Method for preparing high-carbon diamine

Abstract

The invention relates to the technical field of catalytic amination, and discloses a method for preparing high-carbon diamine, which comprises the following steps: in the presence of a noble metal catalyst, reacting high-carbon dihydric alcohol with ammonia in a hydrogen atmosphere to obtain the high-carbon diamine, wherein the high-carbon dihydric alcohol is a dihydric alcohol of C6-C14. The preparation process is simple, continuous production can be realized technologically, no toxic intermediate product is generated in the preparation process, the preparation process is green and environment-friendly, the raw material conversion rate can be greater than 98.5%, and meanwhile, the product yield is greater than 90%.

Description

Technical Field

[0001] The invention relates to the technical field of catalytic amination, and in particular to a method for preparing high-carbon diamines. Background Art

[0002] High carbon diamine is an important organic intermediate, which is widely used in the textile, medicine, pesticide, daily chemical industry, synthetic materials and other industries, and has a strong market demand. Especially in recent years, with the continuous advancement of nylon material synthesis technology, long carbon chain nylon synthesized using high carbon diamine with a specific carbon chain length has the advantages of low density, high strength, low water absorption, low temperature resistance, wear resistance, impact resistance, etc., showing broad application potential in the field of synthetic nylon materials.

[0003] The traditional synthesis route of high-carbon diamines is to use high-carbon dibasic acids as raw materials, firstly undergo high-temperature ammonolysis to obtain high-carbon dinitriles, and then hydrogenate the high-carbon dinitriles to obtain high-carbon diamines. This synthesis route is relatively complicated, the hydrogenation of high-carbon dinitriles is difficult, the product yields of the ammonolysis and hydrogenation steps are low, and the intermediate high-carbon dinitriles are toxic.

[0004] There is an urgent need to develop a new high-carbon diamine synthesis process. Summary of the invention

[0005] The invention aims to solve the problems of complicated process, harsh reaction conditions and generation of toxic intermediates in the existing preparation process of high-carbon diamines, and provides a method for preparing high-carbon diamines, which has simple steps, high atom economy, less three wastes and is green and environmentally friendly.

[0006] In order to achieve the above object, the present invention provides a method for preparing a high-carbon diamine, comprising: reacting a high-carbon diol and ammonia in a hydrogen atmosphere in the presence of a noble metal catalyst to obtain a high-carbon diamine;

[0007] Wherein, the high carbon diol is C6-C 14 of diols.

[0008] Through the above technical scheme, the present invention provides a process route for directly preparing high-carbon diamines by one-step hydroamination of high-carbon diols using a noble metal catalyst. The method has a simple process, can realize continuous production in the process, has no amplification effect, has mild reaction conditions, does not produce toxic intermediates during the preparation process, has high atom economy, is green and environmentally friendly, and has high raw material conversion rate and product yield, and can achieve a raw material conversion rate of more than 98.5%, while the product yield is more than 90%. DETAILED DESCRIPTION

[0009] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0010] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0011] The present invention provides a method for preparing a high-carbon diamine, comprising: reacting a high-carbon diol and ammonia in a hydrogen atmosphere in the presence of a noble metal catalyst to obtain a high-carbon diamine;

[0012] Wherein, the high carbon diol is C6-C 14 of diols.

[0013] In the present invention, the high carbon diamine refers to a diamine having a carbon number of 6-14 in the molecular formula. The synthetic route of the current high carbon diamine is mostly based on high carbon dibasic acid as raw material, firstly high carbon dibasic acid and ammonia are reacted to generate the ammonium salt of high carbon dibasic acid, and the ammonium salt is subjected to heating dehydration to obtain high carbon diamide, and then further dehydrated to obtain high carbon dinitrile, and finally high carbon dinitrile is subjected to hydrogenation reaction to obtain high carbon diamine, wherein, the catalytic hydrogenation difficulty of high carbon dinitrile is relatively large, and in the hydrogenation reaction, side reactions such as the dehydrogenation of amine and the oxidation of amine will occur, resulting in a reduction in the purity of the product, and also affecting the yield of the reaction. In this preparation route, the intermediate product high carbon dinitrile can separate out nitrile ions, and nitrile ions can inhibit cytochrome oxidase, causing intracellular suffocation, being a toxic substance, endangering personnel safety, and being unfavorable for safe production. The inventors of the present invention adopt a hydrogenation process, based on a noble metal catalyst, a high-carbon diol and ammonia are reacted in a hydrogen atmosphere, wherein, under the action of a noble metal catalyst, the high-carbon diol is dehydrogenated to generate a high-carbon dialdehyde, after which the high-carbon dialdehyde is subjected to an amination reaction with ammonia to generate ene imine, and the obtained ene imine is then hydrogenated to finally obtain a high-carbon diamine. Compared with the existing preparation process, the method for preparing high-carbon diamines provided by the present invention directly prepares high-carbon diamines by hydrogenation, without the need for multi-step reaction, and the reaction process is greatly simplified, which is conducive to continuous production, and no toxic intermediates are produced during the preparation process, and the atom economy is high, and it is green and environmentally friendly. The method for preparing high-carbon diamines provided by the present invention also has the characteristics of high raw material conversion rate and product yield, and can achieve a conversion rate of high-carbon diol raw materials greater than 98.5%, and a yield of high-carbon diamine products greater than 90%.

[0014] According to the present invention, in the method for preparing high-carbon diamine, the high-carbon diol refers to a diol having a carbon number of 6-14 in the molecular formula, wherein the two hydroxyl groups in the molecular formula are respectively connected to the two terminal carbons. The general structural formula of the high-carbon diol is HO-R1-OH, wherein -OH represents a hydroxyl group, and R1 is preferably C6-C 14 In the present invention, from the perspective of taking into account the source of the raw materials and the application performance of the obtained high-carbon diamine in nylon, preferably, the high-carbon diol is C8-C 12 of diols.

[0015] According to the present invention, in the method for preparing high carbon diamine, the ammonia is preferably liquid ammonia. Before the reaction, the gaseous ammonia can be pressurized or cooled to obtain liquid ammonia, which is fed into the reaction in the form of liquid ammonia.

[0016] According to the present invention, in the method for preparing high-carbon diamine, the molar ratio of the high-carbon diol: ammonia can be controlled to be 1:(2-20) so that the amination reaction proceeds smoothly and obtains a better reaction effect.

[0017] According to the present invention, in the reaction, preferably, the molar ratio of the high carbon diol: ammonia is 1:(4-12), which is beneficial to improve the purity of the primary amine in the product of the amination reaction, and at the same time will not cause a large amount of excess ammonia, thereby reducing the subsequent ammonia recovery burden.

[0018] According to the present invention, in the method for preparing high carbon diamine, the pressure of hydrogen is 1-6MPa, and the volume space velocity of hydrogen is 5-500h -1 , which is conducive to better balancing the dehydrogenation efficiency of the high-carbon diol and the hydrogenation efficiency of the ethylene imine.

[0019] According to the present invention, in the method for preparing a high-carbon diamine, preferably, the reaction is carried out in the presence of an inert solvent, the inert solvent can dissolve the high-carbon diol, facilitate the reaction, and the solvent will not have a side reaction with the raw material under the reaction conditions. Preferably, the weight ratio of the high-carbon diol: the inert solvent is (5-40):100.

[0020] In the present invention, preferably, the inert solvent can be selected from at least one of dioxane, tetrahydrofuran, tert-butyl alcohol, benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene.

[0021] According to the present invention, in the method for preparing high-carbon diamine, the reaction conditions include: temperature of 140-280°C, pressure of 1-6MPa, volume space velocity of the high-carbon diol of 0.1-3h -1 .

[0022] According to the present invention, if the reaction temperature is too low, the raw material conversion rate will be too low, and if the reaction temperature is too high, the product selectivity of the reaction will be poor. By controlling the reaction temperature to 140-280°C, a better raw material conversion rate and product yield can be obtained.

[0023] According to the present invention, in the method for preparing high-carbon diamines, the noble metal catalyst is preferably a supported catalyst, including a carrier and a noble metal active component supported on the carrier. Preferably, the noble metal active component can be selected from Pt and / or Pd, which can bring better dehydrogenation and hydrogenation performance at a lower dosage.

[0024] According to the present invention, in the noble metal catalyst, preferably, the carrier can be selected from at least one of activated carbon, alumina and diatomaceous earth, and more preferably activated carbon.

[0025] According to the present invention, in the precious metal catalyst, from the perspective of balancing catalytic performance and production cost, preferably, based on the total weight of the precious metal catalyst, the content of precious metal active components (in terms of metal elements) in the precious metal catalyst is 0.1-5 wt %.

[0026] According to the present invention, the noble metal catalyst has the above composition, preferably, the specific surface area of ​​the noble metal catalyst is 800-1000m 2 / g, and the pore volume is 0.5-5mL / g, which can bring better catalytic effect.

[0027] According to the present invention, the noble metal catalyst can be prepared by a conventional method for preparing a supported catalyst, for example, the noble metal catalyst can be prepared by the following method:

[0028] The compound containing precious metal is formulated into a solution containing precious metal, and then an oxidant is added and mixed to obtain a mixed solution; the mixed solution is sprayed onto a carrier, and then allowed to stand to obtain a carrier loaded with precious metals; the carrier loaded with precious metals is washed and dried, and finally subjected to reduction treatment under a hydrogen atmosphere to obtain the precious metal catalyst. Wherein, the precious metal is preferably Pt and / or Pd; the oxidant is preferably hydrogen peroxide (H2O2); the weight ratio of the precious metal (in terms of element): the oxidant is 1:(10-30); the carrier is selected from at least one of activated carbon, alumina and diatomaceous earth; the standing time is 2-4h; the amount of the compound containing precious metal and the carrier is such that, based on the total weight of the precious metal catalyst, the content of the precious metal active component (in terms of metal element) in the precious metal catalyst is 0.1-5% by weight.

[0029] According to the present invention, the method for preparing high carbon diamine is preferably implemented by the following steps:

[0030] (1) performing a first mixing of the high carbon diol and the inert solvent to obtain a first mixed solution; then performing a second mixing of the first mixed solution and liquid ammonia to obtain a second mixed solution;

[0031] (2) heating the fixed bed reactor loaded with the noble metal catalyst to a temperature required for the reaction, introducing hydrogen, and then introducing the second mixed liquid into the reactor for reaction to obtain a product system;

[0032] (3) performing gas-liquid separation on the product system to obtain a crude high-carbon diamine product;

[0033] (4) subjecting the crude high-carbon diamine product to a solvent removal treatment to obtain a high-carbon diamine product.

[0034] According to the present invention, in the above step (1), there is no particular limitation on the manner of the first mixing and the second mixing, as long as uniform first mixed liquid and second mixed liquid can be obtained.

[0035] According to the present invention, in the above step (3), the excess unreacted ammonia, hydrogen and water vapor generated by the reaction in the product system are separated out by the gas-liquid separation to obtain a crude product mixed liquid (crude high carbon diamine product) containing high carbon diamine and the inert solvent.

[0036] According to the present invention, in the above step (4), there is no particular limitation on the desolventizing treatment, as long as the inert solvent in the crude high-carbon diamine product can be removed, for example, by distillation.

[0037] The present invention will be described in detail below by way of examples. In the following examples and comparative examples,

[0038] Catalyst-1: palladium chloride (PdCl2) and nitric acid are prepared into a solution, and then a hydrogen peroxide solution is added and mixed (the weight ratio of Pd:H2O2 is 1:10) to obtain a mixed solution; the mixed solution is sprayed onto an activated carbon carrier, and then allowed to stand for 4 hours to obtain a carrier activated carbon loaded with Pd, which is then washed and dried, and finally reduced in a hydrogen atmosphere to obtain catalyst-1. The active component of catalyst-1 is Pd (the content is 3% by weight, and the percentage of the active component is based on the total weight of the catalyst), and the carrier is activated carbon; the specific surface area of ​​the catalyst is 1000m 2 / g, and the pore volume is 0.6mL / g.

[0039] Catalyst-2: Chloroplatinic acid and hydrochloric acid are prepared into a solution, and then a hydrogen peroxide solution is added and mixed (the weight ratio of Pt:H2O2 is 1:15) to obtain a mixed solution; the mixed solution is sprayed onto an activated carbon carrier, and then allowed to stand for 4 hours to obtain a carrier activated carbon loaded with Pt, which is then washed and dried, and finally reduced in a hydrogen atmosphere to obtain Catalyst-2. The active component of Catalyst-2 is Pt (the content is 2% by weight, and the percentage of the active component is based on the total weight of the catalyst), and the carrier is activated carbon; the specific surface area of ​​the catalyst is 800m 2 / g, and the pore volume is 0.6mL / g.

[0040] Example 1

[0041] (1) decanediol and tert-butyl alcohol are mixed at a weight ratio of 20:100 to obtain a uniform first mixed liquid and the mixed liquid is charged into a raw material tank; then liquid ammonia is charged into the raw material tank and mixed with the first mixed liquid (the molar ratio of decanediol: liquid ammonia is 1:4) to obtain a uniform second mixed liquid for standby use;

[0042] (2) The noble metal catalyst-1 was loaded into a fixed bed reactor, and the temperature of the fixed bed reactor was set to 240°C, the hydrogen pressure (reaction pressure) was 2 MPa, and the volumetric space velocity of hydrogen was 160 h -1 ; Use a plunger pump to pass the second mixed liquid in the raw material tank into the fixed bed reactor for reaction, and control the liquid feed rate so that the space velocity of the high carbon diol is 1h -1 , and obtain the product system;

[0043] (3) performing gas-liquid separation on the obtained product system to separate the excess unreacted ammonia, hydrogen and water vapor generated by the reaction to obtain a crude high-carbon diamine product;

[0044] (4) distilling the obtained high-carbon diamine crude product to remove tert-butyl alcohol to obtain decanediamine product.

[0045] The conversion rate of decanediol and the yield of decanediamine are shown in Table 1.

[0046] Example 2

[0047] (1) dodecanediol and benzene are mixed at a weight ratio of 30:100 to obtain a uniform first mixed liquid and the mixed liquid is charged into a raw material tank; then liquid ammonia is charged into the raw material tank and mixed with the first mixed liquid (the molar ratio of dodecanediol:liquid ammonia is 1:8) to obtain a uniform second mixed liquid for standby use;

[0048] (2) The noble metal catalyst-2 was loaded into a fixed bed reactor, and the temperature of the fixed bed reactor was set to 210°C, the hydrogen pressure (reaction pressure) was 3 MPa, and the volumetric space velocity of hydrogen was 250 h -1; Use a plunger pump to pass the second mixed liquid in the raw material tank into the fixed bed reactor for reaction, and control the liquid feed rate so that the space velocity of the high carbon diol is 1.5h -1 , and obtain the product system;

[0049] (3) performing gas-liquid separation on the obtained product system to separate the excess unreacted ammonia, hydrogen and water vapor generated by the reaction to obtain a crude high-carbon diamine product;

[0050] (4) distilling the obtained crude high-carbon diamine product to remove benzene and obtain the dodecanediamine product.

[0051] The conversion rate of dodecanediol and the yield of dodecanediamine are shown in Table 1.

[0052] Example 3

[0053] (1) Octanediol and toluene are mixed at a weight ratio of 40:100 to obtain a uniform first mixed liquid and charged into a raw material tank; then liquid ammonia is charged into the raw material tank and mixed with the first mixed liquid (the molar ratio of octanediol:liquid ammonia is 1:12) to obtain a uniform second mixed liquid for standby use;

[0054] (2) The noble metal catalyst-1 was loaded into a fixed bed reactor, and the temperature of the fixed bed reactor was set to 190°C, the hydrogen pressure (reaction pressure) was 4 MPa, and the volumetric space velocity of hydrogen was 300 h -1 ; Use a plunger pump to pass the second mixed liquid in the raw material tank into the fixed bed reactor for reaction, and control the liquid feed rate so that the space velocity of the high carbon diol is 2h -1 , and obtain the product system;

[0055] (3) performing gas-liquid separation on the obtained product system to separate the excess unreacted ammonia, hydrogen and water vapor generated by the reaction to obtain a crude high-carbon diamine product;

[0056] (4) distilling the obtained crude high-carbon diamine product to remove toluene and obtain the octanediamine product.

[0057] The conversion rate of octanediamine alcohol and the yield of octanediamine are shown in Table 1.

[0058] Example 4

[0059] (1) tetradecanediol and dioxane are mixed at a weight ratio of 5:100 to obtain a uniform first mixed liquid and the mixed liquid is charged into a raw material tank; then liquid ammonia is charged into the raw material tank and mixed with the first mixed liquid (the molar ratio of tetradecanediol:liquid ammonia is 1:2) to obtain a uniform second mixed liquid for standby use;

[0060] (2) The noble metal catalyst-2 was loaded into a fixed bed reactor, and the temperature of the fixed bed reactor was set to 280°C, the hydrogen pressure (reaction pressure) was 1 MPa, and the volumetric space velocity of hydrogen was 5 h -1 ; Use a plunger pump to pass the second mixed liquid in the raw material tank into the fixed bed reactor for reaction, and control the liquid feed rate so that the space velocity of the high carbon diol is 0.1h -1 , and obtain the product system;

[0061] (3) performing gas-liquid separation on the obtained product system to separate the excess unreacted ammonia, hydrogen and water vapor generated by the reaction to obtain a crude high-carbon diamine product;

[0062] (4) The obtained high-carbon diamine crude product is distilled to remove dioxane to obtain the tetradecane diamine product.

[0063] The conversion rate of tetradecanediol and the yield of tetradecanediamine are shown in Table 1.

[0064] Example 5

[0065] (1) tetradecanediol and tetrahydrofuran are mixed at a weight ratio of 10:100 to obtain a uniform first mixed liquid and the mixed liquid is charged into a raw material tank; then liquid ammonia is charged into the raw material tank and mixed with the first mixed liquid (the molar ratio of tetradecanediol:liquid ammonia is 1:3) to obtain a uniform second mixed liquid for standby use;

[0066] (2) The noble metal catalyst-1 was loaded into a fixed bed reactor, and the temperature of the fixed bed reactor was set to 260°C, the hydrogen pressure (reaction pressure) was 1.5 MPa, and the volumetric space velocity of hydrogen was 80 h -1 ; Use a plunger pump to pass the second mixed liquid in the raw material tank into the fixed bed reactor for reaction, and control the liquid feed rate so that the space velocity of the high carbon diol is 0.5h -1 , and obtain the product system;

[0067] (3) performing gas-liquid separation on the obtained product system to separate the excess unreacted ammonia, hydrogen and water vapor generated by the reaction to obtain a crude high-carbon diamine product;

[0068] (4) distilling the obtained crude high-carbon diamine product to remove tetrahydrofuran and obtain tetradecanediamine product.

[0069] The conversion rate of tetradecanediol and the yield of tetradecanediamine are shown in Table 1.

[0070] Example 6

[0071] (1) tetradecanediol and p-xylene are mixed at a weight ratio of 10:100 to obtain a uniform first mixed liquid and charged into a raw material tank; then liquid ammonia is charged into the raw material tank and mixed with the first mixed liquid (the molar ratio of tetradecanediol:liquid ammonia is 1:4) to obtain a uniform second mixed liquid for standby use;

[0072] (2) The noble metal catalyst-2 was loaded into a fixed bed reactor, and the temperature of the fixed bed reactor was set to 250°C, the hydrogen pressure (reaction pressure) was 2 MPa, and the volumetric space velocity of hydrogen was 160 h -1 ; Use a plunger pump to pass the second mixed liquid in the raw material tank into the fixed bed reactor for reaction, and control the liquid feed rate so that the space velocity of the high carbon diol is 1h -1 , and obtain the product system;

[0073] (3) performing gas-liquid separation on the obtained product system to separate the excess unreacted ammonia, hydrogen and water vapor generated by the reaction to obtain a crude high-carbon diamine product;

[0074] (4) distilling the obtained high-carbon diamine crude product to remove p-xylene to obtain the tetradecane diamine product.

[0075] The conversion rate of tetradecanediol and the yield of tetradecanediamine are shown in Table 1.

[0076] Example 7

[0077] (1) Hexanediol and ethylbenzene are mixed at a weight ratio of 40:100 to obtain a uniform first mixed liquid and charged into a raw material tank; then liquid ammonia is charged into the raw material tank and mixed with the first mixed liquid (the molar ratio of hexanediol:liquid ammonia is 1:14) to obtain a uniform second mixed liquid for standby use;

[0078] (2) The noble metal catalyst-1 was loaded into a fixed bed reactor, and the temperature of the fixed bed reactor was set to 180°C, the hydrogen pressure (reaction pressure) was 5 MPa, and the volumetric space velocity of hydrogen was 300 h -1 ; Use a plunger pump to pass the second mixed liquid in the raw material tank into the fixed bed reactor for reaction, and control the liquid feed rate so that the space velocity of the high carbon diol is 2h -1 , and obtain the product system;

[0079] (3) performing gas-liquid separation on the obtained product system to separate the excess unreacted ammonia, hydrogen and water vapor generated by the reaction to obtain a crude high-carbon diamine product;

[0080] (4) distilling the obtained crude high-carbon diamine product to remove ethylbenzene and obtain the hexamethylenediamine product.

[0081] The conversion rate of hexanediol and the yield of hexamethylenediamine are shown in Table 1.

[0082] Example 8

[0083] (1) Hexanediol and o-xylene are mixed at a weight ratio of 30:100 to obtain a uniform first mixed liquid and the mixed liquid is charged into a raw material tank; then liquid ammonia is charged into the raw material tank and mixed with the first mixed liquid (the molar ratio of hexanediol:liquid ammonia is 1:16) to obtain a uniform second mixed liquid for standby use;

[0084] (2) The noble metal catalyst-2 was loaded into a fixed bed reactor, and the temperature of the fixed bed reactor was set to 160°C, the hydrogen pressure (reaction pressure) was 5.5 MPa, and the volumetric space velocity of hydrogen was 420 h -1 ; Use a plunger pump to pass the second mixed liquid in the raw material tank into the fixed bed reactor for reaction, and control the liquid feed rate so that the space velocity of the high carbon diol is 2.5h -1 , and obtain the product system;

[0085] (3) performing gas-liquid separation on the obtained product system to separate the excess unreacted ammonia, hydrogen and water vapor generated by the reaction to obtain a crude high-carbon diamine product;

[0086] (4) distilling the obtained crude high-carbon diamine product to remove o-xylene to obtain hexamethylenediamine product.

[0087] The conversion rate of hexanediol and the yield of hexamethylenediamine are shown in Table 1.

[0088] Example 9

[0089] (1) Hexanediol and meta-xylene are mixed at a weight ratio of 20:100 to obtain a uniform first mixed liquid and charged into a raw material tank; then liquid ammonia is charged into the raw material tank and mixed with the first mixed liquid (the molar ratio of hexanediol:liquid ammonia is 1:20) to obtain a uniform second mixed liquid for standby use;

[0090] (2) The noble metal catalyst-1 was loaded into a fixed bed reactor, and the temperature of the fixed bed reactor was set to 140°C, the hydrogen pressure (reaction pressure) was 6 MPa, and the volumetric space velocity of hydrogen was 500 h -1 ; Use a plunger pump to pass the second mixed liquid in the raw material tank into the fixed bed reactor for reaction, and control the liquid feed rate so that the space velocity of the high carbon diol is 3h -1 , and obtain the product system;

[0091] (3) performing gas-liquid separation on the obtained product system to separate the excess unreacted ammonia, hydrogen and water vapor generated by the reaction to obtain a crude high-carbon diamine product;

[0092] (4) distilling the obtained crude high-carbon diamine product to remove meta-xylene to obtain hexamethylenediamine product.

[0093] The conversion rate of hexanediol and the yield of hexamethylenediamine are shown in Table 1.

[0094] Comparative Example 1

[0095] (1) decanediol and tert-butyl alcohol are mixed at a weight ratio of 20:100 to obtain a uniform first mixed liquid and the mixed liquid is charged into a raw material tank; then liquid ammonia is charged into the raw material tank and mixed with the first mixed liquid (the molar ratio of decanediol: liquid ammonia is 1:4) to obtain a uniform second mixed liquid for standby use;

[0096] (2) A supported nickel catalyst (activated carbon as carrier, nickel content of 28%) was loaded into a fixed bed reactor, the temperature of the fixed bed reactor was set to 240°C, the hydrogen pressure was 2 MPa (reaction pressure), and the volumetric space velocity of hydrogen was 160 h -1 ; Use a plunger pump to pass the second mixed liquid in the raw material tank into the fixed bed reactor for reaction, and control the liquid feed rate so that the space velocity of the high carbon diol is 1h -1 , and obtain the product system;

[0097] (3) performing gas-liquid separation on the obtained product system to separate the excess unreacted ammonia, hydrogen and water vapor generated by the reaction to obtain a crude high-carbon diamine product;

[0098] (4) distilling the obtained high-carbon diamine crude product to remove tert-butyl alcohol to obtain decanediamine product.

[0099] The conversion rate of decanediol and the yield of decanediamine are shown in Table 1.

[0100] Comparative Example 2

[0101] (1) mixing adipic acid and liquid ammonia (the molar ratio of adipic acid to liquid ammonia is 1:3) to obtain a mixed solution;

[0102] (2) The boron phosphate catalyst is filled into a fixed bed reactor, and the mixed solution obtained in step (1) is passed into the fixed bed reactor, and the reaction temperature is controlled to be 450° C. and the adipic acid space velocity is 0.7 h -1 , to obtain adiponitrile (adiponitrile selectivity is 88.0%);

[0103] (3) mixing a skeleton nickel catalyst (Ni content of 38 wt%), ethanol, liquid ammonia and adiponitrile obtained in step (1) in a weight ratio of 15:30:10:100, adding the mixture into a reactor, charging with hydrogen at 5 MPa (reaction pressure), and then heating to 100° C. for 4 h to obtain a product system (adiponitrile conversion rate of 96.0%);

[0104] (4) cooling the product system, exhausting the gas and releasing the pressure, and rectifying the product to obtain a hexamethylenediamine product;

[0105] The conversion rate of adipic acid and the yield of hexamethylenediamine are shown in Table 1.

[0106] Table 1

[0107]

[0108] Note: In Table 1, the conversion rate of high-carbon diols = (the content of high-carbon diols in the raw material - the content of high-carbon diols in the product) / the content of high-carbon diols in the raw material; the yield of high-carbon diamines = the content of high-carbon diamines in the product / (the content of high-carbon diols in the raw material - the content of high-carbon diols in the product);

[0109] Conversion rate of high-carbon dibasic acid = (high-carbon dibasic acid content in raw material - high-carbon dibasic acid content in product) / high-carbon dibasic acid content in raw material; yield of high-carbon diamine = high-carbon diamine content in product / (high-carbon dibasic acid content in raw material - high-carbon dibasic acid content in product).

[0110] It can be seen from the results of the above Examples 1-9 and Comparative Examples 1-2 that the method for preparing high-carbon diamines of the present invention has a simple preparation process, mild reaction conditions, can achieve continuous production in terms of process, does not produce toxic intermediates during the preparation process, has a raw material conversion rate of greater than 98.5%, and a product yield of greater than 90%.

[0111] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a high carbon diamine, characterized in that: include: In the presence of a noble metal catalyst, a high carbon diol and ammonia are reacted in a hydrogen atmosphere to obtain a high carbon diamine; Wherein, the high carbon diol is C6-C 14 of diols.

2. The method according to claim 1, wherein: The high carbon diol is C8-C 12 of diols.

3. The method according to claim 1 or 2, wherein: The molar ratio of the high carbon diol to ammonia is 1:(2-20).

4. The method according to claim 3, wherein: The molar ratio of the high carbon diol to ammonia is 1:(4-12).

5. The method according to any one of claims 1 to 4, wherein: The pressure of hydrogen is 1-6MPa, and the volume space velocity of hydrogen is 5-500h -1 .

6. The method according to any one of claims 1 to 5, wherein: The reaction is carried out in the presence of an inert solvent; Preferably, the inert solvent is selected from at least one of dioxane, tetrahydrofuran, tert-butyl alcohol, benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene.

7. The method according to any one of claims 1 to 6, wherein: The reaction conditions include: temperature of 140°C-280°C, pressure of 1-6MPa, volume space velocity of the high carbon diol of 0.1-3h -1 .

8. The method according to any one of claims 1 to 7, wherein: The noble metal catalyst comprises: a carrier, and a noble metal active component supported on the carrier; Preferably, the noble metal active component is selected from Pt and / or Pd; Preferably, the carrier is selected from at least one of activated carbon, alumina and diatomaceous earth.

9. The method according to claim 8, wherein: The content of the noble metal active component in the noble metal catalyst is 0.1-5% by weight based on the total weight of the noble metal catalyst.

10. The method according to claim 8 or 9, wherein: The specific surface area of ​​the catalyst is 800-1000m 2 / g, and the pore volume is 0.5-5mL / g.

Images