Preparation method for synthesizing 3, 3, 3-trifluoropropene with assistance of organic amine

Abstract

The invention discloses a preparation method for synthesizing 3, 3, 3-trifluoropropene under the assistance of organic amine, which comprises the following steps: by taking 1, 1, 1, 3-tetrachloropropane and hydrogen fluoride as raw materials, metal chloride as a catalyst and organic amine as a cocatalyst, carrying out one-step liquid phase reaction to synthesize the 3, 3, 3-trifluoropropene; the molar ratio of 1, 1, 1, 3-tetrachloropropane to hydrogen fluoride is (1: 1)-(1: 100), the reaction temperature is 50-200 DEG C, the reaction pressure is 0-3Mpa, and the reaction time is 0.25-7h. The method disclosed by the invention is simple in process route, few in three wastes and green and environment-friendly; the catalyst has low requirements on equipment, is cheap and easy to obtain and can be recycled; under the condition of organic amine assisted catalysis, the catalyst has the advantages of high conversion rate and high selectivity.

Description

Technical Field

[0001] This application relates to the technical field of hydrofluoroolefin synthesis, and specifically to a preparation method for the organic amine-assisted synthesis of 3,3,3-trifluoropropene. Background Art

[0002] 3,3,3-Trifluoropropene is a new type of environmentally friendly refrigerant with an extremely low global warming potential value, GWP = 4, and is considered to be one of the effective alternatives to the third-generation refrigerants. At the same time, 3,3,3-trifluoropropene is also a hydrofluoroolefin with extremely high added value and is an important monomer and intermediate for the synthesis of fluorine-containing polymers, fluorine-containing fine chemicals, pesticides, and pharmaceuticals. The fluorosilicone rubber prepared from this monomer has been widely used in high-tech fields such as aerospace and automobiles due to its characteristics of resistance to high and low temperatures and corrosion resistance. In response to the country's energy conservation and emission reduction policies, with the increasing demand for new energy vehicles, the demand for 3,3,3-trifluoropropene has increased rapidly. Therefore, it is necessary to develop a green, environmentally friendly, and simple process for the preparation of 3,3,3-trifluoropropene.

[0003] At present, there are many studies on the synthesis of 3,3,3-trifluoropropene at home and abroad, mainly including the preparation by liquid-gas two-step reaction, one-step gas-phase reaction, and one-step liquid-phase reaction.

[0004] European Patent EP3325436B1 discloses a method for preparing 1-chloro-3,3,3-trifluoropropane by liquid-phase reaction using 1,1,1,3-tetrachloropropane and hydrogen fluoride as raw materials, and then performing gas-phase reaction to remove hydrogen chloride to obtain 3,3,3-trifluoropropene. However, this method has relatively cumbersome process steps and generates a large amount of three wastes during the preparation process.

[0005] US Patent US2889379A discloses a method for preparing 3,3,3-trifluoropropene by one-step gas-phase fluorination of halogenated hydrocarbons, such as tetrachloropropane, under high-temperature conditions using a fluorinated Cr2O3 catalyst. However, under such high-temperature conditions, the catalyst is extremely prone to carbon deposition and deactivation, resulting in a decrease in conversion rate. Therefore, it is difficult to achieve large-scale industrialization.

[0006] US Patent US2787646 discloses a method for synthesizing 3,3,3-trifluoropropene by one-step liquid-phase fluorination of 1,3,3-trichloropropene with hydrofluoric acid using a composite catalyst of SbF3 and SbF3Cl2. However, this catalyst has strong corrosiveness, high requirements for equipment, and the catalyst components are prone to change during the reaction, resulting in a decrease in its selectivity.

[0007] Chinese Patent CN103965011A discloses a method for preparing 3,3,3-trifluoropropene by a one-step liquid-phase reaction using 1,1,1,3-tetrachloropropane and hydrogen fluoride as raw materials under the catalysis of ionic liquid. However, the preparation method of ionic liquid is relatively complex, and it is expensive when purchased separately, resulting in high industrialization costs.

[0008] In summary, it is urgent to develop a synthesis technology for 3,3,3-trifluoropropene that is simple in process, easy for industrial production, green and environmentally friendly, to improve its conversion rate and selectivity, and reduce production costs and the generation amount of three wastes.

[0009] Application Content

[0010] The purpose of this application is to provide a preparation method for synthesizing 3,3,3-trifluoropropene assisted by organic amine, which involves a preparation method for synthesizing 3,3,3-trifluoropropene by a one-step liquid-phase reaction using 1,1,1,3-tetrachloropropane and hydrogen fluoride as raw materials, metal chloride as a catalyst, and organic amine as a co-catalyst, so as to solve the problems in the above background technology.

[0011] To achieve the above purpose, this application provides the following technical solution: A preparation method for synthesizing 3,3,3-trifluoropropene assisted by organic amine, and the reaction route is:

[0012] It includes: using 1,1,1,3-tetrachloropropane and hydrogen fluoride as raw materials, metal chloride as a catalyst, and organic amine as a co-catalyst, and performing a one-step liquid-phase reaction in an anhydrous and oxygen-free autoclave to synthesize 3,3,3-trifluoropropene; the molar ratio of 1,1,1,3-tetrachloropropane to hydrogen fluoride is 1:1 - 1:100, the reaction temperature is 50°C - 200°C, the reaction pressure is 0 - 3 Mpa, and the reaction time is 0.25 h - 7 h.

[0013] Preferably, the metal chloride is FeCl 3 、CuCl 2 、AlCl 3 、BaCl 2 、MgCl 2 、SnCl 4 、TiCl 4 、NiCl 2 、CaCl 2 、CoCl 2 at least one of them.

[0014] Preferably, the organic amine is at least one of dimethylamine, triethylamine, tri-n-propylamine, N,N-dimethylformamide, pyridine, and aniline.

[0015] Preferably, the mass ratio of 1,1,1,3-tetrachloropropane to the metal chloride catalyst is 1:0.01 - 1:0.5.

[0016] Preferably, the molar ratio of 1,1,1,3 - tetrachloropropane to organic amine is 1:0.05 - 1:8.

[0017] Preferably, the molar ratio of 1,1,1,3 - tetrachloropropane to hydrogen fluoride is 1:10 - 1:60, the reaction temperature is 80°C - 130°C, the reaction pressure is 0.6 Mpa - 2 Mpa, and the reaction time is 0.5 h - 3 h.

[0018] Preferably, the mass ratio of 1,1,1,3 - tetrachloropropane to metal chloride catalyst is 1:0.05 - 1:0.25.

[0019] Preferably, the reaction temperature is 80°C - 130°C; the reaction pressure is 0.6 Mpa - 2 Mpa; the reaction time is 0.5 h - 3 h.

[0020] Compared with the prior art, the beneficial effects of this application are as follows:

[0021] 1. The preparation method of synthesizing 3,3,3 - trifluoropropene assisted by this organic amine uses a one - step liquid - phase reaction to obtain 3,3,3 - trifluoropropene, without the need for two - step reactions of first fluorination and then dehydrochlorination. The process is simple, the content of three wastes is less, and the route is green and environmentally friendly;

[0022] 2. The organic amine co - catalyst used in the preparation method of synthesizing 3,3,3 - trifluoropropene assisted by this organic amine complexes with hydrogen fluoride to form hydrogen fluoride amine salt during the reaction, which can effectively inhibit the further addition fluorination of olefin products, thereby improving its selectivity and prolonging the service life of the catalyst. Under the preferred conditions, the conversion rate of 1,1,1,3 - tetrachloropropane is 95.1%, and the selectivity of 3,3,3 - trifluoropropene is 97.8%;

[0023] 3. The metal chloride catalyst used in the preparation method of synthesizing 3,3,3 - trifluoropropene assisted by this organic amine has weak corrosion, low price and is easy to separate. Under the preferred conditions, its conversion rate can still reach 90.9% after repeated use, which can effectively reduce production costs and is suitable for large - scale industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is the gas chromatogram detection result of Example 7 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts shall fall within the protection scope of this application.

[0026] In the following embodiments of the present invention, raw materials and reagents are obtained through conventional commercial channels unless otherwise specified; component analysis involved in the reactions of the following embodiments is detected by gas chromatography, and the analytical instrument is Agilent GC-7890B gas chromatograph.

[0027] Example 1

[0028] In a 2 L stainless steel autoclave, 10 g of MgCl2 and 143 g of tri-n-propylamine were added. After nitrogen replacement, 1000 g of hydrogen fluoride and 182 g of 1,1,1,3-tetrachloropropane were introduced. The temperature inside the reaction kettle was controlled at 100 °C, and the system pressure was 1.3 - 1.5 Mpa. After holding the reaction for 2 h, the reaction was stopped, and the reaction product was discharged from the top of the distillation column and sequentially treated by washing with water and absorption with alkali washing. The reaction product was analyzed by gas chromatography. The conversion rate of 1,1,1,3-tetrachloropropane was 92.1%, and the selectivity of 3,3,3-trifluoropropene was 88.2%.

[0029] Examples 2 - 4

[0030] The synthesis processes of Examples 2 - 4 were similar to that of Example 1, except for the types of metal chloride catalysts. The types of metal chloride catalysts and reaction results are shown in Table 1.

[0031] Table 1:

[0032] Example Catalyst Conversion rate of 1,1,1,3 - tetrachloropropane (%) Selectivity of 3,3,3 - trifluoropropene (%) 2 <![CDATA[BaCl 2 > 87.8 95.1 3 <![CDATA[NiCl 2 > 90.5 90.2 4 <![CDATA[CaCl 2 > 62.8 75.6 .

[0033] Examples 5 - 8

[0034] The synthesis processes of Examples 5 - 8 were similar to that of Example 1, except for the types of organic amine co-catalysts. The types of organic amine co-catalysts and reaction results are shown in Table 2, and the gas chromatography results of Example 7 are as Figure 1 shown.

[0035] Table 2:

[0036]

[0037] Examples 9 - 12

[0038] The synthesis processes of Examples 9 - 12 were similar to that of Example 1, except for the reaction temperature. The reaction temperature and reaction results are shown in Table 3.

[0039] Table 3:

[0040] Example Reaction temperature (°C) Conversion rate of 1,1,1,3 - tetrachloropropane (%) Selectivity of 3,3,3 - trifluoropropene (%) 9 70 86.2 80.3 10 90 91.8 86.4 11 120 94.1 87.0 12 140 96.5 79.7 .

[0041] Examples 13 - 15

[0042] The synthesis processes of Examples 13 - 15 were similar to that of Example 1, except for the mass ratio of 1,1,1,3 - tetrachloropropane to the metal chloride catalyst and the molar ratio of 1,1,1,3 - tetrachloropropane to the cocatalyst. The mass ratio of 1,1,1,3 - tetrachloropropane to the metal chloride catalyst, the molar ratio of 1,1,1,3 - tetrachloropropane to the cocatalyst, and the reaction results are shown in Table 4.

[0043] Table 4:

[0044]

[0045] Example 16

[0046] The synthesis process of Example 16 was similar to that of Example 1, except that continuous feeding was carried out after the reaction ended, and the catalyst was subjected to 3 - cycle reactions, and the catalytic activity remained basically unchanged. The number of cycles and the reaction results are shown in Table 5.

[0047] Table 5:

[0048] Number of cycles Conversion rate of 1,1,1,3 - tetrachloropropane (%) Selectivity of 3,3,3 - trifluoropropene (%) 1 90.6 88.3 2 91.1 87.7 3 90.9 86.9 .

[0049] The methods used in the present invention are all conventional methods in the art unless otherwise specified.

[0050] The above - mentioned are only the preferred embodiments of the present invention, and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent transformations made to the above - mentioned embodiments according to the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing 3,3,3-trifluoropropene assisted by organic amine, characterized in that: include: With 1,1,1,3-tetrachloropropane and hydrogen fluoride as raw materials, metal chloride as catalyst and organic amine as co-catalyst, a one-step liquid phase reaction is carried out to synthesize 3,3,3-trifluoropropene; the molar ratio of 1,1,1,3-tetrachloropropane to hydrogen fluoride is 1:1-1:100, the reaction temperature is 50°C-200°C, the reaction pressure is 0-3Mpa and the reaction time is 0.25h-7h.

2. The method for preparing 3,3,3-trifluoropropene assisted by organic amine according to claim 1, characterized in that: The metal chloride is at least one of FeCl3, CuCl2, AlCl3, BaCl2, MgCl2, SnCl4, TiCl4, NiCl2, CaCl2, and CoCl2.

3. The method for preparing 3,3,3-trifluoropropene assisted by organic amine according to claim 1, characterized in that: The organic amine is at least one of dimethylamine, triethylamine, tri-n-propylamine, N,N-dimethylformamide, pyridine and aniline.

4. The method for preparing 3,3,3-trifluoropropene assisted by organic amine according to claim 1, characterized in that: The mass ratio of 1,1,1,3-tetrachloropropane to the metal chloride catalyst is 1:0.01-1:0.

5.

5. The method for preparing 3,3,3-trifluoropropene assisted by organic amine according to claim 1, characterized in that: The molar ratio of 1,1,1,3-tetrachloropropane to the organic amine is 1:0.05-1:

8.

6. The method for preparing 3,3,3-trifluoropropene assisted by organic amine according to claim 1, characterized in that: The molar ratio of 1,1,1,3-tetrachloropropane to hydrogen fluoride is 1:10-1:60, the reaction temperature is 80°C-130°C, the reaction pressure is 0.6Mpa-2Mpa, and the reaction time is 0.5h-3h.

7. The method for preparing 3,3,3-trifluoropropene assisted by organic amine according to claim 4, characterized in that: The mass ratio of 1,1,1,3-tetrachloropropane to the metal chloride catalyst is 1:0.05-1:0.

25.

8. The method for preparing 3,3,3-trifluoropropene assisted by organic amine according to claim 1, characterized in that: The reaction temperature is 80°C-130°C; the reaction pressure is 0.6Mpa-2Mpa; and the reaction time is 0.5h-3h.

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