Preparation method of 5-hexenamide
By using inexpensive ferrous and copper salt catalysts to decompose 1,1'-dicyclohexyl peroxide, the safety hazards and high costs of existing technologies are solved, and efficient preparation and recycling of 5-hexenamide and cyclohexanone are achieved.
Patent Information
- Application Number
- CN202511533156.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-24
- Publication Date
- 2026-02-06
AI Technical Summary
Existing methods for preparing 5-hexenamide involve the use of toxic gases or precious metal catalysts, leading to safety hazards and high costs.
1,1'-dicyclohexyl peroxide was used as a raw material and decomposed in the presence of inexpensive ferrous and copper salt catalysts to produce 5-hexenamide, which was then separated and purified through post-treatment steps.
This method enables the efficient, safe, and low-cost preparation of 5-hexenamide with high product selectivity and the recyclability of the byproduct cyclohexanone.
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Figure CN121471097A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for preparing 5-hexenamide, belonging to the field of organic chemical engineering. Background Technology
[0002] 5-Hexenamide, with the molecular formula C6H 11 NO is an important fine chemical intermediate. It can be converted into 5-hexenoic acid through hydrolysis, which is used in resins, plastics, hydrophilic modifiers, surfactants, etc.; it can also be reduced and hydrogenated to obtain 5-hexenamine, which is used to prepare heterocyclic compounds, amino acids, etc.; it can also undergo metathesis to obtain long-chain compounds, which can be used to prepare nylon monomers.
[0003] Regarding the preparation of 5-hexenamide, the literature (J. Am. Chem. Soc. 2016, 138, 5833-5836) provides a process for amidation of 5-hexenoic acid. However, due to the use of isobutyl chloroformate, it is corrosive and easily releases toxic gases, which can be harmful to the human body. The literature (Angew. Chem. Int. Ed. 2008, 47, 3607-3609) mentions a preparation method of 5-hexenonitrile by hydrolysis, but this method uses the precious metal rhodium as a catalyst, which is expensive.
[0004] Therefore, it is necessary to develop a simpler, more efficient, safer, more effective, and cheaper method to obtain 5-hexenamide, thereby overcoming the existing drawbacks. Summary of the Invention
[0005] The purpose of this invention is to provide a method for preparing 5-hexenamide with mild reaction conditions, high product selectivity, and inexpensive raw materials.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0007] A method for preparing 5-hexenamide includes the following steps:
[0008] 1,1'-dicyclohexyl peroxide was dissolved in an alcoholic solvent to obtain solution A;
[0009] Ferrous salt is dissolved in water to obtain an aqueous solution of ferrous salt, and a copper salt catalyst is added to obtain solution B;
[0010] Solution A and solution B were mixed and reacted to obtain a mixture of 5-hexenamide and cyclohexanone.
[0011] The possible reaction process of this invention is as follows:
[0012]
[0013] 1,1'-Bicyclohexyl peroxide first undergoes peroxy bond cleavage under the action of ferrous ions to decompose into cyclohexanone and intermediate 1. Intermediate 1 undergoes further selective conversion to obtain cyclohexanone or the target product 5-hexenamide. Among these, copper salt catalysts may promote the formation of 5-hexenamide and improve its selectivity.
[0014] The ferrous salt is preferably one or more of the following: ferrous chloride, ferrous bromide, ferrous acetate, ferrous carbonate, ferrous sulfate, ferrous ammonium sulfate, ferrous oxalate, sodium hexacyanoferrate, potassium hexacyanoferrate, ferrous citrate, ferrous gluconate, ferrous glycinate, ferrocene, ferrous acetylacetone, ferrous sulfanilamide, and hydrates of the above salts.
[0015] The copper salt catalyst is a divalent copper salt and its hydrate, more preferably one or more of copper chloride, copper bromide, copper iodide, copper acetate, copper sulfate, copper nitrate, copper trifluoromethanesulfonate, copper acetylacetonate, and the hydrates of the above salts. The addition of the copper salt catalyst significantly increases the proportion of 5-hexenamide in the product.
[0016] Furthermore, the amount of the ferrous salt used is 0.5-5 equivalents of 1,1'-dicyclohexyl peroxide, preferably 1-2 equivalents (in molar equivalents).
[0017] Furthermore, the mass ratio of the copper salt catalyst to 1,1'-dicyclohexyl peroxide is 0.01-0.1:1, preferably 0.01-0.05:1.
[0018] Furthermore, the amount of methanol solvent used is 2-20 times the mass of 1,1'-dicyclohexyl peroxide, preferably 8-14 times.
[0019] Furthermore, the concentration of the ferrous salt aqueous solution is 10-40 wt%, preferably 20-30 wt%.
[0020] Furthermore, the reaction temperature is 0-80°C. o C, preferably 20-40 o C.
[0021] Furthermore, the reaction time is 5-60 min, preferably 10-30 min.
[0022] Furthermore, it also includes a post-processing step, wherein after the reaction is completed, an aqueous sulfuric acid solution is added to the reaction system until the solution is clear, and then 5-hexenamide is obtained by extraction, concentration and separation, and further, the separation is column separation.
[0023] Compared with the prior art, the beneficial effects of the present invention are reflected in:
[0024] The method described in this invention uses 1,1'-dicyclohexyl peroxide as a raw material and directly decomposes it into 5-hexenamide under the action of inexpensive ferrous and copper salt catalysts. The reaction has high efficiency, high conversion rate and good selectivity. At the same time, the generated byproduct cyclohexanone can be recycled to prepare 1,1'-dicyclohexyl peroxide. Attached Figure Description
[0025] Figure 1 This is the 1H NMR spectrum of the 5-hexenamide isolated in Example 3. Detailed Implementation
[0026] To facilitate understanding of the present invention, it will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to make the disclosure of the present invention more thorough and complete.
[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments or examples only and is not intended to be limiting of the invention.
[0028] Yield of 5-hexenamide = (mass of 5-hexenamide / molar mass of 5-hexenamide) / number of moles of 1,1'-dicyclohexyl peroxide in the feedstock;
[0029] Cyclohexanone yield = (mass of cyclohexanone / molar mass of cyclohexanone) / number of moles of 1,1'-dicyclohexyl peroxide in the feedstock;
[0030] The mass of 5-hexenamide and cyclohexanone was obtained by HPLC quantitative analysis.
[0031] Example 1
[0032] 20g of 1,1'-dicyclohexylperoxide was dissolved in 200g of methanol to obtain solution A. 29g of ferrous sulfate heptahydrate was dissolved in 116g of water to obtain an aqueous solution of ferrous sulfate. Anhydrous copper acetate (0.4g) was then added to the ferrous sulfate aqueous solution to obtain solution B. Solutions A and B were added to a reactor and stirred continuously at 25°C for 15 minutes. The reaction released a large amount of heat. After the reaction was complete, a 20% sulfuric acid aqueous solution was added to adjust the pH to approximately 2. After cooling to room temperature, samples were taken for HPLC analysis. The analysis confirmed that the conversion rate of 1,1'-dicyclohexylperoxide was over 99%, the mass of 5-hexenamide was 8.7g (yield 81.2%), and the mass of cyclohexanone was 10.9g (yield 117.3%).
[0033] Example 2
[0034] 20g of 1,1'-dicyclohexylperoxide was dissolved in 200g of methanol to obtain solution A. 29g of ferrous sulfate heptahydrate was dissolved in 116g of water to obtain an aqueous solution of ferrous sulfate. Anhydrous copper sulfate (0.4g) was then added to the ferrous sulfate aqueous solution to obtain solution B. Solutions A and B were added to a reactor and stirred continuously at 25℃ for 15min. After the reaction was complete, a 20% sulfuric acid aqueous solution was added to adjust the pH to approximately 2. After cooling to room temperature, samples were taken for HPLC analysis. The analysis confirmed that the conversion rate of 1,1'-dicyclohexylperoxide was over 99%, the yield of 5-hexenamide was 7.5g (70.0%), and the yield of cyclohexanone was 10.6g (114.1%).
[0035] Example 3
[0036] 20g of 1,1'-dicyclohexylperoxide was dissolved in 200g of methanol to obtain solution A. 29g of ferrous sulfate heptahydrate was dissolved in 116g of water to obtain an aqueous solution of ferrous sulfate. Anhydrous copper nitrate (0.4g) was then added to the ferrous sulfate aqueous solution to obtain solution B. Solutions A and B were added to a reactor and stirred continuously at 25℃ for 15min. After the reaction was complete, a 20% sulfuric acid aqueous solution was added to adjust the pH to approximately 2. After cooling to room temperature, samples were taken for HPLC analysis. The analysis confirmed that the conversion rate of 1,1'-dicyclohexylperoxide was over 99%, the mass of 5-hexenamide was 6.9g (64.4% yield), and the mass of cyclohexanone was 11.7g (126.0% yield). Methanol was removed by vacuum distillation, followed by extraction of the aqueous phase twice with ethyl acetate. The organic phase was collected, dried, and subjected to vacuum distillation of a low-boiling solvent. Rapid column chromatography was then used to separate the organic phase to obtain 5-hexenamide (mobile phase: petroleum ether:ethyl acetate = 10:1). The NMR spectrum is shown below. Figure 1 .
[0037] Example 4
[0038] 20g of 1,1'-dicyclohexylperoxide was dissolved in 200g of methanol to obtain solution A. 29g of ferrous sulfate heptahydrate was dissolved in 116g of water to obtain an aqueous solution of ferrous sulfate. Anhydrous copper acetate (0.4g) was then added to the ferrous sulfate aqueous solution to obtain solution B. Solutions A and B were added to a reactor and stirred continuously at 25℃ for 30min. After the reaction was complete, a 20% sulfuric acid aqueous solution was added to adjust the pH to approximately 2. After cooling to room temperature, samples were taken for HPLC analysis. The analysis confirmed that the conversion rate of 1,1'-dicyclohexylperoxide was over 99%, the mass of 5-hexenamide was 8.6g (yield 80.3%), and the yield of cyclohexanone was 10.8g (yield 116.3%).
[0039] Example 5
[0040] 20g of 1,1'-dicyclohexyl peroxide was dissolved in 200g of methanol to obtain solution A; 29g of ferrous sulfate heptahydrate was dissolved in 116g of water and mixed to obtain an aqueous solution of ferrous sulfate. Anhydrous copper acetate was then added to the ferrous sulfate aqueous solution to obtain solution B, with 0.4g of anhydrous copper acetate used. Solutions A and B were added to a reactor and heated at 40°C. o Under temperature C, the mixture was stirred continuously for 30 minutes. After the reaction was complete, a 20% sulfuric acid aqueous solution was added to adjust the pH of the solution to approximately 2. After cooling to room temperature, samples were taken for HPLC analysis. The analysis confirmed that the conversion rate of 1,1'-dicyclohexyl peroxide was over 99%, the mass of 5-hexenamide was 8.8 g (yield 82.2%), and the mass of cyclohexanone was 10.7 g (yield 115.2%).
[0041] Example 6
[0042] 20g of 1,1'-dicyclohexylperoxide was dissolved in 100g of methanol to obtain solution A. 29g of ferrous sulfate heptahydrate was dissolved in 116g of water to obtain an aqueous solution of ferrous sulfate. Anhydrous copper acetate (0.4g) was then added to the ferrous sulfate aqueous solution to obtain solution B. Solutions A and B were added to a reactor and stirred continuously at 25℃ for 15min. After the reaction was complete, a 20% sulfuric acid aqueous solution was added to adjust the pH to approximately 2. After cooling to room temperature, samples were taken for HPLC analysis. The analysis confirmed that the conversion rate of 1,1'-dicyclohexylperoxide was over 99%, the mass of 5-hexenamide was 7.6g (yield 71.0%), and the mass of cyclohexanone was 10.6g (yield 114.1%).
[0043] Example 7
[0044] 20g of 1,1'-dicyclohexylperoxide was dissolved in 200g of methanol to obtain solution A. 56g of ferrous sulfate heptahydrate was dissolved in 116g of water to obtain an aqueous solution of ferrous sulfate. Anhydrous copper acetate (0.4g) was then added to the ferrous sulfate aqueous solution to obtain solution B. Solutions A and B were added to a reactor and stirred continuously at 25℃ for 15min. After the reaction was complete, a 20% sulfuric acid aqueous solution was added to adjust the pH to approximately 2. After cooling to room temperature, samples were taken for HPLC analysis. The analysis confirmed that the conversion rate of 1,1'-dicyclohexylperoxide was over 99%, the yield of 5-hexenamide was 7.0g (65.4%), and the yield of cyclohexanone was 11.5g (123.8%).
[0045] Example 8
[0046] 20g of 1,1'-dicyclohexyl peroxide was dissolved in 200g of methanol to obtain solution A. 41g of ferrous ammonium sulfate hexahydrate was dissolved in 200g of water to obtain an aqueous solution of ferrous ammonium sulfate. Anhydrous copper acetate (0.4g) was then added to the ferrous ammonium sulfate aqueous solution to obtain solution B. Solutions A and B were added to a reactor and stirred continuously at 25°C for 15 minutes. After the reaction was complete, a 20% sulfuric acid aqueous solution was added to adjust the pH to approximately 2. After cooling to room temperature, samples were taken for HPLC analysis. The analysis confirmed that the conversion rate of 1,1'-dicyclohexyl peroxide was over 99%, the mass of 5-hexenamide was 7.2g (67.2% yield), and the mass of cyclohexanone was 11.1g (119.5% yield).
[0047] Example 9
[0048] 20g of 1,1'-dicyclohexylperoxide was dissolved in 200g of methanol to obtain solution A. 29g of ferrous sulfate heptahydrate was dissolved in 116g of water to obtain an aqueous solution of ferrous sulfate. Anhydrous copper sulfate (0.4g) was then added to the ferrous sulfate aqueous solution to obtain solution B. Solutions A and B were added to a reactor and stirred continuously for 15min at 25℃ under a nitrogen atmosphere. After the reaction was complete, a 20% sulfuric acid aqueous solution was added to adjust the pH to approximately 2. After cooling to room temperature, samples were taken for HPLC analysis. The analysis confirmed that the conversion rate of 1,1'-dicyclohexylperoxide was over 99%, the mass of 5-hexenamide was 7.7g (yield 71.9%), and the mass of cyclohexanone was 10.8g (yield 116.3%).
[0049] Example 10
[0050] 20g of 1,1'-dicyclohexylperoxide was dissolved in 200g of methanol to obtain solution A. 29g of ferrous sulfate heptahydrate was dissolved in 116g of water to obtain an aqueous solution of ferrous sulfate. Anhydrous copper sulfate (0.4g) was then added to the ferrous sulfate aqueous solution to obtain solution B. Solutions A and B were added to a reactor and stirred continuously at 80℃ for 15min. After the reaction was complete, a 20% sulfuric acid aqueous solution was added to adjust the pH to approximately 2. After cooling to room temperature, samples were taken for HPLC analysis. The analysis confirmed that the conversion rate of 1,1'-dicyclohexylperoxide was over 99%, the mass of 5-hexenamide was 6.4g (yield 59.8%), and the mass of cyclohexanone was 10.6g (yield 114.1%).
[0051] Example 11
[0052] 20g of 1,1'-dicyclohexylperoxide was dissolved in 200g of isopropanol to obtain solution A. 29g of ferrous sulfate heptahydrate was dissolved in 116g of water to obtain an aqueous solution of ferrous sulfate. Anhydrous copper acetate (0.4g) was then added to the ferrous sulfate aqueous solution to obtain solution B. Solutions A and B were added to a reactor and stirred continuously at 25℃ for 15min. After the reaction was complete, a 20% sulfuric acid aqueous solution was added to adjust the pH to approximately 2. After cooling to room temperature, samples were taken for HPLC analysis. The analysis confirmed that the conversion rate of 1,1'-dicyclohexylperoxide was over 99%, the mass of 5-hexenamide was 4.6g (yield 43.0%), and the mass of cyclohexanone was 12.8g (yield 137.8%).
[0053] Example 12
[0054] 20g of 1,1'-dicyclohexylperoxide was dissolved in 200g of methanol to obtain solution A. 29g of ferrous sulfate heptahydrate was dissolved in 116g of water to obtain an aqueous solution of ferrous sulfate. Anhydrous copper acetate (0.4g) was then added to the ferrous sulfate aqueous solution to obtain solution B. Solutions A and B were added to a reactor and stirred continuously at 25℃ for 120min. After the reaction was complete, a 20% sulfuric acid aqueous solution was added to adjust the pH to approximately 2. After cooling to room temperature, samples were taken for HPLC analysis. The analysis confirmed that the conversion rate of 1,1'-dicyclohexylperoxide was over 99%, the mass of 5-hexenamide was 7.6g (yield 71.0%), and the mass of cyclohexanone was 10.7g (yield 115.2%).
[0055] Example 13
[0056] 20g of 1,1'-dicyclohexylperoxide was dissolved in 200g of methanol to obtain solution A. 29g of ferrous sulfate heptahydrate was dissolved in 116g of water to obtain an aqueous solution of ferrous sulfate. Anhydrous copper acetate (2g) was then added to the ferrous sulfate aqueous solution to obtain solution B. Solutions A and B were added to a reactor and stirred continuously at 25℃ for 15min. After the reaction was complete, a 20% sulfuric acid aqueous solution was added to adjust the pH to approximately 2. After cooling to room temperature, samples were taken for HPLC analysis. The analysis confirmed that the conversion rate of 1,1'-dicyclohexylperoxide was over 99%, the mass of 5-hexenamide was 6.9g (64.4% yield), and the mass of cyclohexanone was 12.0g (129.2% yield).
[0057] Comparative Example 1
[0058] 5-Hexenamide was prepared under substantially the same conditions as in Example 1, except that 1,1'-dicyclohexyl peroxide was dissolved in acetonitrile. After the reaction was complete, a 20% (w / w) aqueous solution of sulfuric acid was added to adjust the pH of the solution to approximately 2. After cooling to room temperature, samples were taken for HPLC analysis. The analysis confirmed that the conversion rate of 1,1'-dicyclohexyl peroxide was over 99%, the mass of 5-hexenamide was 2.6 g (yield 24.3%), and the mass of cyclohexanone was 14.1 g (yield 151.8%).
[0059] Comparative Example 2
[0060] 5-Hexenamide was prepared under substantially the same conditions as in Example 1, except that anhydrous copper acetate was not added. After the reaction was complete, a 20% (w / w) aqueous solution of sulfuric acid was added to adjust the pH of the solution to approximately 2. After cooling to room temperature, samples were taken for HPLC analysis. The analysis confirmed that the conversion rate of 1,1'-dicyclohexyl peroxide was over 99%, the mass of 5-hexenamide was 1.1 g (yield 10.3%), and the mass of cyclohexanone was 11.5 g (yield 123.8%).
[0061] Comparative Example 3
[0062] 20g of 1,1'-dicyclohexyl peroxide was dissolved in 200g of methanol to obtain solution A; 16.6g of anhydrous copper sulfate was dissolved in 116g of water and mixed to obtain an aqueous solution of copper sulfate, resulting in solution B. Solutions A and B were added to a reactor and stirred continuously at 25℃ for 120min. After the reaction was completed, a 20% sulfuric acid aqueous solution was added to adjust the pH of the solution to approximately 2. After cooling to room temperature, samples were taken for HPLC analysis. The analysis confirmed that the conversion rate of 1,1'-dicyclohexyl peroxide was over 99%, the mass of 5-hexenamide was 0g, and the mass of cyclohexanone was 17.5g, representing a conversion rate of 188.4%.
[0063] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0064] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.
Claims
1. A method for preparing 5-hexenamide, characterized in that, Includes the following steps: 1,1'-dicyclohexyl peroxide was dissolved in an alcoholic solvent to obtain solution A; Ferrous salt is dissolved in water to obtain an aqueous solution of ferrous salt, and a copper salt catalyst is added to obtain solution B; Solution A and solution B were mixed and reacted to obtain a mixture of 5-hexenamide and cyclohexanone.
2. The method for preparing 5-hexenamide according to claim 1, characterized in that, The ferrous salt is one or more of the following: ferrous chloride, ferrous bromide, ferrous acetate, ferrous carbonate, ferrous sulfate, ferrous ammonium sulfate, ferrous oxalate, sodium hexacyanoferrate, potassium hexacyanoferrate, ferrous citrate, ferrous gluconate, ferrous glycinate, ferrocene, ferrous acetylacetone, ferrous sulfanamide, and hydrates of the above salts.
3. The method for preparing 5-hexenamide according to claim 1, characterized in that, The copper salt catalyst is one or more of copper chloride, copper bromide, copper iodide, copper acetate, copper sulfate, copper nitrate, copper trifluoromethanesulfonate, copper acetylacetonate, and hydrates of the above salts.
4. The method for preparing 5-hexenamide according to claim 1, characterized in that, The alcohol solvent is one or more of methanol, ethanol, n-propanol, and isopropanol.
5. The method for preparing 5-hexenamide according to claim 1 or 2, characterized in that, The amount of the ferrous salt used is 0.5-5 molar equivalents of 1,1'-dicyclohexyl peroxide.
6. The method for preparing 5-hexenamide according to claim 1 or 3, characterized in that, The mass ratio of the copper salt catalyst to 1,1'-dicyclohexyl peroxide is 0.01-0.1:
1.
7. The method for preparing 5-hexenamide according to claim 1, characterized in that, The amount of the alcohol solvent used is 2-20 times the mass of 1,1'-dicyclohexyl peroxide.
8. The method for preparing 5-hexenamide according to claim 1, characterized in that, The concentration of the aqueous solution of the ferrous salt is 10-40 wt%.
9. The method for preparing 5-hexenamide according to claim 1, characterized in that, The reaction temperature is 0-80°C. o C, the reaction time is 5-60 min.
10. The method for preparing 5-hexenamide according to claim 1, characterized in that, It also includes a post-processing step, which involves adding an aqueous sulfuric acid solution to the reaction system after the reaction is complete until the solution is clear, and then extracting, concentrating and separating to obtain 5-hexenamide.