1,2-propanediamine using this catalyst. The solid-state catalyst is characterized by using oxides of cobalt and lanthanum as the main active components, and one or more oxides of nickel, copper, zinc, cerium, and cadmium as auxiliary active components. The cobalt oxide content is 20-40%, the lanthanum oxide content is 20-40%, and the total content of the auxiliary active components is 20-60%, all by weight. The catalyst preparation method of this invention is simple and easy to implement, suitable for industrial production, and has broad application prospects. The technical solution of this invention can effectively solve the problems existing in the prior art, improve reaction efficiency and product quality, and provide a new solution for the synthesis of 1,2-propanediamine.

Description

Technical Field

[0001] This invention relates to a green, environmentally friendly, and highly selective synthesis method for 1,2-propanediamine, a highly efficient solid catalyst for this method and its preparation, and a method for synthesizing 1,2-propanediamine using this catalyst. Background Technology

[0002] 1,2-Propanediamine is a colorless, transparent, viscous liquid with an ammonia-like odor. It is strongly alkaline and hygroscopic, readily soluble in water, and soluble in acetone, benzene, chloroform, and ethanol. It has optical isomers, but usually exists as a racemic mixture. It is strongly alkaline and hygroscopic, producing white fumes upon contact with air. It poses a risk of combustion and explosion upon contact with open flames, high heat, or oxidizers. Thermal decomposition produces toxic nitrogen oxide fumes. In the pharmaceutical industry, it is used as an intermediate in the production of the anticancer drug propylimide, 1,2-propanediaminetetraacetic acid (PPTE), and is also a raw material for the anticancer drug dextropropanediamine. It can be used as a solvent in nitrocellulose, coatings, vegetable oils, rosin, etc., and as a raw material in the manufacture of gasoline additives. It is a raw material for the synthesis of 2-methyl-4-p-chlorophenylimidazolium, a corrosion inhibitor for copper materials; a raw material for the production of rubber vulcanization accelerators; used in the production of epoxy resin curing accelerators; used as a chain extender in spandex production; and used in the preparation of anionic surfactants.

[0003] Currently, the main methods for preparing 1,2-propanediamine are: (1) It is obtained by amination substitution of 1,2-dichloropropane haloalkane. This reaction is a batch reaction, which consumes a lot of raw materials, generates a lot of waste, and causes serious corrosion to equipment. (2) According to reports, acrylonitrile is used abroad for amination and hydrogenation synthesis, but this method has high pressure and expensive raw material costs; (3) Patent CN113105337B describes the preparation of 1,2-propanediamine using propylene oxide, liquid ammonia, hydrogen, and solid catalyst. The byproducts are isopropanolamine and diisopropanolamine. Separation requires a lot of energy, and the selectivity of 1,2-propanediamine is low. (4) Patent CN 112898167 A discloses a method for producing isopropanolamine and 1,2-propanediamine by cracking 2,6-dimethylpiperazine using Co-Mo-Pd / Al2O3 catalyst. This method requires high temperature and high pressure conditions, and the cracking reaction is not easy to control. It is easy to produce a lot of byproducts. Separation requires a lot of energy, and the production cost is high. (5) CN 111433183 A discloses a method for synthesizing 1,2-propanediamine. This method uses isopropanolamine as a raw material and continuously prepares 1,2-propanediamine and dimethyldiethylenetriamine by reacting isopropanolamine with ammonia under hydrogen conditions in the presence of a supported heterogeneous hydrogenation catalyst. 1,2-propanediamine is obtained by multiple distillations. This method is energy-intensive, with a raw material conversion rate of only 70%-85%, a yield of only 60%-80%, and a selectivity of only 75%-85%, all of which are low.

[0004] Current methods for synthesizing 1,2-propanediamine have several shortcomings in practical production applications: they use halogenated 1,2-dichloropropane as a raw material, which is a carcinogen, posing a significant risk to personnel and causing severe equipment corrosion, while also generating difficult-to-manage waste; the high reaction pressure poses a significant safety risk and high cost; some synthesis reactions exhibit low product selectivity, requiring substantial energy for separation; and even in reactions using water or without solvents, the high temperature and pressure result in poor product yields, complex products, and difficult separation. Furthermore, most of these methods for synthesizing 1,2-propanediamine involve batch processes in batch reactors, which are subject to harsh operating conditions and are challenging. Therefore, developing a highly efficient and selective catalyst to achieve high feed conversion rates, good selectivity, mild operating conditions, and low cost in the synthesis of 1,2-propanediamine is a persistent goal pursued by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a solid catalyst with high catalytic efficiency and low cost, in which the raw materials for the reaction are inexpensive and readily available, the reaction operating conditions are mild and easy to control, and the product 1,2-propanediamine is synthesized with high yield and good selectivity when using this catalyst.

[0006] To achieve the above objectives, the present invention first provides a solid catalyst, wherein the solid catalyst has cobalt and lanthanum oxides as the main active components and one or more oxides of nickel, copper, zinc, cerium and cadmium as auxiliary active components, wherein the cobalt oxide content is 20-40%, the lanthanum oxide content is 20-40%, and the total content of the auxiliary active components is 20-60%, all of which are weight percentages.

[0007] Secondly, the present invention also provides a method for preparing a solid catalyst. The method involves preparing a solution of soluble metal salts of the main active component and the auxiliary active component, preparing a solution of the precipitant, then adding the precipitant solution dropwise into the soluble metal salt of the active component for aging, and then filtering, washing, drying, calcining, shaping, and calcining again to obtain the desired catalyst. Furthermore, the amount of precipitant used is 1-2 times the total molar amount of active metal ions in the active metal oxide solution.

[0008] Furthermore, the precipitant is selected from metal carbonates, ammonia, or urea. The metal carbonate is sodium carbonate, potassium carbonate, or a mixture of both, with a molar ratio of 1:3 to 3:1. The amount of precipitant is 1 to 2 times the total molar amount of active metal ions in the metal salt solution.

[0009] Furthermore, the cleaning process ends when the catalyst's pH value reaches 7. Therefore, when metal carbonates are used as precipitants, the catalyst washing process requires extending the washing time or increasing the washing water temperature to reduce the alkali metal content in the catalyst.

[0010] Furthermore, the concentration of the soluble metal salt solution of the active component is 0.5-2 mol / L, and the concentration of the precipitant solution is 0.1-1 mol / L; Furthermore, the dropping time of the precipitant is controlled at 30-60 min, and the dropping temperature is 60-120℃.

[0011] Furthermore, after the precipitant solution is added dropwise, the aging temperature is 60-120℃, and the aging time is 2-12h.

[0012] Furthermore, the drying temperature is 60-90℃, the drying time is 12-48h, and the calcination temperature is 200-500℃, the time is 4-8h.

[0013] Furthermore, the molding process is based on the quality of the calcined product. 50% guar gum, 10% graphite powder, and 0.1% distilled water are added, stirred evenly, and granulated into Φ2mm particles with a length of 1-2mm. Then, the particles are calcined at 200℃~500℃ for 4-6 hours. Furthermore, the present invention also provides a method for synthesizing 1,2-propanediamine using the above-mentioned catalyst, comprising the following steps: A solid catalyst is loaded into the reactor of a continuous synthesis unit. After assembling the reactor, a reducing gas is first introduced to purge air from the reactor. The temperature is then programmed to reach the reduction temperature, and the catalyst is fully reduced. Isopropanolamine is then preheated in a preheating vaporizer and introduced into the reactor along with liquid ammonia and hydrogen for the synthesis reaction. After the synthesis reaction, the materials are cooled and separated. The liquid phase is collected in a liquid tank, while the gaseous ammonia and hydrogen are recovered from the reaction system and continue to participate in the reaction. The synthesis liquid is then separated by vacuum distillation to obtain high-purity 1,2-propanediamine.

[0014] The programmed heating refers to heating at a rate of 2-10℃ / min, heating to 300-480℃ and then holding for 2-6 hours; the preferred heating rate is 5℃ / min, the preferred heating temperature is 350℃, and the preferred holding time is 4 hours.

[0015] Furthermore, the time for the reducing gas to replace the air in the reactor is 10-20 minutes, and the reducing atmosphere is hydrogen, a hydrogen / argon mixture, or a hydrogen / nitrogen mixture.

[0016] Furthermore, the molar ratio of isopropanolamine to liquid ammonia is 1:7-11, the molar ratio of isopropanolamine to hydrogen is 1:3-10, and the liquid feed space velocity of isopropanolamine is 1.2-6 h⁻¹. -1 The reaction temperature is 160℃-200℃, and the reaction pressure is 2-4MPa.

[0017] Furthermore, during the vacuum distillation, the reboiler temperature is 65℃~80℃, the top temperature is 60℃~73℃, and the reflux ratio is 2:3-1:1. The present invention has the following advantages: This invention employs a one-step gas-solid phase catalytic synthesis of 1,2-propanediamine using isopropanolamine, characterized by readily available raw materials, a simple process, and low pollution. By optimizing reaction conditions and feed ratios, precise control of the reaction process is achieved, thereby improving reaction efficiency and product quality. Distillation is used to separate the crude product, efficiently separating 1,2-propanediamine and further enhancing product quality. The conversion rate of the raw materials reaches over 90%, the yield over 80%, the selectivity for 1,2-propanediamine over 90%, and the content of the separated 1,2-propanediamine reaches over 99%. A highly active, highly selective, long-life, and inexpensive catalyst has also been developed. The catalyst preparation method of this invention is simple and easy to implement, suitable for industrial production, and has broad application prospects. The technical solution of this invention effectively solves the problems existing in the prior art, improves reaction efficiency and product quality, and provides a new solution for the synthesis of 1,2-propanediamine. Detailed Implementation

[0018] Example 1: Preparation of coprecipitation catalyst A Weigh 65g of cobalt acetate tetrahydrate, 60.35g of lanthanum nitrate hexahydrate, and 63.39g of copper nitrate trihydrate into a flask. Add 500mL of distilled water and dissolve in an oil bath at 80℃ with stirring. Dissolve 89.57g of anhydrous sodium carbonate in 500mL of distilled water. After both are completely dissolved, add the sodium carbonate solution dropwise to the metal salt solution at a constant temperature of 80℃ over 40 minutes. Aging at 80℃ for 4 hours is then carried out. Filter the solution and wash the catalyst with distilled water until the pH reaches 7. Place the catalyst in a 70℃ oven for 24 hours. The dried solid was pulverized into powder and calcined at 200℃~500℃ for 4 hours. Guar gum (50% by weight of the calcined product), graphite powder (10% by weight of the calcined product), and distilled water (0.1% by weight of the calcined product) were added. The mixture was stirred until homogeneous and granulated into particles Φ2mm in diameter and 1-2mm in length. This granulation was then carried out at 200℃~500℃ for 4 hours to obtain catalyst A. The active components, oxides of cobalt, lanthanum, and copper, account for 93% of the total catalyst mass. The forming agent accounts for 7% of the total catalyst mass.

[0019] Example 2: Preparation of coprecipitation catalyst B Weigh 65.23 g of cobalt acetate tetrahydrate, 60.65 g of lanthanum nitrate hexahydrate, and 64.13 g of nickel acetate tetrahydrate into a flask. Add 500 mL of distilled water and dissolve by stirring in an oil bath at 80 °C. Dissolve 90.95 g of anhydrous sodium carbonate in 500 mL of distilled water. After both are completely dissolved, add the sodium carbonate solution dropwise to the metal salt solution at a constant temperature of 80 °C over 40 minutes. Aging at 80 °C for 4 hours is then carried out. Filter the solution and wash the catalyst with distilled water until the pH reaches 7. Place the solution in a 70 °C oven for 24 hours. The dried solid was pulverized into powder and calcined at 200℃~500℃ for 4 hours. Guar gum (50% by weight of the calcined product), graphite powder (10% by weight of the calcined product), and distilled water (0.1% by weight of the calcined product) were added. The mixture was stirred until homogeneous and granulated into particles Φ2mm in diameter and 1-2mm in length. This granulation was then carried out at 200℃~500℃ for 4 hours to obtain catalyst B. The active components, oxides of cobalt, lanthanum, and nickel, accounted for 91% of the total catalyst mass. The forming agent accounted for 9% of the total catalyst mass.

[0020] Example 3: Preparation of coprecipitation catalyst C Weigh 56.2 g of cobalt acetate tetrahydrate, 61.65 g of lanthanum nitrate hexahydrate, 32.67 g of copper nitrate trihydrate, and 33.12 g of nickel acetate tetrahydrate into a flask. Add 500 mL of distilled water and dissolve by stirring in an oil bath at 80 °C. Dissolve 88.19 g of anhydrous sodium carbonate in 500 mL of distilled water. After both are completely dissolved, add the sodium carbonate solution dropwise to the metal salt solution at a constant temperature of 80 °C over 40 minutes. Aging at 80 °C for 4 hours is then carried out. Filter the solution and wash the catalyst with distilled water until the pH reaches 7. Place the catalyst in a 70 °C oven for 24 hours. The dried solid was pulverized into powder and calcined at 200℃~500℃ for 4 hours. Guar gum (50% by weight of the calcined product), graphite powder (10% by weight of the calcined product), and distilled water (0.1% by weight of the calcined product) were added. The mixture was stirred until homogeneous and granulated into particles Φ2mm in diameter and 1-2mm in length. This granulation was then carried out at 200℃~500℃ for 4 hours to obtain catalyst C. The active components, oxides of cobalt, lanthanum, copper, and nickel, account for 95% of the total catalyst mass. A forming agent accounts for 5% of the total catalyst mass.

[0021] Example 4: Preparation of coprecipitation catalyst D Weigh 55.54 g of cobalt acetate tetrahydrate, 52.05 g of lanthanum nitrate hexahydrate, 26.78 g of cerium nitrate hexahydrate, and 13.04 g of zinc acetate. Add them to 500 mL of distilled water and dissolve them in an oil bath at 80 °C with stirring. Dissolve 64.77 g of anhydrous sodium carbonate in 500 mL of distilled water. After both are completely dissolved, add the sodium carbonate solution dropwise to the metal salt solution at a constant temperature of 80 °C. The addition should be completed over 40 minutes. Aging should be carried out at a constant temperature of 80 °C for 4 hours. Filter the solution and wash the catalyst with distilled water until the pH reaches 7. Place the solution in a 70 °C oven for 24 hours. The dried solid was pulverized into powder and calcined at 200℃~500℃ for 4 hours. Guar gum (50% by weight of the calcined product), graphite powder (10% by weight of the calcined product), and distilled water (0.1% by weight of the calcined product) were added. The mixture was stirred until homogeneous and granulated into particles Φ2mm in diameter and 1-2mm in length. This granulation was then carried out at 200℃~500℃ for 4 hours to obtain catalyst D. The active components, oxides of cobalt, lanthanum, cerium, and zinc, accounted for 96% of the total catalyst mass. The forming agent accounted for 4% of the total catalyst mass.

[0022] Example 5: Preparation of coprecipitation catalyst E Weigh 46.02 g of cobalt acetate tetrahydrate, 61.35 g of lanthanum nitrate hexahydrate, 32.43 g of copper nitrate trihydrate, 33.62 g of nickel acetate tetrahydrate, and 13.15 g of cerium nitrate hexahydrate into a flask. Add 500 mL of distilled water and dissolve in an oil bath at 80 °C with stirring. Dissolve 85.44 g of anhydrous sodium carbonate in 500 mL of distilled water. After both are completely dissolved, add the sodium carbonate solution dropwise to the metal salt solution at a constant temperature of 80 °C over 40 minutes. Aging at 80 °C for 4 hours is then carried out. Filter the solution and wash the catalyst with distilled water until the pH reaches 7. Place the solution in a 70 °C oven for 24 hours. The dried solid was pulverized into powder and calcined at 200℃~500℃ for 4 hours. Guar gum (50% by weight of the calcined product), graphite powder (10% by weight of the calcined product), and distilled water (0.1% by weight of the calcined product) were added. The mixture was stirred until homogeneous and granulated into particles Φ2mm in diameter and 1-2mm in length. This granulation was then carried out at 200℃~500℃ for 4 hours to obtain catalyst E. The active components, oxides of cobalt, lanthanum, copper, nickel, and cerium, accounted for 95% of the total catalyst mass. A forming agent accounted for 5% of the total catalyst mass.

[0023] Example 6: Preparation of coprecipitation catalyst F Weigh 46.22 g of cobalt acetate tetrahydrate, 61.25 g of lanthanum nitrate hexahydrate, 32.23 g of copper nitrate trihydrate, 33.52 g of nickel acetate tetrahydrate, and 6.42 g of zinc acetate into a flask. Add 500 mL of distilled water and dissolve by stirring in an oil bath at 80 °C. Dissolve 86.81 g of anhydrous sodium carbonate in 500 mL of distilled water. After both are completely dissolved, add the sodium carbonate solution dropwise to the metal salt solution at a constant temperature of 80 °C over 40 minutes. Aging at 80 °C for 4 hours is then carried out. Filter the solution and wash the catalyst with distilled water until the pH reaches 7. Place the catalyst in a 70 °C oven for 24 hours. The dried solid was pulverized into powder and calcined at 200℃~500℃ for 4 hours. Guar gum (50% by weight of the calcined product), graphite powder (10% by weight of the calcined product), and distilled water (0.1% by weight of the calcined product) were added. The mixture was stirred until homogeneous and granulated into particles Φ2mm in diameter and 1-2mm in length. This granulation was then carried out at 200℃~500℃ for 4 hours to obtain catalyst F. The active components, oxides of cobalt, lanthanum, copper, nickel, and zinc, accounted for 96% of the total catalyst mass. The forming agent accounted for 4% of the total catalyst mass.

[0024] Example 7: Synthesis of 1,2-Propanediamine The calcined metal catalyst A (prepared in Example 1) was loaded into the reactor in a volume of 50 mL. The reactor was then assembled, and a nitrogen pressure test was performed to check its airtightness. Hydrogen gas was first introduced for 10 minutes to purge the air from the reactor. The hydrogen volume hourly space velocity was 500 h⁻¹ at atmospheric pressure. -1The reactor was heated at a rate of 2℃ / min until the temperature reached the catalyst reduction temperature of 400℃, and the reduction process took 4 hours. Isopropanolamine liquid was fed at a feed space velocity of 6 h⁻¹. -1 The gas enters a preheating vaporizer for vaporization, with a preheating temperature of 120℃-140℃. Then, isopropanolamine is added to the reactor along with ammonia and hydrogen. The molar ratio of isopropanolamine to liquid ammonia is 1:10, and the molar ratio of isopropanolamine to hydrogen is 1:3. The temperature inside the reactor is controlled at 160℃, and the pressure is 2-4 MPa. After the reaction, the materials were cooled and separated. The synthesized liquid was collected in a liquid phase container, while the gaseous ammonia and hydrogen were recovered from the reaction system and continued to participate in the reaction. Chromatographic analysis of the crude product yielded the following results: conversion of isopropanolamine: 90.17%; selectivity of 1,2-propanediamine: 90.19%; yield of 1,2-propanediamine: 81.32%. The collected crude product was then added to a distillation unit for vacuum distillation separation. The distillation column temperature was controlled at 75°C at the bottom and 61°C at the top, with a reflux ratio of 1.0. The purity of the separated product, 1,2-propanediamine, was 99.16%.

[0025] Example 8: Synthesis of 1,2-Propanediamine The difference from Example 7 is that the reactor heating rate was 10°C / min, the temperature reached the catalyst reduction temperature of 300°C, the reduction lasted for 2 hours, and the liquid isopropanolamine feed space velocity was 1.2 h. -1 The reactor temperature was controlled at 170℃, with all other conditions remaining the same. Chromatographic analysis of the crude product yielded the following results: conversion of isopropanolamine: 91.37%; selectivity of 1,2-propanediamine: 90.96%; yield of 1,2-propanediamine: 83.11%. The collected crude product was then added to a distillation unit for vacuum distillation separation. The distillation column bottom temperature was controlled at 74℃, the top temperature at 62℃, and the reflux ratio at 1.0. The purity of the separated product, 1,2-propanediamine, was 99.26%.

[0026] Example 9: Synthesis of 1,2-Propanediamine The difference from Example 7 is that the reactor heating rate is 5°C / min, the temperature reaches the catalyst reduction temperature of 350°C, the reduction time is 5 hours, and the liquid isopropanolamine feed space velocity is 4 h⁻¹. -1 The reactor temperature was controlled at 180℃, with all other conditions remaining the same. Chromatographic analysis of the crude product yielded the following results: conversion of isopropanolamine: 91.77%; selectivity of 1,2-propanediamine: 92.12%; yield of 1,2-propanediamine: 84.54%. The collected crude product was then added to a distillation unit for vacuum distillation separation. The distillation column bottom temperature was controlled at 77℃, the top temperature at 64℃, and the reflux ratio at 1.0. The purity of the separated product, 1,2-propanediamine, was 99.31%.

[0027] Example 10: Synthesis of 1,2-Propanediamine The difference from Example 7 is that the reactor heating rate is 8°C / min, the temperature reaches the catalyst reduction temperature of 320°C, the reduction time is 2 hours, and the liquid isopropanolamine feed space velocity is 5 h⁻¹. -1 The reactor temperature was controlled at 190℃, with all other conditions remaining the same. Chromatographic analysis of the crude product yielded the following results: conversion of isopropanolamine: 91.51%; selectivity of 1,2-propanediamine: 91%; yield of 1,2-propanediamine: 83.27%. The collected crude product was then subjected to vacuum distillation. The distillation column bottom temperature was controlled at 77℃, the top temperature at 63℃, and the reflux ratio at 1.0. The purity of the separated product, 1,2-propanediamine, was 99.22%.

[0028] Example 11: Synthesis of 1,2-Propanediamine The calcined metal catalyst A (prepared in Example 1) was loaded into the reactor in a 50 mL volume. The reactor was then assembled and pressure tested with nitrogen to check its airtightness. Hydrogen gas was first introduced for 10 minutes to purge air from the reactor. At atmospheric pressure, the hydrogen volume hourly space velocity (HHSV) was 500 h⁻¹. The reactor was heated at a rate of 5 °C / min until the catalyst reduction temperature of 380 °C was reached, and reduction was carried out for 4 hours. Isopropanolamine liquid was then introduced at a feed hourly space velocity (HHSV) of 4 h⁻¹. -1 The product is vaporized in a preheating vaporizer at a preheating temperature of 120℃-140℃. Then, isopropanolamine, ammonia, and hydrogen are added to the reactor. The molar ratio of isopropanolamine to liquid ammonia is 1:9, and the molar ratio of isopropanolamine to hydrogen is 1:3. The reactor temperature is controlled at 180℃, and the pressure is 2-4 MPa. After the reaction, the material is cooled and separated. The liquid phase is collected in a collection tank, while the gaseous ammonia and hydrogen are recovered from the reaction system and continue to participate in the reaction. Chromatographic analysis of the crude product yields the following results: conversion rate of isopropanolamine: 91.47%; selectivity of 1,2-propanediamine: 91.8%; yield of 1,2-propanediamine: 83.97%. The collected crude product is then added to a distillation unit for vacuum distillation separation. The distillation column bottom temperature is controlled at 74℃, the top temperature at 60℃, and the reflux ratio at 1.0. The purity of the separated product, 1,2-propanediamine, is 99.2%.

[0029] Example 12: Synthesis of 1,2-Propanediamine The difference from Example 11 is that: hydrogen gas was first introduced for 20 minutes to purge the air from the reactor; the reactor temperature was increased at a rate of 3°C / min until the catalyst reduction temperature of 450°C was reached; reduction was carried out for 3 hours; the liquid feed space velocity for isopropanolamine was 3 h⁻¹; the molar ratio of isopropanolamine to liquid ammonia was 1:8; and all other conditions were the same. Chromatographic analysis of the crude product yielded the following results: conversion of isopropanolamine: 90.8%; selectivity of 1,2-propanediamine: 91.15%; and yield of 1,2-propanediamine: 82.77%. The collected crude product was then added to a distillation unit for vacuum distillation separation. The distillation column bottom temperature was controlled at 75°C, the top temperature at 60°C, and the reflux ratio at 1.0. The purity of the separated product, 1,2-propanediamine, was 99.03%.

[0030] Example 13: Synthesis of 1,2-Propanediamine The difference from Example 11 is that: hydrogen gas was first introduced for 18 minutes to purge the air from the reactor; the reactor temperature was increased at a rate of 4°C / min until the catalyst reduction temperature of 480°C was reached; reduction was carried out for 5 hours; the liquid feed space velocity for isopropanolamine was 5 h⁻¹; the molar ratio of isopropanolamine to liquid ammonia was 1:7; and all other conditions were the same. Chromatographic analysis of the crude product yielded the following results: conversion of isopropanolamine: 90.1%; selectivity of 1,2-propanediamine: 91.35%; and yield of 1,2-propanediamine: 82.32%. The collected crude product was then added to a distillation unit for vacuum distillation separation. The distillation column bottom temperature was controlled at 77°C, the top temperature at 62°C, and the reflux ratio at 1.0. The purity of the separated product, 1,2-propanediamine, was 99.31%.

[0031] Example 14: Synthesis of 1,2-Propanediamine The difference from Example 11 is that hydrogen gas was first introduced for 13 minutes to purge the air from the reactor, the reactor temperature was increased at a rate of 9°C / min until the catalyst reduction temperature of 330°C was reached, and reduction was carried out for 6 hours. The liquid feed space velocity of isopropanolamine was 1.2 h⁻¹, and the molar ratio of isopropanolamine to liquid ammonia was 1:11. All other conditions were the same. Chromatographic analysis of the crude product yielded the following results: conversion of isopropanolamine: 91.53%; selectivity of 1,2-propanediamine: 91.9%; yield of 1,2-propanediamine: 84.12%. The collected crude product was added to a distillation unit for vacuum distillation separation. The distillation column bottom temperature was controlled at 75°C, the top temperature at 62°C, and the reflux ratio at 1.0. The purity of the separated product, 1,2-propanediamine, was 99.33%.

[0032] Example 15: Synthesis of 1,2-Propanediamine The calcined metal catalyst B (prepared in Example 2) was loaded into the reactor in a 50 mL volume. The reactor was then assembled and pressure tested with nitrogen to check its airtightness. Hydrogen gas was first introduced for 10 minutes to purge air from the reactor. At atmospheric pressure, the hydrogen volume hourly space velocity (HHSV) was 500 h⁻¹. The reactor was heated at a rate of 5 °C / min until the catalyst reduction temperature of 350 °C was reached, and reduction was carried out for 4 hours. The liquid isopropanolamine feed had a HHSV of 4 h⁻¹. -1 The product is vaporized in a preheating vaporizer at a preheating temperature of 120℃-140℃. Monoisopropanolamine, ammonia, and hydrogen are added to the reactor together, with a molar ratio of monoisopropanolamine to liquid ammonia of 1:10 and a molar ratio of monoisopropanolamine to hydrogen of 1:3. The reactor temperature is controlled at 180℃ and the pressure at 2-4 MPa. After reaction, the material is cooled and separated. The liquid phase is collected in a collection tank, while the gaseous ammonia and hydrogen are recovered from the reaction system and continue to participate in the reaction. Chromatographic analysis of the crude product yields the following results: conversion rate of monoisopropanolamine: 91.56%; selectivity of 1,2-propanediamine: 92.23%; yield of 1,2-propanediamine: 84.45%. The collected crude product is then added to a distillation unit for vacuum distillation separation. The distillation column bottom temperature is controlled at 74℃, the top temperature at 62℃, and the reflux ratio at 1.0. The purity of the separated product, 1,2-propanediamine, is 99.45%.

[0033] Example 16: Synthesis of 1,2-Propanediamine The calcined metal catalyst C (prepared in Example 3) was loaded into the reactor in a 50 mL volume. The reactor was then assembled and pressure tested with nitrogen to check its airtightness. Hydrogen gas was first introduced for 20 minutes to purge air from the reactor. At atmospheric pressure, the hydrogen volume hourly space velocity (HHSV) was 500 h⁻¹. The reactor was heated at a rate of 2 °C / min until the catalyst reduction temperature of 300 °C was reached, and reduction was carried out for 2 hours. The liquid isopropanolamine feed had a HHSV of 1.2 h⁻¹. -1 The product is vaporized in a preheating vaporizer at a preheating temperature of 120℃-140℃. Monoisopropanolamine, ammonia, and hydrogen are added to the reactor. The molar ratio of monoisopropanolamine to liquid ammonia is 1:10, and the molar ratio of monoisopropanolamine to hydrogen is 1:3. The reactor temperature is controlled at 180℃, and the pressure is 2-4 MPa. After the reaction, the material is cooled and separated. The liquid phase is collected in a collection tank, while the gaseous ammonia and hydrogen are recovered from the reaction system and continue to participate in the reaction. Chromatographic analysis of the crude product yields the following results: conversion rate of monoisopropanolamine: 94.08%; selectivity of 1,2-propanediamine: 94.94%; yield of 1,2-propanediamine: 89.32%. The collected crude product is then added to a distillation unit for vacuum distillation separation. The distillation column bottom temperature is controlled at 76℃, the top temperature at 60℃, and the reflux ratio at 1.0. The purity of the separated product, 1,2-propanediamine, is 99.5%.

[0034] Example 17: Synthesis of 1,2-Propanediamine The calcined metal catalyst D (prepared in Example 4) was loaded into the reactor in a 50 mL volume. The reactor was then assembled and pressure tested with nitrogen to check its airtightness. Hydrogen gas was first introduced for 15 minutes to purge air from the reactor. At atmospheric pressure, the hydrogen volume hourly space velocity (HHSV) was 500 h⁻¹. The reactor was heated at a rate of 6 °C / min until the catalyst reduction temperature of 400 °C was reached, and reduction was carried out for 5 hours. The liquid isopropanolamine feed had a HHSV of 2 h⁻¹. -1 The product is vaporized in a preheating vaporizer at a preheating temperature of 120℃-140℃. Monoisopropanolamine, ammonia, and hydrogen are added to the reactor. The molar ratio of monoisopropanolamine to liquid ammonia is 1:10, and the molar ratio of monoisopropanolamine to hydrogen is 1:3. The reactor temperature is controlled at 180℃, and the pressure is 2-4 MPa. After the reaction, the material is cooled and separated. The liquid phase is collected in a collection tank, while the gaseous ammonia and hydrogen are recovered from the reaction system and continue to participate in the reaction. Chromatographic analysis of the crude product yields the following results: conversion rate of monoisopropanolamine: 92.38%; selectivity of 1,2-propanediamine: 92.54%; yield of 1,2-propanediamine: 85.49%. The collected crude product is then added to a distillation unit for vacuum distillation separation. The distillation column bottom temperature is controlled at 77℃, the top temperature at 63℃, and the reflux ratio at 1.0. The purity of the separated product, 1,2-propanediamine, is 99.38%.

[0035] Example 18: Synthesis of 1,2-Propanediamine The calcined metal catalyst E (prepared in Example 5) was loaded into the reactor in a volume of 50 mL. The reactor was then assembled, and a nitrogen pressure test was performed to check its airtightness. Hydrogen gas was first introduced for 10 minutes to purge the air from the reactor. The hydrogen volume hourly space velocity was 500 h⁻¹ at atmospheric pressure. -1 The reactor heating rate was 8℃ / min, reaching the catalyst reduction temperature of 450℃, and the reduction process took 6 hours. The liquid isopropanolamine feed space velocity was 5 h⁻¹. -1 The product is vaporized in a preheating vaporizer at a preheating temperature of 120℃-140℃. Monoisopropanolamine, ammonia, and hydrogen are added to the reactor together, with a molar ratio of monoisopropanolamine to liquid ammonia of 1:10 and a molar ratio of monoisopropanolamine to hydrogen of 1:3. The reactor temperature is controlled at 180℃ and the pressure at 2-4 MPa. After reaction, the material is cooled and separated. The liquid phase is collected in a collection tank, while the gaseous ammonia and hydrogen are recovered from the reaction system and continue to participate in the reaction. Chromatographic analysis of the crude product yields the following results: conversion rate of monoisopropanolamine: 96.58%; selectivity of 1,2-propanediamine: 96.55%; yield of 1,2-propanediamine: 93.25%. The collected crude product is then added to a distillation unit for vacuum distillation separation. The distillation column bottom temperature is controlled at 75℃, the top temperature at 62℃, and the reflux ratio at 1.0. The purity of the separated product, 1,2-propanediamine, is 99.62%.

[0036] Example 19: Synthesis of 1,2-Propanediamine The calcined metal catalyst F (prepared in Example 6) was loaded into the reactor in a 50 mL volume. The reactor was then assembled and pressure tested with nitrogen to check its airtightness. Hydrogen gas was first introduced for 12 minutes to purge air from the reactor. At atmospheric pressure, the hydrogen volume hourly space velocity (HHSV) was 500 h⁻¹. The reactor was heated at a rate of 10 °C / min until the catalyst reduction temperature of 480 °C was reached, and reduction was carried out for 3 hours. The liquid isopropanolamine feed had a HHSV of 3 h⁻¹. -1 The product is vaporized in a preheating vaporizer at a preheating temperature of 120℃-140℃. Monoisopropanolamine, ammonia, and hydrogen are added to the reactor. The molar ratio of monoisopropanolamine to liquid ammonia is 1:10, and the molar ratio of monoisopropanolamine to hydrogen is 1:3. The reactor temperature is controlled at 180℃, and the pressure is 2-4 MPa. After the reaction, the material is cooled and separated. The liquid phase is collected in a collection tank, while the gaseous ammonia and hydrogen are recovered from the reaction system and continue to participate in the reaction. Chromatographic analysis of the crude product yields the following results: conversion rate of monoisopropanolamine: 95.28%; selectivity of 1,2-propanediamine: 94.15%; yield of 1,2-propanediamine: 89.71%. The collected crude product is then added to a distillation unit for vacuum distillation separation. The distillation column bottom temperature is controlled at 76℃, the top temperature at 62℃, and the reflux ratio at 1.0. The purity of the separated product, 1,2-propanediamine, is 99.65%.

[0037] Example Using catalysts Isopropanolamine conversion rate 1,2-Propanediamine selectivity 1,2-Propanediamine yield 7 A 90.17% 90.19% 81.32% 8 A 91.37% 90.96% 83.11% 9 A 91.77% 92.12% 84.54% 10 A 91.51% 91% 83.27% 11 A 91.47% 91.8% 83.97% 12 A 90.8% 91.15% 82.77% 13 A 90.1% 91.35% 82.32% 14 A 91.53% 91.9% 84.12% 15 B 91.56% 92.23% 84.45% 16 C 94.08% 94.94% 89.32% 17 D 92.38% 92.54% 85.49% 18 E 96.58% 96.55% 93.25% 19 F 95.28% 94.15% 89.71%

Claims

1. A solid catalyst, characterized in that... The active components are mainly cobalt and lanthanum oxides, and auxiliary active components are one or more oxides of nickel, copper, zinc, cerium and cadmium. The cobalt oxide content is 20-40%, the lanthanum oxide content is 20-40%, and the total content of the auxiliary active components is 20-60%, all of which are weight percentages.

2. The method for preparing the solid catalyst according to claim 1, characterized in that... The soluble metal salts of the main active component and auxiliary active component are prepared into a solution, the precipitant is prepared into a solution, and then the precipitant solution is added dropwise to the soluble metal salt of the active component for aging. After filtration, washing, drying, calcination and molding, the desired catalyst is obtained.

3. The preparation method according to claim 2, characterized in that... The amount of precipitant used is 1-2 times the total molar amount of active metal ions in the active metal oxide solution.

4. The preparation method according to claim 2, characterized in that... The precipitant is selected from metal carbonates, ammonia, or urea.

5. The preparation method according to claim 4, characterized in that... The metal carbonate is sodium carbonate, potassium carbonate, or a mixture thereof, with a molar ratio of 1:3 to 3:

1.

6. The preparation method according to claim 2, characterized in that... The concentration of the soluble metal salt solution of the active component is 0.5-2 mol / L, and the concentration of the precipitant solution is 0.1-1 mol / L.

7. The preparation method according to claim 2, characterized in that... The dropping time of the precipitant is controlled at 30-60 min, and the dropping temperature is 60-120℃.

8. The preparation method according to claim 2, characterized in that... After the precipitant solution is added dropwise, the aging temperature is 60-120℃, and the aging time is 2-12 hours.

9. The preparation method according to claim 2, characterized in that... The drying temperature is 60-90℃, and the drying time is 12-48h; the calcination temperature is 200-500℃, and the time is 4-8h; the molding is based on the mass of the calcined product, adding 50% guar gum, 10% graphite powder, and 0.1% distilled water, stirring evenly and granulating into Φ2mm particles with a length of 1-2mm, and then calcining at 200℃~500℃ for 4-6 hours.

10. A method for synthesizing 1,2-propanediamine using the catalyst of claim 1, characterized in that... Includes the following steps: Solid catalyst is loaded into the reactor of a continuous synthesis unit. After assembling the reactor, reducing gas is first introduced to purge air from the reactor. The temperature is then programmed to rise to the reduction temperature and allow the catalyst to be fully reduced. Isopropanolamine is preheated in a preheating vaporizer and then introduced into the reactor along with liquid ammonia and hydrogen for the synthesis reaction. After the synthesis reaction, the materials are cooled and separated. The liquid phase is collected in a liquid tank, while the gaseous ammonia and hydrogen are recovered from the reaction system and continue to participate in the reaction. The synthesis liquid is then separated by vacuum distillation to obtain high-purity 1,2-propanediamine product. The programmed heating refers to heating at a rate of 2-10℃ / min, heating to 300-480℃ and then holding at that temperature for 2-6 hours; the preferred heating rate is 5℃ / min, the preferred heating temperature is 350℃, and the preferred holding time is 4 hours; the preheating temperature is 120℃-140℃.

11. The synthesis method according to claim 10, characterized in that... The time for the reducing gas to replace the air in the reactor is 10-20 minutes. The reducing gas is hydrogen, a hydrogen / argon mixture, or a hydrogen / nitrogen mixture. The reduction condition is a hydrogen volume hourly space velocity of 500 h⁻¹ at atmospheric pressure.

12. The synthesis method according to claim 11, characterized in that... During the synthesis reaction, the molar ratio of isopropanolamine to liquid ammonia is 1:7-11, the molar ratio of isopropanolamine to hydrogen is 1:3-10, the liquid feed space velocity of isopropanolamine is 1.2-6 h⁻¹, the reaction temperature is 160℃-200℃, and the reaction pressure is 2-4 MPa.

13. The synthesis method according to claim 11, characterized in that... During the vacuum distillation, the bottom temperature of the column is 65℃~80℃, the top temperature is 60℃~73℃, and the distillation reflux ratio is 2:3-1:1.