Separation device for ethyl acetate and cyclohexane

Abstract

The utility model discloses a separation device for ethyl acetate and cyclohexane, which belongs to the technical field of separation and purification, solves the problems of incapability of large-scale separation, high process difficulty and poor separation effect in the prior art, and comprises an extractive distillation tower, the upper part is provided with a polyol solvent inlet, the top is connected with a first condenser, the outlet of the first condenser is connected with a cyclohexane outlet on the other side of the upper part of the extractive distillation tower, and the cyclohexane outlet is connected with a re-separation device. According to the device disclosed by the utility model, the problem of azeotropy of ethyl acetate and cyclohexane is solved by adding polar polyol, the relative volatility of the ethyl acetate and the cyclohexane is changed, and large-scale efficient separation of a mixture of the ethyl acetate and the cyclohexane is realized; the dissolubility of cyclohexane, sodium acetate and ethanol in water is different, so that the separation effect of cyclohexane is further improved, and the whole device is simple in structure.

Description

Technical Field

[0001] The utility model belongs to the technical field of separation and purification, and in particular relates to a device for separating ethyl acetate and cyclohexane. Background Art

[0002] Cyclohexane is primarily used industrially as a solvent for rubber, paints, and varnishes, as a diluent for adhesives, and as an oil extractant. It can also be used to prepare organic compounds such as cyclohexanol and cyclohexanone. Ethyl acetate, also known as ethyl acetate, is an important industrial solvent and a widely used fine chemical product. It has excellent solubility and quick-drying properties. It is primarily used as an industrial solvent in products such as paints, adhesives, rubber, paints, and artificial leather. It is also used as a fragrance ingredient in the preparation of fruit flavors such as pineapple, banana, and strawberry, as well as flavors such as whiskey and cream. In chemical production, a mixture of cyclohexane and ethyl acetate is often produced. To reduce production costs and environmental pollution, this mixture needs to be separated. However, cyclohexane and ethyl acetate form an azeotrope, making them difficult to separate using conventional distillation. Currently, extractive distillation is the common method for separating the two. The principle of extractive distillation is to add an extractant during the distillation process to change the relative volatility of cyclohexane and ethyl acetate, thereby achieving separation. However, after using this method to separate cyclohexane and ethyl acetate, the top cyclohexane still carries a small amount of ethyl acetate, which reduces the separation effect. Using the extractive distillation method to continue to remove the ethyl acetate will easily increase the process difficulty. Utility Model Content

[0003] The purpose of the utility model is to address the deficiencies in the prior art and provide a device for separating ethyl acetate and cyclohexane which can be separated on a large scale, has low process difficulty and good separation effect.

[0004] In order to achieve the above technical purpose, the technical solution adopted by the device for separating ethyl acetate and cyclohexane in the utility model is:

[0005] A device for separating ethyl acetate and cyclohexane comprises an extractive distillation tower, wherein a middle portion of the extractive distillation tower is provided with feed ports for ethyl acetate and cyclohexane, an upper portion is provided with an inlet for a polyol solvent, and a top portion is connected to a first condenser, wherein an outlet of the first condenser is connected to a cyclohexane outlet on the other side of the upper portion of the extractive distillation tower, and the cyclohexane outlet is connected to a re-separation device, wherein the re-separation device comprises a hydrolysis tank connected to the cyclohexane outlet, an overflow port is provided on the other side of the connection between the hydrolysis tank and the cyclohexane outlet, and the overflow port is connected to a cyclohexane collecting tank via a pipeline, a kettle of the extractive distillation tower is connected to a middle feed port of a solvent recovery tower, a top portion of the solvent recovery tower is connected to a second condenser, wherein the outlet of the second condenser is connected to an ethyl acetate outlet on one side of the upper portion of the solvent recovery tower, and the kettle of the solvent recovery tower is connected to the inlet for the polyol solvent.

[0006] Preferably, the polyol is one or more of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol and glycerol.

[0007] Preferably, the number of theoretical plates of the extractive distillation tower is 40-80, and the reflux ratio is 2-5.

[0008] Preferably, a disc-shaped heating strip is further provided in the hydrolysis tank, and a microwave transmitter is provided below the heating strip and is placed at the bottom of the hydrolysis tank.

[0009] Preferably, the number of theoretical plates of the solvent recovery tower is 15-30, and the reflux ratio is 2-5.

[0010] Compared with the prior art, the beneficial effects of the present invention are:

[0011] The utility model solves the azeotropic problem of ethyl acetate and cyclohexane by adding polar polyols, changes their relative volatility, and realizes large-scale and efficient separation of the ethyl acetate and cyclohexane mixture; cyclohexane rich in a small amount of ethyl acetate is placed in an alkaline environment, and the ethyl acetate is decomposed into sodium acetate and ethanol through a hydrolysis reaction; and water is used for extraction and separation by utilizing the different solubilities of cyclohexane, sodium acetate and ethanol in water, thereby further improving the separation accuracy of cyclohexane; the entire device has a simple structure, a high recovery rate, and can realize clean production. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural diagram of the present utility model.

[0013] In the figure: 1. Extractive distillation tower; 2. Feed inlet; 3. Polyol solvent inlet; 4. First condenser; 5. Cyclohexane outlet; 6. Hydrolysis tank; 7. Overflow port; 8. Cyclohexane collection tank; 9. Solvent recovery tower; 10. Second condenser; 11. Ethyl acetate outlet; 12. Heating strip; 13. Microwave emitter. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0015] like Figure 1As shown, a device for separating ethyl acetate and cyclohexane includes an extractive distillation tower 1, wherein the number of theoretical plates of the extractive distillation tower 1 is 40 to 80 and the reflux ratio is 2 to 5. A feed port 2 for ethyl acetate and cyclohexane is provided in the middle of the extractive distillation tower 1, a polyol solvent inlet 3 is provided in the upper portion, and a first condenser 4 is connected to the top. The outlet of the first condenser 4 is connected to a cyclohexane outlet 5 on the other side of the upper portion of the extractive distillation tower 1. The cyclohexane outlet 5 is connected to a re-separation device, which includes a hydrolysis tank 6 connected to the cyclohexane outlet 5. An overflow port 7 is provided on the other side of the connection between the hydrolysis tank 6 and the cyclohexane outlet 5, and the overflow port 7 is connected to the cyclohexane collection tank 8 via a pipeline. The bottom of the extractive distillation tower 1 is connected to the middle feed port of the solvent recovery tower 9. The theoretical number of plates of the solvent recovery tower 9 is 15 to 30, and the reflux ratio is 2 to 5. The top of the solvent recovery tower 9 is connected to a second condenser 10, and the outlet of the second condenser 10 is connected to the ethyl acetate outlet 11 on the upper side of the solvent recovery tower 9. The bottom of the solvent recovery tower 9 is connected to the polyol solvent inlet 3.

[0016] The polyol is one or more of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, and glycerol. Polar polyols are used to break the azeotropic effect of ethyl acetate and cyclohexane, changing their relative volatility, thereby achieving large-scale and efficient separation of the ethyl acetate and cyclohexane mixture.

[0017] A disc-shaped heating strip 12 is further provided in the hydrolysis tank 6, and a microwave launcher 13 is provided below the heating strip 12 and is placed at the bottom of the hydrolysis tank 6. By providing the heating strip 12 and the microwave launcher 13, the separation efficiency is improved.

[0018] When the utility model is working, the solvent is introduced into the upper feed port 2 of the extractive distillation tower 1, and the vapor of cyclohexane is condensed into liquid in the first condenser 4 at the top of the extractive distillation tower 1. A part of it is extracted as the cyclohexane product, and the other part is refluxed into the extractive distillation tower 1. The cyclohexane carrying a small amount of ethyl acetate enters the hydrolysis tank 6, meets the sodium hydroxide aqueous solution at the bottom of the hydrolysis tank 6, and is completely hydrolyzed. The ethyl acetate is completely hydrolyzed into sodium acetate and ethanol under the action of the sodium hydroxide aqueous solution. Sodium acetate and ethanol are soluble in water, while cyclohexane is insoluble in water, so it contains a small amount of ethyl acetate. After the cyclohexane in the ester is completely hydrolyzed, it is allowed to stand and separate into layers. Pure cyclohexane is obtained in the upper layer. Cyclohexane continues to accumulate in the upper layer of the hydrolysis tank 6 under the action of gravity. When the liquid level reaches the set position, it flows into the cyclohexane collection tank 8 through the overflow port 7, and the solvent rich in ethyl acetate is discharged from the bottom of the extractive distillation tower 1. The solvent rich in ethyl acetate is introduced into the solvent recovery tower 9. The low-boiling ethyl acetate is continuously enriched in the vapor phase and rises to the second condenser 10 at the top of the tower to condense into liquid. Part of it is extracted as ethyl acetate product, and the other part is refluxed into the solvent recovery tower 9. The solvent is discharged from the bottom of the tower.

[0019] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A device for separating ethyl acetate and cyclohexane, comprising an extractive distillation column, wherein a feed port for ethyl acetate and cyclohexane is provided in the middle of the extractive distillation column, characterized in that: A polyol solvent inlet is provided at the top, and a first condenser is connected to the top. The outlet of the first condenser is connected to the cyclohexane outlet on the other side of the upper part of the extractive distillation tower. The cyclohexane outlet is connected to a re-separation device, and the re-separation device includes a hydrolysis tank connected to the cyclohexane outlet. An overflow port is provided on the other side of the connection between the hydrolysis tank and the cyclohexane outlet. The overflow port is connected to the cyclohexane collection tank through a pipeline. The extractive distillation tower kettle is connected to the middle feed port of the solvent recovery tower. The top of the solvent recovery tower is connected to a second condenser. The outlet of the second condenser is connected to the ethyl acetate outlet on one side of the upper part of the solvent recovery tower. The solvent recovery tower kettle is connected to the polyol solvent inlet.

2. The separation device of ethyl acetate and cyclohexane according to claim 1, characterized in that: The polyol is one or more of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol and glycerol.

3. The separation device of ethyl acetate and cyclohexane according to claim 1, characterized in that: The number of theoretical plates of the extractive distillation tower is 40-80, and the reflux ratio is 2-5.

4. The separation device of ethyl acetate and cyclohexane according to claim 1, characterized in that: A disc-shaped heating strip is also provided in the hydrolysis tank, and a microwave emitter is provided at the bottom of the hydrolysis tank under the heating strip.

5. The separation device of ethyl acetate and cyclohexane according to claim 1, characterized in that: The number of theoretical plates of the solvent recovery tower is 15 to 30, and the reflux ratio is 2 to 5.

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