Treatment method of 3-methyl-2-nitrobenzoic acid byproduct nitrobenzoic acid mixture

Abstract

The invention discloses a treatment method of a 3-methyl-2-nitrobenzoic acid byproduct nitrobenzoic acid mixture, and belongs to the technical field of organic synthesis. According to the treatment method, a chelating ligand formed by Cu2O and 1, 10-phenanthroline is used as a catalyst, and the solvent and the cosolvent are matched, so that the yield of mixed decarboxylation is increased, and meanwhile, the pollution to the environment is reduced. Compared with a traditional combustion method, the method has the advantages that a large amount of harmful gas generated in the treatment process can be avoided, and the product treatment process is optimized. The decarboxylation method reduces the nitrotoluene treatment cost, has the advantages of high yield, low pollution, simplicity in operation and the like, and is a high-quality method suitable for industrial treatment of mixed nitrobenzoic acid.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis, and particularly relates to a method for treating a nitrobenzoic acid mixture which is a by-product of 3-methyl-2-nitrobenzoic acid. Background Art

[0002] 3-Methyl-2-nitrobenzoic acid is a very important organic compound and pharmaceutical intermediate. Due to the large number of active sites in its molecular structure, it can be widely used in the synthesis of pharmaceuticals, pesticides, dyes, bioengineering, polyester compounds, etc. As a pharmaceutical intermediate, it can be used to synthesize the insecticides chlorantraniliprole and cyantraniliprole. At present, 3-methyl-2-nitrobenzoic acid is prepared by nitrating 3-methylbenzoic acid. The conversion rate of this reaction is 20%-35%, and about 65%-80% of 3-methylbenzoic acid is converted into a mixture of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid. Currently, the main treatment method for the by-products is incineration. This method of treating waste not only pollutes the air and causes secondary pollution to the surrounding environment, but also wastes a large amount of chemical raw materials.

[0003] In summary, incineration is the main treatment method for the three nitrobenzoic acid by-products of 3-methyl-2-nitrobenzoic acid, but this treatment method has problems such as reducing air quality and polluting the environment. With the increasing attention of all sectors of society to environmental protection issues, it is very urgent to propose a treatment method with simple operation, low cost, and little pollution. Summary of the Invention

[0004] Based on the deficiencies of the prior art, the present invention provides a method for treating a nitrobenzoic acid mixture which is a by-product of 3-methyl-2-nitrobenzoic acid, and realizes the recycling of the three by-products through decarboxylation with a copper metal catalyst and a post-treatment step.

[0005] A method for treating a mixture of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid which are by-products of the nitration of 3-methylbenzoic acid, comprising the following steps: Using Cu2O and 1,10-phenanthroline as catalysts, in the presence of a solvent and a co-solvent, catalyzing the decarboxylation of a mixture of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid to generate p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene.

[0006] The solvent is N-methylpyrrolidone, and the co-solvent is quinoline.

[0007] Some specific treatment methods: S1) After the catalytic reaction is completed, water and petroleum ether are added to the reaction mixture, and then the water and petroleum ether are separated; S2) Hydrochloric acid solution is added to the petroleum ether, stirred, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene.

[0008] Some specific treatment methods: The aqueous phase in step S1 is extracted with an organic solvent, and the organic phase is dried to obtain N-methylpyrrolidone; The aqueous phase in step S2 is neutralized with sodium hydroxide to neutralize 65-90% of the hydrochloric acid, then extracted with an organic solvent, and the organic phase is dried to obtain quinoline; The organic solvents are each independently selected from at least one of dichloromethane, ethyl acetate, and diethyl ether.

[0009] Some specific treatment methods: In step S1, the amounts of water and petroleum ether are not particularly limited. The amount of water should be able to dissolve N-methylpyrrolidone, and the petroleum ether should be able to extract the mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene.

[0010] Specifically, the volume ratio of water to petroleum ether is 2-5:1.

[0011] In step S2, there is no requirement for the concentrations of hydrochloric acid and sodium hydroxide, as long as the added amount of HCl is not less than 1 times the amount of substance of quinoline, and sodium hydroxide can neutralize 75-85% of the hydrochloric acid.

[0012] Some specific treatment methods: The obtained mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene is separated by distillation to obtain p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene respectively.

[0013] Some specific treatment methods: The obtained mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene is filtered to obtain p-nitrotoluene, and then the mixture of m-nitrotoluene and o-nitrotoluene is cooled to precipitate m-nitrotoluene, and then filtered to obtain m-nitrotoluene and o-nitrotoluene respectively.

[0014] Some specific treatment methods: The mixture of m-nitrotoluene and o-nitrotoluene is cooled to 0-10 °C to precipitate m-nitrotoluene.

[0015] Some specific treatment methods: The mixture of m-nitrotoluene and o-nitrotoluene is cooled to 0-5 °C to precipitate m-nitrotoluene.

[0016] Some specific treatment methods: The molar ratio of the mixture to Cu2O is 1:0.02-0.07.

[0017] The molar ratio of Cu2O to 1,10-phenanthroline is 1:1-3.

[0018] The reaction temperature is 170 °C to 220 °C.

[0019] The volume ratio of N-methylpyrrolidone to quinoline is 2 to 5:1.

[0020] For some specific treatment methods, the molar ratio of the mixture to Cu2O is 1:0.02 to 0.07.

[0021] The molar ratio of Cu2O to 1,10-phenanthroline is 1:1.5 to 2.5.

[0022] The reaction temperature is 180 °C to 210 °C.

[0023] The volume ratio of N-methylpyrrolidone to quinoline is 2 to 4:1.

[0024] For some specific treatment methods, the molar ratio of the mixture to Cu2O is 1:0.02 to 0.07.

[0025] The molar ratio of Cu2O to 1,10-phenanthroline is 1:1.5 to 2.5.

[0026] The reaction temperature is 180 °C to 210 °C.

[0027] The volume ratio of N-methylpyrrolidone to quinoline is 2.5 to 3.5:1.

[0028]

[0029] The reaction temperature of the described treatment method is 160 °C - 220 °C. Preferably, the reaction temperature is 170 °C - 220 °C.

[0030] The dosage of the solvent N-methylpyrrolidone is preferably 3 to 15 times the amount of nitro toluene in terms of molar amount.

[0031] The dosage of the co-solvent quinoline is preferably 0.85 to 4.3 times the amount of nitro toluene in terms of molar amount.

[0032] For some specific treatment methods, in the mixture of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid, the mass ratio of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid is 1 to 2:1 to 1.5:1.

[0033] For some specific treatment methods, in the mixture of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid, the mass ratio of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid is 1 to 2:1 to 1.2:1.

[0034] Some specific treatment methods, in the mixture of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid, the mass ratio of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid is 1-1.5:1-1.1:1.

[0035] Some specific treatment methods, in the mixture of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid, the mass ratio of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid is 1-1.2:1-1.1:1.

[0036] Application of the above-mentioned method in treating the nitrobenzoic acid mixture which is a by-product of the nitration of 3-methylbenzoic acid.

[0037] Specifically, application of the above-mentioned method in treating the mixture of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid which are by-products of the nitration of 3-methylbenzoic acid to prepare 3-methyl-2-nitrobenzoic acid.

[0038] Advantages of the present invention: Compared with the traditional process, this method for the mixed decarboxylation of nitrobenzoic acid has the following advantages: (1) This method for the mixed decarboxylation of nitrobenzoic acid uses the chelating ligand formed by Cu2O and 1,10-phenanthroline as a catalyst. Through the cooperation of the solvent and the co-solvent, the yield of the mixed decarboxylation is improved while reducing the environmental pollution. (2) Compared with the traditional combustion method, this method can avoid a large amount of harmful gases generated during the treatment process and optimize the process for product treatment. (3) This decarboxylation method reduces the cost of treating nitrotoluene and has the advantages of high yield, low pollution, and simple operation. It is an excellent method suitable for industrial treatment of mixed nitrobenzoic acid. (4) By cooperating with the post-treatment method, a nitrotoluene mixture with a purity greater than 99% can be obtained, and further m-nitrotoluene, p-nitrotoluene, and o-nitrotoluene with relatively high purity can be obtained. (5) Through a special post-treatment process of the present invention, the solvents NMP and quinoline with a recovery purity greater than 99% can be achieved. Description of the drawings

[0039] Figure 1 It is the gas chromatography-mass spectrometry (GC-MS) spectrum of NMP in Example 1.

[0040] Figure 2 It is the liquid chromatography (LC) spectrum of quinoline in Example 1.

[0041] Figure 3 It is the gas chromatography-mass spectrometry (GC-MS) spectrum of the nitration reaction product in Example 48.

[0042] Figure 4 It is the liquid chromatogram of the mixture of three kinds of nitrotoluene in Example 1. DETAILED DESCRIPTION

[0043] The present invention is further described in detail below in conjunction with examples, but the present invention is not limited to the following examples.

[0044] In the specific embodiment, the purity of NMP was measured by gas chromatography-mass spectrometry (model: ISQ7000), and the purity of other substances was measured by high performance liquid chromatography (model: LC-16).

[0045] Implementation Plan 1 In a 25 ml two-necked bottle, add 181.15 mg 5-methyl-2-nitrobenzoic acid, 181.15 mg 3-methyl-5-nitrobenzoic acid, 181.15 mg 3-methyl-4-nitrobenzoic acid, 4.5 mg Cu2O, 10.8 mg 1,10-phenanthroline, 4.5 ml N-methylpyrrolidone, and 1.5 ml quinoline. Reflux at 170 ° C for 12 hours. The total yield of the product is measured to be 27.52%.

[0046] After the catalytic reaction was completed, 10 ml of petroleum ether and 20 ml of water were added to the reaction mixture, and the water and petroleum ether were separated after thorough mixing. The aqueous phase was extracted with 20 ml of dichloromethane, and the organic phase was dried to obtain NMP with a purity of 99.5% (attached Figure 1 ). Add 1.5 ml of 12 mol / l concentrated hydrochloric acid to petroleum ether, stir for 4 h, add 10 ml of water for extraction, and dry the organic phase to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene. The purity of the mixture is 99.956% (attached Figure 4 ). Add 434 mg of sodium hydroxide solid to the aqueous phase containing concentrated hydrochloric acid, add 20 ml of petroleum ether for extraction, and dry the organic phase to obtain quinoline with a purity of 99.897% (attached Figure 2 ).

[0047] The purity of NMP obtained in this example was measured by gas chromatography-mass spectrometry (model: ISQ7000). Figure 1 As shown in the spectrum, it can be concluded that the purity of the purified and recovered NMP is 99.5%. The purity of the p-nitrotoluene, m-nitrotoluene, o-nitrotoluene mixture and quinoline obtained in this example was measured using a high performance liquid chromatograph (model: LC-16). Figure 2 and 4 As shown, the purity of quinoline is 99.897% and the purity of the mixture is 99.956%.

[0048] Implementation Plan 2 In a 25 ml two-necked bottle, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 8.58 mg of Cu2O, 21.6 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline. Reflux at 170°C for 12 hours. The total yield of the product is measured to be 79.45%.

[0049] After the catalytic reaction is completed, 11 ml of n-hexane and 24 ml of water are added to the reaction mixture, and the water and n-hexane are separated after sufficient mixing. The aqueous phase is extracted with 25 ml of ethyl acetate, and the organic phase is dried to obtain NMP with a purity of 90.15%. 1.7 ml of 12 mol / l concentrated hydrochloric acid is added to n-hexane, stirred for 4 hours, 12 ml of water is added for extraction, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 91.224%. 436 mg of sodium hydroxide solid is added to the aqueous phase containing concentrated hydrochloric acid, 25 ml of dichloromethane is added for extraction, and quinoline is dried to obtain a purity of 85.385%.

[0050] Implementation Plan 3 In a 25 ml two-necked bottle, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 13.5 mg of Cu2O, 32.4 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline. Reflux at 170°C for 12 hours. The total yield of the product is measured to be 77.09%.

[0051] After the catalytic reaction is completed, 15 ml of dichloromethane and 32 ml of water are added to the reaction mixture, and the water and dichloromethane are separated after sufficient mixing. The aqueous phase is extracted with 22 ml of ether, and the organic phase is dried to obtain NMP with a purity of 84.25%. 1.7 ml of 12 mol / l concentrated hydrochloric acid is added to dichloromethane, stirred for 4 hours, 12 ml of water is added for extraction, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 72.654%. 435 mg of sodium hydroxide solid is added to the aqueous phase containing concentrated hydrochloric acid, 20 ml of n-hexane is added for extraction, and quinoline is dried to obtain a purity of 86.572%.

[0052] Implementation Plan 4 In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 17.16 mg of Cu2O, 43.2 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 170 °C for 12 h, and the total yield of the product was measured to be 74.21%.

[0053] After the catalytic reaction was completed, 10 ml of n-hexane and 34 ml of water were added to the reaction mixture. After thorough mixing, the water and n-hexane were separated. The aqueous phase was extracted with 23 ml of dichloromethane, and the organic phase was dried to obtain NMP with a purity of 92.68%. 1.7 ml of concentrated hydrochloric acid with a concentration of 12 mol / l was added to the n-hexane, and the mixture was stirred for 4 h. Then 20 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 81.354%. 438 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 20 ml of ethyl acetate was added for extraction. The organic phase was dried to obtain quinoline with a purity of 76.588%.

[0054] Embodiment Five In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 21.45 mg of Cu2O, 54 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 170 °C for 12 h, and the total yield of the product was measured to be 67.30%.

[0055] After the catalytic reaction was completed, 10 ml of ether and 38 ml of water were added to the reaction mixture. After thorough mixing, the water and ether were separated. The aqueous phase was extracted with 21 ml of ethyl acetate, and the organic phase was dried to obtain NMP with a purity of 65.24%. 1.7 ml of concentrated hydrochloric acid with a concentration of 13 mol / l was added to the ether, and the mixture was stirred for 4 h. Then 10 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 65.427%. 439 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 30 ml of n-hexane was added for extraction. The organic phase was dried to obtain quinoline with a purity of 56.836%.

[0056] Embodiment Six In a 25 ml two-necked flask, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 25.74 mg of Cu2O, 64.8 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline. Reflux at 170 °C for 12 h, and the total yield of the product is measured to be 36.52%.

[0057] After the catalytic reaction is completed, add 10 ml of ethyl acetate and 39 ml of water to the reaction mixture. After thorough mixing, separate the water and ethyl acetate. The aqueous phase is extracted with 54 ml of ether, and the organic phase is dried to obtain NMP with a purity of 89.52%. Add 1.7 ml of concentrated hydrochloric acid with a concentration of 12 mol / l to the ethyl acetate, stir for 4 h, add 10 ml of water for extraction, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 88.563%. Add 434 mg of solid sodium hydroxide to the aqueous phase containing concentrated hydrochloric acid, add 35 ml of ether for extraction, and the organic phase is dried to obtain quinoline with a purity of 74.254%.

[0058] Embodiment Seven In a 25 ml two-necked flask, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 31.5 mg of Cu2O, 75.6 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline. Reflux at 170 °C for 12 h, and the total yield of the product is measured to be 32.07%.

[0059] After the catalytic reaction is completed, add 10 ml of n-hexane and 30 ml of water to the reaction mixture. After thorough mixing, separate the water and n-hexane. The aqueous phase is extracted with 50 ml of dichloromethane, and the organic phase is dried to obtain NMP with a purity of 86.23%. Add 2 ml of concentrated hydrochloric acid with a concentration of 10 mol / l to the n-hexane, stir for 4 h, add 15 ml of water for extraction, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 78.965%. Add 445 mg of solid sodium hydroxide to the aqueous phase containing concentrated hydrochloric acid, add 25 ml of ethyl acetate for extraction, and the organic phase is dried to obtain quinoline with a purity of 86.534%.

[0060] Embodiment Eight In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 4.5 mg of Cu2O, 10.8 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 180 °C for 12 h, and the total yield of the product was measured to be 33.12%.

[0061] After the catalytic reaction was completed, 10 ml of dichloromethane and 30 ml of water were added to the reaction mixture. After thorough mixing, the water and dichloromethane were separated. The aqueous phase was extracted with 52 ml of ether, and the organic phase was dried to obtain NMP with a purity of 87.29%. 2 ml of concentrated hydrochloric acid with a concentration of 11 mol / l was added to the dichloromethane, and the mixture was stirred for 4 h. Then 10 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 94.266%. 447 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 20 ml of acetone was added for extraction. The organic phase was dried to obtain quinoline with a purity of 78.654%.

[0062] Embodiment Nine In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 8.58 mg of Cu2O, 21.6 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 180 °C for 12 h, and the total yield of the product was measured to be 89.84%.

[0063] After the catalytic reaction was completed, 10 ml of ether and 37 ml of water were added to the reaction mixture. After thorough mixing, the water and ether were separated. The aqueous phase was extracted with 45 ml of acetone, and the organic phase was dried to obtain NMP with a purity of 90.28%. 2 ml of concentrated hydrochloric acid with a concentration of 12 mol / l was added to the ether, and the mixture was stirred for 4 h. Then 10 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 81.257%. 448 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 25 ml of n-hexane was added for extraction. The organic phase was dried to obtain quinoline with a purity of 99.247%.

[0064] Embodiment Ten In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 13.5 mg of Cu2O, 32.4 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 180 °C for 12 h, and the total yield of the product was measured to be 88.72%.

[0065] After the catalytic reaction was completed, 10 ml of ethyl acetate and 20 ml of water were added to the reaction mixture. After thorough mixing, the water and ethyl acetate were separated. The aqueous phase was extracted with 47 ml of ether, and the organic phase was dried to obtain NMP with a purity of 85.63%. 2 ml of concentrated hydrochloric acid with a concentration of 13 mol / l was added to the ethyl acetate, and the mixture was stirred for 4 h. Then 10 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 78.622%. 449 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 30 ml of chloroform was added for extraction. The organic phase was dried to obtain quinoline with a purity of 63.523%.

[0066] Embodiment XI In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 17.16 mg of Cu2O, 43.2 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 180 °C for 12 h, and the total yield of the product was measured to be 88.43%.

[0067] After the catalytic reaction was completed, 10 ml of n-hexane and 35 ml of water were added to the reaction mixture. After thorough mixing, the water and n-hexane were separated. The aqueous phase was extracted with 44 ml of ethyl acetate, and the organic phase was dried to obtain NMP with a purity of 85.32%. 1.5 ml of concentrated hydrochloric acid with a concentration of 12 mol / l was added to the n-hexane, and the mixture was stirred for 4 h. Then 25 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 81.656%. 408 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 20 ml of ether was added for extraction. The organic phase was dried to obtain quinoline with a purity of 78.962%.

[0068] Embodiment XII In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 21.45 mg of Cu2O, 54 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 180 °C for 12 h, and the total yield of the product was measured to be 84.75%.

[0069] After the catalytic reaction was completed, 10 ml of diethyl ether and 32 ml of water were added to the reaction mixture. After thorough mixing, the water and diethyl ether were separated. The aqueous phase was extracted with 43 ml of ethyl acetate, and the organic phase was dried to obtain NMP with a purity of 92.35%. 1.5 ml of concentrated hydrochloric acid with a concentration of 11 mol / l was added to the diethyl ether, and the mixture was stirred for 4 h. Then 15 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 84.235%. 407 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 20 ml of n-hexane was added for extraction. The organic phase was dried to obtain quinoline with a purity of 81.235%.

[0070] Embodiment Thirteen In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 25.74 mg of Cu2O, 64.8 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 180 °C for 12 h, and the total yield of the product was measured to be 84.74%.

[0071] After the catalytic reaction was completed, 10 ml of acetonitrile and 35 ml of water were added to the reaction mixture. After thorough mixing, the water and acetonitrile were separated. The aqueous phase was extracted with 42 ml of dichloromethane, and the organic phase was dried to obtain NMP with a purity of 52.34%. 1.5 ml of concentrated hydrochloric acid with a concentration of 12 mol / l was added to the acetonitrile, and the mixture was stirred for 4 h. Then 15 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 86.324%. 409 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 23 ml of ethyl acetate was added for extraction. The organic phase was dried to obtain quinoline with a purity of 72.564%.

[0072] Embodiment Fourteen In a 25 ml two-necked flask, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 31.5 mg of Cu2O, 75.6 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline. Reflux at 180 °C for 12 h, and the total yield of the product is measured to be 84.05%.

[0073] After the catalytic reaction is completed, add 10 ml of DMF and 40 ml of water to the reaction mixture. After thorough mixing, separate the water and DMF. The aqueous phase is extracted with 41 ml of ether, and the organic phase is dried to obtain NMP with a purity of 65.32%. Add 1.5 ml of concentrated hydrochloric acid with a concentration of 11 mol / l to the DMF, stir for 4 h, add 10 ml of water for extraction, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 89.325%. Add 412 mg of solid sodium hydroxide to the aqueous phase containing concentrated hydrochloric acid, add 25 ml of acetonitrile for extraction, and the organic phase is dried to obtain quinoline with a purity of 90.239%.

[0074] Embodiment 15 In a 25 ml two-necked flask, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 4.5 mg of Cu2O, 10.8 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline. Reflux at 190 °C for 12 h, and the total yield of the product is measured to be 90.78%.

[0075] After the catalytic reaction is completed, add 10 ml of toluene and 26 ml of water to the reaction mixture. After thorough mixing, separate the water and toluene. The aqueous phase is extracted with 39 ml of ether, and the organic phase is dried to obtain NMP with a purity of 78.96%. Add 2.5 ml of concentrated hydrochloric acid with a concentration of 9.1 mol / l to the toluene, stir for 4 h, add 15 ml of water for extraction, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 89.114%. Add 420 mg of solid sodium hydroxide to the aqueous phase containing concentrated hydrochloric acid, add 24 ml of n-hexane for extraction, and the organic phase is dried to obtain quinoline with a purity of 85.326%.

[0076] Embodiment 16 In a 25 ml two-necked bottle, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 8.58 mg of Cu2O, 21.6 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline. Reflux at 190°C for 12 hours. The total yield of the product is measured to be 92.54%.

[0077] After the catalytic reaction is completed, 10 ml of petroleum ether and 20 ml of water are added to the reaction mixture, and the water and petroleum ether are separated after sufficient mixing. The aqueous phase is extracted with 20 ml of dichloromethane, and the organic phase is dried to obtain NMP with a purity of 99.31%. 2.5 ml of concentrated hydrochloric acid with a concentration of 9 mol / l is added to the petroleum ether, stirred for 4 hours, 10 ml of water is added for extraction, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 99.925%. 425 mg of sodium hydroxide solid is added to the aqueous phase containing concentrated hydrochloric acid, 20 ml of petroleum ether is added for extraction, and quinoline is dried to obtain a purity of 99.814%.

[0078] Implementation Plan 17 In a 25 ml two-necked bottle, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 13.5 mg of Cu2O, 32.4 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline. Reflux at 190°C for 12 hours. The total yield of the product is measured to be 92.16%.

[0079] After the catalytic reaction is completed, 10 ml of acetonitrile and 29 ml of water are added to the reaction mixture, and the water and acetonitrile are separated after sufficient mixing. The aqueous phase is extracted with 37 ml of ethyl acetate, and the organic phase is dried to obtain NMP with a purity of 85.63%. 2.5 ml of 10 mol / l concentrated hydrochloric acid is added to acetonitrile, stirred for 4 hours, 16 ml of water is added for extraction, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 67.895%. 426 mg of solid sodium hydroxide is added to the aqueous phase containing concentrated hydrochloric acid, 30 ml of n-hexane is added for extraction, and quinoline is dried to obtain a purity of 82.458%.

[0080] Implementation Plan 18 In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 17.16 mg of Cu2O, 54 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 190 °C for 12 h, and the total yield of the product was measured to be 91.83%.

[0081] After the catalytic reaction was completed, 10 ml of toluene and 38 ml of water were added to the reaction mixture. After thorough mixing, the water and toluene were separated. The aqueous phase was extracted with 35 ml of ether, and the organic phase was dried to obtain NMP with a purity of 78.96%. 2.5 ml of concentrated hydrochloric acid with a concentration of 11 mol / l was added to the toluene, and the mixture was stirred for 4 h. Then 17 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 71.238%. 429 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 25 ml of ethyl acetate was added for extraction. The organic phase was dried to obtain quinoline with a purity of 81.265%.

[0082] Embodiment XIX In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 21.45 mg of Cu2O, 54 mg of 1,10-phenanthroline, 1.5 ml of N-methylpyrrolidone, and 0.5 ml of quinoline were added. The mixture was refluxed at 190 °C for 12 h, and the total yield of the product was measured to be 91.73%.

[0083] After the catalytic reaction was completed, 10 ml of acetonitrile and 30 ml of water were added to the reaction mixture. After thorough mixing, the water and acetonitrile were separated. The aqueous phase was extracted with 32 ml of ethyl acetate, and the organic phase was dried to obtain NMP with a purity of 79.63%. 2.5 ml of concentrated hydrochloric acid with a concentration of 9 mol / l was added to the acetonitrile, and the mixture was stirred for 4 h. Then 18 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 86.32%. 445 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 30 ml of n-hexane was added for extraction. The organic phase was dried to obtain quinoline with a purity of 76.235%.

[0084] Embodiment XX In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 25.74 mg of Cu2O, 64.8 mg of 1,10-phenanthroline, 1.5 ml of N-methylpyrrolidone, and 0.5 ml of quinoline were added. The mixture was refluxed at 190 °C for 12 h, and the total yield of the product was measured to be 91.47%.

[0085] After the catalytic reaction was completed, 10 ml of n-hexane and 35 ml of water were added to the reaction mixture. After thorough mixing, the water and n-hexane were separated. The aqueous phase was extracted with 30 ml of ether, and the organic phase was dried to obtain NMP with a purity of 92.35%. 2.5 ml of concentrated hydrochloric acid with a concentration of 8 mol / l was added to the n-hexane, and the mixture was stirred for 4 h. Then 19 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 88.365%. 442 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 20 ml of acetone was added for extraction. The organic phase was dried to obtain quinoline with a purity of 87.629%.

[0086] Embodiment XXI In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 31.5 mg of Cu2O, 75.6 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 190 °C for 12 h, and the total yield of the product was measured to be 91.02%.

[0087] After the catalytic reaction was completed, 10 ml of ether and 37 ml of water were added to the reaction mixture. After thorough mixing, the water and ether were separated. The aqueous phase was extracted with 29 ml of ethyl acetate, and the organic phase was dried to obtain NMP with a purity of 89.236%. 3 ml of concentrated hydrochloric acid with a concentration of 10 mol / l was added to the ether, and the mixture was stirred for 4 h. Then 20 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 83.325%. 443 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 20 ml of n-hexane was added for extraction. The organic phase was dried to obtain quinoline with a purity of 91.235%.

[0088] Embodiment XXII In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 4.5 mg of Cu2O, 10.8 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 200 °C for 12 h, and the total yield of the product was measured to be 84.48%.

[0089] After the catalytic reaction was completed, 10 ml of acetonitrile and 34 ml of water were added to the reaction mixture. After thorough mixing, the water and acetonitrile were separated. The aqueous phase was extracted with 27 ml of acetone, and the organic phase was dried to obtain NMP with a purity of 84.65%. 3 ml of concentrated hydrochloric acid with a concentration of 8 mol / l was added to the acetonitrile, and the mixture was stirred for 4 h. Then 21 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 89.632%. 445 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 25 ml of toluene was added for extraction. The organic phase was dried to obtain quinoline with a purity of 86.352%.

[0090] Embodiment Twenty-Three In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 8.58 mg of Cu2O, 21.6 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 200 °C for 12 h, and the total yield of the product was measured to be 91.35%.

[0091] After the catalytic reaction was completed, 10 ml of dichloroethane and 35 ml of water were added to the reaction mixture. After thorough mixing, the water and dichloroethane were separated. The aqueous phase was extracted with 36 ml of ether, and the organic phase was dried to obtain NMP with a purity of 63.98%. 3 ml of concentrated hydrochloric acid with a concentration of 9 mol / l was added to the dichloroethane, and the mixture was stirred for 4 h. Then 22 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 89.635%. 448 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 28 ml of acetonitrile was added for extraction. The organic phase was dried to obtain quinoline with a purity of 68.365%.

[0092] Embodiment Twenty-Four In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 13.5 mg of Cu2O, 32.4 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 200 °C for 12 h, and the total yield of the product was measured to be 90.17%.

[0093] After the catalytic reaction was completed, 10 ml of ether and 27 ml of water were added to the reaction mixture. After thorough mixing, the water and ether were separated. The aqueous phase was extracted with 25 ml of ethyl acetate, and the organic phase was dried to obtain NMP with a purity of 79.63%. 3 ml of concentrated hydrochloric acid with a concentration of 8.5 mol / l was added to the ether, and the mixture was stirred for 4 h. Then 23 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 84.653%. 445 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 20 ml of n-hexane was added for extraction. The organic phase was dried to obtain quinoline with a purity of 90.234%.

[0094] Embodiment Twenty-Five In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 17.16 mg of Cu2O, 43.2 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 200 °C for 12 h, and the total yield of the product was measured to be 89.28%.

[0095] After the catalytic reaction was completed, 10 ml of toluene and 39 ml of water were added to the reaction mixture. After thorough mixing, the water and toluene were separated. The aqueous phase was extracted with 22 ml of dichloromethane, and the organic phase was dried to obtain NMP with a purity of 89.63%. 3.5 ml of concentrated hydrochloric acid with a concentration of 8 mol / l was added to the toluene, and the mixture was stirred for 4 h. Then 36 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 75.362%. 451 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 20 ml of ether was added for extraction. The organic phase was dried to obtain quinoline with a purity of 74.329%.

[0096] Embodiment Twenty-Six In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 21.45 mg of Cu2O, 54 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 200 °C for 12 h, and the total yield of the product was measured to be 88.44%.

[0097] After the catalytic reaction was completed, 10 ml of ethyl acetate and 42 ml of water were added to the reaction mixture. After thorough mixing, the water and ethyl acetate were separated. The aqueous phase was extracted with 20 ml of diethyl ether, and the organic phase was dried to obtain NMP with a purity of 89.63%. 3.5 ml of concentrated hydrochloric acid with a concentration of 11 mol / l was added to the ethyl acetate, and the mixture was stirred for 4 h. Then 10 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 67.235%. 446 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 25 ml of n-hexane was added for extraction. The organic phase was dried to obtain quinoline with a purity of 72.963%.

[0098] Embodiment Twenty-Seven In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 25.74 mg of Cu2O, 64.8 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 200 °C for 12 h, and the total yield of the product was measured to be 88.12%.

[0099] After the catalytic reaction was completed, 10 ml of acetonitrile and 34 ml of water were added to the reaction mixture. After thorough mixing, the water and acetonitrile were separated. The aqueous phase was extracted with 25 ml of ethyl acetate, and the organic phase was dried to obtain NMP with a purity of 65.32%. 3.5 ml of concentrated hydrochloric acid with a concentration of 8.3 mol / l was added to the acetonitrile, and the mixture was stirred for 4 h. Then 10 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 72.656%. 448 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 35 ml of diethyl ether was added for extraction. The organic phase was dried to obtain quinoline with a purity of 63.532%.

[0100] Embodiment Twenty-Eight In a 25-ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 31.5 mg of Cu2O, 75.6 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 200 °C for 12 h, and the total yield of the product was measured to be 86.22%.

[0101] After the catalytic reaction was completed, 10 ml of n-hexane and 37 ml of water were added to the reaction mixture. After thorough mixing, the water and n-hexane were separated. The aqueous phase was extracted with 20 ml of diethyl ether, and the organic phase was dried to obtain NMP with a purity of 75.36%. 3.5 ml of concentrated hydrochloric acid with a concentration of 8.1 mol / l was added to the n-hexane, and the mixture was stirred for 4 h. Then 10 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 78.693%. 450 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 38 ml of ethyl acetate was added for extraction. The organic phase was dried to obtain quinoline with a purity of 74.632%.

[0102] Embodiment Twenty-Nine In a 25-ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 4.5 mg of Cu2O, 10.8 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 210 °C for 12 h, and the total yield of the product was measured to be 82.11%.

[0103] After the catalytic reaction was completed, 10 ml of dichloromethane and 45 ml of water were added to the reaction mixture. After thorough mixing, the water and dichloromethane were separated. The aqueous phase was extracted with 20 ml of diethyl ether, and the organic phase was dried to obtain NMP with a purity of 78.63%. 3.5 ml of concentrated hydrochloric acid with a concentration of 7.9 mol / l was added to the dichloromethane, and the mixture was stirred for 4 h. Then 19 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 82.365%. 450 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 30 ml of n-hexane was added for extraction. The organic phase was dried to obtain quinoline with a purity of 65.329%.

[0104] Embodiment Thirty In a 25 ml two-necked bottle, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 8.58 mg of Cu2O, 21.6 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline. Reflux at 210°C for 12 hours. The total yield of the product is measured to be 89.24%.

[0105] After the catalytic reaction is completed, 10 ml of n-hexane and 34 ml of water are added to the reaction mixture, and the water and n-hexane are separated after sufficient mixing. The aqueous phase is extracted with 20 ml of dichloromethane, and the organic phase is dried to obtain NMP with a purity of 76.35%. 4.3 ml of concentrated hydrochloric acid with a concentration of 7.6 mol / l is added to n-hexane, stirred for 4 hours, 16 ml of water is added for extraction, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 85.369%. 449 mg of solid sodium hydroxide is added to the aqueous phase containing concentrated hydrochloric acid, 25 ml of acetone is added for extraction, and quinoline is dried to obtain a purity of 63.598%.

[0106] Implementation Plan 31 In a 25 ml two-necked bottle, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 13.5 mg of Cu2O, 32.4 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline. Reflux at 210°C for 12 hours. The total yield of the product is measured to be 86.86%.

[0107] After the catalytic reaction is completed, 10 ml of ether and 40 ml of water are added to the reaction mixture, and the water and ether are separated after sufficient mixing. The aqueous phase is extracted with 20 ml of ethyl acetate, and the organic phase is dried to obtain NMP with a purity of 84.32%. 4 ml of concentrated hydrochloric acid with a concentration of 7.5 mol / l is added to the ether, stirred for 4 hours, 15 ml of water is added for extraction, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 89.365%. 445 mg of solid sodium hydroxide is added to the aqueous phase containing concentrated hydrochloric acid, and 29 ml of n-hexane is added for extraction. The organic phase is dried to obtain quinoline with a purity of 63.259%.

[0108] Implementation Plan 32 In a 25 ml two-necked bottle, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 17.16 mg of Cu2O, 43.2 mg of 1,10-phenanthroline, 1.5 ml of N-methylpyrrolidone, and 0.5 ml of quinoline. Reflux at 210°C for 12 hours. The total yield of the product is measured to be 86.49%.

[0109] After the catalytic reaction is completed, 10 ml of acetone and 18 ml of water are added to the reaction mixture, and the water and acetone are separated after sufficient mixing. The aqueous phase is extracted with 20 ml of dichloromethane, and the organic phase is dried to obtain NMP with a purity of 63.325%. 4 ml of concentrated hydrochloric acid with a concentration of 7.4 mol / l is added to acetone, stirred for 4 hours, and 25 ml of water is added for extraction. The organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 85.367%. 448 mg of solid sodium hydroxide is added to the aqueous phase containing concentrated hydrochloric acid, and 30 ml of n-hexane is added for extraction. The organic phase is dried to obtain quinoline with a purity of 81.368%.

[0110] Implementation Plan 33 In a 25 ml two-necked bottle, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 21.45 mg of Cu2O, 54 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline. Reflux at 210°C for 12 hours. The total yield of the product is measured to be 86.47%.

[0111] After the catalytic reaction is completed, 10 ml of acetone and 28 ml of water are added to the reaction mixture, and the water and acetone are separated after sufficient mixing. The aqueous phase is extracted with 20 ml of ether, and the organic phase is dried to obtain NMP with a purity of 89.63%. 4 ml of concentrated hydrochloric acid with a concentration of 7.5 mol / l is added to acetone, stirred for 4 hours, 10 ml of water is added for extraction, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 78.963%. 457 mg of solid sodium hydroxide is added to the aqueous phase containing concentrated hydrochloric acid, 35 ml of dichloroethane is added for extraction, and quinoline is dried to obtain a purity of 89.639%.

[0112] Implementation Plan 34 In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 25.74 mg of Cu2O, 64.8 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 210 °C for 12 h, and the total yield of the product was measured to be 86.16%.

[0113] After the catalytic reaction was completed, 10 ml of cyclohexane and 20 ml of water were added to the reaction mixture. After thorough mixing, the water and cyclohexane were separated. The aqueous phase was extracted with 20 ml of ether, and the organic phase was dried to obtain NMP with a purity of 78.63%. 4 ml of concentrated hydrochloric acid with a concentration of 7.5 mol / l was added to the cyclohexane, and the mixture was stirred for 4 h. Then 10 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 86.365%. 450 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 25 ml of ethyl acetate was added for extraction. The organic phase was dried to obtain quinoline with a purity of 87.635%.

[0114] Embodiment 35 In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 31.5 mg of Cu2O, 75.6 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 210 °C for 12 h, and the total yield of the product was measured to be 85.75%.

[0115] After the catalytic reaction was completed, 10 ml of dichloromethane and 27 ml of water were added to the reaction mixture. After thorough mixing, the water and dichloromethane were separated. The aqueous phase was extracted with 38 ml of ethyl acetate, and the organic phase was dried to obtain NMP with a purity of 86.35%. 4 ml of concentrated hydrochloric acid with a concentration of 7.1 mol / l was added to the dichloromethane, and the mixture was stirred for 4 h. Then 10 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 86.357%. 454 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 26 ml of n-hexane was added for extraction. The organic phase was dried to obtain quinoline with a purity of 79.638%.

[0116] Embodiment 36 In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 4.5 mg of Cu2O, 10.8 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 220 °C for 12 h, and the total yield of the product was measured to be 76.62%.

[0117] After the catalytic reaction was completed, 10 ml of n-hexane and 20 ml of water were added to the reaction mixture. After thorough mixing, the water and n-hexane were separated. The aqueous phase was extracted with 20 ml of acetonitrile, and the organic phase was dried to obtain NMP with a purity of 89.63%. 5 ml of concentrated hydrochloric acid with a concentration of 7 mol / l was added to the n-hexane, and the mixture was stirred for 4 h. Then 10 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 90.638%. 455 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 30 ml of acetone was added for extraction. The organic phase was dried to obtain quinoline with a purity of 84.326%.

[0118] Embodiment 37 In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 8.58 mg of Cu2O, 21.6 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 220 °C for 12 h, and the total yield of the product was measured to be 85.79%.

[0119] After the catalytic reaction was completed, 10 ml of diethyl ether and 40 ml of water were added to the reaction mixture. After thorough mixing, the water and diethyl ether were separated. The aqueous phase was extracted with 20 ml of dichloromethane, and the organic phase was dried to obtain NMP with a purity of 78.96%. 5 ml of concentrated hydrochloric acid with a concentration of 6.9 mol / l was added to the diethyl ether, and the mixture was stirred for 4 h. Then 10 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 85.325%. 455 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 38 ml of ethyl acetate was added for extraction. The organic phase was dried to obtain quinoline with a purity of 87.635%.

[0120] Embodiment 38 In a 25 ml two-necked bottle, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 13.5 mg of Cu2O, 32.4 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline. Reflux at 220°C for 12 hours. The total yield of the product is measured to be 85.78%.

[0121] After the catalytic reaction is completed, 10 ml of acetone and 45 ml of water are added to the reaction mixture, and the water and acetone are separated after sufficient mixing. The aqueous phase is extracted with 25 ml of ether, and the organic phase is dried to obtain NMP with a purity of 78.63%. 5 ml of concentrated hydrochloric acid with a concentration of 6.7 mol / l is added to acetone, stirred for 4 hours, 10 ml of water is added for extraction, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 64.356%. 458 mg of solid sodium hydroxide is added to the aqueous phase containing concentrated hydrochloric acid, and 25 ml of n-hexane is added for extraction. The organic phase is dried to obtain quinoline with a purity of 78.639%.

[0122] Implementation Plan 39 In a 25 ml two-necked bottle, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 17.16 mg of Cu2O, 43.2 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline. Reflux at 220°C for 12 hours. The total yield of the product is measured to be 85.28%.

[0123] After the catalytic reaction is completed, 10 ml of acetonitrile and 40 ml of water are added to the reaction mixture, and the water and acetonitrile are separated after sufficient mixing. The aqueous phase is extracted with 20 ml of ethyl acetate, and the organic phase is dried to obtain NMP with a purity of 89.63%. 5 ml of concentrated hydrochloric acid with a concentration of 6.8 mol / l is added to acetonitrile, stirred for 4 hours, 10 ml of water is added for extraction, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 79.603%. 466 mg of solid sodium hydroxide is added to the aqueous phase containing concentrated hydrochloric acid, 28 ml of dichloromethane is added for extraction, and quinoline is dried to obtain a purity of 79.685%.

[0124] Implementation Plan 40 In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 21.45 mg of Cu2O, 54 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 220 °C for 12 h, and the total yield of the product was measured to be 84.66%.

[0125] After the catalytic reaction was completed, 10 ml of ether and 20 ml of water were added to the reaction mixture. After thorough mixing, the water and ether were separated. The aqueous phase was extracted with 20 ml of ether, and the organic phase was dried to obtain NMP with a purity of 89.63%. 5 ml of concentrated hydrochloric acid with a concentration of 6.6 mol / l was added to the ether, and the mixture was stirred for 4 h. Then 12 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 84.635%. 465 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 40 ml of n-hexane was added for extraction. The organic phase was dried to obtain quinoline with a purity of 89.427%.

[0126] Embodiment Forty-one In a 25 ml two-necked flask, 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 25.74 mg of Cu2O, 64.8 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline were added. The mixture was refluxed at 220 °C for 12 h, and the total yield of the product was measured to be 82.47%.

[0127] After the catalytic reaction was completed, 10 ml of dichloromethane and 43 ml of water were added to the reaction mixture. After thorough mixing, the water and dichloromethane were separated. The aqueous phase was extracted with 20 ml of ethyl acetate, and the organic phase was dried to obtain NMP with a purity of 87.63%. 6 ml of concentrated hydrochloric acid with a concentration of 6.4 mol / l was added to the dichloromethane, and the mixture was stirred for 4 h. Then 15 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 85.361%. 467 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, and 20 ml of acetonitrile was added for extraction. The organic phase was dried to obtain quinoline with a purity of 84.632%.

[0128] Embodiment Forty-two In a 25-ml two-necked flask, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 31.5 mg of Cu2O, 75.6 mg of 1,10-phenanthroline, 4.5 ml of N-methylpyrrolidone, and 1.5 ml of quinoline. Reflux at 220 °C for 12 h, and the total yield of the product is measured to be 80.51%.

[0129] After the catalytic reaction is completed, add 10 ml of n-hexane and 48 ml of water to the reaction mixture. After thorough mixing, separate the water and n-hexane. Extract the aqueous phase with 35 ml of ethyl acetate, and dry the organic phase to obtain NMP with a purity of 76.32%. Add 6 ml of concentrated hydrochloric acid with a concentration of 6.3 mol / l to n-hexane, stir for 4 h, add 18 ml of water for extraction, and dry the organic phase to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 65.324%. Add 464 mg of solid sodium hydroxide to the aqueous phase containing concentrated hydrochloric acid, add 30 ml of acetone for extraction, and dry the organic phase to obtain quinoline with a purity of 87.635%.

[0130] Embodiment Forty-Three In a 25-ml two-necked flask, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 8.58 mg of Cu2O, 21.6 mg of 1,10-phenanthroline, 0.9 ml of N-methylpyrrolidone, and 0.3 ml of quinoline. Reflux at 190 °C for 12 h, and the total yield of the product is measured to be 24.29%.

[0131] After the catalytic reaction is completed, add 10 ml of dichloroethane and 46 ml of water to the reaction mixture. After thorough mixing, separate the water and dichloroethane. Extract the aqueous phase with 20 ml of ethyl acetate, and dry the organic phase to obtain NMP with a purity of 75.36%. Add 6 ml of concentrated hydrochloric acid with a concentration of 6.2 mol / l to dichloroethane, stir for 4 h, add 18 ml of water for extraction, and dry the organic phase to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 82.638%. Add 462 mg of solid sodium hydroxide to the aqueous phase containing concentrated hydrochloric acid, add 35 ml of diethyl ether for extraction, and dry the organic phase to obtain quinoline with a purity of 87.965%.

[0132] Embodiment Forty-Four In a 25 ml two-necked flask, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 8.58 mg of Cu2O, 21.6 mg of 1,10-phenanthroline, 1.5 ml of N-methylpyrrolidone, and 0.5 ml of quinoline. Reflux at 190 °C for 12 h, and the total yield of the product is measured to be 66.15%.

[0133] After the catalytic reaction is completed, add 10 ml of acetone and 38 ml of water to the reaction mixture. After thorough mixing, separate the water and acetone. Extract the aqueous phase with 39 ml of ethyl acetate, and dry the organic phase to obtain NMP with a purity of 78.96%. Add 6 ml of concentrated hydrochloric acid with a concentration of 6.1 mol / l to the acetone, stir for 4 h, add 20 ml of water for extraction, and dry the organic phase to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 86.354%. Add 460 mg of solid sodium hydroxide to the aqueous phase containing concentrated hydrochloric acid, add 25 ml of n-hexane for extraction, and dry the organic phase to obtain quinoline with a purity of 74.523%.

[0134] Embodiment Forty-Five In a 25 ml two-necked flask, add 181.15 mg of 5-methyl-2-nitrobenzoic acid, 181.15 mg of 3-methyl-5-nitrobenzoic acid, 181.15 mg of 3-methyl-4-nitrobenzoic acid, 8.58 mg of Cu2O, 21.6 mg of 1,10-phenanthroline, 3 ml of N-methylpyrrolidone, and 1 ml of quinoline. Reflux at 190 °C for 12 h, and the total yield of the product is measured to be 84.78%.

[0135] After the catalytic reaction is completed, add 10 ml of ether and 41 ml of water to the reaction mixture. After thorough mixing, separate the water and ether. Extract the aqueous phase with 20 ml of dichloromethane, and dry the organic phase to obtain NMP with a purity of 89.65%. Add 6 ml of concentrated hydrochloric acid with a concentration of 6 mol / l to the ether, stir for 4 h, add 10 ml of water for extraction, and dry the organic phase to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 78.632%. Add 465 mg of solid sodium hydroxide to the aqueous phase containing concentrated hydrochloric acid, add 32 ml of ethyl acetate for extraction, and dry the organic phase to obtain quinoline with a purity of 89.674%.

[0136] Embodiment Forty-Six In a 7L two-necked bottle, add 181.15 g 5-methyl-2-nitrobenzoic acid, 181.15 g 3-methyl-5-nitrobenzoic acid, 181.15 g 3-methyl-4-nitrobenzoic acid, 8.58 g Cu2O, 21.6 g 1,10-phenanthroline, 4.5 L N-methylpyrrolidone, and 1.5 L quinoline. Reflux at 190°C for 12 h. The total yield of the product is 92.54%.

[0137] After the catalytic reaction is completed, 10 L petroleum ether and 50 L water are added to the reaction mixture, and the water and petroleum ether are separated after sufficient mixing. The aqueous phase is extracted with 20 L dichloromethane, and the organic phase is dried to obtain NMP with a purity of 99.67%. 6 L of concentrated hydrochloric acid with a concentration of 6 mol / l is added to the petroleum ether, stirred for 4 h, and 10 L of water is added for extraction. The organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 99.958%. p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene are separated by distillation. 465 g of sodium hydroxide is added to the aqueous phase containing concentrated hydrochloric acid, and 35 L of petroleum ether is added for extraction. The organic phase is dried to obtain quinoline with a purity of 99.979%.

[0138] Embodiment 47 Referring to the operating steps and feeding ratios of Example 16, decarboxylation experiments were performed on mixtures of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid and 3-methyl-4-nitrobenzoic acid in different proportions. The specific decarboxylation yields are shown in Table 1.

[0139] Table 1 Decarboxylation data of mixtures with different ratios

[0140] Embodiment 48 In a 25 ml two-necked bottle, add 1.362 g of m-toluic acid and 4.2 ml of fuming nitric acid, and react at 10 ° C for 5 hours. After the nitration reaction is completed, add 1.28 ml of water to the reaction solution, filter it with suction to obtain 3-methyl-2-nitrobenzoic acid solid, add 27.5 ml of water to the filtrate, filter it with suction to obtain a mixture of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid.

[0141] The product composition was analyzed by gas chromatography-mass spectrometry (model: ISQ7000). Figure 3 As shown, the yield of the product 3-methyl-2-nitrobenzoic acid is 35.9%, the yield of the by-product 5-methyl-2-nitrobenzoic acid is 22.9%, the yield of 3-methyl-5-nitrobenzoic acid is 20.7%, and the yield of 3-methyl-4-nitrobenzoic acid is 20.5%. The yield ratio of the three by-products is approximately 1.1:1:1 (see AppendixFigure 3 ).

[0142] In a 25 ml two-necked bottle, 873 mg of a mixture of three benzoic acids, 13.79 mg Cu2O, 34.71 mg 1,10-phenanthroline, 7.23 ml N-methylpyrrolidone, and 2.41 ml quinoline were added. The mixture was refluxed at 190 °C for 12 h. The total yield of the product was measured to be 93.12%.

[0143] After the catalytic reaction is completed, 10 ml of petroleum ether and 25 ml of water are added to the reaction mixture, and the water and petroleum ether are separated after sufficient mixing. The aqueous phase is extracted with 27 ml of dichloromethane, and the organic phase is dried to obtain NMP with a purity of 99.35%. 2.5 ml of 9 mol / l concentrated hydrochloric acid is added to the petroleum ether, stirred for 4 hours, 18 ml of water is added for extraction, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 99.567%. 425 mg of sodium hydroxide solid is added to the aqueous phase containing concentrated hydrochloric acid, 30 ml of petroleum ether is added for extraction, and quinoline is dried to obtain a purity of 99.895%.

[0144] Comparative Example 1 In a 25 ml two-necked bottle, add 1.362 g of m-toluic acid and 4.6 ml of fuming nitric acid, and react at 14 ° C for 5 hours. After the nitration reaction is completed, add 1.31 ml of water to the reaction solution, filter it with suction to obtain 3-methyl-2-nitrobenzoic acid solid, add 27.6 ml of water to the filtrate, filter it with suction to obtain a mixture of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid.

[0145] The product composition was analyzed by gas chromatography-mass spectrometry (model: ISQ7000). The yield of the product 3-methyl-2-nitrobenzoic acid was 30.5%, the yield of the by-product 5-methyl-2-nitrobenzoic acid was 24.1%, the yield of 3-methyl-5-nitrobenzoic acid was 22.8%, and the yield of 3-methyl-4-nitrobenzoic acid was 22.6%. The yield ratio of the three by-products was approximately 1.1:1:1. In a 25 ml two-necked bottle, 947 mg of a mixture of three benzoic acids, 14.96 mg of Cu2O, 37.66 mg of 1,10-phenanthroline, 7.85 ml of N-methylpyrrolidone, and 2.62 ml of quinoline were added. The mixture was refluxed at 180 °C for 12 h. The total yield of the product was measured to be 88.76%.

[0146] After the catalytic reaction was completed, 10 ml of n-hexane and 25 ml of water were added to the reaction mixture. After thorough mixing, the water and n-hexane were separated. The aqueous phase was extracted with 27 ml of ethyl acetate, and the organic phase was dried to obtain NMP with a purity of 83.28%. 2.5 ml of concentrated hydrochloric acid with a concentration of 10 mol / l was added to the n-hexane, stirred for 4 h, 18 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 90.28%. 430 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, 35 ml of dichloromethane was added for extraction, and the organic phase was dried to obtain quinoline with a purity of 90.21%.

[0147] Comparative Example 2 In a 25-ml two-necked flask, 1.362 g of m-methylbenzoic acid and 4.4 ml of fuming nitric acid were added, and the reaction was carried out at 11 °C for 5 h. After the nitration reaction was completed, 1.30 ml of water was added to the reaction solution, and suction filtration was carried out to obtain solid 3-methyl-2-nitrobenzoic acid. 27.8 ml of water was added to the filtrate, and suction filtration was carried out to obtain a mixture of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid.

[0148] The composition of the product was analyzed by gas chromatography-mass spectrometry (model: ISQ7000). The yield of the product 3-methyl-2-nitrobenzoic acid was 34.8%, the yields of the by-products 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid were 22.8%, 21.0%, and 21.4% respectively, and the yield ratio of the three by-products was approximately 1.1:1:1.

[0149] In a 25-ml two-necked flask, 888.02 mg of a mixture of three benzoic acids, 14.05 mg of Cu2O, 35.36 mg of 1,10-phenanthroline, 7.37 ml of N-methylpyrrolidone, and 2.46 ml of quinoline were added, and the mixture was refluxed at 200 °C for 12 h. The total yield of the product was measured to be 89.54%.

[0150] After the catalytic reaction was completed, 10 ml of dichloromethane and 30 ml of water were added to the reaction mixture. After thorough mixing, the water and dichloromethane were separated. The aqueous phase was extracted with 29 ml of ether, and the organic phase was dried to obtain NMP with a purity of 50.23%. 3.5 ml of concentrated hydrochloric acid with a concentration of 9 mol / l was added to the dichloromethane, stirred for 4 h, 18 ml of water was added for extraction, and the organic phase was dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 60.25%. 435 mg of solid sodium hydroxide was added to the aqueous phase containing concentrated hydrochloric acid, 40 ml of ethyl acetate was added for extraction, and the organic phase was dried to obtain quinoline with a purity of 40.25% Comparative Example 3 In a 25 ml two-necked flask, add 1.362 g of m-toluic acid and 4.9 ml of fuming nitric acid, and react at 8 °C for 5 hours. After the nitration reaction is completed, add 1.29 ml of water to the reaction solution, and perform suction filtration to obtain solid 3-methyl-2-nitrobenzoic acid. Add 27.7 ml of water to the filtrate and perform suction filtration to obtain a mixture of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid.

[0151] The composition of the product was analyzed using a gas chromatography-mass spectrometry instrument (model: ISQ7000). The yield of the product 3-methyl-2-nitrobenzoic acid was 33.7%, the yield of the by-product 5-methyl-2-nitrobenzoic acid was 22.5%, the yield of 3-methyl-5-nitrobenzoic acid was 22.0%, and the yield of 3-methyl-4-nitrobenzoic acid was 21.8%. The yield ratio of the three by-products was approximately 1.1:1:1.

[0152] In a 25 ml two-necked flask, add 903.01 mg of a mixture of three benzoic acids, 14.28 mg of Cu2O, 35.92 mg of 1,10-phenanthroline, 7.49 ml of N-methylpyrrolidone, and 2.50 ml of quinoline, and reflux at 210 °C for 12 h. The total yield of the product was measured to be 87.65%.

[0153] After the catalytic reaction is completed, add 10 ml of ethyl acetate and 35 ml of water to the reaction mixture, mix well and separate the water and ethyl acetate. The aqueous phase is extracted with 35 ml of n-hexane, and the organic phase is dried to obtain NMP with a purity of 32.46%. Add 4 ml of concentrated hydrochloric acid with a concentration of 8 mol / l to the ethyl acetate, stir for 4 h, add 45 ml of water for extraction, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene, and o-nitrotoluene with a purity of 50.25%. Add 440 mg of solid sodium hydroxide to the aqueous phase containing concentrated hydrochloric acid, add 30 ml of acetone for extraction, and the organic phase is dried to obtain quinoline with a purity of 58.19%.

Claims

1. A method for treating a mixture of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid and 3-methyl-4-nitrobenzoic acid, which are byproducts of nitration of 3-methylbenzoic acid, characterized in that: The following steps are involved: Using Cu2O and 1,10-phenanthroline as catalysts, in the presence of solvents and co-solvents, a mixture of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid and 3-methyl-4-nitrobenzoic acid was decarboxylated to produce p-nitrotoluene, m-nitrotoluene and o-nitrotoluene. The solvent is N-methylpyrrolidone, and the co-solvent is quinoline.

2. The processing method according to claim 1, characterized in that: S1) After the catalytic reaction is completed, water and petroleum ether are added to the reaction mixture, and then the water and petroleum ether are separated; S2) Hydrochloric acid solution is added to the petroleum ether, stirred, and the organic phase is dried to obtain a mixture of p-nitrotoluene, m-nitrotoluene and o-nitrotoluene.

3. The processing method according to claim 2, characterized in that: The aqueous phase in step S1 is extracted with an organic solvent, and the organic phase is dried to obtain N-methylpyrrolidone; The aqueous phase in step S2 is neutralized with sodium hydroxide and 65-90% hydrochloric acid, extracted with an organic solvent, and the organic phase is dried to obtain quinoline; The organic solvents are independently selected from at least one of dichloromethane, ethyl acetate and diethyl ether.

4. The processing method according to claim 3, characterized in that: In step S2, the amount of HCl added is not less than 1 times the amount of quinoline, and 75-85% hydrochloric acid is neutralized with sodium hydroxide.

5. The processing method according to any one of claims 1 to 4, characterized in that: The obtained mixture of p-nitrotoluene, m-nitrotoluene and o-nitrotoluene is separated by rectification to obtain p-nitrotoluene, m-nitrotoluene and o-nitrotoluene.

6. The processing method according to any one of claims 1 to 4, characterized in that: The molar ratio of the mixture to Cu2O is 1:0.02~0.07; The molar ratio of Cu2O and 1,10-phenanthroline is 1:1~3; The reaction temperature is 170 ℃ ~ 220 ℃; The volume ratio of N-methylpyrrolidone and quinoline is 2~5:

1.

7. The processing method according to claim 6, characterized in that: The molar ratio of the mixture to Cu2O is 1:0.02~0.07; The molar ratio of Cu2O and 1,10-phenanthroline is 1:1.5~2.5; The reaction temperature is 180 ℃ ~ 210 ℃; The volume ratio of N-methylpyrrolidone and quinoline is 2~4:

1.

8. The processing method according to claim 6, characterized in that: The molar ratio of the mixture to Cu2O is 1:0.02~0.07; The molar ratio of Cu2O and 1,10-phenanthroline is 1:1.5~2.5; The reaction temperature is 180 ℃ ~ 210 ℃; The volume ratio of N-methylpyrrolidone and quinoline is 2.5~3.5:

1.

9. The processing method according to any one of claims 1 to 4, characterized in that: The amount of N-methylpyrrolidone used is 3-15 times the amount of the nitrobenzoic acid mixture; The amount of quinoline used is 0.85-4.3 times the amount of the nitrobenzoic acid mixture.

10. The method according to any one of claims 1 to 4, characterized in that: The mass ratio of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid and 3-methyl-4-nitrobenzoic acid in the mixture of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid and 3-methyl-4-nitrobenzoic acid is 1-2:1-1.2:1; Preferably, the mass ratio of 5-methyl-2-nitrobenzoic acid, 3-methyl-5-nitrobenzoic acid, and 3-methyl-4-nitrobenzoic acid is 1-1.5:1-1.1:1.

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