A method for the synthesis of cyclic ketones

Abstract

The application provides a cyclic ketone synthesis method and belongs to the technical field of organic synthesis. The cyclic ketone compound is synthesized by a three-step method of condensation-ether removal-intramolecular condensation with diol methyl ether and ketone compound as raw materials under the action of activated carbon loaded metal catalyst. The reaction condition is mild, the catalyst can be recycled for more than or equal to 10 times and the activity retention rate is more than 90%, and the recovery rate of the acidic or strong acidic ion exchange resin is more than or equal to 98%. The selectivity of the synthesized cyclic ketone is more than 85%. The application realizes efficient, green and large-scale synthesis of the cyclic ketone compound, has significant economic benefits and social benefits, and provides a general technical platform for the fine chemical field.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, and in particular to a method for synthesizing cyclic ketones. Background Technology

[0002] Cyclic ketones are widely used as important fine chemical intermediates. Cyclopentanone is a core raw material for the synthesis of methyl dihydrojasmonate, vanillin, and the anti-anxiety drug buspirone, with an annual demand exceeding 70,000 tons. Cyclohexanone, as a key precursor for caprolactam and nylon-6, is widely used in coating solvents, electronic cleaning agents, and specialty engineering plastics. In addition, cyclobutanone, cyclododecaneone, and others also play important roles in the synthesis of specialty materials and fragrances, forming a complete industrial chain covering multiple fields such as pharmaceuticals, materials, and daily chemicals.

[0003] Regarding the synthesis of cyclohexanone, CN 104672069 B discloses a method for preparing cyclohexanone or substituted cyclohexanone. This method uses phenol, o-methylphenol, p-methylphenol, m-methylphenol, p-tert-butylphenol, or o-methoxyphenol as raw materials, and yields cyclohexanone or substituted cyclohexanone under the action of a Pd-TiN catalyst. This reaction has high raw material costs, is complex, and produces many byproducts. Currently, the production of cyclopentanone mainly relies on the pyrolysis of adipic acid (patent CN 1594259, patent EP306873). However, this route for preparing cyclopentanone depends on the production of adipic acid, involves multiple reaction steps, and includes decarboxylation during production, resulting in a relatively low theoretical yield and poor economic efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a method for synthesizing cyclic ketones to solve the above-mentioned technical problems.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for synthesizing cyclic ketones, in which diol methyl ether and ketone compounds undergo a condensation reaction in the presence of a Ni-Cu / AC catalyst, followed by a sequential deetherification reaction and intramolecular condensation reaction to obtain the cyclic ketone.

[0006] Furthermore, the molar ratio of the glycol methyl ether to the ketone compound is 1~5:1~5, and the amount of Ni-Cu / AC catalyst used is 3~10% of the total mass of the glycol methyl ether and the ketone compound.

[0007] Furthermore, the diol methyl ether includes one or more of ethylene glycol methyl ether, 1,3-propanediol methyl ether, 1,4-butanediol methyl ether, 1,5-pentanediol methyl ether, 1,6-hexanediol methyl ether, 1,7-heptanediol methyl ether, 1,8-octanediol methyl ether, 1,9-nonanediol methyl ether, and 1,10-decanediol methyl ether; The ketone compounds include one or more of acetone, butanone, 2-pentanone, 2-hexanone, 2-heptanone, 2-octanone, 2-nonanone, and 2-decanone.

[0008] Furthermore, the condensation reaction is carried out at a temperature of 80~250℃ for a time of 1~6h.

[0009] Furthermore, the temperature of the deetherification reaction is 120~230℃, and the time is 2~3h; The deetherification reaction uses acidic ion exchange resins, including benzenesulfonic acid ion exchange resin, p-toluenesulfonic acid ion exchange resin, sulfate ion exchange resin, and hydrochloric acid ion exchange resin. The amount of acidic ion exchange resin used is 10-30% of the total mass of the glycol methyl ether and ketone compounds.

[0010] Furthermore, the intramolecular condensation reaction is carried out at a temperature of 100~250℃ for a time of 1~6h.

[0011] Furthermore, the cyclic ketones include one or more of cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, cyclononanone, cyclodecanone, cycloundecanone, cyclododecanone, cyclotridecone, and cyclotetradecone.

[0012] The beneficial effects of this invention are: This invention utilizes glycol methyl ether and ketone compounds as raw materials to synthesize cyclic ketone compounds via a three-step process of condensation-deetherification-intramolecular condensation under the action of a metal catalyst supported on activated carbon. The reaction conditions are mild (80-250℃), the catalyst can be recycled ≥10 times with an activity retention rate >90%, and the benzenesulfonic acid ion exchange resin has a recovery rate ≥98%. The selectivity of the synthesized cyclic ketones is >85%. This invention achieves efficient, green, and large-scale synthesis of cyclic ketone compounds, with significant economic and social benefits, and provides a general-purpose technology platform for the fine chemical industry. Attached Figure Description

[0013] Figure 1 The total ion chromatogram of cyclohexane obtained in Example 1; Figure 2 The mass spectrum of cyclohexane obtained in Example 1 is shown below. Figure 3 Mass spectra were matched to the standard library of cyclohexane (matching degree SI=96); Figure 4 The total ion chromatogram of cyclopentanone obtained in Example 2; Figure 5 The mass spectrum of cyclopentanone obtained in Example 2; Figure 6 Mass spectra were matched to the standard library of cyclopentanone (matching degree SI=97). Detailed Implementation

[0014] This invention provides a method for synthesizing cyclic ketones, wherein diol methyl ether and ketone compounds undergo a condensation reaction in the presence of a Ni-Cu / AC catalyst, followed by a sequential deetherification reaction and intramolecular condensation reaction to obtain the cyclic ketone.

[0015] In this invention, the Ni-Cu / AC catalyst is prepared by impregnating nickel formate, copper formate, and activated carbon in ammonia water and water, followed by calcination.

[0016] In this invention, the Ni-Cu / AC catalyst is a supported catalyst prepared by patent CN119680545A.

[0017] In the preparation method of the Ni-Cu / AC catalyst of the present invention, the ammonia concentration is 25%, and the mass ratio of nickel formate, copper formate, activated carbon, ammonia and water is 5:1:100:100:100; the impregnation temperature is 30°C and the impregnation time is 5h; the calcination temperature is 350°C and the calcination time is 3h.

[0018] In this invention, the molar ratio of the glycol methyl ether and the ketone compound is 1~5:1~5, preferably 2~4:2~4; the amount of Ni-Cu / AC catalyst is 3~10% of the total mass of the glycol methyl ether and the ketone compound, preferably 5~7%.

[0019] In this invention, the diol methyl ether comprises one or more of ethylene glycol methyl ether, 1,3-propanediol methyl ether, 1,4-butanediol methyl ether, 1,5-pentanediol methyl ether, 1,6-hexanediol methyl ether, 1,7-heptanediol methyl ether, 1,8-octanediol methyl ether, 1,9-nonanediol methyl ether, and 1,10-decanediol methyl ether, preferably one or more of ethylene glycol methyl ether, 1,3-propanediol methyl ether, 1,4-butanediol methyl ether, 1,5-pentanediol methyl ether, 1,6-hexanediol methyl ether, 1,7-heptanediol methyl ether, 1,8-octanediol methyl ether, and 1,9-nonanediol methyl ether, and more preferably one or more of ethylene glycol methyl ether, 1,3-propanediol methyl ether, 1,4-butanediol methyl ether, 1,5-pentanediol methyl ether, and 1,6-hexanediol methyl ether.

[0020] In this invention, the ketone compounds include one or more of acetone, butanone, 2-pentanone, 2-hexanone, 2-heptanone, 2-octanone, 2-nonanone, and 2-decanone, preferably one or more of acetone, butanone, 2-pentanone, 2-hexanone, 2-heptanone, 2-octanone, and 2-nonanone, and more preferably one or more of acetone, butanone, and 2-pentanone.

[0021] In this invention, the temperature of the condensation reaction is 80~250℃, preferably 100~200℃; the time is 1~6h, preferably 2~5h.

[0022] In this invention, the temperature of the deetherification reaction is 120~230℃, preferably 150~200℃; the time is preferably 2~3h. The deetherification reaction uses acidic ion exchange resins, including benzenesulfonic acid ion exchange resin, p-toluenesulfonic acid ion exchange resin, sulfate ion exchange resin, and hydrochloric acid ion exchange resin. The amount of acidic ion exchange resin used is 10-30% of the total mass of the glycol methyl ether and ketone compounds, preferably 15-25%.

[0023] In this invention, the acidic ion exchange resin further includes a strongly acidic ion exchange resin.

[0024] In this invention, the temperature of the intramolecular condensation reaction is 100~250℃, preferably 150~220℃; the time is 1~6h, preferably 2~5h.

[0025] In this invention, the cyclic ketone includes one or more of cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, cyclononanone, cyclodecanone, cycloundecanone, cyclododecanone, cyclotridecanone, and cyclotetradecanone, preferably one or more of cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, cyclononanone, cyclodecanone, and cycloundecanone.

[0026] In this invention, directional synthesis is achieved by adjusting the carbon chain length of glycol methyl ether and the carbon chain length of ketones.

[0027] 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.

[0028] Example 1

[0029] 12.197g of acetone, 19.022g of ethylene glycol methyl ether, and 1.255g of catalyst were added to a clean high-pressure reactor. The reactor was sealed, and the sampling valve and purging valve were tightened. The temperature of the reactor was adjusted to 170℃, and the aldol condensation reaction was carried out for 2 hours. After cooling, the reactor was opened, and 1.501g of benzenesulfonic acid ion exchange resin was added. The temperature was raised to 200℃, and the reaction was carried out for 2 hours. After cooling, the reactor was opened again, and 0.256g of catalyst was added, and the reaction was continued for another 2 hours. After the reaction was completed, the reactor was allowed to cool to room temperature, and a sample was taken, filtered, and injected into a gas chromatography-mass spectrometry system. The conversion rate was 83% for acetone, and the selectivity for cyclopentanone was 85%.

[0030] The reaction route is as follows:

[0031] Comparative Example 1

[0032] 12.197g of acetone, 19.022g of ethylene glycol methyl ether, and 1.255g of catalyst were added to a clean high-pressure reactor. The reactor was sealed, and the sampling valve and purging valve were tightened. The temperature of the reactor was adjusted to 170℃, and the aldol condensation reaction was carried out for 2 hours. After cooling, the reactor was opened, and 0.256g of catalyst was added, and the reaction was continued for another 2 hours. After the reaction was completed, the reactor was allowed to cool to room temperature, and a sample was taken, filtered, and analyzed using a gas chromatography-mass spectrometry system. No cyclopentanone was found to be produced; the reaction mixture remained the raw materials: acetone and ethylene glycol methyl ether.

[0033] Example 2

[0034] 16.585g of butanone, 21.305g of ethylene glycol methyl ether, and 2.012g of catalyst were added to a clean high-pressure reactor. The reactor was sealed, and the sampling valve and purging valve were tightened. The temperature of the reactor was adjusted to 160℃, and the aldol condensation reaction was carried out for 5 hours. After cooling, the reactor was opened, and 1.5156g of benzenesulfonic acid ion exchange resin was added. The temperature was raised to 190℃ and the reaction was carried out for 2 hours. After cooling, the reactor was opened again, and 0.421g of catalyst was added, and the reaction was continued for another 2 hours. After the reaction was completed, the reactor was allowed to cool to room temperature, and the sample was taken, filtered, and injected into a gas chromatography-mass spectrometry system. The conversion rate of butanone was 86%, and the selectivity of cyclohexanone was 88%.

[0035] Comparative Example 2

[0036] 16.585g of butanone, 21.305g of ethylene glycol methyl ether, and 2.012g of catalyst were added to a clean high-pressure reactor. The reactor was sealed, and the sampling valve and purging valve were tightened. The temperature of the reactor was adjusted to 160℃, and the aldol condensation reaction was carried out for 5 hours. After cooling, the reactor was opened, and 0.5g of benzenesulfonic acid ion exchange resin was added. The temperature was raised to 190℃ and the reaction was carried out for 2 hours. After cooling, the reactor was opened again, and 0.421g of catalyst was added, and the reaction was continued for another 2 hours. After the reaction was completed, the reactor was allowed to cool to room temperature, and a sample was taken, filtered, and injected into a gas chromatography-mass spectrometry system. The conversion rate of butanone was 32%, and the selectivity of cyclohexanone was 80%.

[0037] As demonstrated by the above embodiments, this invention provides a method for synthesizing cyclic ketones. This invention proposes a general-purpose green synthesis process for cyclic ketones based on activated carbon-supported metal catalysts, which has significant advantages: using glycol methyl ether and ketones as raw materials, and adjusting the carbon chain length of the glycol ether and ketones, a full range of cyclic ketones from cyclopentanone to cyclotetradecone can be synthesized directionally; the raw material price is more than 30% lower than traditional routes; the mild reaction conditions of 80-250℃ reduce energy consumption by 40%; the benzenesulfonic acid ion exchange resin has a recovery rate of ≥98%, avoiding polymerization side reactions; the catalyst metal particle dispersion reaches 85%, and the catalyst can be recycled ≥10 times with an activity retention rate >90%, significantly superior to noble metal systems. This process achieves efficient, green, and large-scale synthesis of cyclic ketone compounds, with significant economic and social benefits, providing a general-purpose technology platform for the fine chemical industry.

[0038] 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 synthesizing a cyclic ketone, characterized in that, Diol methyl ethers and ketones undergo a condensation reaction in the presence of a Ni-Cu / AC catalyst, followed by a sequential deetherification reaction and intramolecular condensation reaction to yield cyclic ketones.

2. The method for synthesizing cyclic ketones according to claim 1, characterized in that, The molar ratio of the glycol methyl ether to the ketone compound is 1~5:1~5, and the amount of Ni-Cu / AC catalyst used is 3~10% of the total mass of the glycol methyl ether and the ketone compound.

3. The method for synthesizing cyclic ketones according to claim 1 or 2, characterized in that, The diol methyl ether includes one or more of ethylene glycol methyl ether, 1,3-propanediol methyl ether, 1,4-butanediol methyl ether, 1,5-pentanediol methyl ether, 1,6-hexanediol methyl ether, 1,7-heptanediol methyl ether, 1,8-octanediol methyl ether, 1,9-nonanediol methyl ether, and 1,10-decanediol methyl ether; The ketone compounds include one or more of acetone, butanone, 2-pentanone, 2-hexanone, 2-heptanone, 2-octanone, 2-nonanone, and 2-decanone.

4. The method for synthesizing cyclic ketones according to claim 3, characterized in that, The condensation reaction is carried out at a temperature of 80~250℃ for 1~6 hours.

5. The method for synthesizing cyclic ketones according to claim 1, 2, or 4, characterized in that, The deetherification reaction is carried out at a temperature of 120~230℃ for 2~3 hours. The deetherification reaction uses acidic ion exchange resins, including benzenesulfonic acid ion exchange resin, p-toluenesulfonic acid ion exchange resin, sulfate ion exchange resin, and hydrochloric acid ion exchange resin. The amount of acidic ion exchange resin used is 10-30% of the total mass of the glycol methyl ether and ketone compounds.

6. The method for synthesizing cyclic ketones according to claim 5, characterized in that, The intramolecular condensation reaction is carried out at a temperature of 100~250℃ for 1~6h.

7. The method for synthesizing cyclic ketones according to claim 4 or 6, characterized in that, The cyclic ketones include one or more of cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, cyclononanone, cyclodecanone, cycloundecanone, cyclododecanone, cyclotridecone, and cyclotetradecone.

Images