Method for preparing high-carbon diamine from high-carbon dihydric alcohol through hydroamination

Abstract

The invention provides a method for preparing high-carbon diamine from high-carbon dihydric alcohol through hydroamination, which comprises the following steps: dissolving high-carbon dihydric alcohol in an inert solution, then mixing with liquid ammonia to obtain a mixed solution, heating a fixed bed reactor filled with a modified noble metal catalyst to a reaction temperature, introducing hydrogen at the same time, and reacting to obtain high-carbon diamine. The active components of the modified noble metal catalyst comprise a palladium element, a chromium element and / or a cobalt element, the carrier is alumina, then adding the mixed solution into a fixed bed reactor, reacting under reaction pressure, and purifying to obtain the high-carbon diamine. According to the method for preparing the high-carbon diamine, multi-step reaction is not needed, the reaction process is greatly simplified, continuous production is facilitated, no toxic intermediate product is generated in the preparation process, atom economy is high, and the method is green and environmentally friendly.

Description

Technical Field

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

[0002] High-carbon diamines are an important class of organic intermediates, widely used in industries such as textiles, pharmaceuticals, pesticides, daily chemicals, and synthetic materials, and enjoy strong market demand. In particular, with the continuous advancement of nylon synthesis technology in recent years, long-chain nylons synthesized using high-carbon diamines with specific carbon chain lengths have demonstrated significant advantages such as low density, high strength, low water absorption, and resistance to low temperatures, wear, and impact, demonstrating broad application potential in the field of synthetic nylon materials.

[0003] The traditional synthesis of high-carbon diamines involves using high-carbon dibasic acids as raw materials, undergoing high-temperature ammonolysis to produce high-carbon dinitriles, which are then hydrogenated to produce the high-carbon diamines. This production route is complex, with low product yields in the ammonolysis and hydrogenation steps. Furthermore, the preparation process generates toxic intermediates, high-carbon dinitriles. These intermediates can release nitrile ions, which inhibit cytochrome oxidase and cause intracellular asphyxiation, endangering the health and safety of production personnel and hindering safe production. These issues have led to the poor competitiveness of this production route.

[0004] The hydroamination process is an environmentally friendly and efficient process for converting alcohols into amines. Its basic principle is that alcohols react directly with ammonia in a hydrogen atmosphere over the presence of a catalyst to produce amines and water. However, in existing hydroamination processes, the highly active nickel-based metal catalysts commonly used as single active components can cause unwanted side reactions during the hydroamination reaction. Primarily, the resulting amination product can react with other substances produced during the reaction to form secondary amine byproducts, resulting in low yields of the desired final product. Summary of the Invention

[0005] The present invention aims to provide a method for preparing a high-carbon diamine by hydroamination of a high-carbon diol. The method adopts a hydroamination process, uses a modified noble metal catalyst, and reacts a high-carbon diol with ammonia in a hydrogen atmosphere, so that the high-carbon diol is dehydrogenated to form a high-carbon dialdehyde under the action of the modified noble metal catalyst. The high-carbon dialdehyde is then subjected to an amination reaction with ammonia to form an eneimine. The obtained eneimine is then subjected to a hydrogenation reaction to ultimately obtain a high-carbon diamine.

[0006] To achieve the above objectives, the present invention proposes the following technical solutions:

[0007] A method for preparing a high-carbon diamine by hydroamination of a high-carbon diol comprises the following steps:

[0008] Step 1: dissolving a higher carbon diol in an inert solvent to obtain a first mixed solution, and then uniformly mixing the first mixed solution with liquid ammonia to obtain a second mixed solution, wherein the higher carbon diol has a general structural formula of HO-R1-OH, wherein R1 is a C6-C14 alkyl group;

[0009] Step 2: heating a fixed bed reactor filled with a modified precious metal catalyst to a reaction temperature while introducing hydrogen, wherein the active components of the modified precious metal catalyst include palladium, chromium and / or cobalt, the carrier of the modified precious metal catalyst is alumina, the mass content of the palladium element is 0.1%-5.0% of the total mass of the modified precious metal catalyst, and the mass content of the chromium element and / or cobalt element is 30%-80% of the mass content of the palladium element;

[0010] Step 3: adding the second mixed solution into the fixed bed reactor in step 2 to react under reaction pressure to obtain a crude high-carbon diamine;

[0011] Step 4: distilling the crude high-carbon diamine to remove the inert solvent to obtain the high-carbon diamine.

[0012] As a preferred technical solution of the present invention, R1 is a C8-C12 alkyl group.

[0013] As a preferred technical solution of the present invention, the preparation method of the modified noble metal catalyst is as follows:

[0014] A palladium ion solution is mixed with a chromium ion solution and / or a cobalt ion solution to obtain a noble metal ion mixed solution, an oxidant is added to the noble metal ion mixed solution to obtain a noble metal ion mixed oxidation solution, the noble metal ion mixed oxidation solution is sprayed on an alumina carrier, and sequentially washed, dried, and reduced to obtain the modified noble metal catalyst.

[0015] As a preferred technical solution of the present invention, the weight ratio of the noble metal ions to the oxidant in the noble metal ion mixed solution is 1:(12-40).

[0016] As a preferred technical solution of the present invention, the inert solvent in step 1 is one or more of dioxane, tetrahydrofuran, tert-butanol, benzene, toluene, ethylbenzene, p-xylene, o-xylene, and m-xylene.

[0017] As a preferred technical solution of the present invention, the molar ratio of the first mixed solution to the liquid ammonia in step 1 is 1:5-1:20.

[0018] As a preferred technical solution of the present invention, the reaction temperature in step 2 is 180°C-260°C.

[0019] As a preferred technical solution of the present invention, the reaction pressure of the hydrogen in step 2 is 1 MPa-6 MPa.

[0020] As a preferred technical solution of the present invention, in step 3, the second mixed solution is heated at a volume space velocity of 0.3-1.5h -1 Add to the fixed bed reactor in step 2.

[0021] The method for preparing higher-carbon diamines by hydroamination of higher-carbon diols provided by the technical solution of the present invention, compared with existing preparation methods, modifies a palladium-containing noble metal catalyst by doping it with specific noble metal elements such as chromium and cobalt, thereby improving the catalytic activity of the catalyst, inhibiting side reactions during the reaction process, and thereby improving the selectivity of the target reaction. Within a relatively optimal process parameter range, the conversion rate of the raw materials can reach over 99%, and the selectivity of the target reaction can reach 96%. In addition, no multi-step reaction is required, and the reaction process is greatly simplified, which is conducive to continuous production. No toxic intermediates are produced during the preparation process, and the atom economy is high, which is environmentally friendly.

[0022] In the hydroamination of higher-carbon diols, in the presence of a catalyst, the terminal hydroxyl groups of the higher-carbon diols first undergo dehydrogenation to form terminal aldehyde groups. These terminal aldehyde groups then react with ammonia to form eneimines, which are then hydrogenated to form terminal amino groups, yielding the target higher-carbon diamines. The resulting higher-carbon diamines are primary amines that can react with intermediate products of terminal aldehyde groups to form secondary amines with larger molecular weights. This results in the simultaneous consumption of the higher-carbon diamines as they are generated, reducing the reaction selectivity and yield. Therefore, it is necessary to suppress these side reactions.

[0023] Therefore, in order to solve the above technical problems, the active component of the catalyst of the present invention is mainly palladium with a smaller atomic radius, and then doped with a small amount of chromium and / or cobalt with a larger atomic radius. The ionic radius of the palladium element is smaller than that of the chromium and cobalt elements, and can be bonded to the active sites inside the intermediate carbon chain, and finally small molecules such as ammonia enter the interior of the intermediate carbon chain to replace the palladium ions to generate the target amination product, thereby promoting the reaction direction to proceed in the main direction; while the chromium and / or cobalt elements can only be bonded to the active sites outside the intermediate carbon chain due to their larger ionic radius, so that more large groups are formed on the surface of the intermediate carbon chain, and there is a more obvious space crowding phenomenon, so that the target amination product and the intermediate carbon chain or the generated intermediate products such as aldehydes cannot continue to bond with each other to generate by-products with longer carbon chains due to the spatial interference phenomenon, that is, the side reaction is inhibited. Therefore, the catalyst of the present invention uses palladium with a smaller ionic radius as the main active component, and adds chromium and / or cobalt with larger ionic radius in a suitable ratio, rationally utilizes the active sites at various positions of the intermediate, and uses the chromium and / or cobalt with larger ionic radius to form a complex spatial structure with smaller gaps in the intermediate carbon chain, thereby preventing the target amination product from continuing to react with the intermediate carbon chain with low activation energy or the generated aldehyde substance to form by-products due to spatial interference, thereby improving the conversion rate of the reactants and the selectivity of the target amination product.

[0024] It should be appreciated that all combinations of the foregoing concepts, as well as additional concepts described in greater detail below, to the extent such concepts are not mutually inconsistent, can be considered to be part of the inventive subject matter of this disclosure. DETAILED DESCRIPTION

[0025] The terms "first," "second," and similar words used in the patent application specification and claims of the present invention do not indicate any order, quantity, or importance, but are only used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "a," "an," "the," and similar words do not indicate a limit on quantity, but rather indicate the presence of at least one. Terms such as "include" or "comprising" mean that the elements or objects preceding the word "include" or "comprising" include the features, wholes, steps, operations, elements, and / or components listed after the word "include" or "comprising," and do not exclude the existence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their collections.

[0026] The present invention provides a method for preparing a high-carbon diamine by hydroamination of a high-carbon diol. The high-carbon diamine refers to a diamine having 6 to 14 carbon atoms in its molecular formula. The method mainly comprises the following steps:

[0027] Step 1: Dissolve a higher carbon diol in an inert solvent to obtain a first mixed solution, then uniformly mix the first mixed solution with liquid ammonia at a molar ratio of 1:5-1:20 to obtain a second mixed solution. The higher carbon diol has a general structural formula of HO-R1-OH, wherein R1 is a C6-C14 alkyl group. In some preferred embodiments, R1 is a C8-C12 alkyl group. The inert solvent is one or more of dioxane, tetrahydrofuran, tert-butyl alcohol, benzene, toluene, ethylbenzene, p-xylene, o-xylene, and m-xylene.

[0028] Step 2: Heating a fixed-bed reactor filled with a modified precious metal catalyst to a reaction temperature of 180°C to 260°C while introducing hydrogen, wherein the modified precious metal catalyst comprises active components of palladium, chromium, and / or cobalt, and the carrier of the modified precious metal catalyst is alumina. Based on the total mass of the modified precious metal catalyst, the mass content of the palladium in the modified precious metal catalyst is 0.1% to 5.0%, and the mass content of the chromium and / or cobalt in the modified precious metal catalyst is 30% to 80% of the mass content of the palladium.

[0029] Step 3: The second mixed solution is heated for 0.3-1.5 hours. -1 The volume space velocity is added to the fixed bed reactor in step 2 and the reaction is carried out at a reaction pressure of 1 MPa-6 MPa to obtain a crude high-carbon diamine. The crude high-carbon diamine is sampled to calculate the conversion rate of the high-carbon diol and the selectivity of the high-carbon diamine.

[0030] Step 4: distilling the crude high-carbon diamine to remove the inert solvent to obtain high-purity high-carbon diamine.

[0031] In an embodiment of the present invention, the noble metal catalyst can be prepared by the following preparation method, specifically as follows:

[0032] The first precious metal compound is prepared into a first precious metal ion solution, the second precious metal compound is prepared into a second precious metal ion solution, and then the first precious metal ion solution and the second precious metal ion solution are uniformly mixed according to the above-mentioned precious metal element mass ratio to obtain a third precious metal ion solution, and then an oxidant is added thereto to obtain a fourth precious metal ion solution, and the fourth precious metal ion solution is sprayed onto a blank carrier (i.e., a carrier not loaded with any active component), and allowed to stand for a period of time to obtain a carrier loaded with a modified precious metal active component, and the carrier loaded with the modified precious metal active component is washed and dried, and finally reduced under a hydrogen atmosphere to obtain the modified precious metal catalyst.

[0033] In some embodiments of the present invention, the first precious metal is preferably palladium, the first precious metal compound is preferably palladium chloride, and the corresponding first metal ion solution is preferably a palladium ion solution prepared from nitric acid; the second precious metal is preferably any one of chromium and cobalt or a mixture of these two metals. Therefore, the second precious metal compound is preferably chromium chloride and / or cobalt chloride, and the corresponding second metal ion solution may include three ion solutions prepared from nitric acid: chromium ion solution, cobalt ion solution, and chromium-cobalt mixed ion solution. The oxidant is preferably hydrogen peroxide (H2O2), and the weight ratio of the first precious metal to the second precious metal (calculated as the precious metal element): oxidant is 1:(12-40). The carrier is preferably alumina. The standing time is preferably 2h-4h. The mass content of the first precious metal (calculated as the precious metal element) in the modified precious metal catalyst is 0.1%-5.0%, and the mass content of the second precious metal (calculated as the precious metal element) is 30%-80% of the mass content of the first precious metal.

[0034] The technical solution of the present invention is described in detail below through specific embodiments.

[0035] Example 1

[0036] Preparation of catalyst:

[0037] A palladium ion solution is prepared by mixing palladium chloride with nitric acid, and a cobalt ion solution is prepared by mixing cobalt chloride with nitric acid to obtain a palladium-cobalt ion mixed solution. The palladium ion solution and the cobalt ion solution are mixed to obtain a palladium-cobalt ion mixed solution, wherein the weight ratio of palladium to cobalt in the palladium-cobalt ion mixed solution is 1:0.5, based on the weight of the precious metal elements. A hydrogen peroxide solution is then added to the palladium-cobalt ion mixed solution to obtain a palladium-cobalt ion mixed oxidation solution, wherein the weight ratio of the precious metal elements to hydrogen peroxide in the palladium-cobalt ion mixed oxidation solution is 1:20. The palladium-cobalt ion mixed oxidation solution is sprayed onto an alumina support, and after standing for 4 hours, the alumina support is washed and dried, and finally reduced under a hydrogen atmosphere to obtain a modified precious metal catalyst loaded with palladium and cobalt elements, which is designated as Catalyst 1. The mass content of palladium in Catalyst 1 is 3%, and the mass content of cobalt is 1.5%.

[0038] Hydroamination reaction:

[0039] Step 1: dissolving decanediol in tert-butyl alcohol and then adding the solution into a raw material tank to obtain a first mixed solution, then adding liquid ammonia into the tank to obtain a second mixed solution, controlling the molar ratio of the first mixed solution to the liquid ammonia to be 1:10, and mixing the solution for later use;

[0040] Step 2: The catalyst 1 is loaded into a fixed bed reactor, the reaction temperature of the fixed bed reactor is set to 200°C, and then hydrogen is introduced, and the reaction pressure of the hydrogen is set to 3 MPa;

[0041] Step 3: Use a plunger pump to inject the second mixed solution in the raw material tank into the fixed bed reactor, and control the space velocity of the second mixed solution to be 1.2h -1 , reacting to obtain the crude decanediamine;

[0042] The crude decanediamine product after gas-liquid separation was sampled and analyzed through a sampling port. The conversion rate of decanediol was calculated to be 99.9%, and the selectivity of decanediamine was 98.8%.

[0043] Step 4: distilling the crude decanediamine to remove the tert-butanol solvent to obtain the decanediamine product.

[0044] Example 2

[0045] Catalyst preparation

[0046] A palladium ion solution is prepared by mixing palladium chloride with nitric acid, and a cobalt ion solution is prepared by mixing cobalt chloride with nitric acid to obtain a palladium-cobalt ion mixed solution. The palladium ion solution and the cobalt ion solution are mixed to obtain a palladium-cobalt ion mixed solution, wherein the weight ratio of palladium element to cobalt element in the palladium-cobalt ion mixed solution is 1:0.3 based on the weight of the precious metal elements. A hydrogen peroxide solution is then added to the palladium-cobalt ion mixed solution to obtain a palladium-cobalt ion mixed oxidation solution, wherein the weight ratio of the precious metal elements to hydrogen peroxide in the palladium-cobalt ion mixed oxidation solution is 1:40. The palladium-cobalt ion mixed oxidation solution is sprayed onto an alumina support, and after standing for 4 hours, the alumina support is washed and dried, and finally reduced under a hydrogen atmosphere to obtain a modified precious metal catalyst loaded with palladium and cobalt elements, which is recorded as Catalyst 2. The mass content of palladium element in Catalyst 2 is 5%, and the mass content of cobalt element is 1.5%.

[0047] Hydroamination

[0048] Step 1: dissolving dodecanediol in tetrahydrofuran and storing the solution in a raw material tank to obtain a first mixed solution, then adding liquid ammonia into the raw material tank to obtain a second mixed solution, controlling the molar ratio of the first mixed solution to the liquid ammonia to be 1:14, and mixing the solution evenly for later use.

[0049] Step 2: The above-mentioned catalyst 2 is loaded into a fixed bed reactor, the reaction temperature of the fixed bed reactor is set to 180°C, and then hydrogen is introduced, and the reaction pressure of hydrogen is set to 4.0 MPa;

[0050] Step 3: Use a plunger pump to inject the second mixed solution in the raw material tank into the fixed bed reactor, and control the space velocity of the second mixed solution to be 1.5h -1 , reacting to obtain the crude dodecanediamine;

[0051] The crude dodecanediamine product of the reaction product after gas-liquid separation was sampled and analyzed through a sampling port. The conversion rate of dodecanediol was calculated to be 99.9%, and the selectivity of dodecanediamine was 99.1%.

[0052] Step 4: distilling the crude dodecanediamine product to remove the tetrahydrofuran solvent, and finally obtaining the dodecanediamine product.

[0053] Example 3

[0054] Catalyst preparation

[0055] A palladium ion solution is prepared by mixing palladium chloride with nitric acid, and a cobalt ion solution is prepared by mixing chromium chloride with nitric acid. The palladium ion solution and the chromium ion solution are mixed to obtain a palladium-chromium ion mixed solution, wherein the weight ratio of palladium to chromium in the palladium-chromium ion mixed solution is 1:0.8, based on the weight of the precious metal elements. A hydrogen peroxide solution is then added to the palladium-chromium ion mixed solution to obtain a palladium-chromium ion mixed oxidation solution, wherein the weight ratio of the precious metal elements to hydrogen peroxide in the palladium-chromium ion mixed oxidation solution is 1:30. The palladium-chromium ion mixed oxidation solution is sprayed onto an alumina support, allowed to stand for 3 hours, washed, dried, and finally reduced under a hydrogen atmosphere to obtain a modified precious metal catalyst loaded with palladium and chromium elements, designated as Catalyst 3. The mass content of palladium in Catalyst 3 is 1%, and the mass content of chromium is 0.8%.

[0056] Hydroamination

[0057] Step 1: Dissolve decanediol in dioxane and store in a raw material tank to obtain a first mixed solution, then add liquid ammonia to the raw material tank to obtain a second mixed solution, control the molar ratio of the first mixed solution to liquid ammonia to be 1:12, mix well and set aside.

[0058] Step 2: The catalyst 3 is loaded into a fixed bed reactor, the reaction temperature of the fixed bed reactor is set to 210°C, and then hydrogen is introduced, and the reaction pressure of hydrogen is set to 3.5 MPa;

[0059] Step 3: Use a plunger pump to inject the second mixed solution in the raw material tank into the fixed bed reactor, and control the space velocity of the second mixed solution to be 1.0h -1 , reacting to obtain the crude decanediamine;

[0060] The crude decanediamine product after gas-liquid separation was sampled and analyzed through a sampling port. The conversion rate of decanediol was calculated to be 99.9%, and the selectivity of decanediamine was 99.1%.

[0061] Step 4: distilling the crude decanediamine to remove the dioxane solvent to obtain the decanediamine product.

[0062] Example 4

[0063] Catalyst preparation

[0064] The palladium chloride and nitric acid are prepared into a palladium ion solution, the chromium chloride and nitric acid are prepared into a chromium ion solution, and the cobalt chloride and nitric acid are prepared into a cobalt ion solution. The palladium ion solution, the chromium ion solution and the cobalt ion solution are mixed to obtain a palladium-chromium-cobalt ion mixed solution, wherein the weight ratio of palladium element: chromium element: cobalt element in the palladium-chromium-cobalt ion mixed solution is 1:0.5:0.3 based on the weight of the precious metal elements. Then, a hydrogen peroxide solution is added to the palladium-chromium-cobalt ion mixed solution to obtain a palladium-chromium-cobalt ion mixed oxidation solution, wherein the weight ratio of the precious metal elements to hydrogen peroxide in the palladium-chromium-cobalt ion mixed oxidation solution is 1:25. The palladium-chromium-cobalt ion mixed oxidation solution is sprayed onto an alumina support, and after standing for 3 hours, the alumina support is washed and dried, and finally reduced under a hydrogen atmosphere to obtain a modified precious metal catalyst loaded with palladium, chromium and cobalt elements, which is recorded as catalyst four. The mass content of palladium in catalyst four is 1%, the mass content of chromium is 0.5%, and the mass content of cobalt is 0.3%.

[0065] Hydroamination

[0066] Step 1: Tetradecanediol is dissolved in p-xylene and stored in a raw material tank to obtain a first mixed solution, and then liquid ammonia is added to the raw material tank to obtain a second mixed solution. The molar ratio of the first mixed solution to the liquid ammonia is controlled to be 1:20, and the mixture is mixed evenly and set aside.

[0067] Step 2: The catalyst 4 is loaded into a fixed bed reactor, the reaction temperature of the fixed bed reactor is set to 220°C, and then hydrogen is introduced, and the reaction pressure of hydrogen is set to 6.0 MPa;

[0068] Step 3: Use a plunger pump to inject the second mixed solution in the raw material tank into the fixed bed reactor, and control the space velocity of the second mixed solution to be 0.8h -1 , the reaction obtains the crude tetradecanediamine;

[0069] The crude tetradecanediamine product after gas-liquid separation was sampled and analyzed through a sampling port. The conversion rate of tetradecanediol was calculated to be 99.8%, and the selectivity of tetradecanediamine was 98.6%.

[0070] Step 4: distilling the crude tetradecanediamine to remove the p-xylene solvent, and finally obtaining the tetradecanediamine product.

[0071] Example 5

[0072] Catalyst preparation

[0073] A palladium ion solution is prepared by mixing palladium chloride with nitric acid, a chromium ion solution is prepared by mixing chromium chloride with nitric acid, and a cobalt ion solution is prepared by mixing cobalt chloride with nitric acid. The palladium ion solution, the chromium ion solution, and the cobalt ion solution are mixed to obtain a palladium-chromium-cobalt ion mixed solution, wherein the weight ratio of palladium element: chromium element: cobalt element in the palladium-chromium-cobalt ion mixed solution is 1:0.2:0.1, based on the weight of the precious metal elements. A hydrogen peroxide solution is then added to the palladium-chromium-cobalt ion mixed solution to obtain a palladium-chromium-cobalt ion mixed oxidation solution, wherein the weight ratio of the precious metal elements to hydrogen peroxide in the palladium-chromium-cobalt ion mixed oxidation solution is 1:25. The palladium-chromium-cobalt ion mixed oxidation solution is sprayed onto an alumina support, allowed to stand for 3 hours, and then the alumina support is washed and dried. Finally, a reduction treatment is performed under a hydrogen atmosphere to obtain a modified precious metal catalyst loaded with palladium, chromium, and cobalt elements, which is designated as Catalyst 5. The mass content of palladium in Catalyst 5 is 1%, the mass content of chromium is 0.2%, and the mass content of cobalt is 0.1%.

[0074] Hydroamination

[0075] Step 1: dissolving dodecanediol in o-xylene and storing the solution in a raw material tank to obtain a first mixed solution, then adding liquid ammonia into the raw material tank to obtain a second mixed solution, controlling the molar ratio of the first mixed solution to the liquid ammonia to be 1:18, and mixing the solution evenly for later use.

[0076] Step 2: The catalyst 5 is loaded into a fixed bed reactor, the reaction temperature of the fixed bed reactor is set to 230°C, and then hydrogen is introduced, and the reaction pressure of the hydrogen is set to 5.0 MPa;

[0077] Step 3: Use a plunger pump to inject the second mixed solution in the raw material tank into the fixed bed reactor, and control the space velocity of the second mixed solution to be 0.7h -1 , reacting to obtain the crude dodecanediamine;

[0078] The crude dodecanediamine product of the reaction product after gas-liquid separation was sampled and analyzed through a sampling port. The conversion rate of dodecanediol was calculated to be 99.4%, and the selectivity of dodecanediamine was 98.3%.

[0079] Step 4: distilling the crude dodecanediamine to remove the o-xylene solvent, and finally obtaining the dodecanediamine product.

[0080] Example 6

[0081] A palladium ion solution is prepared by mixing palladium chloride with nitric acid, a chromium ion solution is prepared by mixing chromium chloride with nitric acid, and a cobalt ion solution is prepared by mixing cobalt chloride with nitric acid. The palladium ion solution, the chromium ion solution, and the cobalt ion solution are mixed to obtain a palladium-chromium-cobalt ion mixed solution, wherein the weight ratio of palladium element: chromium element: cobalt element in the palladium-chromium-cobalt ion mixed solution is 1:0.2:0.3 based on the weight of the precious metal elements. A hydrogen peroxide solution is then added to the palladium-chromium-cobalt ion mixed solution to obtain a palladium-chromium-cobalt ion mixed oxidation solution, wherein the weight ratio of the precious metal elements to hydrogen peroxide in the palladium-chromium-cobalt ion mixed oxidation solution is 1:25. The palladium-chromium-cobalt ion mixed oxidation solution is sprayed onto an alumina support, and after standing for 3 hours, the alumina support is washed and dried, and finally reduced under a hydrogen atmosphere to obtain a modified precious metal catalyst loaded with palladium, chromium, and cobalt elements, which is recorded as Catalyst 6. The mass content of palladium in Catalyst 6 is 1%, the mass content of chromium is 0.2%, and the mass content of cobalt is 0.3%.

[0082] Hydroamination

[0083] Step 1: Tetradecanediol is dissolved in m-xylene and stored in a raw material tank to obtain a first mixed solution, and then liquid ammonia is added to the raw material tank to obtain a second mixed solution. The molar ratio of the first mixed solution to the liquid ammonia is controlled to be 1:16, and the mixture is mixed evenly and set aside.

[0084] Step 2: The above catalyst 6 is loaded into a fixed bed reactor, the reaction temperature of the fixed bed reactor is set to 240°C, and then hydrogen is introduced, and the reaction pressure of hydrogen is set to 4.5 MPa;

[0085] Step 3: Use a plunger pump to inject the second mixed solution in the raw material tank into the fixed bed reactor, and control the space velocity of the second mixed solution to be 0.6h -1 , the reaction obtains the crude tetradecanediamine;

[0086] The crude tetradecanediamine product after gas-liquid separation was sampled and analyzed through a sampling port. The conversion rate of tetradecanediol was calculated to be 99.6%, and the selectivity of tetradecanediamine was 98.5%.

[0087] Step 4: distilling the crude tetradecanediamine to remove the meta-xylene solvent, and finally obtaining the tetradecanediamine product.

[0088] Example 7

[0089] Catalyst preparation

[0090] A palladium ion solution is prepared by mixing palladium chloride with nitric acid, and a cobalt ion solution is prepared by mixing chromium chloride with nitric acid. The palladium ion solution and the chromium ion solution are mixed to obtain a palladium-chromium ion mixed solution, wherein the weight ratio of palladium to chromium in the palladium-chromium ion mixed solution is 1:0.3, based on the weight of the precious metal elements. A hydrogen peroxide solution is then added to the palladium-chromium ion mixed solution to obtain a palladium-chromium ion mixed oxidation solution, wherein the weight ratio of the precious metal elements to hydrogen peroxide in the palladium-chromium ion mixed oxidation solution is 1:12. The palladium-chromium ion mixed oxidation solution is sprayed onto an alumina support, allowed to stand for 2 hours, washed, dried, and finally reduced under a hydrogen atmosphere to obtain a modified precious metal catalyst loaded with palladium and chromium elements, designated as Catalyst 7. The mass content of palladium in Catalyst 7 is 0.5%, and the mass content of chromium is 0.15%.

[0091] Hydroamination

[0092] Step 1: dissolve hexylene glycol in benzene and store it in a raw material tank to obtain a first mixed solution, then fill the raw material tank with liquid ammonia to obtain a second mixed solution, control the molar ratio of the first mixed solution to liquid ammonia to be 1:5, mix well and set aside.

[0093] Step 2: The above catalyst 7 is loaded into a fixed bed reactor, the reaction temperature of the fixed bed reactor is set to 240°C, and then hydrogen is introduced, and the reaction pressure of hydrogen is set to 1 MPa;

[0094] Step 3: Use a plunger pump to inject the second mixed solution in the raw material tank into the fixed bed reactor, and control the space velocity of the second mixed solution to be 0.5h -1 , reacting to obtain the crude hexamethylenediamine;

[0095] The crude hexamethylenediamine product after gas-liquid separation was sampled and analyzed through a sampling port. The conversion rate of hexamethylenediol was calculated to be 99.3%, and the selectivity of hexamethylenediamine was 97.0%.

[0096] Step 4: distilling the crude hexamethylenediamine to remove the benzene solvent, and finally obtaining the hexamethylenediamine product.

[0097] Example 8

[0098] Catalyst preparation

[0099] A palladium ion solution is prepared by mixing palladium chloride with nitric acid, and a cobalt ion solution is prepared by mixing cobalt chloride with nitric acid. The palladium ion solution and the cobalt ion solution are mixed to obtain a palladium-cobalt ion mixed solution, wherein the weight ratio of palladium to cobalt in the palladium-cobalt ion mixed solution is 1:0.8, based on the weight of the precious metal elements. A hydrogen peroxide solution is then added to the palladium-cobalt ion mixed solution to obtain a palladium-cobalt ion mixed oxidation solution, wherein the weight ratio of the precious metal elements to hydrogen peroxide in the palladium-cobalt ion mixed oxidation solution is 1:15. The palladium-cobalt ion mixed oxidation solution is sprayed onto an alumina support, allowed to stand for 2 hours, then washed and dried, and finally reduced under a hydrogen atmosphere to obtain a modified precious metal catalyst loaded with palladium and cobalt elements, designated as Catalyst Eight. The mass content of palladium in Catalyst Eight is 0.1%, and the mass content of cobalt is 0.08%.

[0100] Hydroamination

[0101] Step 1: dissolving octanediol in toluene and storing the solution in a raw material tank to obtain a first mixed solution, then adding liquid ammonia into the raw material tank to obtain a second mixed solution, controlling the molar ratio of the first mixed solution to the liquid ammonia to be 1:8, and mixing the solution evenly for later use.

[0102] Step 2: The catalyst VIII is loaded into a fixed bed reactor, the reaction temperature of the fixed bed reactor is set to 260°C, and then hydrogen is introduced, and the reaction pressure of the hydrogen is set to 2 MPa;

[0103] Step 3: Use a plunger pump to inject the second mixed solution in the raw material tank into the fixed bed reactor, and control the space velocity of the second mixed solution to be 0.3h -1 , reacting to obtain the crude product of octanediamine;

[0104] The crude octanediamine product of the reaction after gas-liquid separation was sampled and analyzed through a sampling port. The conversion rate of octanediol was calculated to be 99.1%, and the selectivity of octanediamine was 96.5%.

[0105] Step 4: distilling the crude octanediamine to remove the toluene solvent, and finally obtaining the octanediamine product.

[0106] Example 9

[0107] Catalyst preparation

[0108] A palladium ion solution is prepared by mixing palladium chloride with nitric acid, and a cobalt ion solution is prepared by mixing cobalt chloride with nitric acid. The palladium ion solution and the cobalt ion solution are mixed to obtain a palladium-cobalt ion mixed solution, wherein the weight ratio of palladium to cobalt in the palladium-cobalt ion mixed solution is 1:0.5, based on the weight of the precious metal elements. A hydrogen peroxide solution is then added to the palladium-cobalt ion mixed solution to obtain a palladium-cobalt ion mixed oxidation solution, wherein the weight ratio of the precious metal elements to hydrogen peroxide in the palladium-cobalt ion mixed oxidation solution is 1:20. The palladium-cobalt ion mixed oxidation solution is sprayed onto an alumina support, and after standing for 2 hours, the alumina support is washed and dried, and finally reduced under a hydrogen atmosphere to obtain a modified precious metal catalyst loaded with palladium and cobalt elements, which is recorded as Catalyst 9. The mass content of palladium in Catalyst 9 is 0.3%, and the mass content of cobalt is 0.15%.

[0109] Hydroamination

[0110] Step 1: dissolve hexylene glycol in ethylbenzene and store it in a raw material tank to obtain a first mixed solution, then fill the raw material tank with liquid ammonia to obtain a second mixed solution, control the molar ratio of the first mixed solution to liquid ammonia to be 1:10, mix well and set aside.

[0111] Step 2: The above-mentioned catalyst 9 is loaded into a fixed bed reactor, the reaction temperature of the fixed bed reactor is set to 250°C, and then hydrogen is introduced, and the reaction pressure of hydrogen is set to 3.0 MPa;

[0112] Step 3: Use a plunger pump to inject the second mixed solution in the raw material tank into the fixed bed reactor, and control the space velocity of the second mixed solution to be 0.4h -1 , reacting to obtain the crude hexanediol;

[0113] The crude hexamethylenediamine product after gas-liquid separation was sampled and analyzed through a sampling port. The conversion rate of hexamethylenediol was calculated to be 99.1%, and the selectivity of hexamethylenediamine was 96.5%.

[0114] Step 4: distilling the crude hexamethylenediamine to remove the ethylbenzene solvent, and finally obtaining the hexamethylenediamine product.

[0115] Comparative Example 1

[0116] Catalyst preparation

[0117] A palladium ion solution is prepared by mixing palladium chloride and nitric acid. A hydrogen peroxide solution is then added to the palladium ion mixed solution to obtain a palladium ion mixed oxidation solution, wherein the weight ratio of the noble metal element to hydrogen peroxide in the palladium ion mixed oxidation solution is 1:20. The palladium ion mixed oxidation solution is sprayed onto an alumina support, allowed to stand for 4 hours, and then washed and dried. Finally, the alumina support is reduced under a hydrogen atmosphere to obtain a modified noble metal catalyst loaded with palladium, designated as Catalyst 10. The palladium content of Catalyst 10 is 3% by weight.

[0118] Hydroamination

[0119] Step 1: dissolving decanediol in tert-butyl alcohol and storing the solution in a raw material tank to obtain a first mixed solution, then adding liquid ammonia into the raw material tank to obtain a second mixed solution, controlling the molar ratio of the first mixed solution to the liquid ammonia to be 1:10, and mixing the solution evenly for later use.

[0120] Step 2: The catalyst 10 is loaded into a fixed bed reactor, the reaction temperature of the fixed bed reactor is set to 200° C., and then hydrogen is introduced, and the reaction pressure of the hydrogen is set to 3.0 MPa;

[0121] Step 3: Use a plunger pump to inject the second mixed solution in the raw material tank into the fixed bed reactor, and control the space velocity of the second mixed solution to be 1.2h -1 , reacting to obtain the crude decanediamine;

[0122] The crude decanediamine product after gas-liquid separation was sampled and analyzed through a sampling port. The conversion rate of decanediol was calculated to be 99.5%, and the selectivity of decanediamine was 94.6%.

[0123] Step 4: distilling the crude decanediamine to remove the tert-butanol solvent to obtain the decanediamine product.

[0124] Comparative Example 2

[0125] Catalyst preparation

[0126] A palladium ion solution is prepared by mixing palladium chloride and nitric acid. A hydrogen peroxide solution is then added to the palladium ion mixed solution to obtain a palladium ion mixed oxidation solution. The weight ratio of the noble metal element to hydrogen peroxide in the palladium ion mixed oxidation solution is 1:40. The palladium ion mixed oxidation solution is sprayed onto an alumina support. After standing for 4 hours, the alumina support is washed and dried, and finally reduced under a hydrogen atmosphere to obtain a modified noble metal catalyst loaded with palladium, designated as Catalyst 11. The palladium content of Catalyst 11 is 5% by weight.

[0127] Hydroamination

[0128] Step 1: dissolving dodecanediol in tetrahydrofuran and storing the solution in a raw material tank to obtain a first mixed solution, then adding liquid ammonia into the raw material tank to obtain a second mixed solution, controlling the molar ratio of the first mixed solution to the liquid ammonia to be 1:14, and mixing the solution evenly for later use.

[0129] Step 2: The above-mentioned catalyst 2 is loaded into a fixed bed reactor, the reaction temperature of the fixed bed reactor is set to 180°C, and then hydrogen is introduced, and the reaction pressure of hydrogen is set to 4.0 MPa;

[0130] Step 3: Use a plunger pump to inject the second mixed solution in the raw material tank into the fixed bed reactor, and control the space velocity of the second mixed solution to be 1.5h -1 , reacting to obtain the crude dodecanediamine;

[0131] The crude dodecanediamine product of the reaction product after gas-liquid separation was sampled and analyzed through a sampling port. The conversion rate of dodecanediol was calculated to be 99.6%, and the selectivity of dodecanediamine was 95.3%.

[0132] Step 4: distilling the crude dodecanediamine product to remove the tetrahydrofuran solvent, and finally obtaining the dodecanediamine product.

[0133] Comparative Example 3

[0134] Catalyst preparation

[0135] A palladium ion solution is prepared by mixing palladium chloride and nitric acid, and a hydrogen peroxide solution is then added to the palladium ion mixed solution to obtain a palladium ion mixed oxidation solution, wherein the weight ratio of the noble metal element to hydrogen peroxide in the palladium ion mixed oxidation solution is 1:30. The palladium ion mixed oxidation solution is sprayed onto an alumina support, and after standing for 3 hours, the alumina support is washed and dried, and finally reduced under a hydrogen atmosphere to obtain a modified noble metal catalyst loaded with palladium, denoted as Catalyst 12. The mass content of palladium in Catalyst 12 is 1%.

[0136] Hydroamination

[0137] Step 1: Dissolve decanediol in dioxane and store in a raw material tank to obtain a first mixed solution, then add liquid ammonia to the raw material tank to obtain a second mixed solution, control the molar ratio of the first mixed solution to liquid ammonia to be 1:12, mix well and set aside.

[0138] Step 2: The catalyst 12 is loaded into a fixed bed reactor, the reaction temperature of the fixed bed reactor is set to 210° C., and then hydrogen is introduced, and the reaction pressure of the hydrogen is set to 3.5 MPa;

[0139] Step 3: Use a plunger pump to inject the second mixed solution in the raw material tank into the fixed bed reactor, and control the space velocity of the second mixed solution to be 1.0h -1 , reacting to obtain the crude decanediamine;

[0140] The crude decanediamine product after gas-liquid separation was sampled and analyzed through a sampling port. The conversion rate of decanediol was calculated to be 99.1%, and the selectivity of decanediamine was 94.5%.

[0141] Step 4: distilling the crude decanediamine to remove the dioxane solvent to obtain the decanediamine product.

[0142] From the above examples and comparative examples, it can be seen that, among them, Examples 1-3 are respectively compared with Comparative Examples 1-3, and the difference is that the modified precious metal catalysts in Examples 1-3 are added with chromium or cobalt metal elements, and the sites at various positions of the intermediate carbon chain are rationally distributed and utilized by precious metal ions with different ionic radii. The palladium ions with smaller radius are bonded to the active sites inside the intermediate carbon chain, making full use of the active sites of the intermediate, thereby improving the activity of the catalyst, so that the raw material conversion rate can reach 99.9%, which is almost completely converted; the chromium and / or cobalt ions with larger radius are bonded to the active sites outside the intermediate carbon chain to form a more complex structure carrying large groups on its surface, thereby making it impossible for the amination product to continue to react with the intermediate carbon chain due to spatial interference, thereby inhibiting the side reaction, so that the yield of high-carbon diamines can reach an average of more than 98%, and the atom economy is extremely high. In addition, Examples 4-9 all use modified precious metal catalysts. Although their high-carbon diol conversion rates are comparable to those of Comparative Examples 1-3, the diamine selectivity of Examples 4-9 is significantly improved. This indicates that the use of palladium elements with a smaller ionic radius as the main active component, combined with a suitable proportion of chromium and / or cobalt elements with larger ionic radii, can inhibit side reactions during the reaction, allowing the modified precious metal catalyst to have a significant effect on improving the selectivity of high-carbon diamines.

[0143] While the present invention has been disclosed above with reference to preferred embodiments, this is not intended to limit the present invention. Persons skilled in the art will readily appreciate that various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A method for preparing a high-carbon diamine by hydroamination of a high-carbon diol, characterized in that: The method comprises the following steps: Step 1: dissolving a higher carbon diol in an inert solvent to obtain a first mixed solution, and then uniformly mixing the first mixed solution with liquid ammonia to obtain a second mixed solution, wherein the higher carbon diol has a general structural formula of HO-R1-OH, wherein R1 is a C6-C14 alkyl group; Step 2: heating a fixed bed reactor filled with a modified precious metal catalyst to a reaction temperature while introducing hydrogen, wherein the active components of the modified precious metal catalyst include palladium, chromium and / or cobalt, the carrier of the modified precious metal catalyst is alumina, the mass content of the palladium element is 0.1%-5.0% of the total mass of the modified precious metal catalyst, and the mass content of the chromium element and / or cobalt element is 30%-80% of the mass content of the palladium element; Step 3: adding the second mixed solution into the fixed bed reactor in step 2 to react under reaction pressure to obtain a crude high-carbon diamine; Step 4: distilling the crude high-carbon diamine to remove the inert solvent to obtain the high-carbon diamine.

2. The method for preparing a higher carbon diamine by hydroamination of a higher carbon diol according to claim 1, characterized in that: The R1 is a C8-C12 alkyl group.

3. The method for preparing a higher carbon diamine by hydroamination of a higher carbon diol according to claim 1 or 2, characterized in that: The preparation method of the modified noble metal catalyst is as follows: A palladium ion solution is mixed with a chromium ion solution and / or a cobalt ion solution to obtain a noble metal ion mixed solution, an oxidant is added to the noble metal ion mixed solution to obtain a noble metal ion mixed oxidation solution, the noble metal ion mixed oxidation solution is sprayed on an alumina carrier, and sequentially washed, dried, and reduced to obtain the modified noble metal catalyst.

4. The method for preparing a higher carbon diamine by hydroamination of a higher carbon diol according to claim 3, characterized in that: The weight ratio of the noble metal ions to the oxidant in the noble metal ion mixed solution is 1:(12-40).

5. The method for preparing a higher carbon diamine by hydroamination of a higher carbon diol according to claim 1, characterized in that: The inert solvent in step 1 is one or more of dioxane, tetrahydrofuran, tert-butanol, benzene, toluene, ethylbenzene, p-xylene, o-xylene, and m-xylene.

6. The method for preparing a higher carbon diamine by hydroamination of a higher carbon diol according to claim 1, characterized in that: The molar ratio of the first mixed solution to the liquid ammonia in the step 1 is 1:5-1:

20.

7. The method for preparing a higher carbon diamine by hydroamination of a higher carbon diol according to claim 1, characterized in that: The reaction temperature in step 2 is 180°C-260°C.

8. The method for preparing a higher carbon diamine by hydroamination of a higher carbon diol according to claim 1, characterized in that: The reaction pressure of the hydrogen in the step 2 is 1 MPa-6 MPa.

9. The method for preparing a higher carbon diamine by hydroamination of a higher carbon diol according to claim 1, characterized in that: In the step 3, the second mixed solution is heated at a volume space velocity of 0.3-1.5h -1 Add to the fixed bed reactor in step 2.