Preparation method of diamine

Abstract

The invention discloses a preparation method of diamine, which comprises the following steps: reacting raw materials in a gas atmosphere containing ammonia gas and hydrogen to obtain the diamine, wherein the raw materials comprise dinitrile and a supported nickel-based catalyst; the reaction pressure is 2 to 10 MPa; the reaction temperature is 50-110 DEG C; the method solves the problems of solvent and product separation, high energy consumption, long process route, potential safety hazard and the like caused by the use of the solvent in the existing diamine preparation method. The preparation method of diamine provided by the invention has the advantages of few operation steps, energy and resource conservation, safety and the like on the premise of realizing efficient conversion of dinitrile and preparing diamine with relatively high purity, and is beneficial to realizing industrial production of diamine.

Description

Technical Field

[0001] The invention relates to a method for preparing diamine. Background Art

[0002] Long-chain diamines (straight-chain diamines with 8 to 20 carbon atoms) are often used to prepare long-chain polyamide materials, such as decanediamine (with 10 carbon atoms) for preparing nylon 1010, nylon 1012, nylon 10T, etc., and dodecanediamine can be used to prepare nylon 1210, nylon 1212, nylon 12T, etc. In addition to the good mechanical properties, wear resistance, lubricity, solvent resistance and molding processability of ordinary nylon, long-chain polyamides also have the characteristics of low water absorption, good dimensional stability, good toughness and softness, excellent wear resistance, and excellent electrochemical properties. Therefore, long-chain polyamides are widely used in automobile brake pipes, oil pipes, bearings, anti-vibration parts, etc. in the automotive field, high-voltage circuit breakers, relay switches, transformers, wire and cable protection materials, etc. in the electrical and electronic fields, and can be used in toothbrush filaments, medical and food packaging materials, clothing, etc. in the civilian field. Due to its wide range of applications and long-term market prospects, the production technology of long-chain diamines has attracted widespread attention from academia and the business community.

[0003] Hu Guosheng's project at North University of China (Pan Yu. Research on the synthesis process and application of decanediamine [D]. Supervisor: Hu Guosheng. North University of China, 2014. Xing Ke. Research on the reaction of long-chain dibasic acids to prepare diamines [D]. North University of China, 2015.) used a kettle reactor to explore the process of hydrogenating decanedinitrile and dodecanedinitrile to prepare decanediamine and dodecanediamine. Among them, sebacate is used as a raw material, the amount of ethanol used is 1.1:1 relative to the mass ratio of sebacate, the potassium hydroxide is 0.6% relative to the mass of sebacate, the catalyst is Raney nickel, the mass ratio is 15% of the mass of sebacate, the hydrogen pressure is 2.1MPa, the stirring speed is 600r / min, the temperature is controlled at 70-95°C, the product is subjected to reduced pressure distillation, and the yield of dodecanediamine is 92%; dodecanedinitrile is used as a raw material, 1.1 times the mass ratio of ethanol is used, 0.8% potassium hydroxide is used as an inhibitor relative to the mass of dodecanedinitrile, the catalyst is Raney nickel, the mass ratio is 15% of the mass of dodecanedinitrile, the hydrogen pressure is 2.1MPa, the stirring speed is 800r / min, the temperature is controlled at 110°C, the catalyst is subsequently filtered to remove the catalyst, the ethanol is distilled to remove the ethanol, the product is subjected to reduced pressure distillation, and the yield of dodecanedinitrile is 92%.

[0004] The research group of Zhu Weihong / Lu Zhongjie from East China University of Science and Technology used a kettle reactor, sebacate as raw material, 10% Raney nickel relative to the mass of sebacate as catalyst, 0.5-1% potassium hydroxide relative to the mass of sebacate as inhibitor, reaction temperature of 70-90°C, reaction pressure of 2.5MPa, stirring speed of 1000r / min, and ethanol in a 1:1 ratio relative to the mass of sebacate. The catalyst was subsequently removed by filtration and the ethanol was distilled off. The product was subjected to reduced pressure distillation to obtain decanediamine with a molar yield of greater than 96.5% and a purity of greater than 99%.

[0005] The Chinese patent (CN101068775B) uses a bath slurry bed reactor, 1,8-octanedionitrile as a raw material, Raney nickel as a catalyst, a small amount of water as a solvent, tetramethylammonium hydroxide as an inhibitor, and reacts at 75°C under a hydrogen pressure of 2.76 MPa to obtain 1,8-octanediamine with a purity of 96.6%. The conversion rate of suberonitrile is 100%.

[0006] Chinese patent (CN111875501A) discloses a multi-stage continuous kettle reactor, which uses Raney nickel as a catalyst, ethanol as a solvent, 2.3MPa hydrogen pressure, and 90°C to catalytically hydrogenate sebacate, and can obtain decanediamine with a molar yield of 98.2%.

[0007] A Chinese patent (CN106748806A) discloses the use of a modified supported Ni-Co-Pd catalyst, aliphatic dinitriles and hydrogen as raw materials, dialkoxymethane as solvent, and the subsequent use of a fluidized bed reactor to achieve the preparation of suberonitrile, sebacate, dodecanedinitrile, tetradecanedinitrile, hexadecanedinitrile, and octadecanedinitrile, with a product purity of >98%.

[0008] Based on the above background technology, alcohol, ether, etc. are more or less used as organic solvents in the reaction process, and alkali is used as a reaction inhibitor to inhibit the generation of reaction by-products. However, in the subsequent processing process, it is inevitable to face problems such as separation of solvent and product, solvent recycling, and solvent recovery efficiency. In particular, small molecule organic solvents represented by ethanol (flash point 13°C) and dimethoxymethane (flash point ~18°C) have a flash point lower than room temperature, are flammable and explosive, and have great safety hazards. Therefore, the inventors have developed a solvent-free long-chain diamine synthesis process. Summary of the invention

[0009] The present invention aims to overcome the problems of separation of solvent and product, high energy consumption, long process route and potential safety hazards caused by the use of organic solvents in the process of preparing diamines from dinitriles in the prior art. A method for preparing diamines is provided. The method can achieve efficient conversion of dinitriles and obtain diamines with higher purity while avoiding the use of solvents in the preparation of diamines, thereby avoiding subsequent solvent recovery and solvent separation processes. The method has the advantages of low energy consumption, short process route and high safety.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions.

[0011] The present invention provides a method for preparing a diamine, comprising the following steps: reacting raw materials in a gas atmosphere containing ammonia and hydrogen to obtain the diamine; wherein:

[0012] The raw materials are composed of dinitriles and supported nickel-based catalysts;

[0013] The reaction pressure is 2.0-10.0 MPa;

[0014] The reaction temperature is 50-110°C.

[0015] In the present invention, the gas atmosphere can be obtained in a conventional manner in the art. Preferably, the gas atmosphere is formed by first removing air and then introducing ammonia and hydrogen.

[0016] The method of removing air may be conventional in the art, preferably using nitrogen and ammonia to replace the air in sequence, and then evacuating the air.

[0017] Preferably, the gas atmosphere is formed by first introducing ammonia and then introducing hydrogen.

[0018] Wherein, after the ammonia gas is introduced, the gas pressure is preferably 0.1-2.0 MPa, for example, 0.3 MPa, 0.5 MPa, 1.0 MPa or 2.0 MPa.

[0019] Wherein, after the hydrogen is introduced, the gas pressure is preferably 2.0 to 10.0 MPa.

[0020] The hydrogen is preferably introduced in n times, where n≥1 and n is an integer.

[0021] Preferably, when n≥2, the gas pressure is 2.0-4.0 MPa after the first hydrogen introduction, and 3.0-10.0 MPa after each subsequent hydrogen introduction. The time interval between each two hydrogen introductions is not particularly limited, and can be, for example, 1-50 hours.

[0022] Preferably, the reaction temperature is raised to 50-110° C. after the first introduction of hydrogen.

[0023] In some specific embodiments, n can be any one of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0024] In some specific embodiments, the hydrogen is introduced twice, the first time the hydrogen is introduced, the pressure is 2.0-4.0 MPa; the temperature is controlled at 50-110° C., the second time the hydrogen is introduced, the pressure is 3.0-10.0 MPa.

[0025] In some specific embodiments, the hydrogen is introduced in 2 to 10 times, the first time hydrogen is introduced, the pressure is 2.0 to 4.0 MPa; the temperature is controlled at 50 to 110° C., and the second to tenth times hydrogen is introduced with an interval of 5 to 35 hours, and the pressure is 3.0 to 10.0 MPa.

[0026] In some specific embodiments, the hydrogen is introduced in 2 to 8 times, the first time hydrogen is introduced, the pressure is 2.0 to 4.0 MPa; the temperature is controlled at 50 to 110° C., and the second to eighth times hydrogen is introduced with an interval of 5 to 15 hours, and the pressure is 3.0 to 10.0 MPa.

[0027] Specifically, for example, the hydrogen is introduced in 5 times. After the first introduction of hydrogen, the gas pressure is 2.0-4.0 MPa; the second, third, fourth, and fifth times of hydrogen are introduced with an interval of 10-15 hours between each two times, and the gas pressure is 3.0-10.0 MPa.

[0028] In a specific embodiment, the hydrogen is introduced in 5 times. After the first introduction of hydrogen, the gas pressure is 3.0 MPa; the second, third, fourth and fifth times of hydrogen are introduced with an interval of 12 hours each, and the gas pressure is 8.0 MPa.

[0029] In a specific embodiment, the hydrogen is introduced in 4 times. After the first introduction of hydrogen, the gas pressure is 3.0 MPa; the second, third and fourth times of hydrogen are introduced with an interval of 6 hours, and the gas pressure is 8.0 MPa.

[0030] In a specific embodiment, the hydrogen is introduced in three times. After the first introduction of hydrogen, the gas pressure is 3.0 MPa; the second and third introductions of hydrogen are separated by 6 hours, and the gas pressure is 8.0 MPa.

[0031] In a specific embodiment, the hydrogen is introduced once, and after the hydrogen is introduced, the gas pressure is 3.0 MPa.

[0032] In a specific embodiment, the hydrogen is introduced in 5 times. After the first introduction of hydrogen, the gas pressure is 3.0 MPa; the second, third, fourth and fifth times of hydrogen are introduced with an interval of 12 hours each, and the gas pressure is 6.0 MPa.

[0033] In a specific embodiment, the hydrogen is introduced in 5 times. After the first introduction of hydrogen, the gas pressure is 3.0 MPa; the second, third, fourth and fifth times of hydrogen are introduced with an interval of 12 hours each, and the gas pressure is 3.0 MPa.

[0034] In a specific embodiment, the hydrogen is introduced in three times. After the first introduction of hydrogen, the gas pressure is 3.0 MPa; the second and third introductions of hydrogen are separated by 5 hours, and the gas pressure is 10.0 MPa.

[0035] In a specific embodiment, the hydrogen is introduced in three times. After the first introduction of hydrogen, the gas pressure is 3.0 MPa; the second and third introductions of hydrogen are separated by 5 hours, and the gas pressure is 8.0 MPa.

[0036] In a specific embodiment, the hydrogen is introduced in three times. After the first introduction of hydrogen, the gas pressure is 3.0 MPa; the second and third introductions of hydrogen are separated by 5 hours, and the gas pressure is 3.0 MPa.

[0037] In the present invention, the ammonia gas may be derived from any one of ammonia gas produced by a synthetic ammonia process, an ammonia water distillation process, and a waste ammonia recovery process.

[0038] In the present invention, the reaction temperature is preferably 80-100°C, for example 90°C.

[0039] In the present invention, the reaction pressure is preferably 7.0-9.0 MPa, for example 8.0 MPa.

[0040] In the present invention, the reaction time may be 1 to 70 hours, further 10 to 66 hours, for example 16 hours, 24 hours, or 66 hours.

[0041] In some specific embodiments, the method for preparing the diamine comprises the following steps: placing a fatty dinitrile and a supported nickel-based catalyst in a closed reactor, introducing ammonia at a pressure of 0.1 to 2.0 MPa, introducing hydrogen at a pressure of 2.0 to 10.0 MPa, controlling the temperature to 50 to 110° C., reacting for 1 to 70 hours, returning to room temperature, and separating the product to obtain the diamine.

[0042] In some specific embodiments, the preparation method of the diamine comprises the following steps: placing a fatty dinitrile and a supported nickel-based catalyst in a closed reactor, introducing ammonia at a pressure of 0.1 to 2.0 MPa, introducing hydrogen at a pressure of 2.0 to 4.0 MPa, controlling the temperature at 50 to 110° C., continuing to introduce hydrogen at a pressure of 3.0 to 10.0 MPa, reacting for 1 to 70 hours, returning to room temperature, and separating the product to obtain the diamine.

[0043] In the present invention, the closed reactor is preferably a reactor, more preferably a high-pressure reactor.

[0044] In the present invention, the dinitrile may be conventional in the art, preferably a fatty dinitrile, and more preferably, the fatty dinitrile has the molecular formula: NC(CH2) n CN, n is any integer from 6 to 18, for example, n is 6, 8, 10, 11 or 14. Wherein, when n is 6, the fatty dinitrile is suberonitrile; when n is 8, the fatty dinitrile is sebacic dinitrile; when n is 10, the fatty dinitrile is dodecanedinitrile (i.e., lauric dinitrile); when n is 11, the fatty dinitrile is tridecanedinitrile; when n is 14, the fatty dinitrile is hexadecane dinitrile.

[0045] In the present invention, the dinitrile may be a dinitrile having one carbon number or a mixture of dinitrile having multiple carbon numbers.

[0046] In the present invention, the diamine is preferably a straight-chain diamine having 8 to 20 carbon atoms. That is, the molecular formula of the diamine is preferably NH2(CH2) n+2 NH2, n is any integer from 6 to 18.

[0047] In the present invention, the weight percentage of the supported nickel-based catalyst in the raw material is preferably 1% to 25%, for example, 4.8%, 13% or 20%.

[0048] In the present invention, the supported nickel-based catalyst at least comprises nickel and a carrier.

[0049] In the present invention, the supported nickel-based catalyst preferably contains nickel, a modified metal and a carrier.

[0050] Preferably, the weight content of nickel is 30% to 80%, the weight content of the modified metal is 2% to 12%, and the rest is the carrier.

[0051] Wherein, the modified metal may be at least one of Li, Na, K, Be, Mg, Ca, Cu, Co, Cr, Zr, Mo, Zn, Cd, Ru, Rh, Pd and Pt. Preferably, the modified metal is magnesium and sodium. Preferably, the modified metal is chromium and sodium.

[0052] In the present invention, the carrier of the supported nickel-based catalyst can be selected from at least one of alumina, silicon oxide, diatomaceous earth, activated carbon, molecular sieve and zeolite.

[0053] More preferably, the carrier is silicon oxide and / or diatomaceous earth.

[0054] In a more preferred embodiment of the present invention, the supported nickel-based catalyst contains nickel, magnesium, sodium and a carrier. Preferably, the weight content of nickel is 30% to 80%, the weight content of magnesium and sodium is 2% to 12%, and the rest is the carrier. Preferably, the weight content of magnesium is 2% to 10%, and the weight content of sodium is 1% to 5%.

[0055] In another more preferred embodiment of the present invention, the supported nickel-based catalyst contains nickel, chromium, sodium and a carrier. Preferably, the weight content of nickel is 30% to 80%, the weight content of chromium and sodium is 2% to 12%, and the rest is the carrier. Preferably, the weight content of chromium is 2% to 10%, and the weight content of sodium is 1% to 5%.

[0056] In the present invention, the nickel in the supported nickel-based catalyst is preferably present in the form of metallic nickel and nickel oxide.

[0057] In the present invention, when the supported nickel-based catalyst contains magnesium, the magnesium is preferably present in the form of magnesium oxide. When the supported nickel-based catalyst contains sodium, the sodium is preferably present in the form of sodium oxide. When the supported nickel-based catalyst contains chromium, the chromium is preferably present in the form of metallic chromium and chromium oxide.

[0058] In the present invention, the supported nickel-based catalyst can be prepared by conventional methods in the art, preferably by coprecipitation. Specifically, the supported nickel-based catalyst is prepared by mixing a raw metal salt solution and a carrier and coprecipitating.

[0059] Wherein, the metal salt preferably includes at least one of nickel nitrate, magnesium nitrate, chromium nitrate and sodium carbonate.

[0060] In a preferred embodiment of the present invention, the supported nickel-based catalyst is prepared by mixing nickel nitrate, magnesium nitrate and sodium carbonate with water, and then adding silicon oxide and / or diatomaceous earth for co-precipitation.

[0061] In another preferred embodiment of the present invention, the supported nickel-based catalyst is prepared by mixing nickel nitrate, chromium nitrate and sodium carbonate with water, and then adding silicon oxide and / or diatomaceous earth for co-precipitation.

[0062] In the present invention, after the reaction is completed, it is preferred that the steps of decompression and residual gas recovery are further included.

[0063] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0064] The reagents and raw materials used in the present invention are commercially available.

[0065] The positive and progressive effects of the present invention are:

[0066] The preparation method of the diamine provided by the present invention can realize the efficient conversion of dinitriles (conversion rate is above 88%) without using organic solvents, and obtain diamines with high purity (purity is above 83%); at the same time, the product loss, pollution and energy consumption caused by the recovery of organic solvents can be avoided, and the characteristics of saving energy and resources and reducing the operation steps are achieved, which is conducive to the industrial production of diamines (especially long carbon chain diamines). DETAILED DESCRIPTION

[0067] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0068] The preparation method of the catalyst used in the following examples is as follows:

[0069] Catalyst A: At room temperature, 1820g of nickel nitrate and 142g of magnesium nitrate were dissolved in 10L of water, and 1050g of sodium carbonate solvent was added to 10L of water. Under vigorous stirring, the nickel-containing solution was added dropwise to the sodium carbonate solution, and 200g of diatomaceous earth was added. After the addition was completed, the mixture was stirred for 3h and filtered. The resulting filter cake was dispersed in 5L of 0.25% NaOH solution, stirred for 2h, filtered, and the filter cake was dried to obtain catalyst powder. The catalyst was granulated to obtain a crude catalyst, which was heated and activated under H2 atmosphere before use.

[0070] Catalyst B: At room temperature, 1820g of nickel nitrate and 119g of chromium nitrate were dissolved in 10L of water, and 1050g of sodium carbonate solvent was added to 10L of water. Under vigorous stirring, the nickel-containing solution was added dropwise to the sodium carbonate solution, and 200g of diatomaceous earth was added. After the addition was completed, the mixture was stirred for 3h and filtered. The resulting filter cake was dispersed in 5L of 0.25% NaOH solution, stirred for 2h, filtered, and the filter cake was dried to obtain catalyst powder. The catalyst was granulated to obtain a crude catalyst, which was heated and activated under H2 atmosphere before use.

[0071] Catalyst C: At room temperature, 1820g of nickel nitrate was dissolved in 10L of water. Separately, 1050g of sodium carbonate solvent was mixed with 10L of water. Under vigorous stirring, the solution containing nickel was added dropwise to the sodium carbonate solution. 200g of diatomaceous earth was added. After the addition was completed, the mixture was stirred for 3h and filtered. The resulting filter cake was dispersed in 5L of 0.25% NaOH solution. The mixture was stirred for 2h and filtered. The filter cake was dried to obtain catalyst powder. The catalyst was granulated to obtain a crude catalyst, which was activated by heating under H2 atmosphere before use.

[0072] The pressure mentioned in the following examples and comparative examples is the atmospheric pressure.

[0073] Example 1

[0074] At room temperature, 20g of sebacate and 1g of catalyst A were added to the reactor, nitrogen was used to replace the gas in the autoclave for 3 times, the nitrogen inlet valve was closed, the autoclave was evacuated to vacuum, ammonia was introduced to make the pressure in the autoclave reach 1.0MPa, and the ammonia inlet valve was closed. Hydrogen was introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve was closed. The heating system of the reactor was turned on to keep the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve was adjusted 4 times at intervals of 12h to replenish hydrogen, and the pressure in the autoclave was kept at 8.0MPa. After reacting for 66h, the heating was stopped, the reaction was restored to room temperature, the residual gas in the autoclave was recovered, and the white waxy solid obtained by separating the catalyst from the product was the target product, decanediamine. The purity of decanediamine was 97.1%, and the conversion rate of decanediamine was 100%.

[0075] Example 2

[0076] At room temperature, 20g of decanedinitrile and 3g of catalyst A are added to the reactor, nitrogen is used to replace the gas in the autoclave for 3 times, the nitrogen inlet valve is closed, the autoclave is evacuated to vacuum, ammonia is introduced to make the pressure in the autoclave reach 1.0MPa, and the ammonia inlet valve is closed. Hydrogen is introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve is closed. The heating system of the reactor is turned on to keep the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve is adjusted 3 times at intervals of 6h to replenish hydrogen, and the pressure in the autoclave is kept at 8.0MPa. After reacting for 24h, the heating is stopped, the reaction is restored to room temperature, the residual gas in the autoclave is recovered, and the white waxy solid obtained by separating the catalyst from the product is the target product decanediamine. The purity of decanediamine is 97.3%, and the conversion rate of decanedinitrile is 100%.

[0077] Example 3

[0078] At room temperature, 20g of sebacate and 5g of catalyst A were added to the reactor, nitrogen was used to replace the gas in the autoclave for 3 times, the nitrogen inlet valve was closed, the autoclave was evacuated to vacuum, ammonia was introduced to make the pressure in the autoclave reach 1.0MPa, and the ammonia inlet valve was closed. Hydrogen was introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve was closed. The heating system of the reactor was turned on to keep the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve was adjusted twice at an interval of 6h to replenish hydrogen, and the pressure in the autoclave was kept at 8.0MPa. After reacting for 16h, the heating was stopped, the reaction was restored to room temperature, the residual gas in the autoclave was recovered, and the white waxy solid obtained by separating the catalyst from the product was the target product, decanediamine. The purity of decanediamine was 97.3%, and the conversion rate of decanediamine was 100%.

[0079] Example 4

[0080] At room temperature, 20g of lauric dinitrile and 1g of catalyst A were added to the reactor, nitrogen was replaced in the autoclave for 3 times, the nitrogen inlet valve was closed, the autoclave was evacuated to vacuum, ammonia was introduced to make the pressure in the autoclave reach 1.0MPa, and the ammonia inlet valve was closed. Hydrogen was introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve was closed. The heating system of the reactor was turned on to keep the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve was adjusted 4 times at intervals of 12h to replenish hydrogen, and the pressure in the autoclave was kept at 8.0MPa. After 66h of reaction, the heating was stopped, the reaction was restored to room temperature, the residual gas in the autoclave was recovered, and the white waxy solid obtained by separating the catalyst from the product was the target product, lauric diamine. The purity of lauric diamine was 98.3%, and the conversion rate of lauric dinitrile was 100%.

[0081] Example 5

[0082] At room temperature, 20g of tridecanil and 1g of catalyst A were added to the reactor, nitrogen was used to replace the gas in the autoclave 3 times, the nitrogen inlet valve was closed, the autoclave was evacuated to vacuum, ammonia was introduced to make the pressure in the autoclave reach 1.0MPa, and the ammonia inlet valve was closed. Hydrogen was introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve was closed. The heating system of the reactor was turned on to keep the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve was adjusted 4 times at intervals of 12h to replenish hydrogen, and the pressure in the autoclave was kept at 8.0MPa. After reacting for 66h, the heating was stopped, the reaction was restored to room temperature, the residual gas in the autoclave was recovered, and the white waxy solid obtained by separating the catalyst from the product was the target product tridecanil. The purity of tridecanil was 97.1%, and the conversion rate of tridecanil was 98%.

[0083] Example 6

[0084] At room temperature, 20g of hexadecane dinitrile and 1g of catalyst A are added to the reactor, nitrogen is used to replace the gas in the autoclave 3 times, the nitrogen inlet valve is closed, the autoclave is evacuated to vacuum, ammonia is introduced to make the pressure in the autoclave reach 1.0MPa, and the ammonia inlet valve is closed. Hydrogen is introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve is closed. The reactor heating system is turned on to keep the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve is adjusted 4 times at intervals of 12h to replenish hydrogen, and the pressure in the autoclave is kept at 8.0MPa. After reacting for 66h, the heating is stopped, the reaction is restored to room temperature, the residual gas in the autoclave is recovered, and the white waxy solid obtained by separating the catalyst from the product is the target product hexadecane diamine. The purity of hexadecane diamine is 98.5%, and the conversion rate of hexadecane dinitrile is 97%.

[0085] Example 7

[0086] At room temperature, 20g of sebacate and 1g of catalyst A were added to the reactor, nitrogen was replaced with gas in the autoclave 3 times, the nitrogen inlet valve was closed, the autoclave was evacuated to vacuum, ammonia was introduced to make the pressure in the autoclave reach 0.5MPa, and the ammonia inlet valve was closed. Hydrogen was introduced to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve was closed. The heating system of the reactor was turned on to keep the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve was adjusted to supplement hydrogen, and the pressure in the autoclave was kept at 8.0MPa. After the reaction was completed for 66h, the heating was stopped, and the reaction was restored to room temperature. The remaining gas in the autoclave was recovered, and the white waxy solid obtained by separating the catalyst from the product was the target product, decanediamine. The purity of decanediamine was 92.5%, and the conversion rate of decanediamine was 100%.

[0087] Example 8

[0088] At room temperature, 20g of sebacate and 1g of catalyst A were added to the reactor, nitrogen was replaced with gas in the autoclave 3 times, the nitrogen inlet valve was closed, the autoclave was evacuated to vacuum, ammonia was introduced to make the pressure in the autoclave reach 0.3MPa, and the ammonia inlet valve was closed. Hydrogen was introduced to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve was closed. The heating system of the reactor was turned on to keep the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve was adjusted to supplement hydrogen, and the pressure in the autoclave was kept at 8.0MPa. After the reaction was completed for 66h, the heating was stopped, and the reaction was restored to room temperature. The remaining gas in the autoclave was recovered, and the white waxy solid obtained by separating the catalyst from the product was the target product, decanediamine. The purity of decanediamine was 83.1%, and the conversion rate of decanediamine was 100%.

[0089] Example 9

[0090] At room temperature, 20g of sebacate and 1g of catalyst A were added to the reactor, nitrogen was used to replace the gas in the autoclave for 3 times, the nitrogen inlet valve was closed, the autoclave was evacuated to vacuum, ammonia was introduced to make the pressure in the autoclave reach 1.0MPa, and the ammonia inlet valve was closed. Hydrogen was introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve was closed. The heating system of the reactor was turned on to keep the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve was adjusted 4 times at intervals of 12h to replenish hydrogen, and the pressure in the autoclave was kept at 6.0MPa. After reacting for 66h, the heating was stopped, the reaction was restored to room temperature, the residual gas in the autoclave was recovered, and the white waxy solid obtained by separating the catalyst from the product was the target product, decanediamine. The purity of decanediamine was 96.2%, and the conversion rate of decanediamine was 91%.

[0091] Example 10

[0092] At room temperature, 20g of sebacate and 1g of catalyst A were added to the reactor, nitrogen was used to replace the gas in the autoclave for 3 times, the nitrogen inlet valve was closed, the autoclave was evacuated to vacuum, the reactor heating system was turned on, the temperature was maintained at 60°C, the pressure in the reactor reached 2.0MPa, and the ammonia inlet valve was closed. Hydrogen was introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve was closed. The reactor heating system was turned on to maintain the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve was adjusted 4 times at intervals of 12h to replenish hydrogen, and the pressure in the reactor was maintained at 8.0MPa. After reacting for 66h, the heating was stopped, the reaction was restored to room temperature, the residual gas in the autoclave was recovered, and the white waxy solid obtained by separating the catalyst from the product was the target product, decanediamine. The purity of decanediamine was 97.5%, and the conversion rate of decanediamine was 88%.

[0093] Embodiment 11

[0094] At room temperature, 20g of sebacate and 1g of catalyst A were added to the reactor, nitrogen was used to replace the gas in the autoclave for 3 times, the nitrogen inlet valve was closed, the autoclave was evacuated to vacuum, ammonia was introduced to make the pressure in the autoclave reach 1.0MPa, and the ammonia inlet valve was closed. Hydrogen was introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve was closed. The heating system of the reactor was turned on to keep the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve was adjusted 4 times at intervals of 12h to replenish hydrogen, and the pressure in the autoclave was kept at 3MPa. After reacting for 16h, the heating was stopped, the reaction was restored to room temperature, the residual gas in the autoclave was recovered, and the white waxy solid obtained by separating the catalyst from the product was the target product, decanediamine. The purity of decanediamine was 95.2%, and the conversion rate of decanediamine was 100%.

[0095] Example 12

[0096] At room temperature, 20g of decanedinitrile and 5g of catalyst A were added to the reactor, nitrogen was used to replace the gas in the autoclave for 3 times, the nitrogen inlet valve was closed, the autoclave was evacuated to vacuum, ammonia was introduced to make the pressure in the autoclave reach 1.0MPa, and the ammonia inlet valve was closed. Hydrogen was introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve was closed. The heating system of the reactor was turned on to keep the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve was adjusted twice at an interval of 5h to replenish hydrogen, and the pressure in the autoclave was kept at 10MPa. After reacting for 16h, the heating was stopped, the reaction was restored to room temperature, the residual gas in the autoclave was recovered, and the white waxy solid obtained by separating the catalyst from the product was the target product, decanediamine. The purity of decanediamine was 96.7%, and the conversion rate of decanedinitrile was 100%.

[0097] Embodiment 13

[0098] At room temperature, 20g of decanedinitrile and 5g of catalyst A were added to the reactor, nitrogen was used to replace the gas in the autoclave for 3 times, the nitrogen inlet valve was closed, the autoclave was evacuated to vacuum, ammonia was introduced to make the pressure in the autoclave reach 1.0MPa, and the ammonia inlet valve was closed. Hydrogen was introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve was closed. The heating system of the reactor was turned on to keep the temperature at 50°C. After reaching the temperature, the hydrogen inlet valve was adjusted twice at an interval of 5h to supplement hydrogen, and the pressure in the autoclave was kept at 8MPa. After reacting for 16h, the heating was stopped, the reaction was restored to room temperature, the residual gas in the autoclave was recovered, and the white waxy solid obtained by separating the catalyst from the product was the target product, decanediamine. The purity of decanediamine was 98.5%, and the conversion rate of decanedinitrile was 72%.

[0099] Embodiment 14

[0100] At room temperature, 20g of decanedinitrile and 5g of catalyst A were added to the reactor, nitrogen was used to replace the gas in the autoclave for 3 times, the nitrogen inlet valve was closed, the autoclave was evacuated to vacuum, ammonia was introduced to make the pressure in the autoclave reach 1.0MPa, and the ammonia inlet valve was closed. Hydrogen was introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve was closed. The heating system of the reactor was turned on to keep the temperature at 110°C. After reaching the temperature, the hydrogen inlet valve was adjusted twice at an interval of 5h to supplement hydrogen, and the pressure in the autoclave was kept at 8MPa. After reacting for 16h, the heating was stopped, the reaction was restored to room temperature, the residual gas in the autoclave was recovered, and the white waxy solid obtained by separating the catalyst from the product was the target product, decanediamine. The purity of decanediamine was 93.7%, and the conversion rate of decanedinitrile was 100%.

[0101] Embodiment 15

[0102] At room temperature, 20g of decanedinitrile and 5g of catalyst B are added to the reactor, nitrogen is used to replace the gas in the autoclave for 3 times, the nitrogen inlet valve is closed, the autoclave is evacuated to vacuum, ammonia is introduced to make the pressure in the autoclave reach 1.0MPa, and the ammonia inlet valve is closed. Hydrogen is introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve is closed. The heating system of the reactor is turned on to keep the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve is adjusted twice at an interval of 5h to replenish hydrogen, and the pressure in the autoclave is kept at 3MPa. After reacting for 16h, the heating is stopped, the reaction is restored to room temperature, the residual gas in the autoclave is recovered, and the white waxy solid obtained by separating the catalyst from the product is the target product decanediamine. The purity of decanediamine is 81.6%, and the conversion rate of decanedinitrile is 100%.

[0103] Example 16

[0104] At room temperature, 20g of sebacate and 5g of catalyst C are added to the reactor, nitrogen is used to replace the gas in the autoclave for 3 times, the nitrogen inlet valve is closed, the autoclave is evacuated to vacuum, ammonia is introduced to make the pressure in the autoclave reach 1.0MPa, and the ammonia inlet valve is closed. Hydrogen is introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve is closed. The heating system of the reactor is turned on to keep the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve is adjusted twice at an interval of 5h to supplement hydrogen, and the pressure in the autoclave is kept at 3MPa. After reacting for 16h, the heating is stopped, the reaction is restored to room temperature, the residual gas in the autoclave is recovered, and the white waxy solid obtained by separating the catalyst from the product is the target product, decanediamine. The purity of decanediamine is 75.4%, and the conversion rate of decanediamine is 100%.

[0105] Comparative Example 1

[0106] At room temperature, 20g of sebacate and 1g of catalyst A were added to the reactor, nitrogen was used to replace the gas in the autoclave for 3 times, the nitrogen inlet valve was closed, the autoclave was evacuated to vacuum, hydrogen was introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve was closed. The reactor heating system was turned on to maintain the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve was adjusted 4 times at intervals of 12h to replenish hydrogen, and the pressure in the reactor was maintained at 3.0MPa. After reacting for 66h, the heating was stopped, and the reaction was restored to room temperature. The remaining gas in the autoclave was recovered, and the white waxy solid obtained by separating the catalyst from the product was the target product, decanediamine. The purity of decanediamine was 73.4%, and the conversion rate of decanediamine was 67%.

[0107] Comparative Example 2

[0108] At room temperature, 20g of sebacate and 1g of catalyst A were added to the reactor, nitrogen was used to replace the gas in the autoclave for 3 times, the nitrogen inlet valve was closed, the autoclave was evacuated to vacuum, hydrogen was introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve was closed. The heating system of the reactor was turned on to keep the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve was adjusted 4 times at intervals of 12h to replenish hydrogen, and the pressure in the reactor was kept at 8.0MPa. After reacting for 66h, the heating was stopped, and the reaction was restored to room temperature. The remaining gas in the autoclave was recovered, and the white waxy solid obtained by separating the catalyst from the product was the target product, decanediamine. The purity of decanediamine was 65.6%, and the conversion rate of decanediamine was 100%.

[0109] Comparative Example 3

[0110] At room temperature, 20g of sebacate and 1g of Raney nickel catalyst (non-supported) were added to the reactor, nitrogen was replaced in the autoclave for 3 times, the nitrogen inlet valve was closed, the autoclave was evacuated to vacuum, ammonia was introduced to make the pressure in the autoclave reach 1.0MPa, and the ammonia inlet valve was closed. Hydrogen was introduced for the first time to make the hydrogen pressure reach 3.0MPa, and the hydrogen inlet valve was closed. The reactor heating system was turned on to keep the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve was adjusted 4 times at intervals of 12h to supplement hydrogen, and the pressure in the autoclave was kept at 8.0MPa. After reacting for 66h, the heating was stopped, the reaction was restored to room temperature, the residual gas in the autoclave was recovered, and the white waxy solid obtained by separating the catalyst from the product was the target product, decanediamine. The purity of decanediamine was 92.1%, and the conversion rate of decanediamine was 23%.

[0111] Comparative Example 4

[0112] At room temperature, 20g of sebacinonitrile was added to the reactor, nitrogen was used to replace the gas in the autoclave for 3 times, the nitrogen inlet valve was closed, the autoclave was evacuated to vacuum, ammonia was introduced to make the pressure in the autoclave reach 1.0MPa, and the ammonia inlet valve was closed. Hydrogen was introduced to make the hydrogen pressure reach 2.0MPa, and the hydrogen inlet valve was closed. The reactor heating system was turned on to maintain the temperature at 90°C. After reaching the temperature, the hydrogen inlet valve was adjusted to supplement hydrogen, and the pressure in the autoclave was maintained at 2MPa. After reacting for 16h, the heating was stopped, and the reaction was restored to room temperature. The remaining gas in the autoclave was recovered, and the reaction did not occur, the conversion rate was 0, and the raw materials remained.

Claims

1. A method for preparing a diamine, characterized in that: The method comprises the following steps: reacting the raw materials in a gas atmosphere containing ammonia and hydrogen to obtain a diamine; wherein, The raw materials are composed of dinitriles and supported nickel-based catalysts; The reaction pressure is 2.0-10.0 MPa; The reaction temperature is 50-110°C.

2. The method for preparing a diamine according to claim 1, characterized in that: The gas atmosphere is formed by first introducing ammonia and then introducing hydrogen.

3. The method for preparing a diamine according to claim 2, characterized in that: After the ammonia is introduced, the gas pressure is 0.1-2.0 MPa; And / or, after the hydrogen is introduced, the gas pressure is 2.0-10.0 MPa; Preferably, the hydrogen is introduced in n times, where n≥1 and n is an integer; Preferably, when n≥2, the gas pressure is 2.0-4.0 MPa after the first introduction of hydrogen; the gas pressure is 3.0-10.0 MPa after each subsequent introduction of hydrogen; preferably, the reaction temperature is increased to 50-110°C after the first introduction of hydrogen.

4. The method for preparing a diamine according to claim 1, characterized in that: The ammonia gas is derived from any one of ammonia gas produced by a synthetic ammonia process, an ammonia water distillation process and a waste ammonia recovery process.

5. The method for preparing a diamine according to claim 1, characterized in that: The reaction temperature is 80-100°C; And / or, the reaction pressure is 7.0-9.0 MPa; And / or, the reaction time is 1 to 70 hours.

6. The method for preparing a diamine according to claim 1, characterized in that: The dinitrile is a fatty dinitrile; Preferably, the molecular formula of the fatty dinitrile is: NC(CH2) n CN, n is any integer from 6 to 18; And / or, the dinitrile is a dinitrile having one carbon number or a mixture of dinitrile having multiple carbon numbers; And / or, the diamine is a straight-chain primary diamine having 8 to 20 carbon atoms.

7. The method for preparing a diamine according to claim 1, characterized in that: In the raw material, the weight percentage of the supported nickel-based catalyst is 1% to 25%; And / or, the supported nickel-based catalyst contains nickel, a modified metal and a carrier; Preferably, the modified metal is at least one of Li, Na, K, Be, Mg, Ca, Cu, Co, Cr, Zr, Mo, Zn, Cd, Ru, Rh, Pd and Pt; More preferably, the modified metals are magnesium and sodium; More preferably, the modified metals are chromium and sodium; Preferably, the weight content of nickel in the supported nickel-based catalyst is 30% to 80%, the weight content of the modified metal is 2% to 12%, and the rest is the carrier; And / or, the carrier of the supported nickel-based catalyst is at least one of alumina, silicon oxide, diatomaceous earth, activated carbon, molecular sieve and zeolite.

8. The method for preparing a diamine according to claim 7, characterized in that: The carrier is silicon oxide and / or diatomaceous earth; And / or, the supported nickel-based catalyst contains nickel, magnesium, sodium and a carrier, wherein the weight content of nickel in the supported nickel-based catalyst is 30% to 80%, the weight content of magnesium and sodium is 2% to 12%, and the rest is the carrier; And / or, the supported nickel-based catalyst contains nickel, chromium, sodium and a carrier, wherein the weight content of nickel in the supported nickel-based catalyst is 30% to 80%, the weight content of chromium and sodium is 2% to 12%, and the rest is the carrier.

9. The method for preparing a diamine according to claim 1, characterized in that: The supported nickel-based catalyst is prepared by a co-precipitation method, wherein the supported nickel-based catalyst is prepared by mixing a raw metal salt solution and a carrier and co-precipitating the mixture; Preferably, the metal salt comprises at least one of nickel nitrate, magnesium nitrate, chromium nitrate and sodium carbonate; Preferably, the supported nickel-based catalyst is prepared by mixing nickel nitrate, magnesium nitrate and sodium carbonate with water, and then adding silicon oxide and / or diatomaceous earth for co-precipitation; Preferably, the supported nickel-based catalyst is prepared by mixing nickel nitrate, chromium nitrate and sodium carbonate with water, and then adding silicon oxide and / or diatomaceous earth for co-precipitation.

10. The method for preparing a diamine according to claim 1, characterized in that: After the reaction is completed, the steps of reducing pressure and recovering the remaining gas are also included.