Modified caprolactam and preparation method thereof

Abstract

The invention belongs to the technical field of chemical synthesis, and provides modified caprolactam and a preparation method thereof.The modified caprolactam is obtained by mixing a ketone compound, a diol compound and a catalyst 1, then performing condensation reaction, and then adding ammonia water, a hydrogen peroxide solution and a catalyst 2 for Beckmann conversion. According to the invention, a ketone compound and a diol compound are creatively and directly reacted, and a branched chain is directly introduced to a caprolactam skeleton, so that the previous multi-step reaction process is skipped. According to the method, the process is simplified, the production cost is reduced, and the quality and the production efficiency of the modified caprolactam product are improved. The modification mechanism provided by the invention has the advantages of simple process, convenience in operation, environmental friendliness and the like, provides a new technical approach for modification of caprolactam, and has wide application prospects and remarkable economic benefits.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical synthesis, and particularly relates to a modified caprolactam and a preparation method thereof. BACKGROUND

[0002] Caprolactam is an important organic chemical raw material, which is widely used in the manufacture of nylon 6, artificial leather, polyamide fiber and L-lysine, and used as a pharmaceutical raw material. The traditional modification mechanism of caprolactam usually includes multiple steps of preparing cyclohexanone, preparing caprolactam from cyclohexanone, and then modifying caprolactam by branching. This method is complex, high in energy consumption, and prone to produce by-products in the production process, affecting the quality and performance of the final product.

[0003] In recent years, although there have been some studies on the modification of caprolactam, most of these studies have focused on optimizing the traditional process conditions or developing new catalysts, and have not fundamentally simplified the modification process. Patent CN119194881A discloses a cashmere fiber acid dyeing and fixing method, which obtains a preformed material by modifying caprolactam with rhamnolipid, polyvinylpyrrolidone and acylation, and obtains a good dyeing and fixing method by mixing various preformed materials. However, this method is too complex, has many intermediate products, and has a complex process.

[0004] Therefore, it is of great significance to develop a more simple and effective modification mechanism for caprolactam. SUMMARY

[0005] The present application relates to the technical field of chemical synthesis, and particularly relates to a modified caprolactam and a preparation method thereof.

[0006] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solutions: The present application provides a preparation method of a modified caprolactam, comprising the following steps: The ketone compound, the diol compound and the catalyst 1 are mixed and subjected to a condensation reaction, then ammonia water, hydrogen peroxide solution and catalyst 2 are added to perform a Beckmann rearrangement, and the modified caprolactam is obtained.

[0007] Preferably, the ketone compound is acetone or ; wherein R4 and R5 are independently methyl, ethyl, propyl or amino.

[0008] Preferably, the diol compound is 1,3-propanediol or ; wherein R1, R2 and R3 are independently methyl, ethyl, propyl or amino.

[0009] Preferably, the molar ratio of the ketone compound to the diol compound is 1:1-2.

[0010] As preferred, the catalyst 1 is an activated carbon supported metal catalyst, and the mass of the catalyst 1 is 3-15% of the sum of the mass of the ketone compound, the diol compound and the catalyst 1.

[0011] As preferred, the temperature of the condensation reaction is 80-270℃, the pressure is 0.5-5MPa, and the time is 2-8h.

[0012] As preferred, the concentration of the ammonia water is 20-30%; The concentration of the hydrogen peroxide solution is 25-35% The sum of the mass of the ammonia water and the hydrogen peroxide solution is 30-60% of the sum of the mass of the ketone compound, the diol compound, the catalyst 1, the ammonia water, the hydrogen peroxide solution and the catalyst 2. The mass ratio of the ammonia water and the hydrogen peroxide solution is 1-6:1-6.

[0013] As preferred, the catalyst 2 is a TS-1 catalyst, and the mass of the catalyst 2 is 3-15% of the sum of the mass of the ketone compound, the diol compound, the catalyst 1, the ammonia water, the hydrogen peroxide solution and the catalyst 2.

[0014] As preferred, the temperature of the Beckmann rearrangement is 50-130℃, the pressure is 0-4MPa, the time is 2-240min, and the pH is ≤11.

[0015] The application also provides the modified caprolactam prepared by the preparation method of the modified caprolactam.

[0016] The application provides a preparation method of a modified caprolactam, which comprises the following steps: mixing a ketone compound, a diol compound and a catalyst 1, and then performing a condensation reaction, and then adding ammonia water, a hydrogen peroxide solution and a catalyst 2 to perform a Beckmann rearrangement, so that the modified caprolactam is obtained. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a mass spectrum report of the product of Example 1; Figure 2 It is a mass spectrum report of the product of Example 2. DETAILED DESCRIPTION

[0018] The application provides a preparation method of modified caprolactam, comprising the following steps: The ketone compound, the diol compound and the catalyst 1 are mixed to perform a condensation reaction, then ammonia water, a hydrogen peroxide solution and the catalyst 2 are added to perform a Beckmann transformation, and the modified caprolactam is obtained.

[0019] In the application, the ketone compound is acetone or ; wherein R4 and R5 are independently methyl, ethyl, propyl or amino.

[0020] In the application, the diol compound is 1,3-propanediol or ; wherein R1, R2 and R3 are independently methyl, ethyl, propyl or amino.

[0021] In the application, the molar ratio of the ketone compound and the diol compound is preferably 1:1-2, further preferably 1:1.2-1.8, and more preferably 1:1.4-1.6.

[0022] In the application, the catalyst 1 is an activated carbon supported metal catalyst, which is prepared according to the patent CN202410296354.9, and the mass of the catalyst 1 is preferably 3-15% of the total mass of the ketone compound, the diol compound and the catalyst 1, further preferably 5-12%, and more preferably 8-10%.

[0023] In the application, the temperature of the condensation reaction is preferably 80-270 DEG C, further preferably 100-250 DEG C, and more preferably 150-200 DEG C, the pressure is preferably 0.5-5 MPa, further preferably 1-4 MPa, and more preferably 2-3 MPa, and the time is preferably 2-8 h, further preferably 3-7 h, and more preferably 4-6 h.

[0024] In the application, the concentration of the ammonia water is preferably 20-30%, further preferably 22-28%, and more preferably 24-26%.

[0025] In the application, the concentration of the hydrogen peroxide solution is preferably 25-35%, further preferably 26-34%, and more preferably 28-32%.

[0026] In the application, the total mass of the ammonia water and the hydrogen peroxide solution is preferably 30-60% of the total mass of the ketone compound, the diol compound, the catalyst 1, the ammonia water, the hydrogen peroxide solution and the catalyst 2, further preferably 40-50%, and more preferably 44-46%.

[0027] In this invention, the mass ratio of ammonia water to hydrogen peroxide solution is preferably 1~6:1~6, more preferably 2~5:2~5, and even more preferably 3~4:3~4.

[0028] In this invention, the catalyst 2 is a TS-1 catalyst, and the mass of the catalyst 2 is preferably 3 to 15% of the total mass of the ketone compound, diol compound, catalyst 1, ammonia water, hydrogen peroxide solution and catalyst 2, more preferably 5 to 12%, and even more preferably 8 to 10%.

[0029] In this invention, the Beckman conversion temperature is preferably 50~130℃, more preferably 60~120℃, and even more preferably 80~100℃; the pressure is preferably 0~4MPa, more preferably 0.5~3.5MPa, and even more preferably 1~3MPa; the time is preferably 2~240min, more preferably 40~200min, and even more preferably 80~150min; and the pH is preferably ≤11, more preferably ≤10, and even more preferably ≤8.

[0030] The reaction principle of this invention is as follows: .

[0031] The present invention also provides a method for preparing the modified caprolactam.

[0032] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0033] Example 1

[0034] First, an activated carbon-supported metal catalyst was prepared. The Ni-Cu / AC catalyst used nickel formate and copper formate to support activated carbon. The catalyst was obtained by impregnation in a mixture of ammonia and water and then calcination. The concentration of ammonia was 25%, and the mass ratio of nickel formate, copper formate, activated carbon, ammonia and water was 5:1:100:100:100. The impregnation temperature was 30℃ and the time was 5h. The calcination temperature was 350℃ and the time was 3h.

[0035] 3-Methylacetone and 1,3-propanediol were selected as reactants and mixed uniformly at a molar ratio of 1:1. An activated carbon-supported metal catalyst (10% of the total mass of the ketone compound, glycol compound, and catalyst 1) was added. The mixture was heated to 200°C and stirred continuously at 2 MPa for 4 hours. After the condensation reaction, the reaction system was cooled to 80°C, and 25% ammonia water and 30% hydrogen peroxide solution were added. The mass of ammonia water and hydrogen peroxide solution was 60% of the total mass of the ketone compound, glycol compound, catalyst 1, ammonia water, hydrogen peroxide solution, and catalyst 2, with a mass ratio of 1:1. Subsequently, TS-1 catalyst (10% of the total mass of the ketone compound, glycol compound, catalyst 1, ammonia water, hydrogen peroxide solution, and catalyst 2) was added. The temperature was raised to 100°C, and the reaction was stirred continuously at 2 MPa for 3 hours. The pH value of the reaction solution was monitored using pH paper and found to be ≤10. After the reaction was complete, the mixture was cooled to room temperature and successively extracted with ethyl acetate (3 × 20 mL), washed with deionized water until neutral, dried over anhydrous sodium sulfate, and distilled to give a white solid product. The conversion rate of the product was determined to be 85% (based on 3-methylacetone), and the selectivity was 99.2%.

[0036] The mass spectrometry report of the 3-methylcaprolactam prepared in Example 1 is as follows: Figure 1 As shown in the figure, 3-methylcaprolactam was successfully synthesized.

[0037] Example 2

[0038] First, activated carbon-supported metal catalysts were prepared. The Pd-Ni / AC catalyst used nickel formate and palladium formate to support activated carbon. The catalyst was obtained by impregnation in a mixture of ammonia and water and then calcination. The concentration of ammonia was 25%, and the mass ratio of nickel formate, palladium formate, activated carbon, ammonia and water was 5:1:100:50:50. The impregnation temperature was 50℃ and the time was 28h. The calcination temperature was 300℃ and the time was 2h.

[0039] 3-Aminoacetone and 1,3-propanediol were selected as reactants and mixed uniformly at a molar ratio of 1:1. An activated carbon-supported catalyst (12% of the total mass of the ketone compound, glycol compound, and catalyst 1) was added. The mixture was heated to 260°C and stirred continuously at 3 MPa for 6 hours. After the condensation reaction, the reaction system was cooled to 90°C, and 25% ammonia water and 30% hydrogen peroxide solution were added. The mass of ammonia water and hydrogen peroxide solution was 35% of the total mass of the ketone compound, glycol compound, catalyst 1, ammonia water, hydrogen peroxide solution, and catalyst 2, with a mass ratio of ammonia water to hydrogen peroxide solution of 1:0.8. Subsequently, TS-1 catalyst (12% of the total mass of the ketone compound, glycol compound, catalyst 1, ammonia water, hydrogen peroxide solution, and catalyst 2) was added. The temperature was raised to 120°C, and the reaction was stirred continuously at 3 MPa for 4 hours. The pH value of the reaction solution was monitored using pH paper and remained ≤10.5. After the reaction was complete, the mixture was cooled to room temperature and extracted successively with ethyl acetate (3 × 25 mL), washed with deionized water until neutral, dried over anhydrous sodium sulfate, and then distilled to give a pale yellow crystalline solid product. The product conversion was determined to be 78% (based on 3-aminoacetone), and the selectivity was 98.5%.

[0040] The mass spectrometry report of the 3-aminocaprolactam prepared in Example 2 is as follows: Figure 2 As shown in the figure, 3-aminocaprolactam was successfully synthesized.

[0041] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing modified caprolactam, characterized in that, Includes the following steps: A condensation reaction was carried out by mixing ketone compounds, diol compounds and catalyst 1, followed by the addition of ammonia water, hydrogen peroxide solution and catalyst 2, and then Beckmann conversion was performed to obtain the modified caprolactam.

2. The method for preparing modified caprolactam as described in claim 1, characterized in that, The ketone compound is acetone or ; Among them, R4 and R5 are independently methyl, ethyl, propyl or amino.

3. The method for preparing modified caprolactam as described in claim 1, characterized in that, The diol compound is 1,3-propanediol or... ; Among them, R1, R2 and R3 are independently methyl, ethyl, propyl or amino.

4. The method for preparing modified caprolactam as described in claim 2 or 3, characterized in that, The molar ratio of the ketone compound to the diol compound is 1:1~2.

5. The method for preparing modified caprolactam as described in claim 1, characterized in that, The catalyst 1 is a metal catalyst supported on activated carbon, and the mass of the catalyst 1 is 3 to 15% of the total mass of the ketone compound, the diol compound and the catalyst 1.

6. The method for preparing modified caprolactam as described in claim 1, characterized in that, The condensation reaction is carried out at a temperature of 80~270℃, a pressure of 0.5~5MPa, and a time of 2~8h.

7. The method for preparing modified caprolactam as described in claim 1, characterized in that, The concentration of the ammonia water is 20-30%; The concentration of the hydrogen peroxide solution is 25-35%; The total mass of ammonia and hydrogen peroxide solution is 30-60% of the total mass of ketone compounds, glycol compounds, catalyst 1, ammonia, hydrogen peroxide solution, and catalyst 2. The mass ratio of ammonia water to hydrogen peroxide solution is 1~6:1~6.

8. The method for preparing modified caprolactam as described in claim 1, characterized in that, The catalyst 2 is a TS-1 catalyst, and the mass of the catalyst 2 is 3 to 15% of the total mass of the ketone compound, diol compound, catalyst 1, ammonia water, hydrogen peroxide solution and catalyst 2.

9. The method for preparing modified caprolactam as described in claim 1, characterized in that, The Beckman conversion was performed at a temperature of 50-130°C, a pressure of 0-4 MPa, a time of 2-240 min, and a pH of ≤11.

10. Modified caprolactam prepared by the method of any one of claims 1 to 9.

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