Preparation method of 2, 3, 3, 3-tetrafluoropropene

Abstract

The invention discloses a preparation method of 2, 3, 3, 3-tetrafluoropropene, which comprises the following steps: by taking ethylene and carbon tetrachloride as raw materials, firstly preparing 1, 1, 1, 3-tetrachloropropane, then decomposing the 1, 1, 1, 3-tetrachloropropane to obtain 1, 1, 3-trichloropropene, reacting the 1, 1, 3-trichloropropene with hydrofluoric acid and chlorine to generate 1-chloro-3, 3, 3-trifluoropropene, and reacting the 1-chloro-3, 3, 3-trifluoropropene with hydrofluoric acid to prepare the 1, 1, 1, 3, 3-tetrafluoropropene. And finally, carrying out gas-phase dehydrochlorination on the 2, 2, 2-tetrafluoro-2-chloropropane to generate the 2, 3, 3, 3-tetrafluoropropene. According to the production route, raw materials are easy to obtain, the cost is low, unreacted raw materials can be recycled for continuous reaction, and emission of three wastes is little; the method is mild in liquid-phase fluorination condition and high in selectivity, and the yield of the intermediate product 2-chloro-1, 1, 1, 2-tetrafluoropropane is high.

Description

Technical Field

[0001] The invention belongs to the field of organic compound preparation, and particularly relates to a method for preparing 2,3,3,3-tetrafluoropropylene. Background Art

[0002] 2,3,3,3-Tetrafluoropropene (HFO-1234yf) possesses excellent physical, chemical, and environmental properties. It can be used as an effective refrigerant, foaming agent, fire extinguishing agent, heat transfer medium, propellant, gaseous dielectric, sterilant carrier, power cycle working fluid, polymer monomer, and pharmaceutical and pesticide intermediate. Its wide range of applications makes its production a significant economic benefit. HFO-1234yf, a representative fourth-generation refrigerant, boasts low global warming potential (GWP) and environmentally friendly properties, making it widely used in automotive air conditioning, commercial refrigeration, and other fields.

[0003] Currently, there are many methods for preparing 2,3,3,3-tetrafluoropropene, such as: (1) preparing 2,3,3,3-tetrafluoropropene using 1,1,2,3,3,3-hexafluoropropene (HFP) as a raw material. This method has a long preparation route, high raw material cost but low yield; (2) reacting 1,1,2,3-tetrachloropropene with a first fluorination reagent to produce a first intermediate composition of 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) and a first chlorine-containing by-product; reacting the first intermediate composition of the first chlorine-containing by-product with a second fluorination reagent to produce 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) and a second intermediate composition of a second chlorine-containing by-product; and then catalytically dehydrochlorinating at least a portion of the HCFC-244bb to produce 2,3,3,3-tetrafluoropropene. This route synthesizes 2,3,3,3-tetrafluoropropene in three steps. HCFO-1233xf is converted into HCFC-244bb in a liquid phase reactor. The third step, the saponification reaction, produces a lot of waste and has a low yield.

[0004] In summary, the existing technology for preparing 2,3,3,3-tetrafluoropropene has problems such as long preparation route, high raw material cost, and low yield. Summary of the Invention

[0005] The present invention aims to provide a method for preparing 2,3,3,3-tetrafluoropropene. In view of the defects in the prior art, ethylene and carbon tetrachloride are used as raw materials to first prepare 1,1,1,3-tetrachloropropane (HCC-250fb), then 1,1,1,3-tetrachloropropane is decomposed to obtain 1,1,3-trichloropropene (HCC-1240za), the 1,1,3-trichloropropene is reacted with hydrofluoric acid and chlorine to produce 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), the 2-chloro-3,3,3-trifluoropropene is reacted with hydrofluoric acid to prepare 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), and finally 2,3,3,3-tetrafluoropropene is produced by gas-phase dehydrochlorination.

[0006] In order to solve the above technical problems, the following technical solutions are adopted:

[0007] The preparation method of 2,3,3,3-tetrafluoropropene is characterized by comprising the following steps:

[0008] (1) In the presence of a catalyst and a co-catalyst, ethylene and carbon tetrachloride are reacted to prepare 1,1,1,3-tetrachloropropane at a reaction temperature of 80°C to 150°C, a reaction pressure of 0 to 3 MPa, and a reaction time of 2 to 10 hours. The reaction formula is as follows:

[0009] CH2=CH2+CCl4→CCl3CH2CH2Cl(HCC-250fb)

[0010] (2) In the presence of a catalyst, 1,1,1,3-tetrachloropropane obtained in step (1) is dehydrochlorinated to prepare 1,1,3-trichloropropene at a reaction temperature of 50° C. to 150° C. The reaction formula is as follows:

[0011] CCl3CH2CH2Cl→CCl2=CHCH2Cl(HCC-1240za)+HCl

[0012] (3) In the presence of a catalyst, the 1,1,3-trichloropropene obtained in step (2) is reacted with hydrofluoric acid in the presence of chlorine to prepare 2-chloro-3,3,3-trifluoropropene at a reaction temperature of 30 to 150° C. The reaction formula is as follows:

[0013] CCl2=CHCH2Cl+3HF+Cl2→CF3CCl=CH2(HCFO-1233xf)+4HCl

[0014] (4) In the presence of a catalyst, the 2-chloro-3,3,3-trifluoropropene obtained in step (3) is reacted with hydrofluoric acid to prepare 2-chloro-1,1,1,2-tetrafluoropropane at a reaction temperature of 30 to 150° C. The reaction formula is as follows:

[0015] CF3CCl=CH2+HF→CF3CFClCH3(HCFC-244bb)

[0016] (5) In the presence of a catalyst, the 2-chloro-1,1,1,2-tetrafluoropropane obtained in step (4) is dehydrochlorinated to prepare 2,3,3,3-tetrafluoropropene, according to the following reaction formula:

[0017] CF3CFClCH3→CF3CF=CH2(HFO-1234yf)+HCl

[0018] Preferably, the catalyst in step (1) is reduced iron powder.

[0019] Preferably, the co-catalyst in step (1) is a phosphate or phosphite, and one or more of tributyl phosphate, dibutyl phosphate, triethyl phosphate, trimethyl phosphite or tributyl phosphite is selected.

[0020] Preferably, the catalyst in step (2) is ferric chloride.

[0021] Preferably, the catalyst in step (3) is one or more of titanium tetrachloride, tin tetrachloride, antimony pentachloride or fluorosulfonic acid.

[0022] Preferably, the catalyst in step (4) is one or more of titanium tetrachloride, tin tetrachloride, antimony pentachloride or fluorosulfonic acid.

[0023] After optimization, the catalyst of step (5) is a gas phase reaction catalyst, and the reaction temperature is 200-450°C.

[0024] Preferably, the gas phase reaction catalyst is selected from one or more of activated carbon, Pd / C, Pt / C or metal halide-supported activated carbon.

[0025] The above technical solution has the following beneficial effects:

[0026] The present invention uses ethylene and carbon tetrachloride as raw materials to first prepare 1,1,1,3-tetrachloropropane (HCC-250fb), then decomposes 1,1,1,3-tetrachloropropane to obtain 1,1,3-trichloropropene (HCC-1240za), and then reacts the 1,1,3-trichloropropene with hydrofluoric acid and chlorine to generate 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf). 2-Chloro-3,3,3-trifluoropropene is reacted with hydrofluoric acid to prepare 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb).

[0027] The raw materials of this route are easily available and the cost is low. The unreacted raw materials can be recycled and reused for further reaction, and the discharge of three wastes is small. The liquid-phase fluorination conditions are mild, the selectivity is high, and the yield of the intermediate product 2-chloro-1,1,1,2-tetrafluoropropane is high. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below with reference to the following examples, but they do not limit the scope of the present invention.

[0029] Example 1

[0030] 2 kg of carbon tetrachloride, 20 g of reduced iron powder, and 20 g of tributyl phosphate were added to a 5 L nitrogen-purged reactor. Stirring was initiated and the reactor temperature was raised to 100°C. At the reaction temperature, ethylene was introduced into the reactor at a rate of 80 g / h. Cooling water was passed through the reactor to remove the reaction heat. 220 g of ethylene was introduced, and the reaction was terminated after 5 h. The liquid phase was sampled for GC-FID analysis. The reaction results are shown in the table below.

[0031]

[0032]

[0033] 250g of 1,1,1,3-tetrachloropropane and 0.1g of ferric chloride were added to a 500ml reactor. The reactor was stirred and the temperature was raised to 100°C. The reaction was terminated after 5 hours. After cooling to 30°C, the liquid phase was sampled and analyzed by GC-FID. The reaction results are shown in the table below. The main products of the reaction were 1,1,3-trichloropropene and 3,3,3-trichloropropene, with a selectivity of 93.43% for 1,1,3-trichloropropene and 6.57% for 3,3,3-trichloropropene.

[0034] The catalyst titanium tetrachloride was added to the reactor, and hydrofluoric acid and chlorine were introduced to react the obtained 1,1,3-trichloropropene to prepare 2-chloro-3,3,3-trifluoropropene. The reaction temperature was 90°C. The reaction results are shown in the following table.

[0035] Compound GC-FID area % 1,1,3-Trichloropropene <![CDATA[CCl2=CHCH2Cl]]> 2.03％ 2-Chloro-3,3,3-trifluoropropene <![CDATA[CF3CCl=CH2]]> 94.83％ 2-Chloro-1,1,1,2-tetrafluoropropane <![CDATA[CF3CFClCH3]]> 1.75％ 3-Chloro-1,1,1,2-tetrafluoropropane <![CDATA[CF3CHFCH2Cl]]> 0.03％ 2,3-Dichloro-1,1,1-trifluoropropane <![CDATA[CF3CHClCH2Cl]]> 0.01％ 1,1,1,2,3-pentafluoropropane <![CDATA[CF3CHFCH2F]]> 0.15％ Other unknown substances 1.20％

[0036] The catalyst, titanium tetrachloride, was added to the reactor and reacted with hydrofluoric acid. The reaction temperature was raised to 90°C. 2-Chloro-3,3,3-trifluoropropene and hydrofluoric acid were introduced into the reactor in a molar ratio of 1:1. The discharge pipe was adjusted with a valve. The gaseous material passed through a water scrubber and an alkaline scrubber. Samples were taken from the alkaline scrubber outlet for GC-FID analysis. The results are shown in the table below.

[0037]

[0038]

[0039] The prepared 2-chloro-1,1,1,2-tetrafluoropropane was introduced into a reactor filled with catalyst Pd / C at a space velocity of 100 h -1 The reaction temperature was 350°C, the reactor outlet was connected to a water scrubber and an alkali scrubber, and samples were taken from the alkali scrubber outlet for GC-FID measurement. The results are shown in the following table.

[0040] Compound GC-FID area % 2-Chloro-1,1,1,2-tetrafluoropropane <![CDATA[CF3CFClCH3]]> 1.03％ 2,3,3,3-tetrafluoropropene <![CDATA[CF3CF=CH2]]> 97.28％ 2-Chloro-3,3,3-trifluoropropene <![CDATA[CF3CCl=CH3]]> 0.23％ 3-Chloro-1,1,1,2-tetrafluoropropane <![CDATA[CF3CHFCH2Cl]]> 1.32％ Other unknown substances 0.14％

[0041] Example 2

[0042] 2 kg of carbon tetrachloride, 20 g of reduced iron powder, and 20 g of tributyl phosphate were added to a 5 L nitrogen-purged reactor. Stirring was initiated and the reactor temperature was raised to 120°C. At the reaction temperature, ethylene was introduced into the reactor at a rate of 80 g / h. Cooling water was passed through the reactor to remove the reaction heat. 220 g of ethylene was introduced, and the reaction was terminated after 5 h. The liquid phase was sampled for GC-FID analysis. The reaction results are shown in the table below.

[0043]

[0044]

[0045] 250g of 1,1,1,3-tetrachloropropane and 0.1g of ferric chloride were added to a 500ml reactor. The reactor was stirred and the temperature was raised to 150°C. The reaction was terminated after 5 hours. After cooling to 30°C, the liquid phase was sampled and analyzed by GC-FID. The reaction results are shown in the table below. The main products of the reaction were 1,1,3-trichloropropene and 3,3,3-trichloropropene, with a selectivity of 96.76% for 1,1,3-trichloropropene and 3.24% for 3,3,3-trichloropropene.

[0046] The catalyst titanium tetrachloride was added to the reactor, and hydrofluoric acid and chlorine were introduced to react the obtained 1,1,3-trichloropropene to prepare 2-chloro-3,3,3-trifluoropropene. The reaction temperature was 100°C. The reaction results are shown in the following table.

[0047] Compound GC-FID area % 1,1,3-Trichloropropene <![CDATA[CCl2=CHCH2Cl]]> 1.92％ 2-Chloro-3,3,3-trifluoropropene <![CDATA[CF3CCl=CH2]]> 94.98％ 2-Chloro-1,1,1,2-tetrafluoropropane <![CDATA[CF3CFClCH3]]> 1.25％ 3-Chloro-1,1,1,2-tetrafluoropropane <![CDATA[CF3CHFCH2Cl]]> 0.08％ 2,3-Dichloro-1,1,1-trifluoropropane <![CDATA[CF3CHClCH2Cl]]> 0.03％ 1,1,1,2,3-pentafluoropropane <![CDATA[CF3CHFCH2F]]> 0.26％ Other unknown substances 1.48％

[0048] The catalyst, titanium tetrachloride, was added to the reactor and hydrofluoric acid was introduced. The reaction temperature was raised to 100°C, and 2-chloro-3,3,3-trifluoropropene and hydrofluoric acid were introduced into the reactor in a molar ratio of 1:1. The discharge pipe was adjusted with a valve. The gaseous material passed through a water scrubber and an alkaline scrubber. Samples were taken from the alkaline scrubber outlet for GC-FID analysis. The results are shown in the table below.

[0049]

[0050]

[0051] The prepared 2-chloro-1,1,1,2-tetrafluoropropane was introduced into a reactor filled with catalyst Pd / C at a space velocity of 100 h -1 The reaction temperature was 380°C. The outlet of the reactor was connected to a water washer and an alkali washer. Samples were taken from the outlet of the alkali washer for GC-FID measurement. The results are shown in the following table.

[0052] Compound GC-FID area % 2-Chloro-1,1,1,2-tetrafluoropropane <![CDATA[CF3CFClCH3]]> 0.92％ 2,3,3,3-tetrafluoropropene <![CDATA[CF3CF=CH2]]> 96.98％ 2-Chloro-3,3,3-trifluoropropene <![CDATA[CF3CCl=CH3]]> 0.45％ 3-Chloro-1,1,1,2-tetrafluoropropane <![CDATA[CF3CHFCH2Cl]]> 1.42％ Other unknown substances 0.23％

[0053] Example 3

[0054] 2 kg of carbon tetrachloride, 20 g of reduced iron powder, and 20 g of tributyl phosphate were added to a 5 L nitrogen-purged reactor. Stirring was initiated and the reactor temperature was raised to 100°C. At the reaction temperature, ethylene was introduced into the reactor at a rate of 80 g / h. Cooling water was passed through the reactor to remove the reaction heat. 220 g of ethylene was introduced, and the reaction was terminated after 5 h. The liquid phase was sampled for GC-FID analysis. The reaction results are shown in the table below.

[0055] Compound GC-FID area % Ethylene <![CDATA[CH2=CH2]]> 0.65％ Carbon tetrachloride <![CDATA[CCl4]]> 31.95％ 1,1,1,3-Tetrachloropropane <![CDATA[CCl3CH2CH2Cl]]> 64.02％ 1,1,2,2-Tetrachloroethylene <![CDATA[CCl2=CCl2]]> 0.05％ Other unknown substances 2.72％ Tributyl phosphate 0.61％

[0056] 250g of 1,1,1,3-tetrachloropropane and 0.1g of ferric chloride were added to a 500ml reactor. The reactor was stirred and the temperature was raised to 120°C. The reaction was terminated after 5 hours. After cooling to 30°C, the liquid phase was sampled and analyzed by GC-FID. The reaction results are shown in the table below. The main products of the reaction were 1,1,3-trichloropropene and 3,3,3-trichloropropene, with a selectivity of 95.34% for 1,1,3-trichloropropene and 4.66% for 3,3,3-trichloropropene.

[0057] The catalyst tin tetrachloride was added to the reactor, and hydrofluoric acid and chlorine were introduced to react the obtained 1,1,3-trichloropropene to prepare 2-chloro-3,3,3-trifluoropropene. The reaction temperature was 90°C. The reaction results are shown in the following table.

[0058] Compound GC-FID area % 1,1,3-Trichloropropene <![CDATA[CCl2=CHCH2Cl]]> 2.91％ 2-Chloro-3,3,3-trifluoropropene <![CDATA[CF3CCl=CH2]]> 93.12％ 2-Chloro-1,1,1,2-tetrafluoropropane <![CDATA[CF3CFClCH3]]> 1.52％ 3-Chloro-1,1,1,2-tetrafluoropropane <![CDATA[CF3CHFCH2Cl]]> 0.06％ 2,3-Dichloro-1,1,1-trifluoropropane <![CDATA[CF3CHClCH2Cl]]> 0.06％ 1,1,1,2,3-pentafluoropropane <![CDATA[CF3CHFCH2F]]> 0.49％ Other unknown substances 1.84％

[0059] The catalyst, tin tetrachloride, was added to the reactor and reacted with hydrofluoric acid. The reaction temperature was raised to 90°C. 2-Chloro-3,3,3-trifluoropropene and hydrofluoric acid were introduced into the reactor in a molar ratio of 1:1. The discharge pipe was adjusted with a valve. The gaseous material passed through a water scrubber and an alkaline scrubber. Samples were taken from the alkaline scrubber outlet for GC-FID analysis. The results are shown in the table below.

[0060] Compound GC-FID area % 2-Chloro-3,3,3-trifluoropropene <![CDATA[CF3CCl=CH2]]> 1.08％ 1,1,1,2,3-pentafluoropropane <![CDATA[CF3CHFCH2F]]> 0.25％ 1,1,1,2,2-pentafluoropropane <![CDATA[CF3CF2CH3]]> 3.52％ 2-Chloro-1,1,1,2-tetrafluoropropane <![CDATA[CF3CFClCH3]]> 94.81％ Other unknown substances 0.34％

[0061] The prepared 2-chloro-1,1,1,2-tetrafluoropropane was introduced into a reactor filled with catalyst Pd / C at a space velocity of 100 h -1The reaction temperature was 300°C, the reactor outlet was connected to a water scrubber and an alkali scrubber, and samples were taken from the alkali scrubber outlet for GC-FID measurement. The results are shown in the following table.

[0062] Compound GC-FID area % 2-Chloro-1,1,1,2-tetrafluoropropane <![CDATA[CF3CFClCH3]]> 1.25％ 2,3,3,3-tetrafluoropropene <![CDATA[CF3CF=CH2]]> 96.24％ 2-Chloro-3,3,3-trifluoropropene <![CDATA[CF3CCl=CH3]]> 0.58％ 3-Chloro-1,1,1,2-tetrafluoropropane <![CDATA[CF3CHFCH2Cl]]> 1.48％ Other unknown substances 0.45％

[0063] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications based on the present invention to solve substantially the same technical problems and achieve substantially the same technical effects are included within the scope of protection of the present invention.

Claims

1. A method for preparing 2,3,3,3-tetrafluoropropylene, characterized in that The steps include: (1) Under the action of catalyst and co-catalyst, ethylene and carbon tetrachloride are reacted to prepare 1,1,1,3- Tetrachloropropane, reaction temperature 80℃~150℃, reaction pressure 0~3MPa, reaction time 2~10h; (2) in the presence of a catalyst, dehydrochlorinating the 1,1,1,3-tetrachloropropane obtained in step (1) to prepare 1,1,3-trichloropropene, the reaction temperature being 50° C. to 150° C.; (3) reacting the 1,1,3-trichloropropene obtained in step (2) with hydrofluoric acid in the presence of chlorine in the presence of a catalyst to prepare 2-chloro-3,3,3-trifluoropropene at a reaction temperature of 30 to 150° C. (4) reacting the 2-chloro-3,3,3-trifluoropropene obtained in step (3) with hydrofluoric acid in the presence of a catalyst to prepare 2-chloro-1,1,1,2-tetrafluoropropane at a reaction temperature of 30 to 150° C.; (5) In the presence of a catalyst, the 2-chloro-1,1,1,2-tetrafluoropropane obtained in step (4) is dehydrochlorinated to prepare 2,3,3,3-tetrafluoropropene.

2. The method for preparing 2,3,3,3-tetrafluoropropene according to claim 1, wherein: The catalyst in step (1) is reduced iron powder.

3. The method for preparing 2,3,3,3-tetrafluoropropene according to claim 1, wherein: The co-catalyst in step (1) is a phosphate or phosphite, and one or more of tributyl phosphate, dibutyl phosphate, triethyl phosphate, trimethyl phosphite or tributyl phosphite is selected.

4. The method for preparing 2,3,3,3-tetrafluoropropene according to claim 1, wherein: The catalyst in step (2) is ferric chloride.

5. The method for preparing 2,3,3,3-tetrafluoropropene according to claim 1, wherein: The catalyst in step (3) is one or more of titanium tetrachloride, tin tetrachloride, antimony pentachloride or fluorosulfonic acid.

6. The method for preparing 2,3,3,3-tetrafluoropropene according to claim 1, wherein: The catalyst in step (4) is one or more of titanium tetrachloride, tin tetrachloride, antimony pentachloride or fluorosulfonic acid.

7. The method for preparing 2,3,3,3-tetrafluoropropene according to claim 1, wherein: The catalyst in step (5) is a gas phase reaction catalyst.

8. The method for preparing 2,3,3,3-tetrafluoropropene according to claim 1, wherein: The reaction temperature of step (5) is 200-450°C.

9. The method for preparing 2,3,3,3-tetrafluoropropene according to claim 7, wherein: The gas phase reaction catalyst is selected from one or more of activated carbon, Pd / C, Pt / C or metal halide-supported activated carbon.

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