Separation method of azeotrope

Abstract

The invention discloses an azeotrope separation method, and belongs to the technical field of chemical engineering. The separation and purification method comprises the following steps: adding an extracting agent into an azeotrope of 1-chloro-3, 3, 3-trifluoropropene and 1, 1, 1, 3, 3-pentachloropropane, and extracting the azeotrope of 1-chloro-3, 3, 3-trifluoropropene and 1, 1, 1, 3, 3-pentachloropropane; wherein the extracting agent is selected from one or more of ethylene glycol, furfural, acetonitrile and DMF (Dimethyl Formamide). According to the separation method disclosed by the invention, the azeotropic equilibrium between the 1-chloro-3, 3, 3-trifluoropropene and the 1, 1, 1, 3, 3-pentachloropropane is destroyed by adding the efficient, cheap and easily available extraction agent, so that the effective separation of the azeotrope of the 1-chloro-3, 3, 3-trifluoropropene and the 1, 1, 1, 3, 3-pentachloropropane is realized. And introducing the separated 1-chloro-3, 3, 3-trifluoropropene and 1, 1, 1, 3, 3-pentachloropropane into a subsequent rectification system for rectification and purification, and finally obtaining two products of high-purity 1-chloro-3, 3, 3-trifluoropropene and 1, 1, 1, 3, 3-pentachloropropane.

Description

Technical Field

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

[0002] Chlorofluorocarbons (CFCs) and other halogenated compounds can lead to the depletion of the earth's ozone layer, while their substitutes, hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs), can lead to global warming. Hydrofluoroolefins (HFOs) and hydrochlorofluoroolefins (HCFOs) do not have the above problems and are being promoted for use as refrigerants, cleaning agents, foaming agents, aerosol sprays, 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 the production of 1,1,1,3,3-pentachloropropane. It is also one of the main candidates for replacing 1,1,1,3,3-pentachloropropane in foaming applications, and has the potential to be used as a refrigerant, solvent or degreasing agent.

[0003] In industry, hydrogen fluoride and 1,1,1,3,3-pentachloropropane are generally used as raw materials to synthesize 1-chloro-3,3,3-trifluoropropene through gas phase fluorination or liquid phase fluorination. This method has the problem of over-fluorination of the raw material 1,1,1,3,3-pentachloropropane to produce the by-product 1,1,1,3,3-pentachloropropane. In addition, because the boiling points of 1-chloro-3,3,3-trifluoropropene and the by-product 1,1,1,3,3-pentachloropropane are similar (the boiling point of 1,1,1,3,3-pentachloropropane is 15.3°C, and the boiling point of 1-chloro-3,3,3-trifluoropropene is 18.7°C), and the relative volatility of these two compounds is close to 1, resulting in the existence of azeotropic phenomenon. The presence of azeotropes makes it difficult to separate 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentachloropropane by conventional distillation methods, making it difficult to obtain high-purity 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentachloropropane.

[0004] Patent application CN202110955520.8 of Shandong Huaan 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 high-concentration 1-chloro-3,3,3-trifluoropropene and a low-concentration 1,1,1,3,3-pentafluoropropane mixture are added to an extractant for extraction; wherein the extractant is selected from one or more of acetone, cyclopentane, n-pentane, and carbon tetrachloride. The method achieves the separation of 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 of more than 90wt%.

[0005] However, the separation of the mixture of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentachloropropane still has the following problems: 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentachloropropane will form azeotropes in certain specific proportions, and no method that can solve this problem has been found in the existing published patents; when the specific gravity of 1,1,1,3,3-pentachloropropane in the mixture of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentachloropropane is higher than that of 1-chloro-3,3,3-trifluoropropene, 1-chloro-3,3,3-trifluoropropene is difficult to separate and purify. Summary of the invention

[0006] The invention provides a method for separating and purifying azeotropes of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentachloropropane. The method solves the problem that it is difficult to break the azeotropic equilibrium of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentachloropropane in the prior art by adding an efficient, inexpensive and readily available extractant into the system, and further obtains high-purity 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentachloropropane by regulating subsequent distillation parameters.

[0007] The technical scheme of the present invention is as follows: adding 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentachloropropane azeotrope 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 azeotropes, comprising the following contents:

[0009] a. introducing azeotrope of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentachloropropane and an extractant into an extractive distillation tower, obtaining 1-chloro-3,3,3-trifluoropropene at the top of the extractive distillation tower and obtaining a mixture of 1,1,1,3,3-pentachloropropane and the extractant in the bottom of the tower;

[0010] b. introducing the mixture of 1,1,1,3,3-pentachloropropane and the extractant obtained in the bottom of the tower in step a into an extractant recovery tower, separating 1,1,1,3,3-pentachloropropane from the top of the extractive distillation tower, obtaining the extractant in the bottom of the tower, and returning the extractant to the extractive distillation tower;

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

[0012] The purity of 1,1,1,3,3-pentachloropropane obtained from the top of the extractive distillation tower 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, the 1-chloro-3,3,3-trifluoropropene obtained at the top of the extractive distillation tower is introduced into a light impurity distillation tower for removing 1-chloro-3,3,3-trifluoropropene, and after the light impurities are removed, the 1-chloro-3,3,3-trifluoropropene is introduced into a heavy impurity distillation tower for removing the heavy impurities, and 1-chloro-3,3,3-trifluoropropene is obtained at the top of the heavy impurity distillation tower for 1-chloro-3,3,3-trifluoropropene;

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

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

[0017] Specifically, the azeotrope of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentachloropropane is obtained by reacting 1,1,1,3,3-pentachloropropane 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-pentachloropropane is 1-15:1.

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

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

[0021] Specifically, the operating conditions of the light impurity distillation tower for 1,1,1,3,3-pentachloropropane are as follows: the operating pressure is 0.02MPa~1.0MPa, the tower top temperature is 10℃~30℃, the tower bottom temperature is 30℃~70℃, and the reflux ratio is 5~15; the operating conditions of the heavy impurity distillation tower for 1,1,1,3,3-pentachloropropane are as follows: the operating pressure is 0.02MPa~1.2MPa, the tower top temperature is 30℃~70℃, the tower bottom temperature is 70℃~100℃, and the reflux ratio is 0.5~3.

[0022] Specifically, the extractive distillation tower, the extractant recovery tower, the light impurity distillation tower for 1-chloro-3,3,3-trifluoropropene, the heavy impurity distillation tower for 1-chloro-3,3,3-trifluoropropene, the light impurity distillation tower for 1,1,1,3,3-pentachloropropane and the heavy impurity distillation tower for 1,1,1,3,3-pentachloropropane have no special requirements on the tower form, and common plate towers, sieve plate towers or packed towers can meet the required process requirements.

[0023] Compared with the prior art, the separation method of the azeotrope described in the present invention has the following advantages: the present invention adopts the method of combining extractive distillation with conventional distillation to achieve separation and purification based on the similar boiling points of 1,1,1,3,3-pentachloropropane and 1-chloro-3,3,3-trifluoropropene (the boiling point of 1,1,1,3,3-pentachloropropane 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, and there is a characteristic of azeotropic phenomenon. The method can obtain two high-purity products of 1-chloro-3,3,3-trifluoropropene with a purity of ≥99.9% and 1,1,1,3,3-pentachloropropane with a purity of ≥99.9%. At the same time, after the extractant is separated from 1,1,1,3,3-pentachloropropane in the extractant recovery tower, no other treatment is required, and it can be directly returned to the extractive distillation tower for recycling.

[0024] The method can successfully break the difficult-to-break azeotropic equilibrium between 1,1,1,3,3-pentachloropropane and 1-chloro-3,3,3-trifluoropropene, and can reduce the generation of other impurities and by-products that are difficult to handle. It has the characteristics of simple and stable operation, low cost, and environmental friendliness. In addition, the method can obtain two high-purity products: HCFO-1233zd with a purity of ≥99.9% and 1,1,1,3,3-pentachloropropane with a purity of ≥99.9%. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the process of the present invention.

[0026] In the figure, 1, extractive distillation tower 2, extractant recovery tower 3, light impurity distillation tower for 1-chloro-3,3,3-trifluoropropene 4, heavy impurity distillation tower for 1-chloro-3,3,3-trifluoropropene 5, light impurity distillation tower for 1,1,1,3,3-pentachloropropane 6, heavy impurity distillation tower for 1,1,1,3,3-pentachloropropane. DETAILED DESCRIPTION

[0027] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments. Figure 1 As shown, in order to more clearly illustrate the overall concept of the present application, a detailed description is given below in an exemplary manner in conjunction with the accompanying drawings.

[0028] Figure 1 In the accompanying drawings, 1 is an extractive distillation tower, 2 is an extractant recovery tower, 3 is a light impurity distillation tower for 1-chloro-3,3,3-trifluoropropene, 4 is a heavy impurity distillation tower for 1-chloro-3,3,3-trifluoropropene, 5 is a light impurity distillation tower for 1,1,1,3,3-pentachloropropane, 6 is a heavy impurity distillation tower for 1,1,1,3,3-pentachloropropane, A is an azeotrope of 1-chloro-3,3,3-trifluoropropene and 1,1,1,3,3-pentachloropropane, B is a mixture of 1,1,1,3,3-pentachloropropane and an extractant in the bottom of the extractive distillation tower 1, C is an extractant in the bottom of the extractant recovery tower 2, and D is a 1-chloro-3,3,3-trifluoropropene obtained from the top of the extractive distillation tower 1. -3,3,3-trifluoropropene, E is 1,1,1,3,3-pentachloropropane at the top of extractant recovery tower 2, F is 1,1,1,3,3-pentachloropropane obtained in the bottom of 1,1,1,3,3-pentachloropropane light impurities rectification tower 5, G is high-purity 1,1,1,3,3-pentachloropropane obtained at the top of 1,1,1,3,3-pentachloropropane heavy impurities rectification tower 6, H is 1-chloro-3,3,3-trifluoropropene obtained in the bottom of 1-chloro-3,3,3-trifluoropropene light impurities rectification tower 3, and I is high-purity 1-chloro-3,3,3-trifluoropropene obtained at the top of 1-chloro-3,3,3-trifluoropropene heavy impurities rectification tower 4.

[0029] Example 1

[0030] A mixture of ethylene glycol: furfural: acetonitrile = 1:1:1 molar ratio was used as the extractant, the mass fraction ratio of the azeotrope was: 1,1,1,3,3-pentachloropropane / 1-chloro-3,3,3-trifluoropropene = 59.47 / 40.53, azeotrope / extractant = 1 / 5~10; the parameters of the extractive distillation tower were set as follows: feed rate 6m 3 / h, reflux volume 1.0-1.5m 3 / h, tower top temperature 40℃~60℃, tower bottom temperature 90℃~100℃, tower top pressure 0.09MPa~0.11MPa; the parameters of the extractant recovery tower are set as: reflux flow 1.5m 3 / h-2.0m 3 / h, tower top temperature 30℃~40℃, tower bottom temperature 100℃-110℃, tower top pressure 0.10MPa-0.15MPa; other tower parameters are set according to the parameter requirements in the content of the invention. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.917% and 1,1,1,3,3-pentachloropropane with a purity of 99.914% are obtained.

[0031] Example 2

[0032] A mixture of ethylene glycol: furfural: acetonitrile = 1:1:1 molar ratio was used as the extractant, the mass fraction ratio of the azeotrope was: 1,1,1,3,3-pentachloropropane / 1-chloro-3,3,3-trifluoropropene = 59.47 / 40.53, azeotrope / extractant = 1 / 10~15; the parameters of the extractive distillation tower were set as follows: feed rate 6m 3 / h, reflux volume 1.0m 3 / h-1.5m 3 / h, tower top temperature 40℃~60℃, tower bottom temperature 90℃~100℃, tower top pressure 0.09MPa~0.11MPa; the parameters of the extractant recovery tower are set as: reflux flow 1.5m 3 / h-2.0m 3 / h, tower top temperature 30℃~40℃, tower bottom temperature 100℃-110℃, tower top pressure 0.10MPa-0.15MPa; other tower parameters are set according to the parameter requirements in the content of the invention. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.939% and 1,1,1,3,3-pentachloropropane with a purity of 99.921% are obtained.

[0033] Example 3

[0034] A mixture of acetonitrile: furfural: DMF = 1:1:1 molar ratio was used as the extractant, the mass fraction ratio of the azeotrope was: 1,1,1,3,3-pentachloropropane / 1-chloro-3,3,3-trifluoropropene = 58 / 42, azeotrope / extractant = 1 / 1~5; the parameters of the extractive distillation tower were set as follows: feed rate 6m 3 / h, reflux volume 1.0m 3 / h-1.5m 3 / h, tower top temperature 40℃~60℃, tower bottom temperature 100℃-110℃, tower top pressure 0.09MPa-0.11MPa; the parameters of the extractant recovery tower are set as: reflux flow 1.5m 3 / h-2.0m 3 / h, tower top temperature 30℃~40℃, tower bottom temperature 110℃-120℃, tower top pressure 0.10MPa-0.15MPa; other tower parameters are set according to the parameter requirements in the content of the invention. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.923% and 1,1,1,3,3-pentachloropropane with a purity of 99.934% are obtained.

[0035] Example 4

[0036] A mixture of acetonitrile: furfural: DMF = 1:1:1 molar ratio was used as the extractant, the mass fraction ratio of the azeotrope was: 1,1,1,3,3-pentachloropropane / 1-chloro-3,3,3-trifluoropropene = 58 / 42, azeotrope / extractant = 1 / 5~10; the parameters of the extractive distillation tower were set as follows: feed rate 6m 3 / h, reflux volume 1.0m 3 / h-1.5m 3 / h, tower top temperature 40℃~60℃, tower bottom temperature 100℃-110℃, tower top pressure 0.09MPa-0.11MPa; the parameters of the extractant recovery tower are set as: reflux flow 1.5m 3 / h-2.0m 3 / h, tower top temperature 30℃~40℃, tower bottom temperature 110℃-120℃, tower top pressure 0.10MPa-0.15MPa; other tower parameters are set according to the parameter requirements in the content of the invention. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.945% and 1,1,1,3,3-pentachloropropane with a purity of 99.957% are obtained.

[0037] Example 5

[0038] A mixture of acetonitrile: furfural: DMF = 1:1:1 molar ratio was used as the extractant, the mass fraction ratio of the azeotrope was: 1,1,1,3,3-pentachloropropane / 1-chloro-3,3,3-trifluoropropene = 58 / 42, azeotrope / extractant = 1 / 10~15; the parameters of the extractive distillation tower were set as follows: feed rate 6m 3 / h, reflux volume 1.0m 3 / h-1.5m 3 / h, tower top temperature 40℃~60℃, tower bottom temperature 100℃-110℃, tower top pressure 0.09MPa-0.11MPa; the parameters of the extractant recovery tower are set as: reflux flow 1.5m 3 / h-2.0m 3 / h, tower top temperature 30℃~40℃, tower bottom temperature 110℃-120℃, tower top pressure 0.10MPa-0.15MPa; other tower parameters are set according to the parameter requirements in the content of the invention. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.963% and 1,1,1,3,3-pentachloropropane with a purity of 99.972% are obtained.

[0039] Example 6

[0040] A mixture of acetonitrile: furfural: DMF = 1:1:1 molar ratio was used as the extractant, the mass fraction ratio of the azeotrope was: 1,1,1,3,3-pentachloropropane / 1-chloro-3,3,3-trifluoropropene = 81.34 / 18.66, azeotrope / extractant = 1 / 5~10; the parameters of the extractive distillation tower were set as follows: feed rate 6m 3 / h, reflux volume 1.0m 3 / h-1.5m 3 / h, tower top temperature 40℃~60℃, tower bottom temperature 100℃-110℃, tower top pressure 0.09MPa-0.11MPa; the parameters of the extractant recovery tower are set as: reflux flow 1.5m 3 / h-2.0m 3 / h, tower top temperature 30℃~40℃, tower bottom temperature 110℃-120℃, tower top pressure 0.10MPa-0.15MPa; other tower parameters are set according to the parameter requirements in the content of the invention. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.951% and 1,1,1,3,3-pentachloropropane with a purity of 99.983% are obtained.

[0041] Example 7

[0042] A mixture of acetonitrile: furfural: DMF = 1:1:1 molar ratio was used as the extractant, the mass fraction ratio of the azeotrope was: 1,1,1,3,3-pentachloropropane / 1-chloro-3,3,3-trifluoropropene = 41.26 / 58.74, azeotrope / extractant = 1 / 5~10; the parameters of the extractive distillation tower were set as follows: feed rate 6m 3 / h, reflux volume 1.0m 3 / h-1.5m 3 / h, tower top temperature 40℃~60℃, tower bottom temperature 100℃-110℃, tower top pressure 0.09MPa-0.11MPa; the parameters of the extractant recovery tower are set as: reflux flow 1.5m 3 / h-2.0m 3 / h, tower top temperature 30℃~40℃, tower bottom temperature 110℃-120℃, tower top pressure 0.10MPa-0.15MPa; other tower parameters are set according to the parameter requirements in the content of the invention. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.970% and 1,1,1,3,3-pentachloropropane with a purity of 99.954% are obtained.

[0043] Example 8

[0044] A mixture of acetonitrile: furfural: DMF = 0.8: 1: 0.8 molar ratio was used as the extractant, the mass fraction ratio of the azeotrope was: 1,1,1,3,3-pentachloropropane / 1-chloro-3,3,3-trifluoropropene = 41.26 / 58.74, azeotrope / extractant = 1 / 5~10; the parameters of the extractive distillation tower were set as follows: feed rate 6m 3 / h, reflux volume 1.0m 3 / h-1.5m 3 / h, tower top temperature 40℃~60℃, tower bottom temperature 100℃-110℃, tower top pressure 0.09MPa-0.11MPa; the parameters of the extractant recovery tower are set as: reflux flow 1.5m 3 / h-2.0m 3 / h, tower top temperature 30℃~40℃, tower bottom temperature 110℃-120℃, tower top pressure 0.10MPa-0.15MPa; other tower parameters are set according to the parameter requirements in the content of the invention. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.968% and 1,1,1,3,3-pentachloropropane with a purity of 99.926% are obtained.

[0045] Example 9

[0046] A mixture of acetonitrile: furfural: DMF = 1.2: 1: 1.2 molar ratio was used as the extractant, the mass fraction ratio of the azeotrope was: 1,1,1,3,3-pentachloropropane / 1-chloro-3,3,3-trifluoropropene = 41.26 / 58.74, azeotrope / extractant = 1 / 5~10; the parameters of the extractive distillation tower were set as follows: feed rate 6m 3 / h, reflux volume 1.0m 3 / h-1.5m 3 / h, tower top temperature 40℃~60℃, tower bottom temperature 100℃-110℃, tower top pressure 0.09MPa-0.11MPa; the parameters of the extractant recovery tower are set as: reflux flow 1.5m 3 / h-2.0m 3 / h, tower top temperature 30℃~40℃, tower bottom temperature 110℃-120℃, tower top pressure 0.10MPa-0.15MPa; other tower parameters are set according to the parameter requirements in the content of the invention. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.916% and 1,1,1,3,3-pentachloropropane with a purity of 99.935% are obtained.

[0047] Example 10

[0048] A mixture of ethylene glycol: furfural: acetonitrile = 0.8:1:0.8 molar ratio was used as the extractant, the mass fraction ratio of the azeotrope was: 1,1,1,3,3-pentachloropropane / 1-chloro-3,3,3-trifluoropropene = 41.26 / 58.74, azeotrope / extractant = 1 / 5~10; the parameters of the extractive distillation tower were set as follows: feed rate 6m 3 / h, reflux volume 1.0m 3 / h-1.5m 3 / h, tower top temperature 40℃~60℃, tower bottom temperature 100℃-110℃, tower top pressure 0.09MPa-0.11MPa; the parameters of the extractant recovery tower are set as: reflux flow 1.5m 3 / h-2.0m 3 / h, tower top temperature 30℃~40℃, tower bottom temperature 110℃-120℃, tower top pressure 0.10MPa-0.15MPa; other tower parameters are set according to the parameter requirements in the content of the invention. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.951% and 1,1,1,3,3-pentachloropropane with a purity of 99.914% are obtained.

[0049] Embodiment 11

[0050] A mixture of acetonitrile: furfural: DMF = 1.2: 1: 1.2 molar ratio was used as the extractant, the mass fraction ratio of the azeotrope was: 1,1,1,3,3-pentachloropropane / 1-chloro-3,3,3-trifluoropropene = 41.26 / 58.74, azeotrope / extractant = 1 / 5~10; the parameters of the extractive distillation tower were set as follows: feed rate 6m 3 / h, reflux volume 1.0m 3 / h-1.5m 3 / h, tower top temperature 40℃~60℃, tower bottom temperature 100℃-110℃, tower top pressure 0.09MPa-0.11MPa; the parameters of the extractant recovery tower are set as: reflux flow 1.5m 3 / h-2.0m 3 / h, tower top temperature 30℃~40℃, tower bottom temperature 110℃-120℃, tower top pressure 0.10MPa-0.15MPa; other tower parameters are set according to the parameter requirements in the content of the invention. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.962% and 1,1,1,3,3-pentachloropropane with a purity of 99.921% are obtained.

[0051] Comparative Example 1

[0052] The process and material ratio are the same as those in Example 7, except that a mixture of acetonitrile:furfural in a molar ratio of 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-pentachloropropane with a purity of 99.122% are obtained.

[0053] Comparative Example 2

[0054] The process and material ratio were the same as those in Example 7, except that acetonitrile was used as the extractant. Finally, 1-chloro-3,3,3-trifluoropropene with a purity of 99.629% and 1,1,1,3,3-pentachloropropane with a purity of 94.331% were obtained.

[0055] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to 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-pentachloropropane 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-pentachloropropane and the extractant at the bottom of the tower; b. introducing the mixture of 1,1,1,3,3-pentachloropropane and the extractant obtained in the bottom of the tower in step a into an extractant recovery tower (2), separating 1,1,1,3,3-pentachloropropane 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-pentachloropropane 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.

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-pentachloropropane obtained at the top of the extractant recovery tower (2) is introduced into a 1,1,1,3,3-pentachloropropane light impurity distillation tower (5) to remove light impurities, and then introduced into a 1,1,1,3,3-pentachloropropane heavy impurity distillation tower (6) to remove heavy impurities, and 1,1,1,3,3-pentachloropropane is obtained at the top of the 1,1,1,3,3-pentachloropropane heavy impurity distillation tower (6).

3. A 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-pentachloropropane contains 40.0wt% to 80.0wt% of 1,1,1,3,3-pentachloropropane and 20.0wt% to 60.0wt% of 1-chloro-3,3,3-trifluoropropene.

4. 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-pentachloropropane is obtained by reacting 1,1,1,3,3-pentachloropropane and HF.

5. 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-pentachloropropane is 1-15:

1.

6. 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.

7. 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.

8. 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-pentachloropropane 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 (6) for 1,1,1,3,3-pentachloropropane 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.

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