A catalyst, a method for preparing the same, and use thereof

Abstract

The application provides a catalyst, a preparation method and application thereof. The catalyst comprises a porous substrate and an auxiliary agent arranged on at least part of the surface of the porous substrate, the porous substrate comprises a Raney cobalt material, and the auxiliary agent comprises metallic rhenium, an alkali metal and an alkaline earth metal; wherein the Raney cobalt material comprises a Co-S chemical bond. The catalyst provided by the application has excellent activity, and can effectively improve the conversion rate of dinitrile compounds and the selectivity of diamines.

Description

Technical Field

[0001] This application belongs to the field of materials technology, and in particular relates to a catalyst, its preparation method and its application. Background Technology

[0002] Diamine compounds (such as hexamethylenediamine and 2-methylpentanediamine) are important intermediates in the chemical industry, widely used in the preparation of synthetic resins, coatings, pharmaceutical intermediates, and high-performance materials. One of their core synthetic routes involves the hydrogenation reaction of dinitrile compounds (such as adiponitrile and 2-methylpentanediamine). This reaction typically requires the selective reduction of the nitrile group (-CN) to an amino group under the action of a catalyst, while avoiding over-reduction or side reactions. Due to the high added value and wide range of applications of diamine compounds, developing efficient and low-cost catalysts and processes is a pressing technical challenge for the chemical industry.

[0003] In industrial production, the efficiency and product selectivity of the dinitrile hydrogenation reaction directly affect production costs and product purity. Current technologies suffer from insufficient catalyst activity, selectivity, and stability, leading to harsh reaction conditions (such as high temperature and pressure), numerous byproducts, and severe equipment corrosion, thus limiting the large-scale application of this process. Summary of the Invention

[0004] This invention provides a catalyst that exhibits higher activity and selectivity in the hydrogenation reaction of dinitrile compounds.

[0005] The present invention also provides a method for preparing a catalyst, which can prepare the above-mentioned catalyst, and the process is simple and low in cost.

[0006] The present invention also provides a method for preparing diamine, which is obtained by using the above-mentioned catalyst to catalyze the hydrogenation reaction of dinitrile compounds, thereby improving the conversion rate of dinitrile compounds and the selectivity of diamine.

[0007] In a first aspect, the present invention provides a catalyst comprising: a porous matrix and an additive disposed on at least a portion of the surface of the porous matrix, wherein the porous matrix comprises Raney cobalt material, and the additive comprises rhenium metal, alkali metal, and alkaline earth metal; wherein the Raney cobalt material comprises Co-S chemical bonds.

[0008] In an alternative embodiment, the Raney cobalt material comprises cobalt and cobalt sulfide compounds, wherein the Co-S chemical bond originates from the cobalt sulfide compounds.

[0009] In an optional embodiment, the additive further includes boron-containing alumina; wherein, based on the total mass of the additive, the mass percentage of the boron-containing alumina is 20% to 60%.

[0010] And / or, in the boron-containing alumina, the mass percentage of boron is 0.5% to 2%.

[0011] In one optional embodiment, the cobalt sulfide compound accounts for 1%-10% by mass;

[0012] And / or, the mass percentage of the rhenium metal is 0.1%-5%;

[0013] And / or, the alkali metal accounts for 0.1%-5% of the total mass;

[0014] And / or, the mass percentage of the alkaline earth metal is 0.1%-5%.

[0015] Secondly, the present invention provides a method for preparing the catalyst as described above, comprising the following steps:

[0016] A first mixture of cobalt-aluminum alloy and rhenium metal is used to obtain Raney cobalt containing rhenium metal by alkaline etching;

[0017] The first intermediate is obtained by co-precipitation treatment of a second mixture including an alkali metal additive, the Raney cobalt containing rhenium, and an alkaline earth metal salt.

[0018] A slurry is prepared by mixing boron-containing pseudoboehmite, the first intermediate, and a binder.

[0019] The slurry was spray-dried and granulated to obtain the second intermediate.

[0020] A third mixture comprising the second intermediate and a sulfur source solution is dried and then subjected to reduction roasting to obtain the catalyst.

[0021] In an optional embodiment, the alkaline etching includes: mixing the first mixture with an alkaline solution at 50-60°C to obtain the Raney cobalt containing rhenium.

[0022] In an alternative embodiment, the boron-containing pseudoboehmite is prepared by the following process:

[0023] At 25~40℃, a precipitant is added to an aluminate solution to obtain a precipitate. The precipitate is mixed with a boron source and aged at 60~90℃ to obtain the boron-containing pseudoboehmite.

[0024] In an optional embodiment, the mass ratio of the pseudoboehmite, the first intermediate, and the binder is 1:(2~4):(0.03~0.25);

[0025] And / or, the ratio of the second intermediate to the sulfur source is 100:(1~10).

[0026] In one optional embodiment, the calcination treatment is carried out at a temperature of 600~1100℃ for a time of 2~18h.

[0027] Thirdly, the present invention provides a method for preparing a diamine, comprising catalytically hydrogenating a dinitrile compound using a catalyst prepared by the method described in the first aspect or the method described in the second aspect.

[0028] The catalyst provided by this invention uses Raney cobalt as a matrix and significantly improves the activity and selectivity of the catalyst and reduces the formation of reaction byproducts by doping with auxiliary elements rhenium, alkali metals, and alkaline earth metals, and introducing Co-S chemical bonds and boron-containing alumina structures. Detailed Implementation

[0029] Exemplary embodiments will be described in detail below. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0030] In this application, the terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. For example, without departing from the scope of the embodiments of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0031] In this application, references to "an embodiment," "an example," or "an example" mean that a specific feature, structure, or characteristic described in connection with that embodiment, example, or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination.

[0032] Existing technologies for the hydrogenation of dinitrile compounds to prepare diamines often face problems of insufficient catalyst activity and selectivity. These catalysts often fail to effectively improve the conversion rate of dinitrile compounds and readily generate byproducts during the reaction, reducing the selectivity of the target product. Furthermore, the preparation process of traditional catalysts is complex and costly, limiting their widespread use in industrial applications. Therefore, this invention provides the following solution.

[0033] In a first aspect, the present invention provides a catalyst comprising: a porous matrix and an additive disposed on at least a portion of the surface of the porous matrix, wherein the porous matrix comprises Raney cobalt material, and the additive comprises rhenium metal, alkali metal, and alkaline earth metal; wherein the Raney cobalt material comprises Co-S chemical bonds.

[0034] In this invention, the porous matrix is ​​made of Raney cobalt material, whose porous structure provides a large number of active sites, which can significantly improve the specific surface area and reaction activity of the catalyst. The Co-S chemical bonds introduced into the Raney cobalt material further enhance the catalytic performance of the catalyst. The introduction of S forms a sulfide interface, enhancing the adsorption active sites for dinitrile compounds, while also effectively inhibiting metal sintering. Furthermore, in this invention, rhenium metal, with its unique electronic properties and catalytic characteristics, effectively promotes the dissociation and activation of hydrogen molecules, reducing the energy barrier in the reaction pathway, thereby improving the activity and selectivity of the catalyst. Alkali metals and alkaline earth metals further optimize the reaction environment by adjusting the surface acidity and basicity of the catalyst, suppressing the occurrence of side reactions and ensuring high selectivity for the target product. Therefore, the synergistic effect of these promoters not only improves the performance of the catalyst but also enhances its stability and durability, enabling it to maintain excellent catalytic activity under high temperature and long-term reaction conditions. Through this multi-component synergistic effect, the catalyst of this invention significantly reduces the formation of by-products while improving reaction activity, selectivity, and stability, thus improving the overall reaction efficiency.

[0035] In one specific embodiment, the Raney cobalt material includes cobalt and cobalt sulfide compounds, wherein the Co-S chemical bond originates from the cobalt sulfide compounds.

[0036] The Raney cobalt material in this invention includes not only cobalt but also cobalt sulfide compounds, where the Co-S chemical bonds are a key source of catalytic activity. The presence of Co-S bonds alters the electronic structure of cobalt, promoting hydrogen activation and transfer, thereby increasing the reaction rate and catalytic efficiency.

[0037] In one specific embodiment, the additive further includes boron-containing alumina; wherein, based on the total mass of the additive, the mass percentage of the boron-containing alumina is 0.1%-5%.

[0038] For example, the mass percentage of the boron-containing alumina is any one or any combination of 0.1%, 0.2%, 1%, 2%, 3%, 4%, and 5%.

[0039] In some embodiments, the boron-containing alumina contains boron at a mass ratio of 0.5% to 2%.

[0040] For example, the mass percentage of boron may be any value or a range of two of the following: 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%.

[0041] The additives of this invention also include boron-containing alumina, the strong electronegativity of B being achieved through substitution. The formation of BO-Al bonds creates an electron-deficient surface, enhancing the catalyst's adsorption capacity for cyano groups (-CN), thereby further improving the catalyst's activity and selectivity. Furthermore, boron-containing alumina, through its interaction with the Raney cobalt matrix, can form stable active sites on the catalyst surface, improving reaction efficiency.

[0042] In one specific embodiment, the cobalt sulfide compound accounts for 1%-10% of the total mass.

[0043] For example, the mass percentage of the cobalt sulfide compound is any one or any two of 1%, 2%, 3%, 5%, 7%, 8%, 9%, 10%.

[0044] In some embodiments, the mass percentage of the rhenium metal is 0.1%-5%.

[0045] For example, the mass percentage of the rhenium metal is any one or any two of 0.1%, 0.2%, 2%, 3%, and 5%.

[0046] In some embodiments, the alkali metal accounts for 0.1%-5% of the total mass.

[0047] For example, the mass percentage of the alkali metal is any one or any two of 0.1%, 0.2%, 0.3%, 2%, 2.5%, 4%, and 5%.

[0048] In some embodiments, the alkaline earth metal accounts for 0.1%-5% of the total mass.

[0049] For example, the mass percentage of the alkaline earth metal is any one or any two of 0.1%, 0.2%, 1%, 3%, 4%, and 5%.

[0050] The mass proportions of the aforementioned additives all effectively improved the activity and stability of the catalyst.

[0051] Secondly, the present invention provides a method for preparing the catalyst as described above, comprising the following steps:

[0052] A first mixture of cobalt-aluminum alloy and rhenium metal is used to obtain Raney cobalt containing rhenium metal by alkaline etching;

[0053] The first intermediate is obtained by co-precipitation treatment of a second mixture including an alkali metal additive, the Raney cobalt containing rhenium, and an alkaline earth metal salt.

[0054] A slurry is prepared by mixing boron-containing pseudoboehmite, the first intermediate, and a binder.

[0055] The slurry was spray-dried and granulated to obtain the second intermediate.

[0056] A third mixture comprising the second intermediate and a sulfur source solution is dried and then subjected to reduction roasting to obtain the catalyst.

[0057] The catalyst preparation method of this invention can prepare the catalyst provided in the first aspect of this invention. By using a combination of cobalt-aluminum alloy and rhenium, and alkaline etching technology, Raney cobalt containing rhenium can be effectively prepared. Alkaline etching not only removes excess aluminum but also exposes more active sites. The co-precipitation step further improves the uniformity and stability of the material through the action of alkali metal additives and solvents. The mixing of boron-containing boehmite with the first intermediate and binder forms a slurry with excellent mechanical strength and heat resistance. Spherical catalysts containing boron-containing alumina embedded in the alloy active phase are prepared by spray mixing. The spherical particles, unlike the original alloy catalyst which has sharp edges, can effectively reduce the pulverization problem during catalyst use. The spray drying granulation step ensures the uniformity and dispersion of the particles. Finally, through reduction calcination treatment, a catalyst with high activity and selectivity is formed. The comprehensive application of this method ensures the excellent performance of the catalyst in a variety of chemical reactions. This preparation method is simple and easy to implement, and does not require the addition of additional alkaline substances during the preparation process, thus avoiding equipment corrosion and environmental pollution. It is easy to scale up industrial production, does not use precious metals, has low production costs, long service life, and has good application prospects.

[0058] In one specific embodiment, the alkaline etching includes: mixing the first mixture with an alkaline solution at 50-60°C to obtain the Raney cobalt containing rhenium.

[0059] In some embodiments, the alkaline etching is performed by synthesizing cobalt and aluminum into an alloy in a certain proportion at 50-60°C, adding rhenium metal to obtain a rhenium-doped cobalt-aluminum alloy, and then etching with sodium hydroxide solution to obtain a rhenium-doped Raney cobalt catalyst.

[0060] In some embodiments, the alkaline solution used in the alkaline etching can be at least one of sodium hydroxide solution, potassium hydroxide solution, and lithium hydroxide solution.

[0061] In some embodiments, cobalt and aluminum are synthesized into an alloy in a ratio of 60%-90% and 10%-40%, respectively, and rhenium is added during the smelting process. This combination not only enhances the mechanical strength and chemical stability of the alloy, but also improves the electronic structure of the catalyst by introducing rhenium, providing more active sites.

[0062] For example, the ratio of cobalt to aluminum can be any of the following values ​​or a range of both: 60%:40%, 70%:30%, 80%:20%, 90%:10%.

[0063] For example, the alkaline etching temperature can be any value or a range of two of the following: 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C, 60°C.

[0064] The selection of the temperature range described above helps improve etching efficiency and ensures the high purity and activity of Raney cobalt. Simultaneously, this temperature condition also helps control the reaction rate and reduce the formation of byproducts.

[0065] In some embodiments, the Raney cobalt containing rhenium is added to a heated alkali metal auxiliary agent solution, and then a heated alkaline earth metal salt solution is added dropwise to obtain a second mixture. The second mixture is subjected to a co-precipitation reaction, and after aging for a period of time, stirring and heating are stopped to obtain a first intermediate.

[0066] In some embodiments, the alkali metal auxiliaries may be one or more of sodium hydroxide (NaOH), potassium hydroxide (KOH), lithium hydroxide (LiOH), rubidium hydroxide (RbOH), and cesium hydroxide (CsOH).

[0067] In some embodiments, the molar concentration of the alkali metal auxiliary agent solution is 0.1~1 mol / L.

[0068] In some embodiments, the alkali metal auxiliary agent solution is heated to 40-70°C, preferably 50-65°C.

[0069] For example, the concentration of the alkali metal auxiliary agent solution can be any value or a range of both, such as 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L;

[0070] For example, the temperature of the alkali metal auxiliary agent solution can be any value or a range of two of the following: 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, 65°C.

[0071] The selection and concentration range of the aforementioned alkali metal promoters can effectively adjust the surface acidity and alkalinity of the catalyst, resulting in more active sites on the catalyst surface and thus improving the catalyst activity; the temperature of the alkali metal promoters can make the Raney cobalt containing rhenium more uniformly dispersed, further improving the catalyst activity.

[0072] In some embodiments, the alkaline earth metal salt can be one or more of calcium nitrate, magnesium nitrate, strontium nitrate, barium nitrate and manganese nitrate, wherein one or more of strontium nitrate and barium nitrate are preferred.

[0073] In some embodiments, the concentration of the alkaline earth metal salt solution is 0.05~0.5 mol / L;

[0074] In some embodiments, the alkaline earth metal salt solution is heated to 40-70°C, preferably 50-65°C;

[0075] In some embodiments, the dropping time of the alkaline earth metal salt solution is controlled at 15-55 min, preferably 18-32 min;

[0076] In some embodiments, the aging time for the co-precipitation treatment of the second mixture is 0.5 to 2 hours;

[0077] For example, the concentration of alkaline earth metal salt can be any value or a range of both of the following: 0.05 mol / L, 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L, 0.3 mol / L, 0.35 mol / L, 0.4 mol / L, 0.45 mol / L, 0.5 mol / L.

[0078] For example, the temperature of the alkaline earth metal salt can be any value or a range of two of the following: 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, 65°C.

[0079] For example, the dripping time of alkaline earth metal salt can be any value or a range of both, such as 18 min, 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, 32 min, etc.

[0080] The aging time for the co-precipitation treatment of the second mixture can be any value of 0.5h, 1h, 1.5h, 2h, or a range of both.

[0081] The selection of alkaline earth metal salts, concentration ranges, heating temperatures, dropping times, and aging times of the second mixture co-precipitation treatment can all enable alkaline earth metal elements to be deposited more uniformly on the surface of the catalyst channels, thereby enhancing the activity of the catalyst.

[0082] In some embodiments, the first intermediate is washed with a solvent or deionized water, and the solvent may be one or a combination of ethanol, isopropanol, acetone and ethyl acetate.

[0083] Washing with the solvents described above can effectively remove impurities and unreacted substances remaining in the first intermediate, ensuring the purity of the prepared catalyst.

[0084] In one specific embodiment, the boron-containing pseudoboehmite is prepared by the following process:

[0085] At 25~40℃, a precipitant is added to an aluminate solution to obtain a precipitate. The precipitate is mixed with a boron source and aged at 60~90℃ to obtain the boron-containing pseudoboehmite.

[0086] In some embodiments, the boron source is one or more of boric acid, borax (sodium tetraborate), and ammonium pentaborate.

[0087] In some embodiments, the aluminate is one or more of sodium aluminate, potassium aluminate, and lithium aluminate.

[0088] In some implementations, the precipitant is .

[0089] For example, the temperature at which the precipitant is added to the aluminate solution can be any value or a range of two of the following: 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C.

[0090] For example, the aging temperature can be any value or a range of two of the following: 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, etc.

[0091] The method described above for preparing boron-containing pseudoboehmite ensures the uniformity and stability of the material through precipitation and aging treatment at specific temperatures. The resulting boron-containing pseudoboehmite, as a component of the catalyst, enhances the catalyst's heat resistance and mechanical strength, thereby improving its performance and service life under high-temperature conditions, while also increasing the catalyst's activity and selectivity.

[0092] In one specific embodiment, the mass ratio of the pseudoboehmite, the first intermediate, and the binder is 1:(2~4):(0.03~0.25).

[0093] And / or, the mass ratio of the second intermediate to the sulfur source is 100:(1~15).

[0094] For example, the mass ratio of boehmite, the first intermediate, and the binder can be a range of 1:2:0.03, 1:2:0.25, 1:4:0.03, 1:4:0.25, or any two of these.

[0095] For example, the ratio of the second intermediate to the sulfur source can be any one of 100:1, 100:2, 100:3, 100:5, 100:10, 100:15 or any combination of both.

[0096] In some embodiments, the adhesive may be at least one of polyethylene glycol, polyvinyl alcohol, carboxymethyl cellulose, and polyacrylic acid.

[0097] The mass ratio range of the aforementioned pseudoboehmite, the first intermediate, and the binder helps to form a catalyst with good structure and performance. The proportion within this range can improve the mechanical strength and chemical stability of the catalyst. In addition, the limited proportion range of the aforementioned second intermediate and sulfur source also helps to improve the activity and selectivity of the catalyst.

[0098] In some embodiments, the solid content of the slurry obtained by mixing boron-containing pseudoboehmite, the first intermediate, and the binder is adjusted using deionized water, and the solid content of the slurry is 20-40%.

[0099] For example, the solid content of the slurry can be any value of 20%, 25%, 30%, 35%, 40% or a range of any two of these.

[0100] In some embodiments, the slurry obtained by mixing boron-containing pseudoboehmite, the first intermediate, and the binder has a pH of 8 to 10.

[0101] For example, the pH value of the slurry can be any value of 8, 8.5, 9, 9.5, 10 or a range of any two of them.

[0102] The solid content of the slurry can control its viscosity and flowability, which helps to uniformly disperse particles in the slurry and prevents particle sedimentation or agglomeration. The solid content within the above range can ensure rapid evaporation of water during the subsequent spray drying granulation process, while forming a catalyst with good mechanical strength and pore structure. The pH value of the slurry can improve its stability, prevent excessive dissolution or agglomeration of particles in the slurry, maintain uniform particle dispersion, and make the catalyst obtained subsequently have more surface active sites.

[0103] In some embodiments, the second intermediate is obtained by spray drying granulation to produce spherical particles with a particle size of 50~150μm.

[0104] For example, the particle size of the second intermediate can be any value or a range of both of the following: 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm.

[0105] The second intermediate obtained above, being a spherical particle, differs from the original alloy catalyst in that it has sharp edges, which can effectively reduce the pulverization problem during the use of the catalyst and improve the performance of the catalyst.

[0106] In some embodiments, the sulfur source solution is at least one of ammonium sulfate solution, thiourea solution, and ammonium thiosulfate solution.

[0107] In some implementations, the concentration of the sulfur source solution is 0.1~0.3 mol / L.

[0108] For example, the concentration of the sulfur source solution can be any value or a range of both, such as 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L, 0.3 mol / L, etc.

[0109] The selection of the sulfur source solution can introduce sulfate ions, which can improve the catalyst activity while preventing metal sintering. The selection of the sulfur source solution concentration ensures the effectiveness of the sulfidation process. This concentration range can also make the sulfide uniformly distributed on the catalyst surface. A uniform sulfide layer can provide more active sites, thereby improving the catalyst activity and conversion rate.

[0110] In one specific embodiment, the calcination treatment is carried out at a temperature of 600~1100℃ for a time of 2~18h.

[0111] For example, the calcination temperature can be any value or a range of two of the following: 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, 1000°C, 1050°C, 1100°C.

[0112] For example, the calcination time can be any value or a range of two such values, such as 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, etc.

[0113] The aforementioned calcination temperature range allows for the effective removal of most solvents and impurities from the catalyst, improving its purity and activity. Furthermore, it helps maintain a suitable pore structure and specific surface area, enhancing catalyst stability and extending its lifespan. The calcination time within this range helps ensure the catalyst's structural integrity and long-term stability, thereby improving its performance in practical applications and significantly enhancing its overall performance.

[0114] In some embodiments, after calcination, a gas is introduced. Perform restoration. The concentration is 5%~100%, preferably 10%~50%, the reduction temperature is 450~750℃, and the reduction time is 2~10h.

[0115] For example, The concentration can be any value from 10%, 20%, 30%, 40%, 50%, or a range of both.

[0116] For example, the reduction temperature can be any value or a range of both of the following: 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, etc.

[0117] For example, the restoration time can be any value or a range of two such values, such as 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h.

[0118] Among them, the above-mentioned reduction process The concentration range ensures the effectiveness of the reduction, the reduction temperature range further ensures the effective reduction of the metal oxide, which can expose more active metal sites, and the reduction time range ensures the sufficiency of the reduction process. The catalyst obtained by reduction under these conditions has excellent catalytic activity.

[0119] Thirdly, the present invention provides a method for preparing a diamine, comprising catalytically hydrogenating a dinitrile compound using a catalyst prepared by the method described in the first aspect or the method described in the second aspect.

[0120] In some embodiments, the mass ratio of the catalyst to the dinitrile compound is 1:(6~12).

[0121] For example, the mass ratio of the catalyst to the dinitrile compound can be any of 1:6, 1:10, 1:12, or any combination thereof.

[0122] Among these, within the aforementioned mass ratio range of catalyst to dinitrile compound, the catalyst exhibits a better conversion rate for the dinitrile compound.

[0123] In some embodiments, the catalyst, a dinitrile compound, and a solvent, wherein the solvent is ethanol, are mixed and reacted.

[0124] In some embodiments, the mass ratio of the dinitrile compound to the solvent is 1:(1.6~3.3).

[0125] For example, the mass ratio of the dinitrile compound to the solvent can be any of 1:1.6, 1:1.8, 1:2, 1:2.3 or any combination thereof.

[0126] Among these, within the aforementioned mass ratio range of dinitrile compounds to solvents, the catalyst exhibits a better conversion rate for the dinitrile compounds.

[0127] The present invention utilizes the catalyst provided in the first aspect or the catalyst prepared by the preparation method provided in the second aspect to catalytically hydrogenate dinitrile compounds to obtain diamines, which can effectively improve the conversion rate of dinitrile compounds and the selectivity of diamines.

[0128] Example 1

[0129] Step 1: Cobalt and aluminum are synthesized into an alloy in a certain proportion, with cobalt content of 70% and aluminum content of 30%; during the smelting process of preparing the cobalt-aluminum alloy, rhenium is added, with the amount added being 1.9% of the mass of cobalt; after smelting, a rhenium-doped cobalt-aluminum alloy is obtained, and the rhenium-doped Raney cobalt is obtained by etching with sodium hydroxide solution.

[0130] Step 2: Prepare a cesium hydroxide solution with a molar concentration of 0.12 mol / L;

[0131] Step 3: While stirring, heat 300 ml of cesium hydroxide solution to 55 °C, then add 202 g of the rhenium-doped cobalt prepared in Step 1 and disperse it evenly.

[0132] Step 4: Prepare 120 ml of a mixed solution of strontium nitrate and barium nitrate, wherein the molar concentration of strontium is 0.1 mol / L and the molar concentration of barium is 0.05 mol / L. Heat the solution to 60°C and add it dropwise at a uniform rate to the solution prepared in Step 3 and the mixed slurry of rhenium-doped Raney cobalt catalyst, completing the addition in 30 min. After the addition is complete, maintain the temperature at 60°C and continue stirring for 1.5 h. Then stop stirring and heating. After the solid product settles to the bottom of the beaker, perform solid-liquid separation.

[0133] Step 5: Wash the bottom solid product obtained in Step 4 repeatedly with 70% ethanol and water until the pH of the washing solution is close to neutral. Dry the unreduced catalyst at 100°C for 8 hours.

[0134] Step 6: Prepare a sodium aluminate solution and purge it into the atmosphere. Using it as a precipitant, precipitation was carried out at 35°C. After aeration was maintained until Al was fully precipitated, the temperature was increased to 80°C and maintained for aging for a period of time. At the same time, boric acid was introduced to obtain boron-containing pseudoboehmite.

[0135] Step 7: The boron-containing pseudoboehmite obtained in Step 6 and the unreduced catalyst precursor obtained in Step 5 are mixed at a mass ratio of 1:3. Polyethylene glycol (accounting for 2% of the total dry material mass) and deionized water are added to adjust the slurry solid content to 30% and the pH value to 9.

[0136] Step 8: Using a centrifugal spray dryer with an inlet temperature of 300℃ and an outlet temperature of 110℃, spherical particles with a particle size of 100μm are obtained.

[0137] Step 9: Impregnate the spray-dried granules in a 0.2 mol / L ammonium sulfate solution, dry them, and then calcine them under an inert atmosphere at 800℃, while passing gas through the atmosphere. The catalyst was prepared by reduction at 600℃ for 4 hours.

[0138] The final catalyst, designated A, contains rhenium metal at a mass ratio of 0.6% based on the total mass of the catalyst.

[0139] The alkali metal (cesium) accounts for 1.5% of the mass.

[0140] The total mass percentage of alkaline earth metals (strontium and barium) is 0.57% (of which strontium accounts for approximately 0.32% and barium accounts for approximately 0.25%).

[0141] The boron-containing alumina accounts for 30% of the total mass, of which boron accounts for 1.0% of the total mass.

[0142] The mass percentage of cobalt sulfide compounds is 5%.

[0143] Example 2

[0144] The difference from Example 1 is as follows:

[0145] Step 2: Prepare a cesium hydroxide solution with a molar concentration of 0.35 mol / L.

[0146] Step 4: Prepare 250 ml of a mixed solution of strontium nitrate and barium nitrate, wherein the molar concentration of strontium is 0.15 mol / L and the molar concentration of barium is 0.06 mol / L.

[0147] The final catalyst, designated B, was determined by elemental analysis to be of a certain mass based on the total mass of the catalyst.

[0148] The mass percentage of metallic rhenium is 1.7%;

[0149] The mass percentage of alkali metals (Cs) is 4.3%;

[0150] Alkaline earth metals (Sr and Ba) account for 4.6% of the total mass.

[0151] Example 3

[0152] The difference from Example 1 is as follows:

[0153] Step 2: Prepare a cesium hydroxide solution with a molar concentration of 0.1 mol / L.

[0154] Step 3: The volume of the added cesium hydroxide solution is 216 ml.

[0155] Step 4: Prepare 72 ml of a mixed solution of strontium nitrate and barium nitrate, wherein the molar concentration of strontium is 0.15 mol / L and the molar concentration of barium is 0.06 mol / L.

[0156] The final catalyst, designated C, was analyzed by elemental analysis based on its total mass.

[0157] The mass percentage of metallic rhenium is 0.6%;

[0158] The mass percentage of alkali metals (Cs) is 0.9%;

[0159] The total mass percentage of alkaline earth metals (Sr and Ba) is 0.3%.

[0160] Example 4

[0161] The difference from Example 1 is as follows:

[0162] Step 4: Prepare 120 ml of strontium nitrate solution, barium-free, with a strontium molar concentration of 0.2 mol / L.

[0163] The final catalyst, designated D, was analyzed by elemental analysis based on its total mass.

[0164] The mass percentage of metallic rhenium is 0.6%;

[0165] The mass percentage of alkali metals (Cs) is 1.5%;

[0166] The total mass percentage of alkaline earth metals (Sr, this catalyst does not contain Ba) is 0.6%.

[0167] Example 5

[0168] The difference from Example 1 is as follows:

[0169] Step 4: Prepare 120 ml of barium nitrate solution, which is free of strontium and has a barium molar concentration of 0.2 mol / L.

[0170] The final catalyst, designated E, was determined by elemental analysis to be based on the total mass of the catalyst.

[0171] The mass percentage of metallic rhenium is 0.6%;

[0172] The mass percentage of alkali metals (Cs) is 1.5%;

[0173] The total mass percentage of alkaline earth metals (Ba, this catalyst does not contain Sr) is 1.0%.

[0174] Example 6

[0175] The difference from Example 1 is as follows:

[0176] Step 2: Prepare a rubidium hydroxide solution with a molar concentration of 0.2 mol / L.

[0177] Step 4: Prepare 220 ml of a mixed solution of strontium nitrate and barium nitrate, wherein the molar concentration of strontium is 0.1 mol / L and the molar concentration of barium is 0.05 mol / L.

[0178] The final catalyst, designated F, was determined by elemental analysis to be based on the total mass of the catalyst.

[0179] The mass percentage of metallic rhenium is 0.6%;

[0180] The mass percentage of alkali metals (Rb) is 1.5%.

[0181] The total mass percentage of alkaline earth metals (Sr and Ba) is 1.0%.

[0182] Example 7

[0183] The difference from Example 1 is as follows:

[0184] Step 2: Prepare a potassium hydroxide solution with a molar concentration of 0.25 mol / L.

[0185] Step 3: Add 500ml of potassium hydroxide solution.

[0186] Step 4: Prepare 190 ml of a mixed solution of strontium nitrate and barium nitrate, wherein the molar concentration of strontium is 0.2 mol / L and the molar concentration of barium is 0.1 mol / L.

[0187] The final catalyst, designated G, was determined by elemental analysis to be of a certain mass based on the total mass of the catalyst.

[0188] The mass percentage of metallic rhenium is 0.6%;

[0189] The mass percentage of alkali metal (K) is 1.5%;

[0190] The total mass percentage of alkaline earth metals (Sr and Ba) is 1.8%.

[0191] Example 8

[0192] The difference from Example 1 is as follows:

[0193] Step 4: Prepare 120 ml of a mixed solution of strontium nitrate and magnesium nitrate, wherein the molar concentration of strontium is 0.1 mol / L and the molar concentration of magnesium is 0.05 mol / L.

[0194] The final catalyst, designated H, was determined by elemental analysis based on its total mass.

[0195] The mass percentage of metallic rhenium is 0.6%;

[0196] The mass percentage of alkali metals (Cs) is 1.5%;

[0197] The total mass percentage of alkaline earth metals (Sr and Mg) is 0.4%.

[0198] Example 9

[0199] The difference from Example 1 is as follows:

[0200] Step 4: Prepare 120 ml of a mixed solution of strontium nitrate and barium nitrate, wherein the molar concentration of strontium is 0.05 mol / L and the molar concentration of barium is 0.1 mol / L.

[0201] The final catalyst, designated I, was analyzed by elemental analysis, based on the total mass of the catalyst.

[0202] The mass percentage of metallic rhenium is 0.6%;

[0203] The mass percentage of alkali metals (Cs) is 1.5%;

[0204] The total mass percentage of alkaline earth metals (Sr and Ba) is 0.6%.

[0205] Example 10

[0206] The difference from Example 1 is as follows:

[0207] Step 4: Prepare 120 ml of a mixed solution of strontium nitrate and calcium nitrate, wherein the molar concentration of strontium is 0.05 mol / L and the molar concentration of calcium is 0.1 mol / L.

[0208] The final catalyst, designated J, was determined by elemental analysis based on its total mass.

[0209] The mass percentage of metallic rhenium is 0.6%;

[0210] The mass percentage of alkali metals (Cs) is 1.5%;

[0211] The total mass percentage of alkaline earth metals (Sr and Ba) is 0.4%.

[0212] Example 11

[0213] The difference from Example 1 is as follows:

[0214] Step 1: Cobalt and aluminum are synthesized into an alloy in a certain proportion, with cobalt content being 85% and aluminum content being 15%.

[0215] The catalyst was ultimately designated K.

[0216] Comparative Example 1

[0217] The difference from Example 1 is that rhenium is not added in step 1.

[0218] The final catalyst was numbered L.

[0219] Comparative Example 2

[0220] The difference from Example 1 is that no alkaline earth metals are added after step 3, the temperature is maintained at 60°C, and stirring is continued for 1.5 hours. Then, stirring and heating are stopped, and the solid will settle to the bottom of the beaker. The upper liquid is separated, and the bottom solid material is removed. Subsequent processing is the same as in Example 1.

[0221] The catalyst was ultimately designated as M.

[0222] Comparative Example 3

[0223] The difference from Example 1 is that step 3 is omitted, i.e., no alkali metal is introduced.

[0224] The catalyst was ultimately designated as N.

[0225] Comparative Example 4

[0226] Step 1: Cobalt and aluminum are synthesized into an alloy in a certain proportion, with cobalt content of 70% and aluminum content of 30%. During the smelting process of preparing the cobalt-aluminum alloy, rhenium is added at a rate of 1.9% of the cobalt mass. After smelting, a rhenium-doped cobalt-aluminum alloy is obtained, and Raney cobalt doped with rhenium is obtained by etching with sodium hydroxide solution.

[0227] Step 2: Wash the solid product prepared in Step 1 repeatedly with 70% ethanol and water until the pH of the washing solution is close to neutral. Dry the solid product at 100℃ for 8 hours.

[0228] Step 3: Place the dried catalyst precursor into a tube furnace with corundum tubes, and calcine it under a nitrogen protective atmosphere at 700℃ for 6 hours. Then, introduce 10 v% of the catalyst precursor into the atmosphere. The catalyst was reduced for 8 hours in a mixed atmosphere of 90% nitrogen at 580°C. Then, the catalyst was purged with nitrogen and cooled. The valves at both ends of the furnace tube, which had been cooled to room temperature, were closed and removed. One end of the furnace tube was connected to a deionized water pipeline and the valve on that side was opened. Then, the valve at the other end of the furnace tube was slowly opened to allow deionization to fill the furnace tube and soak the catalyst. Finally, the water-containing catalyst was removed.

[0229] This comparative example does not contain alkaline earth metals or alkali metals.

[0230] The final catalyst was designated O, with a rhenium content of 1% of cobalt.

[0231] Test case

[0232] Step A1: Add 2-methylglutaronitrile, the catalyst described in this embodiment, and solvent ethanol to a 500 mL high-pressure hydrogenation reactor. After sealing the reactor, purge it with nitrogen gas, typically 2-3 times, to remove air from the reactor and ensure the reaction system operates in an oxygen-free environment. After purging, introduce hydrogen gas to prepare for the hydrogenation reaction.

[0233] Step A2: Carry out the hydrogenation reaction under stirring and a hydrogen atmosphere, controlling the reaction pressure at 2-3 MPa and the reaction temperature at 75-90℃. Maintain the hydrogen pressure and reaction temperature for 1-2 hours.

[0234] Step A3: After the reaction is complete, stop heating and reduce the temperature and pressure to remove the reaction product from the reactor;

[0235] Step A4: Separate the catalyst from the reaction solution by filtration, distillation or other separation methods. The catalyst can be recovered and reused. The products in the reaction solution can be purified by further distillation, crystallization or other methods to obtain the target compound.

[0236] Conversion rate and selectivity analysis methods:

[0237] After the reaction, the test product was removed from the reactor, allowed to stand, and the supernatant was separated. The catalyst precipitated in the lower layer was digested. A quantitative amount of the supernatant was taken, and a quantitative amount of internal standard toluene was added. After mixing thoroughly, the mixture was analyzed by gas chromatography. Simultaneously, the unreacted mixture was analyzed. The chromatographic data were quantified using the internal standard method. The reaction performance was then calculated using the following formula:

[0238] Conversion rate of dionitrile % = [(Concentration of dionitrile in feed - Actual concentration of dionitrile in product) / Concentration of dionitrile in feed] × 100%

[0239] The selectivity of diamine (%) = [concentration of diamine / (concentration of dionitrile in feed - actual concentration of dionitrile in product)] × 100%

[0240] The component data of catalysts A to O obtained in Examples 1 to 11 and Comparative Examples 1 to 4 are summarized in Table 1.

[0241] Catalyst A prepared in Example 1 was tested under different reaction conditions, and the test results are shown in Table 2.

[0242] Furthermore, the catalysts A to O prepared in Examples 1 to 11 and Comparative Examples 1 to 4 were tested, and the test results are shown in Table 3.

[0243] Furthermore, the effects of reaction promoters on catalyst M prepared in Comparative Example 3 and catalyst O prepared in Comparative Example 4 were tested. Sodium hydroxide and water were added to catalyst M and O during the test. The test results are shown in Table 4.

[0244] Table 1

[0245]

[0246] Table 2

[0247]

[0248] Table 2 shows the performance of catalyst A under different reaction conditions. The changes in catalyst conversion and selectivity were observed by adjusting the amount of catalyst added, the ratio of 2-methylglutaronitrile to ethanol, the reaction temperature, pressure, and time. The results show that catalyst A exhibits the best overall performance, achieving a conversion rate of 99.5% and a selectivity of 93.1% under the following conditions: reaction pressure of 2.5 MPa, temperature of 75 °C, and reaction time of 1.5 h. This indicates that under these conditions, catalyst A can most effectively promote the conversion of 2-methylglutaronitrile and selectively generate 2-methylpentanediamine.

[0249] Table 3

[0250]

[0251] Table 3 compares the performance of catalysts A to O prepared in Examples 1 to 11 and Comparative Examples 1 to 4. Under the same reaction conditions, catalyst A exhibited the highest conversion (99.5%) and selectivity (93.1%), demonstrating its superior performance in dinitrile conversion and diamine selectivity. Other catalysts, such as B, C, and D, also showed high conversion and selectivity, but not as high as catalyst A. The performance of comparative catalysts L, M, N, and O was significantly lower than that of the example catalysts, especially in terms of selectivity. This indicates that the catalysts prepared in this invention have a significant advantage in improving the conversion of dinitrile and the selectivity of diamine.

[0252] Table 4

[0253]

[0254] In the table, "-" indicates that the data is not available.

[0255] Table 4 further explores the effects of reaction promoters on the performance of catalysts M and O. Without the addition of promoters, the conversion rates and selectivity of catalysts M and O were relatively low. However, after adding 0.5 g of sodium hydroxide and 2 g of water, the conversion rate of catalyst M increased from 85.5% to 92.6%, and the selectivity increased from 54.6% to 68.3%; the conversion rate of catalyst O increased from 90.7% to 95.2%, and the selectivity increased from 52.8% to 70.7%. This indicates that the reaction promoters significantly improved the activity and selectivity of the catalysts. However, even without promoters, catalyst A prepared in Example 1 of this invention still exhibited the best overall performance, further demonstrating the superiority of the catalyst prepared in this invention.

[0256] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

Claims

1. A catalyst, characterized in that, The invention comprises: a porous matrix and an additive disposed on at least a portion of the surface of the porous matrix, wherein the porous matrix comprises Raney cobalt material, and the additive comprises rhenium metal, alkali metal, and alkaline earth metal; wherein the Raney cobalt material comprises Co-S chemical bonds.

2. The catalyst according to claim 1, characterized in that, The Raney cobalt material includes cobalt and cobalt sulfide compounds, and the Co-S chemical bond originates from the cobalt sulfide compounds.

3. The catalyst according to claim 2, characterized in that, The additives also include boron-containing alumina; wherein, based on the total mass of the additives, the mass percentage of the boron-containing alumina is 20% to 60%. And / or, in the boron-containing alumina, the mass percentage of boron is 0.5-2%.

4. The catalyst according to any one of claims 2-3, characterized in that, The cobalt sulfide compounds constitute 1%-10% of the total mass of the catalyst. And / or, the mass percentage of the rhenium metal is 0.1%-5%; And / or, the alkali metal accounts for 0.1%-5% of the total mass; And / or, the mass percentage of the alkaline earth metal is 0.1%-5%.

5. A method for preparing a catalyst according to any one of claims 1 to 4, characterized in that, Includes the following steps: A first mixture of cobalt-aluminum alloy and rhenium metal is used to obtain Raney cobalt containing rhenium metal by alkaline etching; The first intermediate is obtained by co-precipitation treatment of a second mixture including an alkali metal additive, the Raney cobalt containing rhenium, and an alkaline earth metal salt. A slurry is prepared by mixing boron-containing pseudoboehmite, the first intermediate, and a binder. The slurry was spray-dried and granulated to obtain the second intermediate. A third mixture comprising the second intermediate and a sulfur source solution is dried and then subjected to reduction roasting to obtain the catalyst.

6. The preparation method according to claim 5, characterized in that, The alkaline etching process includes mixing the first mixture with an alkaline solution at 50-60°C to obtain the Raney cobalt containing rhenium.

7. The preparation method according to claim 5, characterized in that, The boron-containing pseudoboehmite is prepared by the following process: At 25~40℃, a precipitant is added to an aluminate solution to obtain a precipitate. The precipitate is mixed with a boron source and aged at 60~90℃ to obtain the boron-containing pseudoboehmite.

8. The preparation method according to claim 5, characterized in that, The mass ratio of the pseudoboehmite, the first intermediate, and the binder is 1:(2~4):(0.03~0.25); And / or, the mass ratio of the second intermediate to the sulfur source is 100:(1~10).

9. The preparation method according to claim 5, characterized in that, The calcination process is carried out at a temperature of 600~1100℃ for 2~18 hours.

10. A method for preparing diamines by hydrogenation of dinitrile compounds, characterized in that, This includes catalytic hydrogenation of dinitrile compounds using a catalyst prepared by any one of the catalysts described in claims 1 to 4 or by any one of the catalysts described in claims 5 to 9.

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