Preparation method of 5-methyl-N-aryl-2-pyrrolidone compound

Abstract

The invention discloses a preparation method of a 5-methyl-N-aryl-2-pyrrolidone compound, which is characterized in that biomass derivatives levulinic acid and nitro-aromatic hydrocarbon are used as initial raw materials, formic acid is used as a hydrogen source, a non-noble metal multifunctional catalyst NiMnAl (at) NC is used as a catalyst, and the 5-methyl-N-aryl-2-pyrrolidone is synthesized by adopting'one-pot 'reductive amination. The non-noble metal multifunctional catalyst NiMnAl (at) NC comprises a nitrogen-doped carbon-based carrier NC derived from a metal-organic framework material and metals Ni, Mn and Al embedded into the NC. The preparation method disclosed by the invention has the advantages of high yield of 5-methyl-N-aryl-2-pyrrolidone, environment-friendly process, simplicity in operation and recyclability of the catalyst, and has obvious industrial production advantages.

Description

Technical Field

[0001] The invention belongs to the technical field of pharmaceutical chemical industry, and specifically relates to a method for preparing a 5-methyl-N-aryl-2-pyrrolidone compound. Background Art

[0002] N-aryl pyrrolidone compounds are an important class of nitrogen heterocyclic compounds, which are widely used in the synthesis of medicines, pesticides, fine chemicals, etc. Therefore, it is of great value to develop a synthesis technology of N-aryl pyrrolidone that is economical, efficient, safe, environmentally friendly, and easy to operate.

[0003] With the increasing shortage of fossil resources and the deteriorating environment, biomass, as a green renewable resource, has received increasing attention at home and abroad. Levulinic acid is an important biomass-based platform compound that can be obtained from lignocellulosic waste by simple acid hydrolysis. Therefore, using the biomass-derived platform molecule levulinic acid as a substrate and reductively aminating amine compounds to synthesize pyrrolidone is a green and sustainable process route. Amine compounds can usually be obtained from nitro compounds (especially nitroaromatics) by hydrogenation. Therefore, the "one-pot" reductive amination of nitroaromatic compounds with levulinic acid to synthesize pyrrolidone is a more economical and attractive route.

[0004] For example, Chaudhari et al. prepared a nano-Ir catalyst fixed with polyvinylpyrrolidone (Ir-PVP). Under the conditions of H2 (1MPa) and 30°C, 64-95% of the target product can be obtained after 72 hours of reaction of levulinic acid and nitroaromatics in methanol solvent (Green Chemistry, 2020, 22(22): 7760-7764). Vidal et al. prepared a TiO2 nanotube-supported Pt catalyst (Pt / TiO2-NT) for the synthesis of 5-methyl-N-aryl-2-pyrrolidone. The reaction was carried out under the conditions of H2 (1MPa) and 120°C for 48 hours, and the yield was 55-61% (ChemSusChem, 2017, 10(1): 119-128). Gao et al. prepared a Cophen@C-800-HCl catalyst. On this catalyst, aliphatic, aromatic and heterocyclic nitro compounds can selectively undergo a one-pot reductive amination reaction with levulinic acid and be converted into the desired pyrrolidone with a yield of 80-97% (Chem Catalysis, 2022, 2(1): 178-194). Chinese invention patent CN1764376A discloses a method for reacting 5-methyl-N-aryl-2-pyrrolidone compounds with levulinic acid and nitro compounds as raw materials under the catalytic action of a supported metal catalyst. However, the yield of the target product is not high. At present, the "one-pot" reductive amination of levulinic acid and nitro compounds to synthesize 5-methyl-N-aryl-2-pyrrolidone mostly uses precious metal catalysts, which has a high production cost; in addition, hydrogen is mainly used as a hydrogen source, the hydrogen pressure used is relatively high, and the operating risk is relatively high. Summary of the invention

[0005] The purpose of the present invention is to provide an environmentally friendly method for synthesizing 5-methyl-N-aryl-2-pyrrolidone compounds by "one-pot" reduction amination in a reaction solvent, using biomass derivatives levulinic acid and nitroaromatics as raw materials, formic acid as a hydrogen source, and a non-precious metal multifunctional catalyst NiMnAl@NC, so as to solve the problems existing in the existing production process, such as low yield of target product, high cost of using precious metal catalysts, and greater operating risk of hydrogen as a hydrogen source.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a 5-methyl-N-aryl-2-pyrrolidone compound, specifically comprising: using levulinic acid and nitroaromatic hydrocarbons shown in formulas I and II as starting materials, using formic acid as a hydrogen source, reacting in a reaction solvent at a temperature of 100 to 170° C. for 4 to 15 hours under the action of a non-precious metal multifunctional catalyst, to obtain a 5-methyl-N-aryl-2-pyrrolidone shown in formula III, and the reaction formula is as follows:

[0008]

[0009] In the formula, the H on the benzene ring is substituted by a substituent R or not, and when substituted, the substituent R is an alkyl, alkoxy or halogen;

[0010] The non-precious metal multifunctional catalyst is NiMnAl@NC, which comprises a nitrogen-doped carbon-based carrier NC derived from a metal-organic framework material and metals Ni, Mn and Al embedded in the NC.

[0011] The present invention adopts non-precious metal multifunctional catalyst NiMnAl@NC, in which Ni is the main hydrogenation active site in the catalyst; the introduction of metal Mn and Al can improve the dispersion of Ni and provide suitable Acidic sites are more conducive to the occurrence of reductive amination reactions.

[0012] The nitrogen-doped carbon-based carrier has a large specific surface area and pore volume, allowing the metal to be evenly dispersed on the carrier; at the same time, the surface of the nitrogen-doped carbon-based carrier has abundant pores, which can promote the mass transfer and diffusion of reactants, and confine or anchor the effective active ingredients of metal Ni, Mn and metal Al, thereby improving the activity and stability of the catalyst.

[0013] Furthermore, the NiMnAl@NC multifunctional catalyst has a Ni content of 5-15 wt%, a Mn content of 1-10 wt%, and an Al content of 5-30 wt%.

[0014] The appropriate metal content makes the catalyst have good catalytic performance. When the Ni content is too low, the hydrogenation active component content is low, resulting in low hydrogenation activity of the catalyst; when the Mn and Al content is too low, Low acidity means insufficient acid active sites on the catalyst, which will affect the reaction rate.

[0015] Furthermore, the preparation method of the NiMnAl@NC multifunctional catalyst includes the following steps: dissolving Ni salt, Mn salt and Al salt in N,N-dimethylformamide to form solution A, dissolving 2-aminoterephthalic acid in N,N-dimethylformamide to form solution B, mixing solution A and solution B, stirring evenly at room temperature, transferring to a hydrothermal synthesis reactor, heat treating at 100-150°C for 12-24h, after cooling, filtering with a Buchner funnel, washing with N,N-dimethylformamide and methanol several times, and then drying at 100°C for 6-12h and grinding into powder to obtain a metal-organic framework material catalyst precursor, and finally calcining in a nitrogen atmosphere at 600-900°C for 1-6h to prepare a non-precious metal multifunctional catalyst NiMnAl@NC.

[0016] During the high-temperature cracking process of the metal-organic framework catalyst precursor in an inert gas, the soluble salt of metal Ni decomposes at high temperature and is in situ reduced to metal Ni by carbon, forming small-sized active metal particles that are evenly distributed on the carrier. At the same time, Mn and Al are in the form of MnO x 2-Aminoterephthalic acid forms a nitrogen-doped carbon-based carrier, leaving a large number of pores in the carrier, thereby increasing the specific surface area of ​​the catalyst and improving the mass transfer efficiency of the reactants, thereby efficiently synthesizing 5-methyl-N-aryl-2-pyrrolidone.

[0017] Further, the Ni salt is one of nickel nitrate, nickel acetate or nickel chloride, the Mn salt is one of manganese acetate, manganese nitrate or manganese chloride, and the Al salt is aluminum nitrate or aluminum chloride.

[0018] Furthermore, the molar ratio of Ni salt to 2-aminoterephthalic acid is 1:1-10, the molar ratio of Mn salt to 2-aminoterephthalic acid is 1:1-5, and the molar ratio of Al salt to 2-aminoterephthalic acid is 1:0.5-2.

[0019] Furthermore, the molar ratio of levulinic acid to nitroaromatic hydrocarbon is 1:1-2, and the mass ratio of levulinic acid to NiMnAl@NC multifunctional catalyst is 1:0.05-0.3.

[0020] Furthermore, the molar ratio of levulinic acid to formic acid is 1:1-16.

[0021] Furthermore, the solvent is water, ethanol, methanol, tetrahydrofuran or toluene, and the volume amount of the solvent is 10-50 mL / g based on the mass of levulinic acid.

[0022] Furthermore, the reaction temperature is 100-170° C., the reaction time is 4-15 h, preferably 140-160° C., the reaction time is 8-12 h.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1) The non-precious metal multifunctional catalyst NiMnAl@NC provided by the present invention has excellent catalytic activity and stability, is simple to prepare, and has low preparation cost;

[0025] 2) The present invention uses formic acid as a hydrogen source, and in a reaction solvent, levulinic acid and nitroaromatic hydrocarbons are used in a one-pot method to prepare 5-methyl-N-aryl-2-pyrrolidone, and the yield of 5-methyl-N-aryl-2-pyrrolidone can reach more than 90%. The reaction conditions are mild, green and environmentally friendly, the product yield is high, and the process is simple;

[0026] 3) The non-precious metal multifunctional catalyst of the present invention has a small dosage, can be recycled and reused, and has a low production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the XRD spectrum of the NiMnAl@NC-700 catalyst prepared in the present invention. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is described below with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0029] The preparation method of the 5-methyl-N-aryl-2-pyrrolidone compound of the present invention uses levulinic acid and nitroaromatic hydrocarbon as raw materials, uses formic acid as a hydrogen source, and uses a "one-pot method" to perform a reductive amination reaction in a solvent under the action of a non-precious metal multifunctional catalyst to prepare 5-methyl-N-aryl-2-pyrrolidone;

[0030] The non-noble metal multifunctional catalyst used in the present invention is NiMnAl@NC, which comprises a nitrogen-doped carbon-based carrier NC derived from a metal-organic framework material and metals Ni, Mn and Al embedded in the NC.

[0031] The preparation method of the non-precious metal multifunctional catalyst NiMnAl@NC of the present invention is as follows: 0.4511 g (1.55 mmol) of nickel nitrate hexahydrate, 0.3797 g (1.55 mmol) of manganese acetate tetrahydrate and 1.6506 g (4.4 mmol) of aluminum nitrate nonahydrate are dissolved in 30 mL of N,N-dimethylformamide to form solution A, 1.35 g (7.5 mmol) of 2-aminoterephthalic acid is dissolved in 35 mL of Solution B was formed in N, N-dimethylformamide, and solution A and solution B were mixed and stirred evenly at room temperature, transferred to a hydrothermal synthesis reactor, heat treated at 120°C for 24h, cooled, filtered with a Buchner funnel, washed with N, N-dimethylformamide and methanol 3 times, then dried at 100°C for 12h and ground into powder to obtain a catalyst precursor material, and finally calcined at 700°C for 2h under a nitrogen atmosphere, and then naturally cooled to room temperature to obtain a black solid powder named NiMnAl@NC-700. The catalyst was tested by ICP-OES, with Ni content of 9.14wt%, Mn content of 2.25wt%, and Al content of 17.77wt%.

[0032] According to the same method as above, different non-precious metal multifunctional catalysts were prepared by changing the different calcination temperatures of the catalyst precursor materials, and were named NiMnAl@NC-A.

[0033] The XRD spectrum of the catalyst prepared by the present invention is as follows: Figure 1As shown. The characteristic peaks of metallic Ni were observed at 2θ=44.4°, 51.9° and 76.2°, and the diffraction peaks at 37.3°, 42.6° and 61.9° were attributed to NiO. The diffraction peaks at 2θ=34.9°, 40.5°, 58.7° and 70.2° correspond to the (111), (200), (220) and (311) crystal planes of MnO, respectively, and the diffraction peaks at 42.6° and 66.5° correspond to MnO2, which indicates the successful doping of Mn. No peak of Al2O3 was detected in the XRD spectrum, mainly because the aggregation and crystal formation of Al2O3 were restricted during calcination. In this catalyst, Al2O3 exists in an amorphous form.

[0034] The catalyst prepared above was used in the following examples.

[0035] Embodiment 1:

[0036] 0.115g (1mmol) of levulinic acid, 0.160g (1.3mmol) of nitrobenzene, 0.560g (12mmol) of formic acid, 20mg of NiMnAl@NC-700 catalyst and 4mL of water were added to a 25mL high-pressure reactor. The reactor was sealed and purged with nitrogen five times. The reaction temperature was 160℃, the reaction time was 8h, the conversion rate of levulinic acid was 100%, and the yield of 5-methyl-N-phenyl-2-pyrrolidone was 91.4%.

[0037] Embodiment 2:

[0038] 0.115g (1mmol) of levulinic acid, 0.160g (1.3mmol) of nitrobenzene, 0.560g (12mmol) of formic acid, 20mg of NiMnAl@NC-700 catalyst and 4mL of water were added to a 25mL high-pressure reactor. The reactor was sealed and purged with nitrogen five times. The reaction temperature was 160℃, the reaction time was 6h, the conversion rate of levulinic acid was 87.0%, and the yield of 5-methyl-N-phenyl-2-pyrrolidone was 78.7%.

[0039] Embodiment 3:

[0040] 0.115g (1mmol) of levulinic acid, 0.160g (1.3mmol) of nitrobenzene, 0.373g (8mmol) of formic acid, 50mg of NiMnAl@NC-600 catalyst and 4mL of water were added to a 25mL high-pressure reactor. The reactor was sealed and purged with nitrogen five times. The reaction temperature was 160℃, the reaction time was 8h, the conversion rate of levulinic acid was 82.7%, and the yield of 5-methyl-N-phenyl-2-pyrrolidone was 76.6%.

[0041] Embodiment 4:

[0042] 0.115g (1mmol) of levulinic acid, 0.160g (1.3mmol) of nitrobenzene, 0.560g (12mmol) of formic acid, 50mg of NiMnAl@NC-600 catalyst and 4mL of water were added to a 25mL autoclave. The autoclave was sealed and purged with nitrogen five times. The reaction temperature was 160°C, the reaction time was 12h, the conversion rate of levulinic acid was 89.4%, and the yield of 5-methyl-N-phenyl-2-pyrrolidone was 85.2%.

[0043] Embodiment 5:

[0044] 0.115g (1mmol) of levulinic acid, 0.160g (1.3mmol) of nitrobenzene, 0.560g (12mmol) of formic acid, 20mg of NiMnAl@NC-600 catalyst and 4mL of water were added to a 25mL high-pressure reactor. The reactor was sealed and purged with nitrogen five times. The reaction temperature was 160℃, the reaction time was 12h, the conversion rate of levulinic acid was 68.0%, and the yield of 5-methyl-N-phenyl-2-pyrrolidone was 63.0%.

[0045] Embodiment 6:

[0046] 0.115g (1mmol) of levulinic acid, 0.160g (1.3mmol) of nitrobenzene, 0.560g (12mmol) of formic acid, 20mg of NiMnAl@NC-700 catalyst and 4mL of toluene were added to a 25mL high-pressure reactor. The reactor was sealed and purged with nitrogen five times. The reaction temperature was 160℃, the reaction time was 8h, the conversion rate of levulinic acid was 62.7%, and the yield of 5-methyl-N-phenyl-2-pyrrolidone was 61.4%.

[0047] Embodiment 7:

[0048] 0.115g (1mmol) of levulinic acid, 0.160g (1.3mmol) of nitrobenzene, 0.560g (12mmol) of formic acid, 20mg of NiMnAl@NC-700 catalyst and 4mL of water were added to a 25mL high-pressure reactor. The reactor was sealed and purged with nitrogen five times. The reaction temperature was 160℃, the reaction time was 6h, the conversion rate of levulinic acid was 87.0%, and the yield of 5-methyl-N-phenyl-2-pyrrolidone was 78.7%.

[0049] Embodiment 8:

[0050] 0.115g (1mmol) of levulinic acid, 0.160g (1.3mmol) of nitrobenzene, 0.747g (16mmol) of formic acid, 20mg of NiMnAl@NC-700 catalyst and 4mL of water were added to a 25mL high-pressure reactor. The reactor was sealed and purged with nitrogen five times. The reaction temperature was 160℃, the reaction time was 12h, the conversion rate of levulinic acid was 98.2%, and the yield of 5-methyl-N-phenyl-2-pyrrolidone was 87.4%.

[0051] Embodiment 9-12:

[0052] The other operations were the same as in Example 1, and the molar ratio of levulinic acid to nitrobenzene was changed to obtain the following reaction results (Table 1):

[0053] Table 1 Summary of the yield of 5-methyl-N-phenyl-2-pyrrolidone at different molar ratios of levulinic acid and nitrobenzene

[0054]

[0055]

[0056] Embodiment 13-18:

[0057] The other operations were the same as those in Example 7, and the number of times the catalyst was recycled was changed (after each reaction, the reaction solution was centrifuged and the catalyst was recovered and reused), and the following reaction results were obtained as shown in Table 2:

[0058] Table 2 Summary of the yield of 5-methyl-N-phenyl-2-pyrrolidone under different catalyst cycle times

[0059] Example Catalyst repetition times Levulinic acid conversion rate (%) Yield of 5-methyl-N-phenyl-2-pyrrolidone (%) 13 1 90.2 76.9 14 2 86.5 76.0 15 3 85.8 75.4 16 4 84.0 74.0 17 5 83.9 73.4 18 6 81.1 71.7

[0060] Embodiment 19-21:

[0061] The other operations were the same as those in Example 1, and the following reaction results were obtained by changing different nitroaromatic hydrocarbons (Table 3):

[0062] Table 3 Summary of reactions under different nitroaromatics

[0063]

[0064]

[0065] According to the above factors affecting the product yield, suitable reaction conditions can be obtained: the molar ratio of levulinic acid to nitroaromatics is 1:1.3, the molar ratio of levulinic acid to formic acid is 1:12, the reaction solvent is water, the reaction temperature is 160°C, and the reaction time is 8h. At the same time, it can be seen from Table 2 that the catalyst has excellent reusability. It can be seen from Table 3 that the catalyst shows good substrate applicability.

Claims

1. A method for preparing a 5-methyl-N-aryl-2-pyrrolidone compound, characterized in that: Using levulinic acid and nitroaromatic hydrocarbons as raw materials and formic acid as a hydrogen source, a one-pot reductive amination reaction is carried out in a solvent under the action of a non-precious metal multifunctional catalyst to prepare 5-methyl-N-aryl-2-pyrrolidone; The non-precious metal multifunctional catalyst is NiMnAl@NC, which comprises a nitrogen-doped carbon-based carrier NC derived from a metal-organic framework material and metals Ni, Mn and Al embedded in the NC.

2. The method for preparing a 5-methyl-N-aryl-2-pyrrolidone compound according to claim 1, characterized in that: The non-precious metal multifunctional catalyst NiMnAl@NC has a metal Ni content of 5-15wt%, a metal Mn content of 1-10wt%, and a metal Al content of 5-30wt%.

3. The method for preparing a 5-methyl-N-aryl-2-pyrrolidone compound according to claim 1, characterized in that: The preparation method of the non-precious metal multifunctional catalyst NiMnAl@NC includes the following steps: dissolving Ni salt, Mn salt and Al salt in N,N-dimethylformamide to form solution A, dissolving 2-aminoterephthalic acid in N,N-dimethylformamide to form solution B, mixing solution A and solution B, stirring evenly at room temperature, transferring to a hydrothermal synthesis reactor, heat treating at 100-150° C. for 12-24 hours, filtering with a Buchner funnel after cooling, washing with N,N-dimethylformamide and methanol several times, and then drying at 100° C. for 6-12 hours and grinding into powder to obtain a metal-organic framework material catalyst precursor, and finally calcining in a nitrogen atmosphere at 600-900° C. for 1-6 hours to prepare the non-precious metal multifunctional catalyst NiMnAl@NC.

4. The method for preparing a 5-methyl-N-aryl-2-pyrrolidone compound according to claim 3, characterized in that: The Ni salt is one of nickel nitrate, nickel acetate or nickel chloride, the Mn salt is one of manganese acetate, manganese nitrate or manganese chloride, and the Al salt is aluminum nitrate or aluminum chloride.

5. The method for preparing a 5-methyl-N-aryl-2-pyrrolidone compound according to claim 4, characterized in that: The molar ratio of Ni salt to 2-aminoterephthalic acid is 1:1-10, the molar ratio of Mn salt to 2-aminoterephthalic acid is 1:1-5, and the molar ratio of Al salt to 2-aminoterephthalic acid is 1:0.5-2.

6. The method for preparing a 5-methyl-N-aryl-2-pyrrolidone compound according to claim 1, characterized in that: The molar ratio of levulinic acid to nitroaromatic hydrocarbons is 1:1-2, and the mass ratio of levulinic acid to NiMnAl@NC multifunctional catalyst is 1:0.05-0.

3.

7. The method for preparing a 5-methyl-N-aryl-2-pyrrolidone compound according to claim 1, characterized in that: The molar ratio of levulinic acid to formic acid is 1:1-16.

8. The method for preparing a 5-methyl-N-aryl-2-pyrrolidone compound according to claim 1, characterized in that: The solvent is water, ethanol, methanol, tetrahydrofuran or toluene, and the volume amount of the solvent is 10-50 mL / g based on the mass of levulinic acid.

9. The method for preparing a 5-methyl-N-aryl-2-pyrrolidone compound according to claim 1, characterized in that: The reaction temperature is 100-170°C, the reaction time is 4-15h, preferably 140-160°C, the reaction time is 8-12h.

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