Catalyst and application thereof
By preparing porous catalysts with iron single atoms supported on nitrogen-doped carbon, the problems of difficult catalyst separation and harsh reaction conditions were solved, and the preparation of nitrile compounds with high selectivity, stability and high yield was achieved, which is suitable for industrial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-22
- Publication Date
- 2026-03-27
AI Technical Summary
Existing technologies for the catalytic oxidation of ammonia to produce nitrile compounds suffer from problems such as difficulty in catalyst separation and reuse, and the harsh conditions for amine dehydrogenation to produce nitrile reactions result in a large number of byproducts, making it difficult to carry out the process with high selectivity under mild conditions.
A porous catalyst using iron single atoms supported on nitrogen-doped carbon was prepared by template sacrificial method to form a porous structure, avoiding metal agglomeration. Combined with calcination and acid washing treatment, a stable catalyst was formed, which is suitable for oxidation reactions of amino compounds.
It achieves highly selective catalytic conversion of amino-containing compounds into nitrile compounds under mild conditions, with high yield, suitable for industrial production, and the catalyst has good stability and can be recycled.
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Figure CN121732162A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of catalysts for organic synthesis, and particularly to a catalyst and its applications. Background Technology
[0002] Nitriles are an important class of nitrogen-containing functional group compounds, widely used as indispensable organic synthesis intermediates in the synthesis of pesticides, pharmaceuticals, biomass, and other fine chemicals. For example, 2,5-dichlorobenzonitrile is an intermediate in the preparation of various pesticides and ulcer drugs (Biomed Res. Int. 2015, 381264), citrate is an important monomer for the synthesis of various perfumes and fragrances (Synth. Commun. 2007, 15, 2579-2591), and 4-amino-2-trifluoromethylbenzonitrile can be used to synthesize bicalutamide, a potent anti-androgen inhibitor commonly used to treat prostate cancer (J. Biol. Chem. 2013, 288, 19359-69). Currently, the cyanidation methods commonly used in industrial production typically employ toxic reagents such as metal cyanides under high temperature and pressure. These harsh reaction conditions greatly limit the production and application of nitriles (Nat. Catal. 2023, 8, 16274–16282). The direct conversion of organic functional groups into cyano groups by catalytic oxygen and ammonia not only avoids the use of toxic cyaniding reagents, but also further reduces production costs by using inexpensive oxygen or even air directly as an oxidant (Angew. Chem. Int. Ed. 2018, 57, 14240–14244).
[0003] Various homogeneous and heterogeneous catalysts have been developed for the ammonia oxidation to nitrile reaction, typically used for the conversion of functional groups such as methyl, hydroxyl, aldehyde, or ketone. For example, studies have shown that using CuBr as a catalyst, ammonia water as the nitrogen source, and oxygen as the oxidant, the ammoxidation of cyclohexanone to adiponitrile can be catalyzed under mild reaction conditions (80℃ / 5 bar O2) (J. Am. Chem. Soc. 2025, 147, 1155-1161). However, the use of homogeneous catalysts in industrial production faces challenges such as difficulty in catalyst separation and non-reusability. In contrast, non-precious metal single-atom catalysts are widely used in various catalytic reactions due to their low cost, extremely high atom utilization, good stability, and ease of separation (Angew. Chem. Int. Ed. 2023, 62, e202219306). Currently, many studies also use non-precious metal single-atom catalysts to catalyze ammonia oxidation reactions. For example, Sun et al. synthesized a ZIF-derived iron single-atom catalyst that can catalyze the conversion of various alcohols to nitriles at room temperature and pressure (Nat. Commun. 2022, 13, 1848).
[0004] Besides the functional group transformation via ammonia oxidation, the direct dehydrogenation of amines to nitrile is also a highly efficient and environmentally friendly method. In 1979, Otsuka et al. first discovered that RhH(PiPr3)3 could catalyze the dehydrogenation of benzylamine to benzonitrile, but the yield was very low (J. Chem. Soc. Chem. Commun. 1979, 870-871). After decades of research, the dehydrogenation of amines to nitrile has made much progress. Lu et al. synthesized a Ru@UiO-66(Ce) catalyst that can catalyze the dehydrogenation of primary amines to nitrile in an aqueous phase without pressurization under a nitrogen atmosphere (Green. Chem. 2019, 21, 5386). Similarly, Tian et al. designed and synthesized a Co metal complex that can catalyze the dehydrogenation of amines to nitrile under conditions without hydrogen acceptor and oxidant (J. Am. Chem. Soc. 2024, 146, 11801-11810). Besides oxidative dehydrogenation, amines can also be converted to nitrile, but this often results in the formation of byproducts such as imines. For example, Coeck et al. used Pt / C as a catalyst and, after pre-activation, reacted under high temperature and high pressure conditions for 72 hours to convert amines to nitrile in a high yield (Chem. Sci., 2023, 14, 7944–7955). Therefore, developing new catalytic systems capable of highly selectively oxidizing amines to nitrile under relatively mild conditions is a highly challenging research area. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to provide a catalyst and its application, wherein the catalyst is an iron single atom supported in a nitrogen-doped carbon porous material, which has the advantages of good catalytic effect when applied to the catalytic preparation of nitrile compounds from amino-containing compounds.
[0006] To solve the above-mentioned technical problems, a first aspect of the present invention is to provide a catalyst obtained by the following method:
[0007] Step S1: Dissolve the iron salt and metal chelate in a solvent, add nano-metal oxide to the system, mix well, and then remove the solvent to obtain the precursor;
[0008] Step S2: The precursor obtained in step S1 is calcined in an inert atmosphere, and then acid-washed to remove the nano-metal oxides to obtain the catalyst.
[0009] In this invention, a template sacrificial method is used to prepare the catalyst. The metal chelate can effectively prevent metal agglomeration and forms a carbon skeleton (nitrogen doping) during calcination and pyrolysis. After acid washing, the metal oxide forms a certain porous structure. The final catalyst is an iron single atom supported in a nitrogen-doped carbon porous material, which has a large specific surface area, which is beneficial to improving the catalytic effect. In addition, the raw material cost is low and the preparation process is simple. Furthermore, the catalyst of this invention has good stability and recyclability.
[0010] Specifically, in step S1, the iron salt is selected from one or more of ferrous acetate, ferrous acetate, ferrous chloride, and ferrous sulfate;
[0011] The metal chelate is selected from one or more of 1,10-phenanthroline, bipyridine, and 8-hydroxyquinoline;
[0012] The solvent is selected from one or more of ethanol, methanol, and acetonitrile;
[0013] The nano-metal oxide is selected from one or more of nano-magnesium oxide, nano-calcium oxide, and nano-zinc oxide.
[0014] Specifically, the molar ratio of iron salt to metal chelate is 1:2-5; the molar ratio of iron salt to nano metal oxide is 1:50-200.
[0015] Specifically, in step S1, the method for mixing the system uniformly includes heating to 40-80°C and stirring.
[0016] Solvent removal methods include evaporation at 100-500 rpm;
[0017] The particle size range of nano-metal oxides is 20-800 nm.
[0018] Specifically, in step S2, the inert atmosphere includes a nitrogen atmosphere and / or an argon atmosphere;
[0019] The calcination temperature is 600℃-800℃, and the calcination time is 1-3 hours.
[0020] The acid used for pickling is one or more of nitric acid, sulfuric acid, and hydrochloric acid.
[0021] Specifically, the heating rate for calcination is 2-15℃ / min;
[0022] The concentration of acid used for pickling is 1-3 mol / L.
[0023] To address the aforementioned technical problems, a second aspect of the present invention is to provide the application of the aforementioned catalyst in the preparation of nitrile compounds from amino-containing compounds.
[0024] In this invention, the catalyst composite system prepared above exhibits mild reaction conditions, good substrate compatibility, and the reaction is carried out in an aqueous phase without the need for additional organic reagents when catalyzing the oxidation of amino-containing compounds to nitrile compounds. It also demonstrates good selectivity and high product yield.
[0025] In this invention, the catalyst prepared above catalyzes the oxidation of a compound to a nitrile compound, and the reaction formula is shown below:
[0026]
[0027] Wherein, R is selected from hydrogen, substituted or unsubstituted C1-C20 straight-chain alkyl, substituted or unsubstituted C1-C20 branched alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C2-C20 straight-chain alkenyl, substituted or unsubstituted C2-C20 branched alkenyl, substituted or unsubstituted C6-C20 cycloalkenyl, substituted or unsubstituted C6-C20 azacyclic, substituted or unsubstituted C2-C20 straight-chain oxalyl, substituted or substituted C6-C20 aryl, substituted or unsubstituted C2-C30 heteroaryl, and sulfonic acid group; substituted or unsubstituted means unsubstituted or selected from the following One or more substituents in the group consisting of: deuterium atom, halogen atom, amino, trifluoromethyl, substituted or unsubstituted C1-C20 straight-chain alkyl, substituted or unsubstituted C1-C20 branched alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C2-C20 straight-chain alkenyl, substituted or unsubstituted C2-C20 branched alkenyl, substituted or unsubstituted C6-C20 cycloalkenyl, substituted or unsubstituted C6-C20 azacyclic, substituted or unsubstituted C2-C20 straight-chain oxalyl, substituted or substituted C6-C20 aryl, substituted or unsubstituted C2-C30 heteroaryl;
[0028] The preferred amino-containing compounds are those that are:
[0029]
[0030] Specifically, the reaction materials for preparing nitrile compounds from amino-containing compounds include the amino-containing compound, a nitrogen source, and a catalyst. When the amino-containing compound content is 0.1-0.5 mmol, the mass ratio of the catalyst to ammonia is 1-2:96-100. Preferably, the reaction pressure for preparing nitrile compounds from amino-containing compounds is 5-15 Bar, the reaction temperature is 30-40℃, and the reaction time is 8-24 h. Understandably, the catalyst provided by this invention offers mild reaction conditions and simple operation in the preparation of nitrile compounds from amino-containing compounds, making it suitable for industrial production.
[0031] Specifically, the nitrogen source is selected from one or more of ammonia, urea, and hydroxylamine hydrochloride. Attached Figure Description
[0032] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0033] Figure 1aThis is a TEM image of the iron single-atom catalyst prepared in Example 1 of this invention at a size of 200 nm.
[0034] Figure 1b This is a TEM image of the iron single-atom catalyst prepared in Example 1 of this invention at a size of 100 nm.
[0035] Figure 2a This is a mapping diagram of the C element distribution in the iron single-atom catalyst prepared in Example 1 of the present invention;
[0036] Figure 2b This is a mapping diagram of the N element distribution in the iron single-atom catalyst prepared in Example 1 of the present invention;
[0037] Figure 2c This is a mapping diagram of the O element distribution in the iron single-atom catalyst prepared in Example 1 of the present invention;
[0038] Figure 2d This is a mapping diagram of the Fe element distribution in the iron single-atom catalyst prepared in Example 1 of the present invention;
[0039] Figure 3 The XRD pattern of the iron single-atom catalyst prepared in Example 1 of this invention;
[0040] Figure 4 Aberration-corrected electron microscopy image of the iron single-atom catalyst prepared in Example 1 of this invention;
[0041] Figures 5a-5e The above are NMR images of some of the products in Example 3 of this invention;
[0042] Figures 6a-6e This is an NMR spectrum of some of the products in Example 3 of the present invention. Detailed Implementation
[0043] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0044] Example 1 Catalyst Preparation
[0045] Step S1: Add 266 mg of ferric acetate and 720 mg of 1,10-phenanthroline to 100 mL of ethanol, sonicate for 30 min, then add 6 g of nano-magnesium oxide (particle size 100 nm), reflux and stir at 60 °C for 12 h, mix evenly, and remove the ethanol solvent by rotary evaporation to obtain the precursor.
[0046] Step S2: The precursor obtained in step S1 is heated to 700°C in a tube furnace under a nitrogen atmosphere at a heating rate of 5°C / min, calcined at 700°C for 2 hours, and then naturally cooled down. It is then acid-washed with a 2 mol / L hydrochloric acid aqueous solution at 60°C for 6 hours. The acid washing is repeated three times, followed by washing and drying to obtain the catalyst.
[0047] The catalyst was characterized as follows:
[0048] TEM characterization: Catalyst samples were subjected to TEM characterization, and the characterization results are as follows. Figure 1a and Figure 1b As shown, the obtained sample exhibits a distinct layered porous structure; after mapping, as... Figures 2a-2d As shown, iron is uniformly distributed in the sample in the form of single atoms.
[0049] XRD characterization: The catalyst sample was subjected to XRD characterization, and the characterization results are as follows: Figure 3 As shown, the sample exhibits only two characteristic peaks belonging to graphite carbon around 26° and 43°, with no other significant characteristic peaks. This further clarifies the single-atom structure of the catalyst.
[0050] Aberration-corrected electron microscopy characterization: Catalyst samples were subjected to aberration-corrected electron microscopy characterization. The characterization results are as follows: Figure 4 As shown, the isolated bright spots of iron single atoms (marked with red circles) can be clearly observed, indicating its single-atom structure.
[0051] Example 2 Catalyst Preparation
[0052] The preparation method is the same as in Example 1, except that the calcination temperature is different. The calcination temperature in this example is 800℃.
[0053] Comparative Example 1: Catalyst Preparation
[0054] The preparation method is the same as in Example 1, except that no nano-metal oxides are added during the catalyst preparation process.
[0055] Example 3: Application of the catalyst in the preparation of nitrile compounds from amino-containing compounds
[0056] 0.2 mmol of the amino-containing substrate, 5 mg of the catalyst obtained in Example 1, and 0.5 mL of ammonia (28 wt%) were added sequentially to a glass bottle. The mixture was stirred for 8 h at 10 Bar pressure and 35 °C under air atmosphere. Ethyl acetate was then added for extraction. After separating the organic phase, the yield of the target product was determined by gas chromatography using tetradecane as the internal standard. The substrate types and corresponding yields are shown in Tables 1 and 2.
[0057] Table 1
[0058]
[0059] Table 2
[0060]
[0061] Example 4: Application of catalysts in the preparation of nitrile compounds from amino-containing compounds
[0062] The preparation method of nitrile compounds is the same as in Example 3, except that the catalyst used is the catalyst prepared in Example 2, wherein the raw material is the amino-containing substrate when n=3 in Example 3, and the product yield obtained by gas chromatography is 75%.
[0063] Comparative Example 2: Application of catalysts in the preparation of nitrile compounds from amino-containing compounds
[0064] The preparation method of nitrile compounds is the same as in Example 3, except that the catalyst used is the catalyst prepared in Comparative Example 1, wherein the raw material is the amino-containing substrate when n=3 in Example 3, and the product yield calculated by gas chromatography is 5%.
[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A catalyst, characterized in that, It is obtained by the following method: Step S1: Dissolve the iron salt and metal chelate in a solvent, add nano-metal oxide to the system, mix well, and then remove the solvent to obtain the precursor; Step S2: The precursor obtained in step S1 is calcined in an inert atmosphere, and then acid-washed to remove the nano-metal oxides to obtain the catalyst.
2. The catalyst according to claim 1, characterized in that, In step S1, the iron salt is selected from one or more of ferrous acetate, ferrous acetate, ferrous chloride, and ferrous sulfate; The metal chelate is selected from one or more of 1,10-phenanthroline, bipyridine, and 8-hydroxyquinoline; The solvent is selected from one or more of ethanol, methanol, and acetonitrile; The nano-metal oxide is selected from one or more of nano-magnesium oxide, nano-calcium oxide, and nano-zinc oxide.
3. The catalyst according to claim 2, characterized in that, The molar ratio of iron salt to metal chelate is 1:2-5; The molar ratio of iron salt to nano-metal oxide is 1:50-200.
4. The catalyst according to claim 1, characterized in that, In step S1, the method for ensuring uniform mixing of the system includes heating to 40-80°C and stirring. Solvent removal methods include evaporation at 100-500 rpm; The particle size range of nano-metal oxides is 20-800 nm.
5. The catalyst according to claim 1, characterized in that, In step S2, the inert atmosphere includes a nitrogen atmosphere and / or an argon atmosphere; The calcination temperature is 600℃-800℃, and the calcination time is 1-3 hours. The acid used for pickling is one or more of nitric acid, sulfuric acid, and hydrochloric acid.
6. The catalyst as described in claim 5, characterized in that, The heating rate for calcination is 2-15℃ / min; The concentration of acid used for pickling is 1-3 mol / L.
7. The use of the catalyst according to any one of claims 1-6 in the preparation of nitrile compounds from amino-containing compounds.
8. The application as described in claim 7, characterized in that, The reaction materials for preparing nitrile compounds from amino-containing compounds include amino-containing compounds, nitrogen sources, and catalysts. When the amino-containing compound is 0.1-0.5 mmol, the required mass ratio of catalyst to ammonia is 1-2:96-100.
9. The application as described in claim 7, characterized in that, The reaction pressure for preparing nitrile compounds from amino-containing compounds is 5-15 Bar, the reaction temperature is 30-40℃, and the reaction time is 8-24 h.
10. The application as described in claim 8, characterized in that, The nitrogen source is selected from one or more of ammonia, urea, and hydroxylamine hydrochloride.