A method for separating an azeotrope

Abstract

A method for separating an azeotrope, belonging to the field of chemical engineering technology. The separation and purification method includes: adding an azeotrope of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane to an extractant for extraction; wherein, the extractant is selected from one or more of ethylene glycol, furfural, acetonitrile, and DMF. The separation method of the present invention destroys the azeotropic equilibrium between 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane by adding an efficient, inexpensive and easily available extractant, so as to achieve the effective separation of the azeotrope of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane. The separated 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane are introduced into a subsequent distillation system for distillation and purification, and finally two products of high-purity 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane are obtained.

Description

Technical Field

[0001] The present application relates to a method for separating azeotropes and belongs to the field of chemical engineering technology. The present application relates to a method for separating azeotropes and belongs to the field of chemical engineering technology. Background Art

[0002] Chlorofluorocarbons (CFCs) and various other halogenated compounds can cause depletion of the Earth's ozone layer, while their substitutes hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) can cause global warming. Hydrofluoroolefins (HFOs) and hydrochlorofluoroolefins (HCFOs) do not have the above problems and are being promoted for use in refrigerants, cleaning agents, foaming agents, aerosol propellants, etc. Among them, 1,1,1,3,3-pentachloropropane is an important raw material for foaming agents in current industrial applications, and 1-chloro-3,3,3-trifluoropropene can be used as a raw material for producing 1,1,1,3,3-pentafluoropropane, and is also one of the main candidates for replacing 1,1,1,3,3-pentafluoropropane in foam foaming applications, and also has the potential to be used as a refrigerant, solvent or degreasing agent.

[0003] Industrially, hydrogen fluoride and 1,1,1,3,3-pentachloropropane are generally used as raw materials to synthesize 1-chloro-3,3,3-trifluoropropene by gas-phase fluorination or liquid-phase fluorination. Such methods have the problem that the raw material 1,1,1,3,3-pentachloropropane is over-fluorinated to produce the by-product 1,1,1,3,3-pentafluoropropane. Also, because the boiling points of 1-chloro-3,3,3-trifluoropropene and the by-product 1,1,1,3,3-pentafluoropropane are close (the boiling point of 1,1,1,3,3-pentafluoropropane is 15.3 °C, and the boiling point of 1-chloro-3,3,3-trifluoropropene is 18.7 °C), and the relative volatilities of these two compounds are close to 1, an azeotropic phenomenon exists. The existence of the azeotrope makes it difficult to separate 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane by conventional distillation means, thus making it difficult to obtain high-purity 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane.

[0004] The patent application CN202110955520.8 of Shandong Hua'an New Materials Co., Ltd. discloses a method for separating a mixture of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane. A mixture of high-concentration 1-chloro-3,3,3-trifluoropropene and low-concentration 1,1,1,3,3-pentafluoropropane is added with an extractant for extraction; wherein, the extractant is selected from one or more of acetone, cyclopentane, n-pentane, and carbon tetrachloride. This method can separate 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane, and can obtain 1-chloro-3,3,3-trifluoropropene with a purity of more than 99.9% and 1,1,1,3,3-pentafluoropropane with a content greater than 90 wt%.

[0005] However, there are still the following problems in the separation of the mixture of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane: 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane will form an azeotrope at certain specific ratios, and no method to solve this problem has been found in the currently disclosed patents; when the proportion of 1,1,1,3,3-pentafluoropropane in the mixture of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane is higher than that of 1-chloro-3,3,3-trifluoropropene, it is difficult to separate and purify 1-chloro-3,3,3-trifluoropropene. Summary of the Invention

[0006] The present invention provides a method for separating and purifying the azeotrope of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane. By adding an efficient, inexpensive and easily available extractant to the system, the problem of difficultly breaking the azeotropic equilibrium of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane in the prior art is solved, and high-purity 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane are obtained through subsequent rectification parameter regulation.

[0007] The technical solution of the present invention is as follows: adding the azeotrope of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane to an extractant mixture for extraction; wherein the extractant mixture is selected from one or more of ethylene glycol, furfural, acetonitrile, and DMF.

[0008] A method for separating an azeotrope, including the following:

[0009] a. Introducing the azeotrope of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane and an extractant into an extractive distillation column, obtaining 1-chloro-3,3,3-trifluoropropene at the top of the extractive distillation column, and obtaining 1,1,1,3,3-pentafluoropropane and an extractant mixture at the bottom of the column;

[0010] b. Introducing the 1,1,1,3,3-pentafluoropropane and the extractant mixture obtained at the bottom of the column in step 1 into an extractant recovery column, separating 1,1,1,3,3-pentafluoropropane at the top of the extractive distillation column, and obtaining the extractant at the bottom of the column, and returning the extractant to the extractive distillation column;

[0011] The purity of the 1-chloro-3,3,3-trifluoropropene obtained at the top of the extractive distillation column in step a is ≥99.9%;

[0012] The purity of the 1,1,1,3,3-pentafluoropropane obtained at the top of the extractive distillation column in step b is ≥99.9%;

[0013] The extractant is a mixed extractant of ethylene glycol, furfural and acetonitrile in a molar ratio of 0.8 - 1.2:1:0.8 - 1.2 or a mixed extractant of ethylene glycol, furfural and DMF in a molar ratio of 0.8 - 1.2:1:0.8 - 1.2.

[0014] Specifically, 1-chloro-3,3,3-trifluoropropene obtained at the top of the extractive distillation column is introduced into a light impurity distillation column for removing 1-chloro-3,3,3-trifluoropropene. After removing the light impurities, it is then introduced into a heavy impurity distillation column for 1-chloro-3,3,3-trifluoropropene to remove the heavy impurities, and 1-chloro-3,3,3-trifluoropropene is obtained at the top of the heavy impurity distillation column for 1-chloro-3,3,3-trifluoropropene;

[0015] Specifically, 1,1,1,3,3-pentafluoropropane obtained at the top of the extractant recovery column is introduced into a light impurity distillation column for 1,1,1,3,3-pentafluoropropane. After removing the light impurities, it is then introduced into a heavy impurity distillation column for 1,1,1,3,3-pentafluoropropane to remove the heavy impurities, and 1,1,1,3,3-pentafluoropropane is obtained at the top of the heavy impurity distillation column for 1,1,1,3,3-pentafluoropropane.

[0016] Specifically, in the azeotrope of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentachloropropane, the content of 1,1,1,3,3-pentachloropropane is 40.0 wt% - 80.0 wt%, and the content of 1-chloro-3,3,3-trifluoropropene is 20.0 wt% - 60.0 wt%.

[0017] Specifically, the azeotrope of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane is obtained by the reaction of 1,1,1,3,3-pentafluoropropane and HF.

[0018] Specifically, the mass ratio of the extractant to the azeotrope of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane is 1 - 15:1.

[0019] Specifically, the operating conditions of the extractive distillation column are as follows: the operating pressure is 0.05 MPa - 1.2 MPa, the top temperature is 30°C - 70°C, the bottom temperature is 80°C - 120°C, and the reflux ratio is 0.5 - 5; the operating conditions of the extractant recovery column are as follows: the operating pressure is 0.05 MPa - 1.0 MPa, the top temperature is 20°C - 80°C, the bottom temperature is 80°C - 130°C, and the reflux ratio is 5 - 15.

[0020] Specifically, the operating conditions of the light impurity rectification column for 1-chloro-3,3,3-trifluoropropene are as follows: the operating pressure is 0.02 MPa to 1.0 MPa, the top temperature is 10°C to 30°C, the bottom temperature is 30°C to 70°C, and the reflux ratio is 5 to 15; the operating conditions of the heavy impurity rectification column for 1-chloro-3,3,3-trifluoropropene are as follows: the operating pressure is 0.02 MPa to 1.2 MPa, the top temperature is 30°C to 70°C, the bottom temperature is 70°C to 100°C, and the reflux ratio is 0.5 to 3.

[0021] Specifically, the operating conditions of the light impurity rectification column for 1,1,1,3,3-pentafluoropropane are as follows: the operating pressure is 0.02 MPa to 1.0 MPa, the top temperature is 10°C to 30°C, the bottom temperature is 30°C to 70°C, and the reflux ratio is 5 to 15; the operating conditions of the heavy impurity rectification column for 1,1,1,3,3-pentafluoropropane are as follows: the operating pressure is 0.02 MPa to 1.2 MPa, the top temperature is 30°C to 70°C, the bottom temperature is 70°C to 100°C, and the reflux ratio is 0.5 to 3.

[0022] Specifically, there are no special requirements for the form of the extraction rectification column, the extractant recovery column, the light impurity rectification column for 1-chloro-3,3,3-trifluoropropene, the heavy impurity rectification column for 1-chloro-3,3,3-trifluoropropene, the light impurity rectification column for 1,1,1,3,3-pentafluoropropane, and the heavy impurity rectification column for 1,1,1,3,3-pentafluoropropane. Common plate columns, sieve plate columns, or packed columns can all meet the required process requirements.

[0023] Compared with the prior art, the method for separating an azeotrope of the present invention has the following advantages: According to the characteristics that the boiling points of 1,1,1,3,3-pentafluoropropane and 1-chloro-3,3,3-trifluoropropene are close (the boiling point of 1,1,1,3,3-pentafluoropropane is 15.3°C, and the boiling point of 1-chloro-3,3,3-trifluoropropene is 18.7°C), and the relative volatility of the two compounds is close to 1, resulting in an azeotropic phenomenon, the present invention adopts a combination of extraction rectification and conventional rectification to achieve separation and purification. This method can obtain two high-purity products: 1-chloro-3,3,3-trifluoropropene with a purity ≥ 99.9% and 1,1,1,3,3-pentafluoropropane with a purity ≥ 99.9%. At the same time, after the extractant is separated from 1,1,1,3,3-pentafluoropropane in the extractant recovery column, it can be directly returned to the extraction rectification column for recycling without other treatment.

[0024] This method can successfully break the difficult-to-break azeotropic equilibrium between 1,1,1,3,3-pentafluoropropane and 1-chloro-3,3,3-trifluoropropene, and can reduce the generation of other difficult-to-treat impurities and by-products. It has the characteristics of simple and stable operation, low cost, and environmental friendliness. Moreover, this method can obtain two high-purity products: 1-chloro-3,3,3-trifluoropropene with a purity ≥ 99.9% and 1,1,1,3,3-pentafluoropropane with a purity ≥ 99.9%. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic flow chart of the present invention.

[0026] In the figure, 1 is the extractive distillation column, 2 is the extractant recovery column, 3 is the light impurity distillation column of 1-chloro-3,3,3-trifluoropropene, 4 is the heavy impurity distillation column of 1-chloro-3,3,3-trifluoropropene, 5 is the light impurity distillation column of 1,1,1,3,3-pentafluoropropane, and 6 is the heavy impurity distillation column of 1,1,1,3,3-pentafluoropropane. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following describes the present application in detail with reference to the embodiments, but the present application is not limited to these embodiments. As Figure 1 shown, in order to more clearly explain the overall concept of the present application, the following will be described in detail by way of examples with reference to the accompanying drawings of the specification.

[0028] Figure 1 In the accompanying drawings, 1 is the extractive distillation column, 2 is the extractant recovery column, 3 is the light impurity distillation column of 1-chloro-3,3,3-trifluoropropene, 4 is the heavy impurity distillation column of 1-chloro-3,3,3-trifluoropropene, 5 is the light impurity distillation column of 1,1,1,3,3-pentafluoropropane, 6 is the heavy impurity distillation column of 1,1,1,3,3-pentafluoropropane, A is the azeotrope of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane, B is the mixture of 1,1,1,3,3-pentafluoropropane and the extractant at the bottom of the extractive distillation column 1, C is the extractant at the bottom of the extractant recovery column 2, D is 1-chloro-3,3,3-trifluoropropene obtained at the top of the extractive distillation column 1, E is 1,1,1,3,3-pentafluoropropane obtained at the top of the extractant recovery column 2, F is 1,1,1,3,3-pentafluoropropane obtained at the bottom of the light impurity distillation column 5 of 1,1,1,3,3-pentafluoropropane, G is high-purity 1,1,1,3,3-pentafluoropropane obtained at the top of the heavy impurity distillation column 6 of 1,1,1,3,3-pentafluoropropane, H is 1-chloro-3,3,3-trifluoropropene obtained at the bottom of the light impurity distillation column 3 of 1-chloro-3,3,3-trifluoropropene, and I is high-purity 1-chloro-3,3,3-trifluoropropene obtained at the top of the heavy impurity distillation column 4 of 1-chloro-3,3,3-trifluoropropene. Embodiment

[0029] A mixture with a molar ratio of ethylene glycol:furfural:acetonitrile = 1:1:1 is used as the extractant. The mass fraction ratio of the azeotrope is 1,1,1,3,3-pentafluoropropane / 1-chloro-3,3,3-trifluoropropene = 59.47 / 40.53, and the azeotrope / extractant = 1 / 5 - 10; The parameters of the extractive distillation column are set as follows: the feeding rate is 6 m 3 / h, the reflux flow rate is 1.0 - 1.5 m 3 / h, the top temperature of the column is 40°C - 60°C, the bottom temperature of the column is 90°C - 100°C, and the top pressure of the column is 0.09 MPa - 0.11 MPa; The parameters of the extractant recovery column are set as follows: the reflux flow rate is 1.5 m 3 / h - 2.0 m 3 / h, the top temperature of the column is 30°C - 40°C, the bottom temperature of the column is 100°C - 110°C, and the top pressure of the column is 0.10 MPa - 0.15 MPa; The parameters of the remaining tower equipment are set according to the parameter requirements in the invention content. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.917% and 1,1,1,3,3-pentafluoropropane with a purity of 99.914% are obtained. Example

[0030] A mixture with a molar ratio of ethylene glycol:furfural:acetonitrile = 1:1:1 is used as the extractant. The mass fraction ratio of the azeotrope is 1,1,1,3,3-pentafluoropropane / 1-chloro-3,3,3-trifluoropropene = 59.47 / 40.53, and the azeotrope / extractant = 1 / 10 - 15; The parameters of the extractive distillation column are set as follows: the feeding rate is 6 m 3 / h, the reflux flow rate is 1.0 m 3 / h - 1.5 m 3 / h, the top temperature of the column is 40°C - 60°C, the bottom temperature of the column is 90°C - 100°C, and the top pressure of the column is 0.09 MPa - 0.11 MPa; The parameters of the extractant recovery column are set as follows: the reflux flow rate is 1.5 m 3 / h - 2.0 m 3 / h, the top temperature of the column is 30°C - 40°C, the bottom temperature of the column is 100°C - 110°C, and the top pressure of the column is 0.10 MPa - 0.15 MPa; The parameters of the remaining tower equipment are set according to the parameter requirements in the invention content. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.939% and 1,1,1,3,3-pentafluoropropane with a purity of 99.921% are obtained. Example

[0031] A mixture with a molar ratio of acetonitrile:furfural:DMF = 1:1:1 is used as the extractant. The mass fraction ratio of the azeotrope is 1,1,1,3,3-pentafluoropropane / 1-chloro-3,3,3-trifluoropropene = 58 / 42, and the azeotrope / extractant = 1 / 1 - 5; The parameters of the extractive distillation column are set as follows: the feeding rate is 6 m 3 / h, reflux rate 1.0 m 3 / h - 1.5 m 3 / h, top tower temperature 40°C - 60°C, bottom tower temperature 100°C - 110°C, top tower pressure 0.09 MPa - 0.11 MPa; the parameters of the extractant recovery tower are set as: reflux rate 1.5 m 3 / h - 2.0 m 3 / h, top tower temperature 30°C - 40°C, bottom tower temperature 110°C - 120°C, top tower pressure 0.10 MPa - 0.15 MPa; the parameters of the remaining towers are set according to the parameter requirements in the invention content. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.923% and 1,1,1,3,3-pentafluoropropane with a purity of 99.934% are obtained. Example

[0032] A mixture with a molar ratio of acetonitrile:furfural:DMF = 1:1:1 is used as the extractant, the mass fraction ratio of the azeotrope: 1,1,1,3,3-pentafluoropropane / 1-chloro-3,3,3-trifluoropropene = 58 / 42, azeotrope / extractant = 1 / 5 - 10; the parameters of the extractive distillation tower are set as: feed rate 6 m 3 / h, reflux rate 1.0 m 3 / h - 1.5 m 3 / h, top tower temperature 40°C - 60°C, bottom tower temperature 100°C - 110°C, top tower pressure 0.09 MPa - 0.11 MPa; the parameters of the extractant recovery tower are set as: reflux rate 1.5 m 3 / h - 2.0 m 3 / h, top tower temperature 30°C - 40°C, bottom tower temperature 110°C - 120°C, top tower pressure 0.10 MPa - 0.15 MPa; the parameters of the remaining towers are set according to the parameter requirements in the invention content. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.945% and 1,1,1,3,3-pentafluoropropane with a purity of 99.957% are obtained. Example

[0033] A mixture with a molar ratio of acetonitrile:furfural:DMF = 1:1:1 is used as the extractant, the mass fraction ratio of the azeotrope: 1,1,1,3,3-pentafluoropropane / 1-chloro-3,3,3-trifluoropropene = 58 / 42, azeotrope / extractant = 1 / 10 - 15; the parameters of the extractive distillation tower are set as: feed rate 6 m 3 / h, reflux rate 1.0 m 3 / h - 1.5 m 3 / h, top tower temperature 40°C - 60°C, bottom tower temperature 100°C - 110°C, top tower pressure 0.09 MPa - 0.11 MPa; the parameters of the extractant recovery tower are set as: reflux rate 1.5 m 3 / h - 2.0 m 3 / h, the top temperature of the tower is 30°C - 40°C, the bottom temperature of the tower is 110°C - 120°C, and the top pressure of the tower is 0.10 MPa - 0.15 MPa; the parameters of the other towers are set according to the parameter requirements in the invention content. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.963% and 1,1,1,3,3-pentafluoropropane with a purity of 99.972% are obtained. Example

[0034] A mixture with a molar ratio of acetonitrile:furfural:DMF = 1:1:1 is used as the extractant. The mass fraction ratio of the azeotrope is: 1,1,1,3,3-pentafluoropropane / 1-chloro-3,3,3-trifluoropropene = 81.34 / 18.66, and the azeotrope / extractant = 1 / 5 - 10; the parameters of the extractive distillation column are set as follows: the feeding rate is 6 m 3 / h, the reflux ratio is 1.0 m 3 / h - 1.5 m 3 / h, the top temperature of the tower is 40°C - 60°C, the bottom temperature of the tower is 100°C - 110°C, and the top pressure of the tower is 0.09 MPa - 0.11 MPa; the parameters of the extractant recovery column are set as follows: the reflux ratio is 1.5 m 3 / h - 2.0 m 3 / h, the top temperature of the tower is 30°C - 40°C, the bottom temperature of the tower is 110°C - 120°C, and the top pressure of the tower is 0.10 MPa - 0.15 MPa; the parameters of the other towers are set according to the parameter requirements in the invention content. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.951% and 1,1,1,3,3-pentafluoropropane with a purity of 99.983% are obtained. Example

[0035] A mixture with a molar ratio of acetonitrile:furfural:DMF = 1:1:1 is used as the extractant. The mass fraction ratio of the azeotrope is: 1,1,1,3,3-pentafluoropropane / 1-chloro-3,3,3-trifluoropropene = 41.26 / 58.74, and the azeotrope / extractant = 1 / 5 - 10; the parameters of the extractive distillation column are set as follows: the feeding rate is 6 m 3 / h, the reflux ratio is 1.0 m 3 / h - 1.5 m 3 / h, the top temperature of the tower is 40°C - 60°C, the bottom temperature of the tower is 100°C - 110°C, and the top pressure of the tower is 0.09 MPa - 0.11 MPa; the parameters of the extractant recovery column are set as follows: the reflux ratio is 1.5 m 3 / h - 2.0 m 3 / h, the top temperature of the tower is 30°C - 40°C, the bottom temperature of the tower is 110°C - 120°C, and the top pressure of the tower is 0.10 MPa - 0.15 MPa; the parameter settings of the other tower equipment are set according to the parameter requirements in the invention content. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.970% and 1,1,1,3,3-pentafluoropropane with a purity of 99.954% are obtained. Example

[0036] A mixture with a molar ratio of acetonitrile:furfural:DMF = 0.8:1:0.8 is used as the extractant, and the mass fraction ratio of the azeotrope is: 1,1,1,3,3-pentafluoropropane / 1-chloro-3,3,3-trifluoropropene = 41.26 / 58.74, and the azeotrope / extractant = 1 / 5 - 10; the parameter settings of the extractive distillation column are: the feeding speed is 6 m 3 / h, the reflux ratio is 1.0 m 3 / h - 1.5 m 3 / h, the top temperature of the tower is 40°C - 60°C, the bottom temperature of the tower is 100°C - 110°C, and the top pressure of the tower is 0.09 MPa - 0.11 MPa; the parameter settings of the extractant recovery column are: the reflux ratio is 1.5 m 3 / h - 2.0 m 3 / h, the top temperature of the tower is 30°C - 40°C, the bottom temperature of the tower is 110°C - 120°C, and the top pressure of the tower is 0.10 MPa - 0.15 MPa; the parameter settings of the other tower equipment are set according to the parameter requirements in the invention content. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.968% and 1,1,1,3,3-pentafluoropropane with a purity of 99.926% are obtained. Example

[0037] A mixture with a molar ratio of acetonitrile:furfural:DMF = 1.2:1:1.2 is used as the extractant, and the mass fraction ratio of the azeotrope is: 1,1,1,3,3-pentafluoropropane / 1-chloro-3,3,3-trifluoropropene = 41.26 / 58.74, and the azeotrope / extractant = 1 / 5 - 10; the parameter settings of the extractive distillation column are: the feeding speed is 6 m 3 / h, the reflux ratio is 1.0 m 3 / h - 1.5 m 3 / h, the top temperature of the tower is 40°C - 60°C, the bottom temperature of the tower is 100°C - 110°C, and the top pressure of the tower is 0.09 MPa - 0.11 MPa; the parameter settings of the extractant recovery column are: the reflux ratio is 1.5 m 3 / h - 2.0 m 3 / h, the top temperature of the tower is 30°C to 40°C, the bottom temperature of the tower is 110°C - 120°C, and the top pressure of the tower is 0.10 MPa - 0.15 MPa; the parameter settings of the remaining tower equipment are set according to the parameter requirements in the invention content. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.916% and 1,1,1,3,3-pentafluoropropane with a purity of 99.935% are obtained. Example

[0038] A mixture with a molar ratio of ethylene glycol:furfural:acetonitrile = 0.8:1:0.8 is used as the extractant. The mass fraction ratio of the azeotrope is: 1,1,1,3,3-pentafluoropropane / 1-chloro-3,3,3-trifluoropropene = 41.26 / 58.74, and the azeotrope / extractant = 1 / 5 - 10; the parameter settings of the extractive distillation column are as follows: the feeding speed is 6 m 3 / h, the reflux ratio is 1.0 m 3 / h - 1.5 m 3 / h, the top temperature of the tower is 40°C to 60°C, the bottom temperature of the tower is 100°C - 110°C, and the top pressure of the tower is 0.09 MPa - 0.11 MPa; the parameter settings of the extractant recovery column are as follows: the reflux ratio is 1.5 m 3 / h - 2.0 m 3 / h, the top temperature of the tower is 30°C to 40°C, the bottom temperature of the tower is 110°C - 120°C, and the top pressure of the tower is 0.10 MPa - 0.15 MPa; the parameter settings of the remaining tower equipment are set according to the parameter requirements in the invention content. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.951% and 1,1,1,3,3-pentafluoropropane with a purity of 99.914% are obtained. Example

[0039] A mixture with a molar ratio of acetonitrile:furfural:DMF = 1.2:1:1.2 is used as the extractant. The mass fraction ratio of the azeotrope is: 1,1,1,3,3-pentafluoropropane / 1-chloro-3,3,3-trifluoropropene = 41.26 / 58.74, and the azeotrope / extractant = 1 / 5 - 10; the parameter settings of the extractive distillation column are as follows: the feeding speed is 6 m 3 / h, the reflux ratio is 1.0 m 3 / h - 1.5 m 3 / h, the top temperature of the tower is 40°C to 60°C, the bottom temperature of the tower is 100°C - 110°C, and the top pressure of the tower is 0.09 MPa - 0.11 MPa; the parameter settings of the extractant recovery column are as follows: the reflux ratio is 1.5 m 3 / h - 2.0 m 3 / h, the top temperature of the tower is 30°C to 40°C, the bottom temperature of the tower is 110°C - 120°C, and the top pressure of the tower is 0.10 MPa - 0.15 MPa; the settings of the remaining tower parameters are set according to the parameter requirements in the invention content. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.962% and 1,1,1,3,3-pentafluoropropane with a purity of 99.921% are obtained.

[0040] Comparative Example 1

[0041] The process and material ratio are the same as those in Example 7, except that a mixture with a molar ratio of acetonitrile:furfural = 1.2:1 is used as the extractant. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.763% and 1,1,1,3,3-pentafluoropropane with a purity of 99.122% are obtained.

[0042] Comparative Example 2

[0043] The process and material ratio are the same as those in Example 7, except that acetonitrile is used as the extractant. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.629% and 1,1,1,3,3-pentafluoropropane with a purity of 94.331% are obtained.

[0044] As described above, it is only the preferred embodiment of the present invention, and it is not a limitation of the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution content of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for separating azeotropes, characterized in that: a. introducing an azeotrope of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane and an extractant into an extractive distillation tower (1), obtaining 1-chloro-3,3,3-trifluoropropene at the top of the extractive distillation tower (1) and obtaining a mixture of 1,1,1,3,3-pentafluoropropane and the extractant at the bottom of the tower; b. introducing the mixture of 1,1,1,3,3-pentafluoropropane and the extractant obtained in the bottom of the tower in step 1 into an extractant recovery tower (2), separating 1,1,1,3,3-pentafluoropropane at the top of the extractant recovery tower (2), obtaining the extractant in the bottom of the tower, and returning the extractant to the extractive distillation tower (1); The purity of 1-chloro-3,3,3-trifluoropropene obtained from the top of the extractive distillation tower (1) in step a is ≥99.9%; The purity of 1,1,1,3,3-pentafluoropropane obtained at the top of the extractant recovery tower (2) in step b is ≥99.9%; The extractant is a mixed extractant of ethylene glycol, furfural and acetonitrile in a molar ratio of 0.8-1.2:1:0.8-1.2 or a mixed extractant of ethylene glycol, furfural and DMF in a molar ratio of 0.8-1.2:1:0.8-1.2; The azeotropic composition of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane contains 40.0wt% to 80.0wt% of 1,1,1,3,3-pentafluoropropane and 20.0wt% to 60.0wt% of 1-chloro-3,3,3-trifluoropropene.

2. A method for separating an azeotrope according to claim 1, characterized in that: The 1-chloro-3,3,3-trifluoropropene obtained at the top of the extractive distillation tower (1) is introduced into a 1-chloro-3,3,3-trifluoropropene light impurity distillation tower (3) to remove light impurities, and then introduced into a 1-chloro-3,3,3-trifluoropropene heavy impurity distillation tower (4) to remove heavy impurities, and 1-chloro-3,3,3-trifluoropropene is obtained at the top of the 1-chloro-3,3,3-trifluoropropene heavy impurity distillation tower (4); The 1,1,1,3,3-pentafluoropropane obtained at the top of the extractant recovery tower (2) is introduced into a 1,1,1,3,3-pentafluoropropane light impurity distillation tower (5) to remove light impurities, and then introduced into a 1,1,1,3,3-pentafluoropropane heavy impurity distillation tower (6) to remove heavy impurities, and 1,1,1,3,3-pentafluoropropane is obtained at the top of the 1,1,1,3,3-pentafluoropropane heavy impurity distillation tower (6).

3. The method for separating an azeotrope according to claim 1, characterized in that: The azeotrope of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane is obtained by reacting 1,1,1,3,3-pentachloropropane and HF.

4. The method for separating an azeotrope according to claim 1, characterized in that: The mass ratio of the extractant to the azeotrope of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentafluoropropane is 1-15:

1.

5. The method for separating an azeotrope according to claim 1, wherein: The operating conditions of the extractive distillation tower (1) are as follows: operating pressure of 0.05MPa-1.2MPa, tower top temperature of 30°C-70°C, tower bottom temperature of 80°C-120°C, and reflux ratio of 0.5-5; the operating conditions of the extractant recovery tower are as follows: operating pressure of 0.05MPa-1.0MPa, tower top temperature of 20°C-80°C, tower bottom temperature of 80°C-130°C, and reflux ratio of 5-15.

6. The method for separating an azeotrope according to claim 2, characterized in that: The operating conditions of the light impurity distillation tower (3) for 1-chloro-3,3,3-trifluoropropene are as follows: operating pressure of 0.02MPa~1.0MPa, tower top temperature of 10°C~30°C, tower bottom temperature of 30°C~70°C, and reflux ratio of 5~15; the operating conditions of the heavy impurity distillation tower (4) for 1-chloro-3,3,3-trifluoropropene are as follows: operating pressure of 0.02MPa~1.2MPa, tower top temperature of 30°C~70°C, tower bottom temperature of 70°C~100°C, and reflux ratio of 0.5~3.

7. The method for separating an azeotrope according to claim 2, characterized in that: The operating conditions of the light impurity distillation tower (5) for 1,1,1,3,3-pentafluoropropane are as follows: the operating pressure is 0.02MPa~1.0MPa, the tower top temperature is 10°C~30°C, the tower bottom temperature is 30°C~70°C, and the reflux ratio is 5~15; the operating conditions of the heavy impurity distillation tower (6) for 1,1,1,3,3-pentafluoropropane are as follows: the operating pressure is 0.02MPa~1.2MPa, the tower top temperature is 30°C~70°C, the tower bottom temperature is 70°C~100°C, and the reflux ratio is 0.5~3.

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