Method for recovering cyclohexene oxide from cyclohexanone byproduct light oil

Abstract

The invention provides a method for recovering cyclohexene oxide from cyclohexanone by-product light oil. The method comprises the following steps: firstly, removing low-boiling-point impurities such as alcohol and aldehyde in the cyclohexanone by-product light oil through vacuum distillation; secondly, adding saturated sodium salt to remove cyclohexanone through complexation reaction; adding an acidic catalyst again to convert cyclohexene oxide into 1, 2-cyclohexanediol with a higher boiling point, and removing substances with a boiling point close to that of cyclohexene oxide through vacuum distillation; finally, alkali liquor is added, and cyclohexene oxide is generated through cyclization reaction; the purity of the cyclohexene oxide is greater than 99%, and the recovery rate of the cyclohexene oxide is greater than 87%.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of cyclohexene oxide recovery and relates to a method for recovering cyclohexene oxide from cyclohexanone by-product light oil. BACKGROUND

[0002] Cyclohexene oxide is a colorless or light yellow liquid with a fragrance, which is composed of a six-membered cyclohexane ring and a three-membered epoxy group in structure, forming a unique "bridged ring" structure, which gives cyclohexene oxide high reactivity. As a result, the three-membered epoxy ring is easily opened under the catalysis of acid or base and reacts with water, alcohol, amine, acid and other nucleophiles. This high reactivity makes it widely used in organic synthesis and fine chemical industry.

[0003] The production method of cyclohexene oxide is mainly cyclohexene oxidation or extraction from cyclohexanone by-product light oil. Generally, when cyclohexane is prepared into cyclohexanone, the by-product light oil contains 30-40% of cyclohexene oxide and a large amount of organic substances such as alcohol, aldehyde and ketone. Therefore, the separation and recovery of cyclohexene oxide from the by-product light oil of cyclohexanone can improve the added value of cyclohexane in the preparation of cyclohexanone, thereby enhancing the economic benefits of the product.

[0004] Patent No. CN113816928A discloses a clean production method for recovering and purifying cyclohexene oxide from oxidized light oil. The method is as follows: the cyclohexane oxidized light oil is subjected to first vacuum rectification at 100℃-150℃ and -0.06MPa--0.1MPa to obtain first cyclohexene oxide crude product; then the first cyclohexene oxide crude product is subjected to second vacuum rectification at 100℃-150℃ and -0.06MPa--0.08MPa to obtain second cyclohexene oxide crude product; then the second cyclohexene oxide crude product is subjected to third vacuum rectification at 90℃-150℃ and -0.08MPa--0.1MPa to obtain third cyclohexene oxide crude product; finally, the third cyclohexene oxide crude product is subjected to oxidation reaction, and then subjected to fourth vacuum rectification at 90℃-150℃ and -0.06MPa--0.1MPa to obtain cyclohexene oxide. The cyclohexene oxide is separated by multiple vacuum rectification in the process, and the purity can reach 99%, the recovery rate is ≥80%, and the process is simple, but the product recovery rate is not high.

[0005] Patent CN109970682A discloses a method for recovering cyclohexane oxide from cyclohexane-oxidized light oil. The method involves reacting cyclohexane-oxidized light oil with CO2 in the presence of an addition catalyst to obtain cyclohexene carbonate. Then, the cyclohexene carbonate is decarboxylated in the presence of a decarboxylation catalyst, followed by distillation to obtain cyclohexane oxide. The purity of the obtained product can reach 99.9%. This process requires intermittent CO2 replenishment, has a long reaction time of approximately 20 hours, and is complex, requiring high-pressure reaction equipment, increasing costs and risks.

[0006] Patent CN1180702A discloses a method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexane oxidation. The method involves pre-distilling the byproduct and then continuously adding only one azeotropic agent, strictly controlling the instantaneous ratio of the azeotropic agent (water) to the cyclohexane oxide in the refining vessel. The product purity can reach 96%, and the recovery rate is greater than 80%. While the process is relatively simple, both the product purity and recovery rate are not high. Summary of the Invention

[0007] The purpose of this invention is to provide a method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, in order to solve the problems of low recovery rate and low product purity in existing methods.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: This application provides a method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, the method comprising: The light oil, a byproduct of cyclohexanone, was subjected to vacuum distillation at a vacuum degree of -76 kPa, and the fraction collected at 95-110℃ was used to obtain crude cyclohexane oxide. Saturated sodium salt was added to the crude cyclohexane oxide, and after shaking to separate the layers, an acidic catalyst was added to the upper oil phase to react and generate crude 1,2-cyclohexanediol. The crude 1,2-cyclohexanediol was subjected to vacuum distillation at a vacuum degree of -76 kPa, and the fraction at a temperature above 145°C was collected. An alkaline solution was added to the fraction above 145°C. The upper oil phase after the reaction was purified by vacuum distillation, and the fraction at 95-100°C was collected to obtain cyclohexane oxide.

[0009] The present invention has the following beneficial effects: In this application, firstly, impurities such as alcohols and aldehydes with low boiling points in the light oil, a byproduct of cyclohexanone, are removed by vacuum distillation; secondly, saturated sodium salt is added to remove cyclohexanone through a complexation reaction; thirdly, an acidic catalyst is added to convert cyclohexane oxide into 1,2-cyclohexanediol with a higher boiling point, and substances with boiling points close to those of cyclohexane oxide are removed by vacuum distillation; finally, an alkaline solution is added to generate cyclohexane oxide through a cyclization reaction; and cyclohexane oxide with a purity >99% and a recovery rate >87% is obtained by vacuum distillation purification. Detailed Implementation

[0010] This application provides a method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, the method comprising: S01: The light oil, a byproduct of cyclohexanone, is subjected to vacuum distillation at a vacuum degree of -76 kPa and a reflux ratio of 2-8:1 to remove impurities such as alcohols and aldehydes with low boiling points. The fraction at 95-110℃ is collected to obtain crude cyclohexane oxide with a content of 70-80%.

[0011] S02: Add 1-1.3 times the volume of saturated sodium salt to crude cyclohexane oxide to induce a complexation reaction between the saturated sodium salt and cyclohexanone in the crude cyclohexane oxide, forming water-insoluble sodium α-hydroxysulfonate crystals, thus removing cyclohexanone. After the reaction, the mixture is shaken, separated, and the upper oil phase is obtained. An acidic catalyst is added to the upper oil phase, and the reaction is carried out at 35-40℃ for 3-5 hours to induce ring-opening hydrogenation of the oxygen-containing ring of cyclohexane oxide, generating 1,2-cyclohexanediol with a higher boiling point, thus obtaining crude 1,2-cyclohexanediol.

[0012] In this application, the saturated sodium salt is one or more of sodium bisulfite, sodium bicarbonate, sodium carbonate, and sodium hydrogen phosphate; the acid catalyst is one or more of sulfuric acid, p-benzenesulfonic acid, phosphoric acid, carbonic acid, aluminum chloride, and ferric chloride, and the amount of acid catalyst added is 1.1-1.3 times the molar amount of cyclohexane oxide in the cyclohexanone by-product light oil.

[0013] SO3: Crude 1,2-cyclohexanediol is subjected to vacuum distillation at a vacuum degree of -76 kPa and a reflux ratio of 2-8:1 to remove substances with boiling points lower than 1,2-cyclohexanediol, and the fraction with a boiling point above 145°C is collected.

[0014] S04: Add a 10% (w / w) alkaline solution to the fraction above 145℃ to induce a cyclization reaction of 1,2-cyclohexanediol, producing cyclohexane oxide, resulting in an upper oil phase containing cyclohexane oxide. The upper oil phase is then purified by vacuum distillation under a vacuum of -76 kPa and a reflux ratio of 5-8:1. The fraction at 95-100℃ is collected to obtain cyclohexane oxide with a purity >99% and a recovery rate >87%.

[0015] In this application, the alkaline solution is one or more of sodium hydroxide, potassium hydroxide, and barium hydroxide, and the amount of alkaline solution added is 0.8-1.2% of the mass of cyclohexane oxide in the light oil of cyclohexanone by-product.

[0016] The technical solution of the present invention will be further explained and described below through specific embodiments.

[0017] Example 1 This application provides a method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, the method comprising: S101: Take 100g of cyclohexanone by-product light oil, wherein the content of cyclohexane oxide is 35.76%. The cyclohexanone by-product light oil is subjected to vacuum distillation under a vacuum of -76kPa and a reflux ratio of 5:1. The fraction at 95-110℃ is collected to obtain crude cyclohexane oxide, wherein the content of cyclohexane oxide is 73.69%, the content of cyclohexanone is 18.96%, and the rest are impurities such as alcohols and aldehydes.

[0018] S102: Crude cyclohexane oxide was placed in a separatory funnel. Saturated sodium bisulfite, with a volume equal to that of crude cyclohexane oxide, was added. After the reaction was complete, the mixture was shaken to separate the layers, yielding an upper oil phase. The upper oil phase was washed three times with pure water. Then, p-benzenesulfonic acid, with a molar volume equal to that of cyclohexane oxide, was added to the upper oil phase. The mixture was reacted at 40°C for 3 hours to obtain crude 1,2-cyclohexanediol.

[0019] S103: Crude 1,2-cyclohexanediol was subjected to vacuum distillation at a vacuum of -76 kPa and a reflux ratio of 5:1, and the fractions above 145 °C were collected.

[0020] S104: A sodium hydroxide solution with a mass concentration of 10% and a mass concentration of 0.8% cyclohexane oxide was added to the fraction above 145℃ to obtain an upper oil phase containing cyclohexane oxide. The upper oil phase was purified by vacuum distillation under a vacuum of -76 kPa and a reflux ratio of 5:1. The fraction at 95-100℃ was collected to obtain 31.18 g of cyclohexane oxide. Gas chromatography analysis showed that the purity of cyclohexane oxide was 99.06% and the recovery rate was 87.19%.

[0021] Example 2 This application provides a method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, the method comprising: S201: The light oil, a byproduct of cyclohexanone in Example 1, was subjected to vacuum distillation at a vacuum degree of -76 kPa and a reflux ratio of 6:1. The fraction at 95-110°C was collected to obtain crude cyclohexane oxide, wherein the content of cyclohexane oxide was 74.16%, the content of cyclohexanone was 18.32%, and the rest were impurities such as alcohols and aldehydes.

[0022] S202: Crude cyclohexane oxide was placed in a separatory funnel. Saturated sodium hydrogen phosphate (1.3 times the volume of the crude cyclohexane oxide) was added to the crude cyclohexane oxide. After the reaction was complete, the mixture was shaken to separate the layers, yielding the upper oil phase. The upper oil phase was washed three times with pure water. Then, p-benzenesulfonic acid (1.1 times the molar amount of cyclohexane oxide) was added to the upper oil phase, and the mixture was reacted at 40°C for 3 hours to obtain crude 1,2-cyclohexanediol.

[0023] S203: Crude 1,2-cyclohexanediol was subjected to vacuum distillation at a vacuum of -76 kPa and a reflux ratio of 6:1, and the fractions above 145 °C were collected.

[0024] S204: Sodium hydroxide with a mass concentration of 10% and a mass concentration of 1.2% cyclohexane oxide was added to the fraction above 145℃ to obtain an upper oil phase containing cyclohexane oxide. The upper oil phase was purified by vacuum distillation under a vacuum of -76 kPa and a reflux ratio of 7:1. The fraction at 95-100℃ was collected to obtain 31.35 g of cyclohexane oxide. Gas chromatography analysis showed that the purity of cyclohexane oxide was 99.12% and the recovery rate was 87.19%.

[0025] Example 3 This application provides a method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, the method comprising: S301: The light oil, a byproduct of cyclohexanone in Example 1, was subjected to vacuum distillation at a vacuum degree of -76 kPa and a reflux ratio of 7:1. The fraction at 95-110°C was collected to obtain crude cyclohexane oxide, wherein the content of cyclohexane oxide was 76.23%, the content of cyclohexanone was 17.49%, and the rest were impurities such as alcohols and aldehydes.

[0026] S302: Crude cyclohexane oxide was placed in a separatory funnel. Saturated sodium bicarbonate, with a volume equal to the crude cyclohexane oxide, was added. After the reaction was complete, the mixture was shaken to separate the layers, yielding an upper oil phase. The upper oil phase was washed three times with pure water. Phosphoric acid, with a molar volume equal to that of cyclohexane oxide, was added to the upper oil phase. The mixture was reacted at 35°C for 5 hours to obtain crude 1,2-cyclohexanediol.

[0027] S303: Crude 1,2-cyclohexanediol was subjected to vacuum distillation at a vacuum of -76 kPa and a reflux ratio of 6:1, and the fractions above 145 °C were collected.

[0028] S304: Potassium hydroxide with a mass concentration of 10% and a mass concentration of 0.9% cyclohexane oxide was added to the fraction above 145℃ to obtain an upper oil phase containing cyclohexane oxide. The upper oil phase was purified and purified by distillation under reduced pressure at a vacuum of -76 kPa and a reflux ratio of 6:1. The fraction at 95-100℃ was collected to obtain 31.20 g of cyclohexane oxide. Gas chromatography analysis showed that the purity of cyclohexane oxide was 99.19% and the recovery rate was 87.25%.

[0029] Example 4 This application provides a method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, the method comprising: S401: The light oil, a byproduct of cyclohexanone in Example 1, was subjected to vacuum distillation at a vacuum degree of -76 kPa and a reflux ratio of 8:1. The fraction at 95-110°C was collected to obtain crude cyclohexane oxide, wherein the content of cyclohexane oxide was 76.82%, the content of cyclohexanone was 16.93%, and the rest were impurities such as alcohols and aldehydes.

[0030] S402: Crude cyclohexane oxide was placed in a separatory funnel. Saturated sodium bisulfite, with a volume equal to that of the crude cyclohexane oxide, was added. After the reaction was complete, the mixture was shaken to separate the layers, yielding an upper oil phase. The upper oil phase was washed three times with pure water. Sulfuric acid, with a molar volume equal to that of the cyclohexane oxide, was then added to the upper oil phase. The mixture was reacted at 38°C for 4 hours to obtain crude 1,2-cyclohexanediol.

[0031] S403: Crude 1,2-cyclohexanediol was subjected to vacuum distillation at a vacuum of -76 kPa and a reflux ratio of 8:1, and the fractions above 145 °C were collected.

[0032] S404: Potassium hydroxide with a mass concentration of 10% and a mass concentration of 1.1% cyclohexane oxide was added to the fraction above 145℃ to obtain an upper oil phase containing cyclohexane oxide. The upper oil phase was purified and purified by distillation under reduced pressure at a vacuum of -76 kPa and a reflux ratio of 8:1. The fraction at 95-100℃ was collected to obtain 31.22 g of cyclohexane oxide. Gas chromatography analysis showed that the purity of cyclohexane oxide was 99.15% and the recovery rate was 87.31%.

[0033] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, characterized in that, include: The light oil, a byproduct of cyclohexanone, was subjected to vacuum distillation at a vacuum degree of -76 kPa, and the fraction collected at 95-110℃ was used to obtain crude cyclohexane oxide. Saturated sodium salt was added to the crude cyclohexane oxide, and after shaking to separate the layers, an acidic catalyst was added to the upper oil phase to react and generate crude 1,2-cyclohexanediol. The crude 1,2-cyclohexanediol was subjected to vacuum distillation at a vacuum degree of -76 kPa, and the fraction at a temperature above 145°C was collected. An alkaline solution was added to the fraction above 145°C. The upper oil phase after the reaction was purified by vacuum distillation, and the fraction at 95-100°C was collected to obtain cyclohexane oxide.

2. The method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, according to claim 1, is characterized in that, The sodium salt is one or more of sodium bisulfite, sodium bicarbonate, sodium carbonate, and sodium hydrogen phosphate.

3. The method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, according to claim 1, is characterized in that, The amount of saturated sodium salt added is 1-1.3 times the volume of the crude cyclohexane oxide.

4. The method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, according to claim 1, is characterized in that, The acidic catalyst is one or more of sulfuric acid, p-benzenesulfonic acid, phosphoric acid, carbonic acid, aluminum chloride, and ferric chloride.

5. The method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, according to claim 1, is characterized in that, The amount of acidic catalyst added is 1.1-1.3 times the molar amount of cyclohexane oxide in the light oil of the cyclohexanone byproduct.

6. The method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, according to claim 1, is characterized in that, The alkaline solution is one or more of sodium hydroxide, potassium hydroxide, and barium hydroxide.

7. The method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, according to claim 1, is characterized in that, The amount of alkali solution added is 0.8-1.2% of the mass of cyclohexane oxide in the light oil, a byproduct of cyclohexanone.

8. The method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, according to claim 1, is characterized in that, The reflux ratio for vacuum distillation is 2-8:1, and the reflux ratio for vacuum purification distillation is 5-8:

1.

9. The method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, according to claim 1, is characterized in that, The reaction temperature after adding the acidic catalyst is 35-40℃.

10. The method for recovering cyclohexane oxide from light oil, a byproduct of cyclohexanone, according to claim 1, is characterized in that, The mass concentration of the alkaline solution is 10%.