Preparation method and application of cobalt-based catalyst

Abstract

The invention provides a preparation method and application of a cobalt-based catalyst, and relates to the technical field of chemical production. The cobalt-based catalyst includes cobalt, a transition metal element, and a Group IIIA element other than aluminum. Transition metal elements and IIIA group elements except aluminum are introduced into the cobalt-based catalyst, and the electronic structure and active sites of the cobalt-based catalyst are changed. The method not only can cooperate with catalytic reaction and promote the formation and conversion of intermediates, but also can enhance the adsorption and activation capability on substrates, reduce the reaction activation energy and guide the reaction to be carried out along a specific path. Finally, the effect of efficiently harvesting the 2-methyl pentamethylene diamine and the 3-methylpiperidine at the same time is achieved.

Description

Technical Field

[0001] This application relates to the technical field of chemical production, and particularly relates to a preparation method and application of a cobalt-based catalyst. Background Art

[0002] In the modern chemical industry, amines and nitrogen-containing cyclic compounds are widely used in fields such as pharmaceuticals, pesticides, and materials. As an important chemical intermediate, 2-methylpentanediamine can be used to synthesize high-performance epoxy resin curing agents and materials such as polyurethanes; 3-methylpiperidine can be used to synthesize various drugs in the pharmaceutical field and also plays an important role in the pesticide field. Therefore, developing a method that can efficiently produce 2-methylpentanediamine and 3-methylpiperidine simultaneously has important economic value and broad market prospects.

[0003] Currently, the synthesis of 2-methylpentanediamine and 3-methylpiperidine mainly relies on traditional chemical synthesis methods. For 2-methylpentanediamine, multi-step reactions are usually adopted. First, intermediates such as 2-methylglutaronitrile are synthesized, and then the final product is obtained through methods such as hydrogenation reduction. The synthesis of 3-methylpiperidine usually also involves a complex multi-step reaction process, including multiple intermediate products and reaction steps. It can be seen that these traditional methods cannot efficiently harvest 2-methylpentanediamine and 3-methylpiperidine simultaneously. Summary of the Invention

[0004] This application provides a preparation method and application of a cobalt-based catalyst to achieve the effect of efficiently harvesting 2-methylpentanediamine and 3-methylpiperidine simultaneously.

[0005] In a first aspect, this application provides a cobalt-based catalyst, characterized in that the cobalt-based catalyst comprises: cobalt, a transition metal element, and a Group IIIA element other than aluminum.

[0006] In a possible implementation manner, the Group IIIA element other than aluminum comprises: one or a combination of more of boron, gallium, indium, and thallium.

[0007] In a possible implementation manner, the mass content of the Group IIIA element other than aluminum is 0.1% - 3% of the mass of cobalt in the cobalt-based catalyst.

[0008] In a possible implementation manner, the transition metal element comprises: one or a combination of more of the Group VIII, Group VIB, and Group IB elements.

[0009] In a possible implementation manner, if the Group VIII element comprises a combination of one or more elements of iron, nickel, ruthenium, rhodium, palladium, iridium, and platinum, the mass content of the Group VIII element is 1% - 7% of the mass of cobalt in the cobalt-based catalyst.

[0010] In a possible embodiment, if the Group VIB element includes one or a combination of elements such as chromium, molybdenum, and tungsten, the mass content of the Group VIB element is 1% to 6% of the mass of cobalt in the cobalt-based catalyst.

[0011] In a possible embodiment, if the Group IB element includes one or a combination of elements such as copper, silver, and gold, the mass content of the Group IB element is 100 ppm to 1000 ppm of the mass of cobalt in the cobalt-based catalyst.

[0012] Second, the present application provides a method for preparing a cobalt-based catalyst, and the preparation method includes:

[0013] Synthesize a cobalt-aluminum alloy from cobalt, aluminum, a transition metal element, and a Group IIIA element other than aluminum;

[0014] Etch the aluminum in the cobalt-aluminum alloy to obtain a cobalt-based catalyst precursor;

[0015] Immerse the cobalt-based catalyst precursor in an aqueous solution of an alkali metal promoter;

[0016] Separate the cobalt-based catalyst precursor from the impregnated cobalt-based catalyst precursor, and dry the separated cobalt-based catalyst precursor;

[0017] Under an inert atmosphere, calcine the dried cobalt-based catalyst precursor, and introduce hydrogen during the calcination process to cause a reduction reaction between the cobalt-based catalyst precursor and hydrogen to obtain the cobalt-based catalyst described in the first aspect and / or various possible embodiments of the first aspect.

[0018] In a possible embodiment, the aqueous solution of the alkali metal promoter includes one or a combination of sodium hydroxide, potassium hydroxide, lithium hydroxide, lithium carbonate, rubidium hydroxide, cesium hydroxide, cesium nitrate, cesium sulfate, etc., and the concentration of the alkali metal in the aqueous solution of the alkali metal promoter is 0.1 mol / L to 1 mol / L.

[0019] Third, the present application provides an application of the cobalt-based catalyst described in the first aspect and / or various possible embodiments of the first aspect, including:

[0020] Add 2-methylglutaronitrile, a cobalt-based catalyst, and a solvent to a sealed reactor, and introduce nitrogen into the sealed reactor to discharge the air in the reactor;

[0021] Introduce hydrogen into the reactor to cause a hydrogenation reaction between 2-methylglutaronitrile and hydrogen under the catalysis of the cobalt-based catalyst;

[0022] When the hydrogenation reaction is completed and the reactor is maintained at normal temperature and pressure, take out the reaction product from the reactor;

[0023] Separate the cobalt-based catalyst from the reaction solution in the reaction product by a separation method;

[0024] Purify the reaction solution to obtain a mixture of 2-methylpentanediamine and 3-methylpiperidine.

[0025] The preparation method and application of the cobalt-based catalyst provided by this application, the cobalt-based catalyst includes cobalt, transition metal elements, and Group IIIA elements other than aluminum. This application introduces transition metal elements and Group IIIA elements other than aluminum into the cobalt-based catalyst, changing the electronic structure and active sites of the cobalt-based catalyst. This can not only synergistically catalyze the reaction, promote the formation and transformation of intermediates, but also enhance the adsorption and activation ability of the substrate at the same time, reduce the reaction activation energy, and guide the reaction to proceed along a specific path. Finally, the effect of efficiently harvesting 2-methylpentanediamine and 3-methylpiperidine simultaneously is achieved. Detailed implementation mode

[0026] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] 2-Methylglutaronitrile (MGN for short) is an organic chemical substance with the chemical formula C6H8N2. It is one of the main by-products in the synthesis process of adiponitrile. Its treatment and utilization have an important impact on the economic benefits of the entire adiponitrile production process. With the progress of technology and the growth of market demand, the utilization and further processing of 2-methylglutaronitrile are receiving more and more attention. 2-Methylglutaronitrile can be further hydrogenated to 2-methylpentamethylenediamine (MPMD for short), which is a useful chemical raw material and can be used to produce curing agents, chain extenders, etc.

[0028] In addition, the hydrogenation of 2-methylglutaronitrile also produces 3-methylpiperidine, which is a colorless liquid with an amine odor and can be used as an organic synthesis intermediate, especially in the pharmaceutical industry. 3-Methylpiperidine can be used to synthesize a variety of compounds, including but not limited to the following uses: 1) As an intermediate for synthesizing other chemicals, such as in the synthesis of certain drugs, pesticides, and fragrances; 2) As a raw material in the synthesis of vitamin B3 (niacin) and related compounds; 3) As a solvent, catalyst, or auxiliary agent in chemical synthesis; 4) As a cross-linking agent or curing agent in the synthesis of certain types of resins and polymers.

[0029] The synthesis method of 3-methylpiperidine includes preparing it by catalytic hydrogenation of 2-methylglutaronitrile. It can also be synthesized by other methods, such as reacting the corresponding halogenated hydrocarbon with silver cyanide, or by alkylation of piperidine. The downstream products of 3-methylpiperidine have relatively high added value. If 2-methylpentanediamine and 3-methylpiperidine can be obtained in high yields through the hydrogenation reaction of 2-methylglutaronitrile, higher economic benefits will be achieved for 2-methylglutaronitrile manufacturers.

[0030] Currently, catalysts such as Raney nickel and Raney cobalt are widely used in the hydrogenation reaction of 2-methylglutaronitrile compounds. For example, Patent CN103977819A introduces a modified Raney nickel catalyst, which improves the activity and selectivity of the catalyst by doping elements such as iron, chromium, and molybdenum in the nickel-aluminum alloy. However, the Raney nickel catalyst is prone to deactivation during use, and its selectivity for certain nitrile compounds is not ideal.

[0031] In addition, Patent CN111377820B proposes doping ruthenium (Ru) and molybdenum (Mo) metals in the Raney nickel catalyst for the hydrogenation of 2-methylglutaronitrile to prepare 2-methylpentanediamine. Doping ruthenium can improve the selectivity of the product, but ruthenium belongs to precious metals and has a high cost, which is not conducive to large-scale industrial applications.

[0032] Some studies have also tried to add basic additives to the catalyst or adopt basic reaction conditions to improve the selectivity of amines. For example, Patent CN115335356A proposes adding potassium hydroxide and other basic compounds to the Raney nickel catalyst to improve the selectivity of the hydrogenation of dinitrile to diamine. However, excessive basic additives will cause problems such as equipment corrosion and environmental pollution.

[0033] Rare earth metal oxides have also been used to modify catalysts to improve their performance. Patent CN109647419A reports a rare earth metal oxide-modified nickel-based catalyst for the hydrogenation of dinitrile to diamine. This catalyst achieves a highly selective hydrogenation reaction under lower temperature and without basic reagents. However, rare earth metals have a high price and limited resources.

[0034] In terms of improving the stability of the catalyst, Patent CN1143734C proposes a method for modifying Raney nickel and Raney cobalt catalysts. By treating with compounds such as carbon monoxide and carbon dioxide, the selectivity of the catalyst in the nitrile hydrogenation reaction is improved. However, this method has complex steps, and the feasibility of the modification process for industrial applications is limited.

[0035] In summary, although the prior art has improved the selectivity and activity in the development of catalysts, it still lacks a solution that can efficiently harvest 2-methylpentanediamine and 3-methylpiperidine at the same time. Whether it is the modification of Raney nickel and Raney cobalt, or the addition of alkaline additives, these improvement measures often cannot take into account the selectivity of 2-methylpentanediamine and 3-methylpiperidine at the same time in the hydrogenation reaction, resulting in a low total yield of both. At the same time, these technical improvements are also faced with the impact of catalyst deactivation on the continuity and economic benefits of production. Therefore, there is an urgent need in the prior art for a new catalytic system or process method that can achieve high selectivity and parallel preparation of 2-methylpentanediamine and 3-methylpiperidine on the basis of maintaining the long-term stability of the catalyst, thereby greatly improving the economic benefits and practicality of the entire production process.

[0036] In view of the above problems, the present application provides a cobalt-based catalyst, which includes cobalt, a transition metal element, and a Group IIIA element other than aluminum, wherein the transition metal element includes a combination of one or more of Group VIII, Group VIB, and Group IB elements in the periodic table. The catalyst significantly improves the selectivity and yield of hydrogenating 2-methylglutaronitrile to prepare 2-methylpentanediamine and 3-methylpiperidine, and has good industrial application prospects.

[0037] The present application embodiment provides a cobalt-based catalyst, characterized in that the cobalt-based catalyst includes: cobalt, transition metal elements and Group IIIA elements other than aluminum. It can be understood that the cobalt-based catalyst provided in the present application embodiment includes cobalt, transition metal elements and Group IIIA elements other than aluminum. Further, the present application embodiment changes the electronic structure and active sites of the cobalt-based catalyst by introducing transition metal elements and Group IIIA elements other than aluminum into the cobalt-based catalyst. This operation can not only coordinate the catalytic reaction and promote the formation and conversion of intermediates, but also simultaneously enhance the adsorption and activation ability of the substrate, reduce the reaction activation energy, and guide the reaction along a specific path. Ultimately, the effect of simultaneously and efficiently harvesting 2-methylpentanediamine and 3-methylpiperidine is achieved.

[0038] In some embodiments, the Group IIIA element other than aluminum includes a combination of one or more of boron, gallium, indium, and thallium.

[0039] Furthermore, the mass content of Group IIIA elements other than aluminum is 0.1% to 3% of the mass of cobalt in the cobalt-based catalyst. If the mass content of Group IIIA elements other than aluminum is too low, the acidic and electronic properties of the cobalt-based catalyst cannot be effectively adjusted, resulting in insufficient active sites of the cobalt-based catalyst and the inability to efficiently harvest 2-methylpentanediamine and 3-methylpiperidine simultaneously. If the mass content of Group IIIA elements other than aluminum is too high, the surface of the cobalt-based catalyst is overly covered, hindering the reactants from contacting the active sites, thereby reducing the overall activity of the cobalt-based catalyst and making it impossible to efficiently harvest 2-methylpentanediamine and 3-methylpiperidine simultaneously.

[0040] In some embodiments, the transition metal elements include one or more combinations of elements from Group VIII, Group VIB, and Group IB. Preferably, the transition metal elements simultaneously include a combination of Group VIII, Group VIB, and Group IB. More preferably, the transition metal elements include at least two Group IB elements.

[0041] In some embodiments, if the Group VIII elements include one or more combinations of elements such as iron, nickel, ruthenium, rhodium, palladium, iridium, and platinum, the mass content of the Group VIII elements is 1% to 7% of the mass of cobalt in the cobalt-based catalyst. Among them, the Group VIII elements can interact with cobalt and other existing elements to form new active centers, thereby improving the selectivity and activity of the cobalt-based catalyst for specific reactions. In addition, the Group VIII elements reduce the activation energy of the reaction through their interaction with the substrate molecules, guiding the reaction along a specific path that is favorable for the formation of 2-methylpentanediamine and 3-methylpiperidine, thereby increasing the yields of the two products and achieving efficient harvesting. It should be noted that the mass content of the Group VIII elements is 1% to 7% of the mass of cobalt in the cobalt-based catalyst. If the mass content of the Group VIII elements is too low, their function of adjusting the electronic structure of the cobalt-based catalyst, forming new active centers, and increasing the substrate adsorption and activation ability cannot be exerted, resulting in an insignificant catalytic effect on 2-methylpentanediamine and 3-methylpiperidine and a decrease in yield; if the mass content of the Group VIII elements is too high, the stability of the cobalt-based catalyst will be changed, leading to easy deactivation of the cobalt-based catalyst.

[0042] In some embodiments, if the VIB group elements include a combination of one or more elements of chromium, molybdenum and tungsten, the mass content of the VIB group elements is 1% to 6% of the mass of cobalt in the cobalt-based catalyst. Among them, the VIB group elements can enhance the structural stability of the cobalt-based catalyst, prevent deactivation under high temperature or harsh conditions, and produce a synergistic reaction with other components of the cobalt-based catalyst, further improving the activity and selectivity of the cobalt-based catalyst. It should be noted that the mass content of the VIB group elements is 1% to 6% of the mass of cobalt in the cobalt-based catalyst. If the mass content of the VIB group elements is too low, the cobalt-based catalyst will lack sufficient active sites, resulting in a decrease in the yield of 2-methylpentanediamine and 3-methylpiperidine; if the mass content of the VIB group elements is too high, the surface of the cobalt-based catalyst will be oversaturated, hindering the adsorption and reaction of other reactants and reducing the overall catalytic activity of the cobalt-based catalyst.

[0043] In some embodiments, if the Group IB elements include a combination of one or more elements of copper, silver and gold, the mass content of the Group IB elements is 100ppm to 1000ppm of the mass of cobalt in the cobalt-based catalyst. Among them, the Group IB elements interact with other elements in the cobalt-based catalyst to adjust the electron distribution of the cobalt-based catalyst, forming an active site that is more conducive to the reaction, thereby improving the catalytic activity of the cobalt-based catalyst, extending the stability and economy of the cobalt-based catalyst, reducing the replacement frequency of the cobalt-based catalyst, and improving the stability and economy of the process. In addition, the Group IB elements reduce the activation energy of the reaction by interacting with the substrate molecules, guiding the reaction along a specific path that is conducive to the generation of 2-methylpentanediamine and 3-methylpiperidine, thereby increasing the yield of the two products and achieving efficient harvesting. It should be noted that the mass content of group IB elements is 100ppm~1000ppm of the mass of cobalt in the cobalt-based catalyst. If the mass content of group IB elements is too low, the electronic structure of the catalyst cannot be fully changed and effective active sites cannot be formed, and the catalytic effect on the reaction is weak, resulting in a reduction in the production of 2-methylpentanediamine and 3-methylpiperidine; if the mass content of group IB elements is too high, the original structure of the cobalt-based catalyst will be destroyed, and its stability will be reduced. During the reaction, the cobalt-based catalyst is easily deactivated, shortening the service life of the cobalt-based catalyst, increasing the frequency of catalyst replacement, and reducing the stability and economy of the process.

[0044] Furthermore, the embodiment of the present application also provides a method for preparing a cobalt-based catalyst. The preparation method includes: synthesizing a cobalt-aluminum alloy from cobalt, aluminum, a transition metal element, and a Group IIIA element other than aluminum; etching aluminum in the cobalt-aluminum alloy to obtain a cobalt-based catalyst precursor; placing the cobalt-based catalyst precursor in an aqueous solution of an alkali metal promoter for impregnation; separating the cobalt-based catalyst precursor from the impregnated cobalt-based catalyst precursor and drying the separated cobalt-based catalyst precursor; calcining the dried cobalt-based catalyst precursor in an inert atmosphere and introducing hydrogen during the calcination process to cause a reduction reaction between the cobalt-based catalyst precursor and hydrogen to obtain the cobalt-based catalyst described in the previous embodiments.

[0045] In this embodiment, it can be understood that the method for preparing a cobalt-based catalyst includes the following steps:

[0046] Step S1: Synthesize an alloy from cobalt, aluminum, a Group IIIA element other than aluminum, and a transition metal element in a certain proportion, where the content of cobalt is 70%-90% and the content of aluminum is 10%-30%. During the smelting process of preparing the cobalt-aluminum alloy, add the transition metal element to the cobalt-aluminum alloy to obtain a cobalt-aluminum alloy doped with transition elements. Then, etch aluminum in the cobalt-aluminum alloy with an alkali solution to obtain a Raney cobalt catalyst doped with transition metal elements, that is, obtain a Raney cobalt catalyst precursor;

[0047] Step S2: Prepare an aqueous solution of an alkali metal promoter with a certain concentration. Among them, the aqueous solution of the alkali metal promoter includes one or a combination of sodium hydroxide, potassium hydroxide, lithium hydroxide, lithium carbonate, rubidium hydroxide, cesium hydroxide, cesium nitrate, cesium sulfate, etc., and the concentration of the alkali metal in the aqueous solution of the alkali metal promoter is 0.1 mol / L to 1 mol / L;

[0048] Step S3: Under stirring, heat the aqueous solution of the alkali metal promoter to a certain temperature, then add the Raney cobalt catalyst precursor prepared in Step S1 to make it evenly dispersed, and keep it impregnated at a certain temperature for a period of time;

[0049] Step S4: Separate the impregnated Raney cobalt catalyst precursor. Then dry the Raney cobalt catalyst precursor, the drying temperature is 80°C to 120°C, and the drying time is 6h to 12h;

[0050] Step S5: First calcine the dried Raney cobalt catalyst precursor in an inert atmosphere, and then introduce a certain concentration of H 2 for reduction to obtain the final Raney cobalt catalyst.

[0051] Among them, the temperature range for heating the aqueous solution of the alkali metal promoter described in Step S3 is 40°C to 70°C, and the preferred temperature range is 50°C to 65°C. The impregnation time is 0.5 to 2 hours.

[0052] The inert atmosphere described in step S5 is a protective atmosphere of inert gases such as nitrogen (N2), argon (Ar), or helium (He); the calcination temperature described in step S5 is 600°C to 1100°C, preferably in the range of 650°C to 900°C, and the holding time ranges from 2h to 18h, preferably 4h to 10h; the H 2 concentration is 5% to 100%, preferably 10% to 50%. The activation temperature is 450°C to 750°C, and the reduction time is 2h to 10h, preferably 4h to 9h.

[0053] Furthermore, due to the specific electronic properties of the Raney cobalt catalyst precursor doped with transition metal elements, the addition of alkali metals can further adjust the electron distribution. This change in the electronic structure can enhance the adsorption and activation ability of the cobalt-based catalyst for reactant molecules, thereby improving the catalytic activity of the cobalt-based catalyst.

[0054] Even further, in the preparation of the cobalt-based catalyst, by optimizing the reaction conditions, it is not necessary to add alkali substances additionally, avoiding the dependence on a large amount of alkaline additives, avoiding the corrosion of equipment and environmental pollution, while simplifying the reaction process, making the performance of the cobalt-based catalyst more stable, and improving the safety and convenience of operation. This innovation reduces production costs, improves the purity of the cobalt-based catalyst product, and enhances the safety and environmental friendliness of the reaction.

[0055] In the embodiment of the present application, the cobalt-based catalyst precursor is subjected to a reduction reaction with hydrogen to remove the oxides and impurities on the surface of the cobalt-based catalyst, expose the active sites of the cobalt-based catalyst, and improve the activity of the cobalt-based catalyst.

[0056] The embodiment of the present application also provides an application of a cobalt-based catalyst, which includes: adding 2-methylglutaronitrile, a cobalt-based catalyst, and a solvent into a sealed reactor, introducing nitrogen into the sealed reactor to discharge the air in the reactor; introducing hydrogen into the reactor to cause a hydrogenation reaction of 2-methylglutaronitrile and hydrogen under the catalytic action of the cobalt-based catalyst; when the hydrogenation reaction is completed and the reactor is maintained at normal temperature and pressure, taking out the reaction product from the reactor; separating the cobalt-based catalyst from the reaction solution in the reaction product by a separation method; and purifying the reaction solution to obtain a mixture of 2-methylpentanediamine and 3-methylpiperidine.

[0057] In this embodiment, when using nitrogen to displace the air in the sealed reactor, it is usually necessary to perform 2 to 3 times to discharge the air in the reactor and ensure that the reaction system operates in an anaerobic environment. After the air in the sealed reactor is displaced, hydrogen is introduced to prepare for the hydrogenation reaction. The hydrogenation reaction needs to be carried out under stirring conditions. Further, in the hydrogenation reaction, the following conditions need to be controlled: the reaction pressure is controlled in the range of 1 MPa to 6 MPa; the reaction temperature is controlled in the range of 70 °C to 120 °C; the hydrogen pressure and reaction temperature are maintained; the reaction time is controlled in the range of 0.5 h to 5 h.

[0058] After the hydrogenation reaction is completed, it is necessary to stop heating the reactor and reduce the reactor to normal temperature and pressure. Then, the reaction product in the reactor is taken out.

[0059] The cobalt-based catalyst in the reaction product is separated from the reaction solution by filtration, distillation or other separation means. Among them, the cobalt-based catalyst can be recovered and reused, and the product in the reaction solution can be purified by further rectification, crystallization or other methods to obtain the target compound, that is, a mixture of 2-methylpentanediamine and 3-methylpiperidine. In some embodiments, after the hydrogenation reaction is completed, the reaction product in the reactor is taken out, and after standing, the upper-layer liquid is separated, and the cobalt-based catalyst precipitated in the lower layer is subjected to digestion treatment. Take a certain amount of the upper-layer liquid, add a certain amount of the internal standard substance toluene to it, and after the internal standard substance toluene is mixed evenly with the upper-layer liquid, it is analyzed by gas chromatography. At the same time, the unreacted mixed raw materials are also analyzed. Among them, the chromatographic data is quantified by the internal standard method, and then the reaction performance is calculated by the following formula:

[0060] Conversion rate of 2-methylglutaronitrile %

[0061] =[(Concentration of 2-methylglutaronitrile in raw materials - Actual concentration of 2-methylglutaronitrile in product) / Concentration of 2-methylglutaronitrile in raw materials] × 100%;

[0062] Selectivity of 2-methylpentanediamine %

[0063] =[Concentration of 2-methylpentanediamine in product / (Concentration of 2-methylglutaronitrile in raw materials - Actual concentration of 2-methylglutaronitrile in product)] × 100%;

[0064] Selectivity of 3-methylpiperidine %

[0065] =[Concentration of 3-methylpiperidine in product / (Concentration of 2-methylglutaronitrile in raw materials - Actual concentration of 2-methylglutaronitrile in product)] × 100%;

[0066] Total selectivity % = Selectivity of 2-methylpentanediamine % + Selectivity of 3-methylpiperidine %.

[0067] Further, the mass ratio of the added cobalt-based catalyst to 2-methylglutaronitrile is 5% to 35%, preferably 12% to 28%; the mass ratio of 2-methylglutaronitrile to the solvent is 20% to 120%, preferably 30% to 60%.

[0068] In the embodiments of the present application, by providing an application of a cobalt-based catalyst, it is demonstrated that the cobalt-based catalyst provided in the previous embodiments can achieve the effect of efficiently harvesting 2-methylpentanediamine and 3-methylpiperidine simultaneously.

[0069] Hereinafter, the cobalt-based catalyst and its application provided in the present application will be further introduced in conjunction with specific embodiments.

[0070] In the following embodiments, unless otherwise specified, the experimental methods used can all adopt conventional methods in the art.

[0071] In the following embodiments, unless otherwise specified, all raw materials can be obtained through commercial purchase or conventional methods.

[0072] Embodiment:

[0073] Embodiment 1:

[0074] Step 1: Cobalt, aluminum, gallium, nickel, chromium, and gold are synthesized into an alloy in proportion, where the mass ratio of cobalt to aluminum is 7:3, the addition amount of gallium is 0.5% of the mass of cobalt, the addition amount of nickel is 5% of the mass of cobalt, the addition amount of chromium is 4% of the mass of cobalt, and the addition amount of gold is 560 ppm of the mass of cobalt. After smelting, the doped cobalt-aluminum alloy is obtained, and the doped Raney cobalt catalyst precursor is obtained by etching with sodium hydroxide solution.

[0075] Step 2: Prepare a cesium hydroxide solution with a molar concentration of 0.12 mol / L.

[0076] Step 3: Heat 300 ml of the cesium hydroxide solution to 50 °C, and then add 202 g of the doped Raney cobalt catalyst precursor prepared in Step 1 and impregnate for 1 hour.

[0077] Step 4: Filter through a Buchner funnel to separate the impregnated Raney cobalt catalyst precursor. Dry the separated Raney cobalt catalyst precursor, with a drying temperature of 100 °C and a drying time of 8 hours.

[0078] Step 5: Place the dried Raney cobalt catalyst precursor into the tube furnace of the corundum furnace tube. First, calcine it under a nitrogen protection atmosphere at a calcination temperature of 700 °C for a holding time of 6 hours. Then introduce a mixed atmosphere of 10 v% H2 and 90 v% nitrogen into the atmosphere. Under the condition of 580 °C, reduce it for 8 hours. Then displace it with nitrogen and cool it down. Close the valves at the front and rear ends of the furnace tube cooled to room temperature and take it out. Connect one end of the furnace tube to the deionized water pipeline and open the valve on this side. Then slowly open the valve at the other end of the furnace tube. Fill the deionized water into the furnace tube and soak the catalyst. Finally, take out the water-containing catalyst, and the catalyst is numbered A.

[0079] Example 2:

[0080] The difference from Example 1 is that thallium is used to replace gallium, and the catalyst is numbered B.

[0081] Example 3:

[0082] The difference from Example 1 is that copper is used to replace gold, and the catalyst is numbered C.

[0083] Example 4:

[0084] The difference from Example 1 is that indium is used to replace gallium, and the catalyst is numbered D.

[0085] Example 5:

[0086] The difference from Example 1 is that in Step 1, the mass ratio of cobalt to aluminum is 8:2, and the catalyst is numbered E.

[0087] Example 6:

[0088] The difference from Example 5 is that in Step 1, the addition amount of gallium is 0.2% of the mass of cobalt, the addition amount of nickel is 3% of the mass of cobalt, the addition amount of chromium is 3% of the mass of cobalt, and the addition amount of gold is 800 ppm of the mass of cobalt, and the catalyst is numbered F.

[0089] Example 7:

[0090] The difference from Example 6 is that thallium is used to replace gallium and copper is used to replace gold, and the catalyst is numbered G.

[0091] Example 8:

[0092] The difference from Example 7 is that iron and nickel are added simultaneously, where the addition amount of nickel is 1.8% of the mass of cobalt and the addition amount of iron is 0.5% of the mass of cobalt, and the catalyst is numbered H.

[0093] Example 9:

[0094] The difference from Example 8 is that gold and copper are added simultaneously, where the addition amount of gold is 600 ppm of the mass of cobalt, the addition amount of copper is 300 ppm of the mass of cobalt, and the catalyst number is I.

[0095] Example 10:

[0096] The difference from Example 9 is that chromium and molybdenum are added simultaneously, where the addition amount of chromium is 2% of the mass of cobalt, the addition amount of molybdenum is 1% of the mass of cobalt, and the catalyst number is J.

[0097] Example 11:

[0098] The difference from Example 10 is that iron, nickel and ruthenium are added simultaneously, where the addition amount of nickel is 1.8% of the mass of cobalt, the addition amount of iron is 0.5% of the mass of cobalt, the addition amount of ruthenium is 0.2% of the mass of cobalt, and the catalyst number is K.

[0099] Comparative Example 1:

[0100] Step 1: Cobalt and aluminum are synthesized into an alloy in a certain proportion, where the content of cobalt is 70% and the content of aluminum is 30%. After smelting, a cobalt-aluminum alloy is obtained, and a Raney cobalt catalyst precursor is obtained by etching with sodium hydroxide solution.

[0101] Step 2: The catalyst precursor is placed in a tubular furnace of a corundum furnace tube. A mixed atmosphere of 10 v% H2 and 90 v% nitrogen is introduced into the atmosphere. Under the condition of 580 °C, it is reduced for 8 hours, then replaced with nitrogen and cooled down. The valves at both ends of the furnace tube cooled to room temperature are closed and taken out. One end of the furnace tube is connected to a deionized water pipeline and the valve on this side is opened. Then the valve at the other end of the furnace tube is slowly opened. Deionized water is filled into the furnace tube to soak the catalyst. Finally, the water-containing catalyst is taken out, and the catalyst number is L.

[0102] Comparative Example 2:

[0103] The difference from Comparative Example 1 is that in Step 1: Cobalt and aluminum are synthesized into an alloy in a proportion, where the content of cobalt is 80% and the content of aluminum is 20%. After smelting, a cobalt-aluminum alloy is obtained, and a Raney cobalt catalyst precursor is obtained by etching with sodium hydroxide solution, and the catalyst number is M.

[0104] Comparative Example 3:

[0105] The difference from Comparative Example 1 is that in Step 1: Cobalt, aluminum, nickel, chromium, and gold are synthesized into an alloy in a certain proportion, where the mass ratio of cobalt to aluminum is 7:3, the addition amount of nickel is 5% of the mass of cobalt, the addition amount of chromium is 4% of the mass of cobalt, and the addition amount of gold is 560 ppm of the mass of cobalt. After smelting, a doped cobalt-aluminum alloy is obtained, and a doped Raney cobalt catalyst is obtained by etching with sodium hydroxide solution, and the catalyst number is N.

[0106] Comparative Example 4:

[0107] The difference from Comparative Example 1 is as follows: Step 1: Cobalt, aluminum, and gallium are synthesized into an alloy in a certain proportion, where the mass ratio of cobalt to aluminum is 7:3, and the addition amount of gallium is 0.5% of the mass of cobalt. After smelting, the doped cobalt-aluminum alloy is obtained, and the doped Raney cobalt catalyst is obtained by etching with sodium hydroxide solution, with the catalyst numbered O.

[0108] Comparative Example 5:

[0109] Step 1: Cobalt, aluminum, gallium, nickel, chromium, and gold are synthesized into an alloy in a certain proportion, where the mass ratio of cobalt to aluminum is 7:3, the addition amount of gallium is 0.5% of the mass of cobalt, the addition amount of nickel is 5% of the mass of cobalt, the addition amount of chromium is 4% of the mass of cobalt, and the addition amount of gold is 560 ppm of the mass of cobalt. After smelting, the doped cobalt-aluminum alloy is obtained, and the precursor of the doped Raney cobalt catalyst is obtained by etching with sodium hydroxide solution.

[0110] Step 2: The catalyst precursor is placed in a tubular furnace of a corundum furnace tube, and a mixed atmosphere of 10 v% H2 and 90 v% nitrogen is introduced in the atmosphere. Under the condition of 580 °C, it is reduced for 8 hours, then replaced with nitrogen and cooled down. The valves at the front and rear ends of the furnace tube cooled to room temperature are closed and taken out. One end of the furnace tube is connected to a deionized water pipeline and the valve on this side is opened. Then the valve at the other end of the furnace tube is slowly opened, deionized water is filled into the furnace tube to soak the catalyst, and finally the water-containing catalyst is taken out, with the catalyst numbered P.

[0111] Comparative Example 6:

[0112] The difference from Example 1 is that gallium is not added in Step 1, and the catalyst is numbered Q.

[0113] Examples 12 to 22:

[0114] Step A1: 2-Methylglutaronitrile, the catalyst of the present invention example, and the solvent ethanol are added together to a 500 mL high-pressure hydrogenation reactor. After closing the reactor, it is replaced with nitrogen, usually 2 - 3 times, to discharge the air in the reactor and ensure that the reaction system operates in an anaerobic environment. After the replacement is completed, hydrogen is introduced to prepare for the hydrogenation reaction.

[0115] Step A2: The hydrogenation reaction is carried out under stirring conditions and in a hydrogen atmosphere. The reaction pressure is controlled at 2.5 MPa, and the reaction temperature is controlled at 75 °C. Maintaining the hydrogen pressure and reaction temperature, the reaction is carried out for 1.5 hours.

[0116] Step A3: After the reaction is completed, heating is stopped and the temperature and pressure are reduced, and the reaction product is taken out from the reactor.

[0117] Step A4: Separate the catalyst from the reaction solution by filtration, distillation or other separation means. The catalyst can be recovered and reused. The product in the reaction solution can be purified by further rectification, crystallization or other methods to obtain the target compound.

[0118] The conditions of the specific examples are shown in Table 1.

[0119] Table 1: Conditions of Examples 12 - 22

[0120]

[0121]

[0122] From the data in the above table, it can be seen that the cobalt - based catalyst provided in the examples of this application can achieve the effect of efficiently harvesting 2 - methylpentanediamine and 3 - methylpiperidine simultaneously.

[0123] Comparative Examples 7 - 12:

[0124] The difference from Examples 12 - 22 is that the catalysts used are L - Q prepared in the comparative examples. The conditions of the specific examples are shown in Table 2.

[0125] Table 2: Conditions of Comparative Examples 7 - 12

[0126]

[0127] From the data in the above table, it can be seen that compared with the cobalt - based catalyst without adding transition metal elements or Group IIIA elements except aluminum, the cobalt - based catalyst added with transition metal elements and Group IIIA elements except aluminum can achieve the effect of efficiently harvesting 2 - methylpentanediamine and 3 - methylpiperidine.

[0128] Examples 23 - 27:

[0129] The specific conditions of Experimental Examples 23 - 27 are shown in Table 3.

[0130] Table 3: Conditions of Examples 23 - 27

[0131]

[0132] From the data in the table, it can be seen that under the same cobalt - based catalyst, the selectivities of 2 - methylpentanediamine and 3 - methylpiperidine are related to the addition amount of the cobalt - based catalyst, the addition amount of 2 - methylglutaronitrile, the addition amount of ethanol, temperature, pressure and reaction time.

[0133] Furthermore, under the same cobalt-based catalyst conditions, appropriate addition amounts of cobalt-based catalyst, 2-methylglutaronitrile, ethanol, temperature, pressure, and reaction time can achieve the effect of efficiently harvesting 2-methylpentanediamine and 3-methylpiperidine simultaneously.

[0134] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cobalt-based catalyst, characterized in that The cobalt-based catalyst includes cobalt, a transition metal element, and a Group IIIA element except aluminum.

2. The cobalt-based catalyst according to claim 1, characterized in that The Group IIIA elements other than aluminum include: one or more of boron, gallium, indium and thallium.

3. The cobalt-based catalyst according to claim 2, characterized in that The mass content of the Group IIIA elements other than aluminum is 0.1% to 3% of the mass of cobalt in the cobalt-based catalyst.

4. The cobalt-based catalyst according to any one of claims 1 to 3, characterized in that The transition metal element includes: a combination of one or more of Group VIII, Group VIB and Group IB elements.

5. The cobalt-based catalyst according to claim 4, characterized in that If the Group VIII elements include a combination of one or more elements selected from the group consisting of iron, nickel, ruthenium, rhodium, palladium, iridium and platinum, the mass content of the Group VIII elements is 1% to 7% of the mass of cobalt in the cobalt-based catalyst.

6. The cobalt-based catalyst according to claim 4, characterized in that If the VIB group element includes a combination of one or more elements of chromium, molybdenum and tungsten, the mass content of the VIB group element is 1% to 6% of the mass of cobalt in the cobalt-based catalyst.

7. The cobalt-based catalyst according to claim 4, characterized in that If the Group IB elements include a combination of one or more elements of copper, silver and gold, the mass content of the Group IB elements is 100 ppm to 1000 ppm of the mass of cobalt in the cobalt-based catalyst.

8. A method for preparing a cobalt-based catalyst, characterized in that: include: Combining cobalt, aluminum, transition metal elements and Group IIIA elements other than aluminum to form a cobalt-aluminum alloy; Etching aluminum in the cobalt-aluminum alloy to obtain a cobalt-based catalyst precursor; The cobalt-based catalyst precursor is placed in an aqueous solution of an alkali metal promoter for immersion; separating the cobalt-based catalyst precursor from the impregnated cobalt-based catalyst precursor, and drying the separated cobalt-based catalyst precursor; The dried cobalt-based catalyst precursor is calcined in an inert atmosphere, and hydrogen is introduced during the calcination process to cause a reduction reaction between the cobalt-based catalyst precursor and the hydrogen to obtain the cobalt-based catalyst as claimed in any one of claims 1 to 7.

9. The method according to claim 8, characterized in that The aqueous solution of the alkali metal auxiliary agent includes one or more combinations of sodium hydroxide, potassium hydroxide, lithium hydroxide, lithium carbonate, rubidium hydroxide, cesium hydroxide, cesium nitrate, and cesium sulfate. The concentration of the alkali metal in the aqueous solution of the alkali metal auxiliary agent is 0.1 mol / L~1 mol / L.

10. Use of a cobalt-based catalyst as claimed in any one of claims 1 to 7, characterized in that: include: Add 2-methylglutaronitrile, a cobalt-based catalyst and a solvent into a sealed reactor, and introduce nitrogen into the sealed reactor to exhaust the air in the reactor; Introducing hydrogen into the reactor to allow the 2-methylglutaronitrile to undergo a hydrogenation reaction with the hydrogen under the catalytic action of the cobalt-based catalyst; When the hydrogenation reaction is completed and the reactor is maintained at normal temperature and pressure, taking out the reaction product from the reactor; Separating the cobalt-based catalyst in the reaction product from the reaction liquid by a separation method; The reaction solution is purified to obtain a mixture of 2-methylpentanediamine and 3-methylpiperidine.

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