Methods for preparing fluorine-containing propylene and intermediate thereof

Abstract

Disclosed in the present invention are methods for preparing fluorine-containing propylene and a fluorochloropropane intermediate thereof. The method for preparing the fluorochloropropane intermediate comprises: subjecting dichloromethane, difluoromethane, and a fluorine-containing olefin of general formula CF2=CR1R2 to a liquid-phase addition reaction under the action of an addition catalyst to prepare fluorochloropropane of general formula of CF3CR1R2CH2Cl, wherein the content of the fluorine-containing olefin in a reaction system is monitored during the reaction process, and the content of the fluorine-containing olefin thereof is controlled to be less than or equal to 5%; and the addition catalyst is a mixed catalyst formed from a metal fluoride, a metal chloride, and a metal oxide, and the metal is selected from metal elements in group IIIA, IVB, or VA. The obtained fluorochloropropane intermediate is subjected to a hydrogen chloride removal reaction under the action of activated carbon or a metal alkali solution to obtain fluorine-containing propylene. The method of the present invention has the advantages of a simple process flow, mild reaction conditions, easy product separation, good product purity, a remarkably improved service life of the addition catalyst, etc.

Description

A method for preparing fluorinated propylene and its intermediates Technical Field

[0001] The present invention relates to the preparation of fluorochloropropanes and fluorine-containing propenes, and in particular to a method for preparing a fluorochloropropane intermediate of the general formula CF3CR1R2CH2Cl by reacting a fluorine-containing olefin CF2=CR1R2 with dichloromethane and difluoromethane in the presence of a metal Lewis acid mixed catalyst, and then obtaining the fluorine-containing propene by dehydrochlorination. Background Art

[0002] 3,3,3-Trifluoropropene, 2-chloro-3,3,3-trifluoropropene, 2,3,3,3-tetrafluoropropene, and 1-chloro-2,3,3,3-tetrafluoropropene are four common fluorinated propenes. 2,3,3,3-tetrafluoropropene, in particular, has gradually replaced R134a as the mainstream refrigerant in new energy vehicle air conditioning due to its superior environmental performance and refrigeration performance similar to 1,1,1,2-tetrafluoroethane (R134a). Fluorinated propenes are typically prepared by dehydrochlorinating chlorofluoropropanes, so obtaining chlorofluoropropanes is crucial to their preparation.

[0003] 1-Chloro-3,3,3-trifluoropropane (HCFC-253fb), 2,3-dichloro-1,1,1-trifluoropropane (HCFC-243db), 3-chloro-1,1,1,2-tetrafluoropropane (HCFC-244eb) and 2,3-dichloro-1,1,1,2-tetrafluoropropane (HCFC-234ba) are important fluorine-containing fine chemicals. They can be used to prepare new refrigerants HCFO-1224yd and HFO-1234yf through dehalogenation reactions, and therefore have great application potential.

[0004] Currently, there are few studies on the synthesis of 1-chloro-3,3,3-trifluoropropane, 3-chloro-1,1,1,2-tetrafluoropropane and 2,3-dichloro-1,1,1,2-tetrafluoropropane compounds.

[0005] (1) Synthesis of 1-chloro-3,3,3-trifluoropropane

[0006] Patent US2644845A discloses a method for preparing 1-chloro-3,3,3-trifluoropropane using 1,1,1-trifluoropropane and chlorine as raw materials through photochlorination. The preparation method is simple, but the product yield is low. Under irradiation with a 200W incandescent lamp and a reaction temperature of 110°C, the yield of 1-chloro-3,3,3-trifluoropropane is only 56%.

[0007] Patent CN1488614A discloses a two-step method for synthesizing 1-chloro-3,3,3-trifluoropropane, comprising: 1) preparing the intermediate 1,3,3,3-tetrachloropropane from carbon tetrachloride and ethylene in the presence of ferric chloride or a phosphate initiator; 2) liquid-phase fluorination of 1,3,3,3-tetrachloropropane with anhydrous hydrogen fluoride in the presence of tin tetrachloride or titanium tetrachloride catalyst to produce 1-chloro-3,3,3-trifluoropropane. This process requires minimal equipment, consumes little energy, and allows for easy separation and purification of the product. However, it suffers from low raw material utilization. Under optimal conditions, the carbon tetrachloride conversion rate is 75%, while the product yield in the fluorination step is only 65%.

[0008] Patent CN107162871A discloses a two-step method for preparing 1-chloro-3,3,3-trifluoropropane. Using activated carbon as a catalyst and trifluoromethane as a starting material, a catalytic chlorination reaction occurs in a fixed-bed reactor to obtain the intermediate chlorotrifluoromethane. Chlorotrifluoromethane is then telomerized with ethylene in the presence of an iron-molybdenum catalyst to produce 1-chloro-3,3,3-trifluoropropane. This process can achieve a yield of 86%, but the intermediate product requires purification steps such as alkaline washing, drying, and extraction, resulting in complex post-processing. Furthermore, the reaction temperature is relatively high, exceeding 300°C for gas-phase chlorination.

[0009] (2) Synthesis of 2,3-dichloro-1,1,1-trifluoropropane

[0010] Patent CN101168494A discloses a method for synthesizing 2,3-dichloro-1,1,1-trifluoropropane using 1,1,1,2,3-pentachloropropane as a raw material through liquid-phase fluorination in the presence of catalysts such as chromium fluoride, magnesium fluoride, and titanium fluoride. While the process is simple and the raw materials are readily available, the product yield is relatively low. After a reaction temperature of 90-130°C and a reaction time of 4-10 hours, the product yield is only approximately 85%.

[0011] Patent CN10197936A discloses a method for synthesizing 2,3-dichloro-1,1,1-trifluoropropane using 1,1,1-trifluoropropene and chlorine as raw materials in a tubular or kettle reactor under ultraviolet light. This method achieves a raw material conversion rate of 95% and a selectivity exceeding 90%, but it requires high equipment requirements and poses significant health risks.

[0012] (III) Synthesis of 3-chloro-1,1,1,2-tetrafluoropropane

[0013] Patent WO2019003896A discloses a method for preparing 2-chloro-1,1,1,2-tetrafluoropropane and / or 3-chloro-1,1,1,2-tetrafluoropropane using 1,1,1,2-tetrafluoropropane as a raw material through a liquid-phase photocatalytic chlorination reaction. The process is simple, but the main product is 2-chloro-1,1,1,2-tetrafluoropropane, the selectivity of 3-chloro-1,1,1,2-tetrafluoropropane is less than 20%, and there are many by-products with similar boiling points, making separation and purification difficult.

[0014] Patent CN115023490A discloses a method for preparing 3-chloro-1,1,1,2-tetrafluoropropane. 2,3,3,3-tetrafluoropropene is hydrogenated in the presence of a palladium-carbon catalyst to obtain 1,1,1,2-tetrafluoropropane, which is then reacted with chlorine to obtain a mixture of HCFC-244bb, HCFC-244eb, and HCFC-234ea. The mixture is then distilled and purified to obtain 3-chloro-1,1,1,2-tetrafluoropropane. However, the patent does not disclose the reaction conditions and reaction results.

[0015] (IV) Synthesis of 2,3-dichloro-1,1,1,2-tetrafluoropropane

[0016] Patents CN103524293A, CN105753638A, CN105777484A, etc. disclose the use of a fluorination catalyst to produce a fluorinated product having the general formula CF 3-X Cl x CH 2-y Cl y CH 3-z Cl z A method for synthesizing 2,3-dichloro-1,1,1,2-tetrafluoropropane by using a compound as a starting material and performing two-step fluorination in the gas phase and liquid phase. Under preferred conditions, the raw material conversion rate reaches 93.7% and the selectivity can reach 83.5%. However, the reaction temperature of this method is relatively high, the required gas phase fluorination temperature is 200-350°C, and the liquid phase fluorination temperature is 110-150°C. In addition, the reaction process requires the combination of gas phase fluorination and liquid phase fluorination, which makes the process difficult. In addition, the patent does not disclose the service life of the catalyst.

[0017] In summary, the synthesis of chlorofluoropropanes in the prior art is either obtained by chlorination or fluorination, but the product yield is low; or obtained by a two-step reaction, but the technical route is relatively complex, and the yield of the target product is not high. The reaction conditions are harsh, and there are problems such as high difficulty in product separation and purification. Summary of the Invention

[0018] In order to solve the above technical problems, the present invention proposes a method for preparing chlorofluoropropane intermediates by an addition process. The method has simple process, mild reaction conditions, easy product separation, good product purity, and significantly improved catalyst life.

[0019] The purpose of the present invention is achieved through the following technical solutions:

[0020] A method for preparing chlorofluoropropanes by an addition process comprises: in the presence of an addition catalyst, dichloromethane, difluoromethane, and a fluorine-containing olefin represented by the following formula I undergo a liquid phase addition reaction to obtain a chlorofluoropropane represented by the following formula II. The reaction formula is as follows:

[0021] wherein R1 is selected from hydrogen or fluorine, and R2 is selected from hydrogen or chlorine;

[0022] The addition catalyst is a mixed catalyst formed of a metal fluoride, a metal chloride, and a metal oxide, wherein the metal is selected from a metal element of Group IIIA, IVB, or VA. Preferably, the metal is selected from at least one of Al, Sb, Ti, Zr, Hf, Nb, Ta, Ga, or In.

[0023] That is, the metal fluoride is selected from at least one of AlF3, TiF4, SbF5, ZrF4, HfF4, NbF5, TaF5, GaF3 or InF3; the metal chloride is selected from at least one of AlCl3, TiCl4, SbCl5, ZrCl4, HfCl4, NbCl5, TaCl5, GaCl3 or InCl3; the metal oxide is selected from at least one of Al2O3, TiO2, Sb2O5, ZrO2, HfO2, Nb2O5, TaO2, Ga2O3 or In2O3.

[0024] More preferably,

[0025] The metal fluoride is selected from at least one of AlF3, TiF4, SbF5, ZrF4 or HfF4;

[0026] The metal chloride is selected from at least one of AlCl3, TiCl4, SbCl5, ZrCl4 or HfCl4;

[0027] The metal oxide is selected from at least one of Al2O3, TiO2, Sb2O5, ZrO2 or HfO2.

[0028] More preferably, the metal in the metal fluoride, metal chloride and metal oxide is the same metal.

[0029] The fluorine, chlorine, and oxygen in the addition catalyst of the present invention are derived from the corresponding metal fluoride, metal chloride, and metal oxide, respectively. By varying the content of the metal fluoride, metal chloride, and metal oxide in the addition catalyst, the content of fluorine, chlorine, and oxygen in the addition catalyst can be adjusted.

[0030] In order to improve the reaction effect, in the addition catalyst, the molar content of fluorine element accounts for 40-70% of the total molar amount of anions, the molar content of chlorine element accounts for 20-50% of the total molar amount of anions, and the molar content of oxygen element accounts for 10-30% of the total molar amount of anions; preferably, the molar content of fluorine element is between 50-60%, the molar content of chlorine element is between 30-40%, and the molar content of oxygen element is between 10-20%.

[0031] The addition catalyst of the present invention can efficiently dissociate the raw materials difluoromethane and dichloromethane to form F - 、CH2F + 、Cl - 、CH2Cl + Active ions, the addition reaction of halogenated hydrocarbons and halogenated olefins belongs to electrophilic addition. According to Markovnikov's rule and the electronegativity of the charged group, F - 、CH2Cl + It can undergo directional addition reaction with fluorine-containing olefin compounds to obtain the addition product CF3CR1R2CH2Cl with high selectivity.

[0032] The fluorine-containing olefin of the present invention is selected from at least one of vinylidene fluoride (CF2=CH2F), difluorochloroethylene (CF2=CHCl), trifluoroethylene (CF2=CHF) or trifluorochloroethylene (CF2=CFCl), and the corresponding fluorochloropropanes are 1-chloro-3,3,3-trifluoropropane (CF3CH2CH2Cl), 2,3-dichloro-1,1,1-trifluoropropane (CF3CHClCH2Cl), 3-chloro-1,1,1,2-tetrafluoropropane (CF3CHFCH2Cl) and 2,3-dichloro-1,1,1,2-tetrafluoropropane (CF3CFClCH2Cl).

[0033] In the method for preparing chlorofluoropropanes described in the present invention, the ratio of raw materials, the ratio of raw materials to addition catalysts, reaction temperature, reaction time, feeding method, etc. will affect the reaction results, especially the catalyst life and the selectivity of the target product. Therefore,

[0034] The molar ratio of dichloromethane to fluorine-containing olefin is (0.5-2):1; preferably, the molar ratio of dichloromethane to fluorine-containing olefin is (0.5-1):1; more preferably, the molar ratio of dichloromethane to fluorine-containing olefin is (0.6-0.7):1.

[0035] Furthermore, the ratio of dichloromethane to the addition catalyst is ≥ 2. When the ratio is less than 2, the liquid holdup in the reactor is insufficient, the reaction system cannot be effectively stirred, and the product yield is reduced. Preferably, the ratio of dichloromethane to the addition catalyst is 2 to 10; more preferably, the ratio of dichloromethane to the addition catalyst is 4 to 6.

[0036] The present invention has discovered that during the addition process for preparing chlorofluoropropanes, the raw fluorinated olefins are easily adsorbed onto the catalyst's active centers and polymerize, thereby preventing contact between the reactants and the active centers, resulting in reduced catalyst activity and even catalyst deactivation. Therefore, the present invention monitors the fluorinated olefin content in the reaction system during the reaction and controls the content to ≤5%, preferably ≤3%, and more preferably ≤1%. When the fluorinated olefin content in the reaction system exceeds 5%, the catalyst's active centers are gradually occupied by the fluorinated olefin polymer, causing the catalyst to gradually deactivate.

[0037] To minimize polymerization of fluorinated olefins at active centers during the reaction and further extend the catalyst's service life, the fluorinated olefins described herein are continuously pressurized and fed via a metering pump. The continuous feed rate is primarily determined by the rate of consumption of the fluorinated olefins within the reaction system. To prevent accumulation of fluorinated olefins within the reaction system, the feed rate is generally between 20 and 120 g / h, preferably between 60 and 80 g / h. Once the fluorinated olefin content in the reaction system is monitored to be greater than 5%, the feed rate is reduced. In actual operation, the feed rate can be appropriately reduced when the fluorinated olefin content in the reaction system approaches or reaches 5%.

[0038] Furthermore, in order to avoid the deactivation of the catalyst due to polymerization of the fluorinated olefins at the active centers of the catalyst, the fluorinated olefins should react as completely as possible. Therefore, the total amount of the fluorinated olefins added satisfies the following relationship:

[0039] and

[0040] in, is the molar amount of fluorinated olefin, is the molar amount of difluoromethane, is the molar amount of dichloromethane. During the actual reaction, the fluorinated olefin is continuously fed. Once the difluoromethane or dichloromethane starting material in the reaction system is detected to be completely consumed, the fluorinated olefin feed is immediately stopped. At this point, the total fluorinated olefin feed amount must satisfy the above relationship. This prevents excessive polymerization of the fluorinated olefin on the active sites, which could affect the catalyst activity and service life.

[0041] The content of fluorinated olefins in the reaction system is mainly monitored by chromatographic analysis of the material composition.

[0042] In the method for preparing chlorofluoropropanes of the present invention, metal fluoride, metal chloride and metal oxide are added to a reactor (a reactor or a tubular reactor) in a certain ratio, and then dichloromethane is added to the reactor. Dichloromethane can be added to the reactor together with dichloromethane, or can be continuously introduced into the reactor, or can be mixed with fluorine-containing olefins to form a mixed gas and then continuously introduced into the reactor.

[0043] Alternatively, the addition catalyst and dichloromethane are uniformly mixed and then continuously introduced into the reactor, and difluoromethane and fluorine-containing olefin are continuously introduced into the reactor separately or mixed and then continuously introduced into the reactor.

[0044] In the method for preparing chlorofluoropropanes of the present invention, any of the aforementioned feeding methods may be employed, as long as the fluorinated olefin is continuously fed. Preferably, the addition catalyst is pre-loaded into the reactor, followed by the addition of dichloromethane and difluoromethane, and the fluorinated olefin is continuously pressurized and fed via a metering pump.

[0045] In the method for preparing fluorochloropropanes of the present invention, the reaction temperature is -20 to 100°C, and the reaction time is 4 to 20 hours. Preferably, the reaction temperature is 0 to 80°C, and the reaction time is 6 to 15 hours; more preferably, the reaction temperature is 30 to 50°C, and the reaction time is 8 to 12 hours.

[0046] The reaction pressure of the present invention does not need to be controlled, and only needs to ensure that the reactor is sealed. It is determined by the saturated vapor pressure of difluoromethane in the reactor, which is generally around 2 MPa. During the reaction, the reaction pressure gradually decreases as difluoromethane is consumed.

[0047] Because the saturated vapor pressures of difluoromethane and fluorinated olefins are much greater than that of dichloromethane, dichloromethane primarily exists in liquid form during the reaction. Furthermore, the fluorochloropropane produced by the addition reaction is liquid. Therefore, the addition process of the present invention is preferably a solvent-free reaction, eliminating the need for additional solvents, effectively reducing the number of product separation steps.

[0048] Specifically, the addition product after the reaction can be filtered to effectively separate the addition catalyst and the chlorofluoropropane. In the obtained chlorofluoropropane, the boiling point difference between the target product CF3CR1R2CH2Cl and the by-product CF2ClCR1R2CH2Cl is 15 to 30°C. The chlorofluoropropane intermediate with a purity of ≥99% can be obtained by rectification or distillation.

[0049] The present invention also provides a method for preparing fluorinated propylene, which comprises:

[0050] (1) preparing a chlorofluoropropane intermediate by any of the methods described above;

[0051] (2) The fluorochloropropane intermediate is subjected to a dehydrochlorination reaction under the action of activated carbon or a metal alkali solution to prepare fluorinated propene.

[0052] In step (1), a chlorofluoropropane reaction solution is prepared by the aforementioned method, and the reaction solution is subjected to solid-liquid separation to remove the addition catalyst, and then distilled to obtain a chlorofluoropropane intermediate.

[0053] Step (2) can be a gas phase dehalogenation reaction or a liquid phase dehalogenation reaction.

[0054] The gas phase dehalogenation reaction is carried out under the action of activated carbon at a reaction temperature of 200-500° C., preferably 300-350° C. The activated carbon is selected from fruit shell activated carbon, coal activated carbon or wood activated carbon, preferably fruit shell activated carbon.

[0055] The liquid-phase dehalogenation reaction is carried out in the presence of a metal alkali solution, preferably in the presence of a metal alkali solution and a quaternary ammonium salt, wherein the molar ratio of the fluorochloropropane intermediate to the metal alkali is 1:(0.1-5), preferably 1:(1-2). The reaction temperature of the liquid-phase dehalogenation reaction is 10-100°C, preferably 30-60°C. The metal alkali solution is selected from at least one of sodium hydroxide solution, potassium hydroxide solution, sodium carbonate solution, potassium carbonate solution, sodium bicarbonate solution, and potassium bicarbonate solution, and the mass concentration of the metal alkali solution is 5-60wt%. Preferably, the metal alkali solution is selected from sodium hydroxide solution or potassium hydroxide solution, more preferably potassium hydroxide solution, and the mass concentration of the metal alkali solution is 10-40wt%. The quaternary ammonium salt is selected from at least one of tetrabutylammonium bromide, tetramethylammonium hydroxide, and tetramethylammonium chloride, more preferably tetramethylammonium hydroxide.

[0056] The method for preparing fluorinated propylene of the present invention specifically comprises the following steps:

[0057] The liquid phase addition step comprises the following steps: 1) dichloromethane, difluoromethane and a fluorine-containing olefin undergo a liquid phase addition reaction in a first reactor under the action of an addition catalyst, wherein the fluorine-containing olefin is selected from at least one of vinylidene fluoride, difluorochloroethylene, trifluoroethylene or trifluorochloroethylene; 2) after the reaction is completed, unreacted gaseous materials are collected, and the reaction liquid in the reactor is subjected to solid-liquid separation, the solid portion is used as the addition catalyst, and the liquid portion is further distilled to obtain a fluorochloropropane intermediate; the unreacted gaseous materials and the addition catalyst can be reused.

[0058] Gas-phase / liquid-phase dehydrochlorination step: 3) loading an activated carbon catalyst into a second reactor, or adding a metal alkali solution into the second reactor, or adding a mixture of a metal alkali solution and a quaternary ammonium salt into the second reactor; 4) setting a corresponding reaction temperature, and passing a chlorofluoropropane intermediate into the second reactor for a gas-phase / liquid-phase dehydrochlorination reaction; 5) alkali washing, neutralization, and rectification of the reaction product to obtain a fluorinated propene product.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] 1. The present invention only requires a one-step addition reaction to prepare chlorofluoropropane, which has a simple process flow, mild reaction conditions and high product yield.

[0061] 2. The present invention monitors the content of fluorinated olefins in the reaction system and adjusts the feed to inhibit the polymerization of fluorinated olefins on the active center, thereby significantly improving the service life of the catalyst.

[0062] 3. The post-processing operation of the ternary liquid-phase addition process of the present invention is simple, the product is easy to separate, and the product purity is high, which is very suitable for industrial application. DETAILED DESCRIPTION

[0063] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all possible alternatives, improvements and equivalents within the scope of the claims.

[0064] In the first aspect of this embodiment, a preparation and comparative preparation example of a chlorofluoropropane intermediate is provided.

[0065] Example 1

[0066] This embodiment provides a method for preparing 1-chloro-3,3,3-trifluoropropane, comprising the following steps:

[0067] 20.2g (0.24mol) of anhydrous aluminum trifluoride, 18.7g (0.14mol) of anhydrous aluminum trichloride, and 6.1g (0.06mol) of aluminum oxide were weighed and added to a reactor. The reactor lid was sealed and vacuumed. 225g of dichloromethane was then added using a sampler. The reactor was placed in a -30°C cooling circulation pump for 30 minutes. After removing the reactor, 125g of difluoromethane was added. Vinylidene fluoride was pressure-fed at a rate of 60g / h using a metering pump for 5 hours. After the additions were completed, the above raw materials were reacted for another 5 hours at a temperature of 30°C and a stirring speed of 300rpm.

[0068] During the reaction, the reaction pressure and temperature in the reactor were recorded, and the vinylidene fluoride content in the reactor was monitored. Specifically, samples were taken every 30 minutes and analyzed by gas chromatography. The results showed that the vinylidene fluoride content in the reaction system was ≤2.8% throughout the reaction. After the reaction was completed, the temperature in the reactor cooled to room temperature, and the gas phase valve was opened to collect the gaseous materials (unreacted difluoromethane and a small amount of addition product). The liquid phase in the reactor was filtered, and the solid portion was the addition catalyst. The filtrate was subjected to distillation to obtain the target product, 1-chloro-3,3,3-trifluoropropane, with a purity of 99.7%.

[0069] The liquid and gaseous materials of the addition reaction were subjected to chromatographic analysis, respectively, and the calculations showed that the conversion of vinylidene fluoride was 96.2%, the selectivity of 1-chloro-3,3,3-trifluoropropane was 85.6%, the selectivity of the by-product 1,3-dichloro-1,1-difluoropropane was 13.7%, and a small amount of other by-products were generated (qualitative analysis by GC-MS showed that they were isomers of 1-chloro-3,3,3-trifluoropropane).

[0070] Example 2

[0071] The operation of this embodiment is the same as that of embodiment 1, except that the feed rate of vinylidene fluoride is first increased to 100 g / h for 1 hour, and then the feed rate of difluoromethane is reduced to 50 g / h for 4 hours. After the feeding is completed, the reaction stirring is continued for 5 hours.

[0072] By monitoring the changes in the vinylidene fluoride content in the reactor during the reaction, it was found that the vinylidene fluoride content in the reactor gradually increased as the reaction progressed. After a reaction time of 1 hour, the vinylidene fluoride content in the reaction system reached 4.1%. After that, the vinylidene fluoride feed rate was reduced to 50g / h, and the vinylidene fluoride content in the reactor gradually decreased to 0.8%.

[0073] Chromatographic analysis of the liquid and gaseous phases of the addition reaction revealed a vinylidene fluoride conversion of 94.4%, an 83.5% selectivity for 1-chloro-3,3,3-trifluoropropane, and a 15.8% selectivity for the byproduct 1,3-dichloro-1,1-difluoropropane. Small amounts of other byproducts were also generated, which qualitatively identified as isomers of 1-chloro-3,3,3-trifluoropropane by GC-MS analysis. The purity of the distilled 1-chloro-3,3,3-trifluoropropane product reached 99.6%.

[0074] Example 3

[0075] The operation of this embodiment is the same as that of embodiment 1, except that the feed rate of vinylidene fluoride is first increased to 90 g / h, and the feed time is 2 h, and then the feed rate of vinylidene fluoride is reduced to 40 g / h, and the feed time is 3 h. After the feeding is completed, the stirring reaction is continued for 5 h.

[0076] By monitoring the changes in the vinylidene fluoride content in the kettle during the reaction, it was found that the vinylidene fluoride content in the kettle gradually increased as the reaction progressed, reaching 4.8% after a reaction time of 2 hours. After that, the vinylidene fluoride feed rate was reduced to 40g / h, and the vinylidene fluoride content in the kettle gradually decreased to 1.3%.

[0077] Chromatographic analysis of the liquid and gaseous products of the addition reaction revealed a vinylidene fluoride conversion of 88.4%, a selectivity of 79.3% for 1-chloro-3,3,3-trifluoropropane, and a selectivity of 19.7% for the byproduct 1,3-dichloro-1,1-difluoropropane. Small amounts of other byproducts were also generated, which qualitatively identified as isomers of 1-chloro-3,3,3-trifluoropropane by GC-MS analysis. After distillation, the purity of the 1-chloro-3,3,3-trifluoropropane reached 99.7%.

[0078] Example 4

[0079] The operation of this embodiment is the same as that of Example 1, except that the addition catalyst is changed to 48.4 g (0.19 mol) of anhydrous hafnium tetrafluoride, 41.9 g (0.14 mol) of anhydrous antimony pentachloride and 12.2 g (0.12 mol) of aluminum oxide, and other conditions remain unchanged.

[0080] The liquid and gaseous materials of the addition reaction were subjected to chromatographic analysis, respectively, and the calculations showed that the conversion of vinylidene fluoride was 86.4%, the selectivity of 3-chloro-1,1,1-trifluoropropane was 76.7%, the selectivity of the by-product 1,3-dichloro-1,1-difluoropropane was 23.0%, and a small amount of other by-products were generated, which were qualitatively analyzed by GC-MS to be isomers of 3-chloro-1,1,1-trifluoropropane.

[0081] Example 5

[0082] The operation of this example is the same as that of Example 1, except that the addition catalyst is changed to 39.4 g (0.21 mol) of anhydrous niobium pentafluoride, 39.6 g (0.18 mol) of anhydrous zirconium tetrachloride and 30.5 g (0.11 mol) of indium trioxide, and other conditions remain unchanged.

[0083] The liquid and gaseous materials of the addition reaction were subjected to chromatographic analysis, respectively, and the calculations showed that the conversion of vinylidene fluoride was 76.1%, the selectivity of 3-chloro-1,1,1-trifluoropropane was 69.8%, the selectivity of the by-product 1,3-dichloro-1,1-difluoropropane was 29.3%, and a small amount of other by-products were generated, which were qualitatively analyzed by GC-MS to be isomers of 3-chloro-1,1,1-trifluoropropane.

[0084] Example 6

[0085] The operation of this embodiment is the same as that of Example 1, except that the addition catalyst is changed to 47.6 g (0.22 mol) of anhydrous antimony pentafluoride, 24.7 g (0.13 mol) of anhydrous titanium tetrachloride and 26.5 g (0.06 mol) of tantalum pentoxide, and other conditions remain unchanged.

[0086] The liquid and gaseous materials of the addition reaction were subjected to chromatographic analysis, respectively, and the calculations showed that the conversion of vinylidene fluoride was 83.7%, the selectivity of 3-chloro-1,1,1-trifluoropropane was 76.2%, the selectivity of the by-product 1,3-dichloro-1,1-difluoropropane was 23.2%, and a small amount of other by-products were generated, which were qualitatively analyzed by GC-MS to be isomers of 3-chloro-1,1,1-trifluoropropane.

[0087] Examples 7 to 12

[0088] The operating steps of Examples 7 to 12 are the same as those of Example 1, except that the mass of anhydrous aluminum trifluoride, anhydrous aluminum chloride, and aluminum oxide in the mixed catalyst is changed to control the composition of fluorine, chlorine, and oxygen elements in the addition catalyst. The specific reaction results are shown in Table 1 below:

[0089] Table 1 Effects of different fluorine, chlorine and oxygen content in addition catalysts on addition reaction results

[0090] Examples 13 to 28

[0091] The operating steps of Examples 13 to 28 were the same as those of Example 1, except that the type of metal cations of the addition catalyst was changed, the composition of fluorine, chlorine, and oxygen elements remained unchanged, and the reaction temperature was adjusted to match the catalyst activity. The specific reaction results are shown in Table 2 below:

[0092] Table 2 Effect of different metal cations in addition catalysts on the effect of addition reaction

[0093] Examples 29 to 38

[0094] The operating steps of Examples 29 to 38 were the same as those of Example 1, except that the reaction conditions were changed, wherein the addition catalyst charge remained unchanged, the vinylidene fluoride feed rate remained unchanged, and the molar charge ratio of difluoromethane to vinylidene fluoride remained unchanged. The specific reaction results are shown in Table 3 below:

[0095] Table 3 Addition reaction results under different reaction conditions

[0096] Examples 39 to 50

[0097] The operating steps of Examples 39 to 50 are the same as those of Example 1, except that the type of fluorinated olefin was changed to obtain different chlorofluoropropanes, and the reaction temperature and total reaction time were adjusted. The reaction results are shown in Table 4:

[0098] Table 4 Addition reaction results of different raw materials

[0099] Examples 51 to 53

[0100] Examples 51 to 53 are respectively experiments on applying the addition catalyst in the preparation process of 1-chloro-3,3,3-trifluoropropane in Examples 1 to 3. The reaction results are shown in Table 5 below:

[0101] Table 5 Experimental results of catalyst application at different vinylidene fluoride contents Note: The number of applications in the table refers to the number of times the catalyst is repeatedly evaluated. The number of applications for the first use of the catalyst is 0, and the number of applications for the second use is 1.

[0102] Comparative Examples 1 to 6

[0103] The specific operating steps of Comparative Examples 1 to 6 are the same as those of Example 1, except that the addition catalyst is changed to anhydrous aluminum trifluoride, or anhydrous aluminum chloride, or aluminum oxide, or a combination of any two of anhydrous aluminum trifluoride, anhydrous aluminum chloride, and aluminum oxide. The fluorine, chlorine, and oxygen content in the addition catalyst are adjusted by changing the addition amount. Other reaction conditions remain unchanged. The reaction results are shown in Table 6 below:

[0104] Table 6 Catalytic reaction effects of different element contents

[0105] Comparative Example 7

[0106] The specific operation of this comparative example is the same as that of Example 1, except that the composition of fluorine, chlorine and oxygen elements in the addition catalyst remains unchanged, the total amount of addition catalyst added is reduced to 1 g, the amount of raw material dichloromethane added is increased to 600 g, the raw material vinylidene fluoride is increased to 750 g, the amount of difluoromethane added is increased to 200 g, and other conditions remain unchanged.

[0107] Chromatographic analysis of the liquid and gas phase materials of the addition reaction showed that the conversion of vinylidene fluoride was only 8.9%, the selectivity of 1-chloro-3,3,3-trifluoropropane was 43.5%, and the selectivity of the by-product 1,3-dichloro-1,1-difluoropropane was 55.8%.

[0108] Comparative Example 8

[0109] The specific operation of this comparative example is the same as that of Example 1, except that the amount of dichloromethane added is increased to 800 g, the amount of vinylidene fluoride added is reduced to 20 g, and the amount of difluoromethane added is increased to 200 g, while other conditions remain unchanged.

[0110] The liquid and gaseous materials of the addition reaction were analyzed by chromatography, and the calculation results showed that the conversion of vinylidene fluoride was 99.7%, the selectivity of 1-chloro-3,3,3-trifluoropropane was 39.5%, and the selectivity of by-product 1,3-dichloro-1,1-difluoropropane was 59.8%.

[0111] Comparative Example 9

[0112] The specific operation of this comparative example is the same as that of Example 1, except that the raw material feeding method is changed, 300g of vinylidene fluoride is pre-filled in the reactor, and dichloromethane and difluoromethane are fed by metering pumps. The dichloromethane feed rate is 45g / h, and the difluoromethane feed rate is 25g / h. The total feed amounts are 225g and 125g, respectively.

[0113] The liquid and gaseous materials of the addition reaction were analyzed by chromatography, and the calculation results showed that the conversion of vinylidene fluoride was 48.5%, the selectivity of 1-chloro-3,3,3-trifluoropropane was 52.7%, and the selectivity of by-product 1,3-dichloro-1,1-difluoropropane was 46.4%.

[0114] Comparative Example 10

[0115] The specific operation of this comparative example is the same as that of Example 10, except that the feed rate of vinylidene fluoride is constant at 150 g / h, the feed time is 2 h, and the reaction is stirred for 7 h after the feeding is completed. A catalyst application experiment is carried out under the same reaction conditions. The reaction results are shown in Table 7 below:

[0116] Table 7 Catalyst application reaction results at different feed rates

[0117] The second aspect of this embodiment provides the preparation of fluorine-containing propylene.

[0118] Example 54

[0119] This embodiment provides a method for preparing 3,3,3-trifluoropropene, using 3-chloro-1,1,1-trifluoropropane (purity of 99.7%) prepared in Example 1 as a raw material to carry out a gas-phase dehydrochlorination reaction, and the specific steps are as follows:

[0120] A 19mm inner diameter, 800mm long Inconel alloy reaction tube was used as the second reactor. 20mL of coconut shell activated carbon with a particle size of 10-20 mesh was loaded into the middle of the second reactor. A reaction line was connected and nitrogen was introduced for purging at a rate of 100mL / min. The reaction temperature was set at 350°C with a heating rate of 5°C / min, and the reactor began to heat up. Once the catalyst bed reached the reaction temperature, the nitrogen flow rate was adjusted to 20mL / min. Simultaneously, 99.7% pure 3-chloro-1,1,1-trifluoropropane was continuously introduced into the fixed-bed reactor at a rate of 5.0g / h to initiate the reaction.

[0121] Online GC and GC / MS analysis of the gas mixture flowing out of the reactor showed that the conversion rate of 3-chloro-1,1,1-trifluoropropane was 99.6%, and the selectivity of the product 3,3,3-trifluoropropene was 99.3%.

[0122] Example 55

[0123] This embodiment provides a method for preparing 2-chloro-3,3,3-trifluoropropene, which includes an addition process and a dehydrochlorination process. The specific steps are as follows:

[0124] (1) Addition process:

[0125] 20.2 g (0.24 mol) of anhydrous aluminum trifluoride, 18.7 g (0.14 mol) of anhydrous aluminum trichloride, and 6.1 g (0.06 mol) of aluminum oxide were weighed and added to a reactor. The reactor lid was sealed and vacuumed. 225 g of dichloromethane was then added using a sampler. The reactor was placed in a -30°C cooling circulation pump for 30 minutes. After removing the reactor, 125 g of difluoromethane was added. Difluorochloroethylene was then pressure-fed via a metering pump at a rate of 120 g / h for 5 hours. After the additions were completed, the reaction continued at 30°C and stirred at 300 rpm for 5 hours.

[0126] During the reaction, the reaction pressure and temperature in the reactor were recorded, and the difluorochloroethylene content in the reactor was monitored. Samples were taken every 30 minutes and analyzed by gas chromatography. The results showed that the difluorochloroethylene content in the reaction system was ≤2.6% throughout the reaction. After the reaction was completed, the temperature in the reactor cooled to room temperature, and the gas phase valve was opened to collect the gaseous materials (unreacted difluoromethane and a small amount of addition product). The liquid phase in the reactor was filtered, and the solid portion was the addition catalyst. The filtrate was subjected to rectification to obtain 2,3-dichloro-1,1,1-trifluoropropane with a purity of 99.6%.

[0127] The liquid and gaseous materials of the addition reaction were subjected to chromatographic analysis, respectively, and the calculation results showed that the conversion of difluorochloroethylene was 95.3%, the selectivity of 2,3-dichloro-1,1,1-trifluoropropane was 84.5%, the selectivity of by-product 1,2,3-trichloro-1,1-difluoropropane was 14.7%, and a small amount of other by-products were generated (qualitative analysis by GC-MS showed that they were isomers of 2,3-dichloro-1,1,1-trifluoropropane).

[0128] (2) Dehydrochlorination process:

[0129] A reaction tube made of Inconel alloy with an inner diameter of 19 mm and a length of 800 mm was used as the second reactor. Coconut shell activated carbon with a volume of 20 mL and a particle size of 10 to 20 mesh was filled into the middle of the second reactor. The reaction pipeline was connected and nitrogen was introduced for purging at a nitrogen flow rate of 100 mL / min. The reaction temperature was set to 350°C and the heating rate was 5°C / min, and the reactor began to heat up. After the catalyst bed reached the reaction temperature, the nitrogen flow rate was adjusted to 20 mL / min, and at the same time, 2,3-dichloro-1,1,1-trifluoropropane with a purity of 99.6% was continuously introduced into the second reactor at a rate of 5.0 g / h to start the reaction.

[0130] Online GC and GC / MS analysis of the gas mixture flowing out of the reactor showed that the conversion rate of 2,3-dichloro-1,1,1-trifluoropropane was 99.4%, and the selectivity of the product 2-chloro-3,3,3-trifluoropropene was 97.1%.

[0131] Example 56

[0132] This embodiment provides a method for preparing 2,3,3,3-tetrafluoropropene, which includes an addition process and a dehydrochlorination process. The specific steps are as follows:

[0133] (1) Addition process:

[0134] 20.2 g (0.24 mol) of anhydrous aluminum trifluoride, 18.7 g (0.14 mol) of anhydrous aluminum chloride, and 6.1 g (0.06 mol) of aluminum oxide were weighed and added to a reactor. The reactor lid was sealed and vacuumed. 225 g of dichloromethane was then added using a sampler. The reactor was placed in a -30°C cooling circulation pump for 30 minutes. After removing the reactor, 125 g of difluoromethane was added. Trifluoroethylene was pressurized and fed at a rate of 75 g / h using a metering pump for 5 hours. After the additions were completed, the above raw materials were reacted for another 5 hours at a temperature of 30°C and a stirring speed of 300 rpm.

[0135] During the reaction, the reaction pressure and temperature in the reactor were recorded, and the trifluoroethylene content in the reactor was monitored. Samples were taken every 30 minutes and analyzed by gas chromatography. The results showed that the trifluoroethylene content in the reaction system was ≤2.5% throughout the reaction. After the reaction was completed, the temperature in the reactor cooled to room temperature, and the gas phase valve was opened to collect the gaseous materials (unreacted difluoromethane and a small amount of addition product). The liquid phase in the reactor was filtered, and the solid portion was the addition catalyst. The filtrate was subjected to distillation to obtain the target product, 3-chloro-1,1,1,2-tetrafluoropropane, with a purity of 99.8%.

[0136] The liquid and gaseous materials of the addition reaction were subjected to chromatographic analysis, respectively, and the calculations showed that the conversion of trifluoroethylene was 98.6%, the selectivity of 3-chloro-1,1,1,2-tetrafluoropropane was 88.5%, the selectivity of the by-product 1,3-dichloro-1,1,2-trifluoropropane was 9.4%, and a small amount of other by-products were generated (qualitative analysis by GC-MS showed that they were isomers of 3-chloro-1,1,1,2-tetrafluoropropane).

[0137] (2) Dehydrochlorination process:

[0138] A reaction tube made of Inconel alloy with an inner diameter of 19 mm and a length of 800 mm was used as the second reactor. Coconut shell activated carbon with a volume of 20 mL and a particle size of 10 to 20 mesh was filled into the middle of the second reactor. The reaction pipeline was connected and nitrogen was introduced for purging at a nitrogen flow rate of 100 mL / min. The reaction temperature was set to 350°C and the heating rate was 5°C / min, and the reactor began to heat up. After the catalyst bed reached the reaction temperature, the nitrogen flow rate was adjusted to 20 mL / min, and at the same time, 3-chloro-1,1,1,2-tetrafluoropropane with a purity of 99.8% was continuously introduced into the second reactor at a rate of 5.0 g / h to start the reaction.

[0139] Online GC and GC / MS analysis of the gas mixture flowing out of the reactor showed that the conversion rate of 3-chloro-1,1,1,2-tetrafluoropropane was 99.0%, and the selectivity of the product 2,3,3,3-tetrafluoropropene was 99.2%.

[0140] Example 57

[0141] This embodiment provides a method for preparing 1-chloro-2,3,3,3-tetrafluoropropene, which includes an addition process and a dehydrochlorination process. The specific steps are as follows:

[0142] (1) Addition process:

[0143] 20.2 g (0.24 mol) of anhydrous aluminum trifluoride, 18.7 g (0.14 mol) of anhydrous aluminum chloride, and 6.1 g (0.06 mol) of aluminum oxide were weighed and added to a reactor. The reactor lid was sealed and vacuumed. 225 g of dichloromethane was then added using a sampler. The reactor was placed in a -30°C cooling circulation pump for 30 minutes. After removing the reactor, 125 g of difluoromethane was added. Chlorotrifluoroethylene was pressure-fed at a rate of 100 g / h using a metering pump for 5 hours. After the additions were completed, the above raw materials were reacted for another 5 hours at a temperature of 30°C and a stirring speed of 300 rpm.

[0144] During the reaction, the reaction pressure and temperature in the reactor were recorded, and the chlorotrifluoroethylene content in the reactor was monitored. Samples were taken every 30 minutes and analyzed by gas chromatography. The results showed that the chlorotrifluoroethylene content in the reaction system was ≤3.0% throughout the reaction. After the reaction was completed, the temperature in the reactor cooled to room temperature, and the gas phase valve was opened to collect the gaseous materials (unreacted difluoromethane and a small amount of addition product). The liquid phase in the reactor was filtered, and the solid portion was the addition catalyst. The filtrate was subjected to distillation to obtain the target product, 2,3-dichloro-1,1,1,2-tetrafluoropropane, with a purity of 99.5%.

[0145] The liquid and gaseous materials of the addition reaction were subjected to chromatographic analysis, respectively, and the calculation results showed that the conversion of trifluorochloroethylene was 97.1%, the selectivity of 2,3-dichloro-1,1,1,2-tetrafluoropropane was 79.8%, the selectivity of by-product 1,2,3-trichloro-1,1,2-trifluoropropane was 12.6%, and a small amount of other by-products were generated (qualitative analysis by GC-MS showed that they were isomers of 2,3-dichloro-1,1,1,2-tetrafluoropropane).

[0146] (2) Dehydrochlorination process:

[0147] A reaction tube made of Inconel alloy with an inner diameter of 19 mm and a length of 800 mm was used as the second reactor. Coconut shell activated carbon with a volume of 20 mL and a particle size of 10 to 20 mesh was filled into the middle of the second reactor. The reaction pipeline was connected and nitrogen was introduced for purging at a nitrogen flow rate of 100 mL / min. The reaction temperature was set to 350°C and the heating rate was 5°C / min, and the reactor began to heat up. After the catalyst bed reached the reaction temperature, the nitrogen flow rate was adjusted to 20 mL / min, and at the same time, 2,3-dichloro-1,1,1,2-tetrafluoropropane with a purity of 99.5% was continuously introduced into the second reactor at a rate of 5.0 g / h to start the reaction.

[0148] Online GC and GC / MS analysis of the gas mixture flowing out of the reactor showed that the conversion rate of 2,3-dichloro-1,1,1,2-tetrafluoropropane was 95.9% and the selectivity of the product 1-chloro-2,3,3,3-tetrafluoropropene was 98.7%.

[0149] Example 58

[0150] The operation of this embodiment is the same as that of Example 54, except that in the dehydrochlorination step, 10-20 mesh coal-based activated carbon is used instead of coconut shell-based activated carbon, and other operations remain unchanged.

[0151] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 3-chloro-1,1,1-trifluoropropane was 99.2% and the selectivity of the product 3,3,3-trifluoropropene reached 95.1%.

[0152] Example 59

[0153] The operation of this embodiment is the same as that of Example 54, except that in the dehydrochlorination step, the reaction temperature is reduced to 300° C., and other operations remain unchanged.

[0154] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 3-chloro-1,1,1-trifluoropropane was 75.8% and the selectivity of the product 3,3,3-trifluoropropene was 99.2%.

[0155] Example 60

[0156] The operation of this embodiment is the same as that of Example 54, except that in the dehydrochlorination step, the reaction temperature is reduced to 320°C, and other operations remain unchanged.

[0157] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 3-chloro-1,1,1-trifluoropropane was 86.9% and the selectivity of the product 3,3,3-trifluoropropene was 99.1%.

[0158] Example 61

[0159] The operation of this embodiment is the same as that of Example 54, except that the dehydrochlorination process adopts a liquid phase process. The specific steps are as follows:

[0160] An Inconel alloy autoclave with a volume of 250 mL was used as the second reactor, and 20 g of 3-chloro-1,1,1-trifluoropropane (purity 99.7%), 40 g of 25 wt% KOH solution and 1 g of tetramethylammonium hydroxide were added to the reactor respectively. After the reactor was sealed, 1.0 MPa nitrogen was passed through to replace the air in the reactor, and the process was repeated three times. After the air in the reactor was completely replaced, the reaction temperature was set to 50 ° C, the stirring rate was 300 rpm, and the reaction time was 5 h.

[0161] After the reaction is completed, the reaction product is separated and distilled to obtain the target product 3,3,3-trifluoropropene. The reaction product is analyzed by gas chromatography, and it is known that the conversion rate of 3-chloro-1,1,1-trifluoropropane is 90.8%, and the selectivity of the main product 3,3,3-trifluoropropene is 91.2%.

[0162] Example 62

[0163] The operation of this embodiment is the same as that of Example 61, with the only difference being that in the dehydrochlorination step, 25 wt % NaOH solution (40 g) is used instead of 25 wt % KOH solution, and other operations remain unchanged.

[0164] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 3-chloro-1,1,1-trifluoropropane was 70.6% and the selectivity of the main product 3,3,3-trifluoropropene was 81.6%.

[0165] Example 63

[0166] The operation of this example is the same as that of Example 61, except that in the dehydrochlorination step, the reaction temperature is increased to 80°C, and other operations remain unchanged.

[0167] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 3-chloro-1,1,1-trifluoropropane was 95.1% and the selectivity of the main product 3,3,3-trifluoropropene was 80.8%.

[0168] Example 64

[0169] The operation of this embodiment is the same as that of Example 55, except that in the dehydrochlorination step, 10-20 mesh coal-based activated carbon is used instead of coconut shell-based activated carbon, and other operations remain unchanged.

[0170] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 2,3-dichloro-1,1,1-trifluoropropane was 98.6% and the selectivity of the product 2-chloro-3,3,3-trifluoropropene was 96.7%.

[0171] Example 65

[0172] The operation of this embodiment is the same as that of Example 55, except that in the dehydrochlorination step, the reaction temperature is reduced to 300° C., and other operations remain unchanged.

[0173] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 2,3-dichloro-1,1,1-trifluoropropane was 78.8% and the selectivity of the product 2-chloro-3,3,3-trifluoropropene was 97.8%.

[0174] Example 66

[0175] The operation of this embodiment is the same as that of Example 55, except that in the dehydrochlorination step, the reaction temperature is reduced to 320°C, and other operations remain unchanged.

[0176] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 2,3-dichloro-1,1,1-trifluoropropane was 86.8% and the selectivity of the product 2-chloro-3,3,3-trifluoropropene was 98.1%.

[0177] Example 67

[0178] The operation of this embodiment is the same as that of embodiment 55, except that the dehydrochlorination process adopts a liquid phase process. The specific steps are as follows:

[0179] An Inconel alloy autoclave with a volume of 250 mL was used as the second reactor, and 20 g of 2,3-dichloro-1,1,1-trifluoropropane (purity 99.6%), 40 g of 25 wt% KOH solution and 1 g of tetramethylammonium hydroxide were added to the reactor respectively. After the reactor was sealed, 1.0 MPa nitrogen was passed through to replace the air in the reactor, and the process was repeated three times. After the air in the reactor was completely replaced, the reaction temperature was set to 50 ° C, the stirring rate was 300 rpm, and the reaction time was 5 h.

[0180] After the reaction, the reaction product was separated and distilled to obtain the target product, 2-chloro-3,3,3-trifluoropropene. Gas chromatography analysis of the reaction product revealed that the conversion rate of 2,3-dichloro-1,1,1-trifluoropropane was 83.9%, and the selectivity of the product, 2-chloro-3,3,3-trifluoropropene, was 96.9%.

[0181] Example 68

[0182] The operation of this embodiment is the same as that of Example 67, except that in the dehydrochlorination step, 25 wt % NaOH solution (40 g) is used instead of 25 wt % KOH solution, and other operations remain unchanged.

[0183] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 2,3-dichloro-1,1,1-trifluoropropane was 70.8% and the selectivity of the product 2-chloro-3,3,3-trifluoropropene was 93.6%.

[0184] Example 69

[0185] The operation of this example is the same as that of Example 67, except that in the dehydrochlorination step, the reaction temperature is increased to 80°C, and other operations remain unchanged.

[0186] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 2,3-dichloro-1,1,1-trifluoropropane was 89.7% and the selectivity of the product 2-chloro-3,3,3-trifluoropropene was 92.9%.

[0187] Example 70

[0188] The operation of this embodiment is the same as that of Example 56, except that in the dehydrochlorination step, 10-20 mesh coal-based activated carbon is used instead of coconut shell-based activated carbon, and other operations remain unchanged.

[0189] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 3-chloro-1,1,1,2-tetrafluoropropane was 95.0% and the selectivity of the product 2,3,3,3-tetrafluoropropene was 99.1%.

[0190] Example 71

[0191] The operation of this embodiment is the same as that of Example 56, except that in the dehydrochlorination step, the reaction temperature is reduced to 300° C., and other operations remain unchanged.

[0192] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 3-chloro-1,1,1,2-tetrafluoropropane was 80.8% and the selectivity of the product 2,3,3,3-tetrafluoropropene was 99.2%.

[0193] Example 72

[0194] The operation of this example is the same as that of Example 56, except that in the dehydrochlorination step, the reaction temperature is reduced to 320°C, and other operations remain unchanged.

[0195] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 3-chloro-1,1,1,2-tetrafluoropropane was 85.9% and the selectivity of the product 2,3,3,3-tetrafluoropropene was 99.1%.

[0196] Example 73

[0197] The operation of this embodiment is the same as that of Example 56, except that the dehydrochlorination process adopts a liquid phase process. The specific steps are as follows:

[0198] An Inconel alloy autoclave with a volume of 250 mL was used as the second reactor, and 20 g of 3-chloro-1,1,1,2-tetrafluoropropane (purity 99.8%), 40 g of 25 wt% KOH solution and 1 g of tetramethylammonium hydroxide were added to the reactor respectively. After the reactor was sealed, 1.0 MPa nitrogen was passed through to replace the air in the reactor, and the process was repeated three times. After the air in the reactor was completely replaced, the reaction temperature was set to 50 ° C, the stirring rate was 300 rpm, and the reaction time was 5 h.

[0199] After the reaction, the reaction product was separated and distilled to obtain the target product 2,3,3,3-tetrafluoropropene. Gas chromatography analysis of the reaction product showed that the conversion rate of 3-chloro-1,1,1,2-tetrafluoropropane was 90.9% and the selectivity of the product 2,3,3,3-tetrafluoropropene was 96.7%.

[0200] Example 74

[0201] The operation of this embodiment is the same as that of Example 73, with the only difference being that in the dehydrochlorination step, 25 wt % NaOH solution (40 g) is used instead of 25 wt % KOH solution, and other operations remain unchanged.

[0202] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 3-chloro-1,1,1,2-tetrafluoropropane was 88.8% and the selectivity of the product 2,3,3,3-tetrafluoropropene was 97.5%.

[0203] Example 75

[0204] The operation of this embodiment is the same as that of Example 73, except that in the dehydrochlorination step, the reaction temperature is increased to 80°C, and other operations remain unchanged.

[0205] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 3-chloro-1,1,1,2-tetrafluoropropane was 92.4% and the selectivity of the product 2,3,3,3-tetrafluoropropene was 91.8%.

[0206] Example 76

[0207] The operation of this embodiment is the same as that of Example 57, except that in the dehydrochlorination step, 10-20 mesh coal-based activated carbon is used instead of coconut shell-based activated carbon, and other operations remain unchanged.

[0208] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 2,3-dichloro-1,1,1,2-tetrafluoropropane was 90.8% and the selectivity of the product 1-chloro-2,3,3,3-tetrafluoropropene was 95.1%.

[0209] Example 77

[0210] The operation of this embodiment is the same as that of Example 57, except that in the dehydrochlorination step, the reaction temperature is reduced to 300° C., and other operations remain unchanged.

[0211] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 2,3-dichloro-1,1,1,2-tetrafluoropropane was 67.8% and the selectivity of the product 1-chloro-2,3,3,3-tetrafluoropropene was 97.9%.

[0212] Example 78

[0213] The operation of this embodiment is the same as that of Example 57, except that in the dehydrochlorination step, the reaction temperature is reduced to 320°C, and other operations remain unchanged.

[0214] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 2,3-dichloro-1,1,1,2-tetrafluoropropane was 80.4% and the selectivity of the product 1-chloro-2,3,3,3-tetrafluoropropene was 96.7%.

[0215] Example 79

[0216] The operation of this embodiment is the same as that of Example 57, except that the dehydrochlorination process adopts a liquid phase process. The specific steps are as follows:

[0217] An Inconel alloy autoclave with a volume of 250 mL was used as the second reactor, and 20 g of 2,3-dichloro-1,1,1,2-tetrafluoropropane (purity 99.5%), 40 g of 25 wt% KOH solution and 1 g of tetramethylammonium hydroxide were added to the reactor respectively. After the reactor was sealed, 1.0 MPa nitrogen was passed through to replace the air in the reactor, and the process was repeated three times. After the air in the reactor was completely replaced, the reaction temperature was set to 50 ° C, the stirring rate was 300 rpm, and the reaction time was 5 h.

[0218] After the reaction, the reaction product was separated and distilled to obtain the target product, 1-chloro-2,3,3,3-tetrafluoropropene. Gas chromatography analysis of the reaction product revealed that the conversion of 2,3-dichloro-1,1,1,2-tetrafluoropropane was 84.1%, and the selectivity of the product, 1-chloro-2,3,3,3-tetrafluoropropene, was 97.8%.

[0219] Example 80

[0220] The operation of this embodiment is the same as that of Example 79, except that in the dehydrochlorination step, 25 wt % NaOH solution (40 g) is used instead of 25 wt % KOH solution, and other operations remain unchanged.

[0221] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 2,3-dichloro-1,1,1,2-tetrafluoropropane was 81.0% and the selectivity of the product 1-chloro-2,3,3,3-tetrafluoropropene was 97.3%.

[0222] Example 81

[0223] The operation of this example is the same as that of Example 79, except that in the dehydrochlorination step, the reaction temperature is increased to 80°C, and other operations remain unchanged.

[0224] Online GC and GC / MS analysis of the dehydrochlorination product showed that the conversion of 2,3-dichloro-1,1,1,2-tetrafluoropropane was 89.9% and the selectivity of the product 1-chloro-2,3,3,3-tetrafluoropropene was 90.9%.

Claims

1. A method for preparing fluorochloropropane by addition process, characterized in that: The method comprises: in the presence of an addition catalyst, dichloromethane, difluoromethane and a fluorine-containing olefin shown in the following formula I are subjected to a liquid phase addition reaction to prepare a fluorochloropropane shown in the structural formula II, and the reaction formula is as follows: In the formula, R1 is selected from hydrogen or fluorine, and R2 is selected from hydrogen or chlorine; The addition catalyst is a mixed catalyst formed by metal fluoride, metal chloride and metal oxide, wherein the metal is selected from group IIIA, IVB or VA metal elements.

2. The method for preparing fluorochloropropane according to claim 1, characterized in that: The metal is selected from at least one of Al, Sb, Ti, Zr, Hf, Nb, Ta, Ga or In.

3. The method for preparing fluorochloropropane according to claim 2, characterized in that: The metal fluoride is selected from at least one of AlF3, TiF4, SbF5, ZrF4 or HfF4; The metal chloride is selected from at least one of AlCl3, TiCl4, SbCl5, ZrCl4 or HfCl4; The metal oxide is selected from at least one of Al2O3, TiO2, Sb2O5, ZrO2 or HfO2.

4. The method for preparing fluorochloropropane according to any one of claims 1 to 3, characterized in that: The metal in the metal fluoride, metal chloride and metal oxide is the same metal.

5. The method for preparing fluorochloropropane according to claim 4, characterized in that: In the addition catalyst, the molar content of fluorine element accounts for 40-70% of the total molar content of anions, the molar content of chlorine element accounts for 20-50% of the total molar content of anions, and the molar content of oxygen element accounts for 10-30% of the total molar content of anions.

6. The method for preparing fluorochloropropane according to claim 5, characterized in that: In the addition catalyst, the molar content of fluorine element accounts for 50-60% of the total molar amount of anions, the molar content of chlorine element accounts for 30-40% of the total molar amount of anions, and the molar content of oxygen element accounts for 10-20% of the total molar amount of anions.

7. The method for preparing fluorochloropropane according to any one of claims 1 to 6, characterized in that: During the reaction, the content of fluorine-containing olefin in the reaction system is monitored and controlled to be ≤5%.

8. The method for preparing fluorochloropropane according to claim 1, characterized in that: The fluorine-containing olefin is selected from at least one of vinylidene fluoride, difluorochloroethylene, trifluoroethylene or trifluorochloroethylene, and the fluorochloropropane is selected from at least one of 1-chloro-3,3,3-trifluoropropane, 2,3-dichloro-1,1,1-trifluoropropane, 3-chloro-1,1,1,2-tetrafluoropropane or 2,3-dichloro-1,1,1,2-tetrafluoropropane.

9. The method for preparing fluorochloropropane according to claim 1, characterized in that: The molar ratio of dichloromethane to fluorine-containing olefin is (0.5-2):

1.

10. The method for preparing fluorochloropropane according to claim 1, characterized in that: The ratio of dichloromethane to the addition catalyst is 2 to 10.

11. The method for preparing fluorochloropropane according to claim 1, characterized in that: During the addition reaction, the total amount of fluorinated olefin added satisfies the following relationship: and in, is the molar amount of fluorinated olefin, is the molar amount of difluoromethane, is the molar amount of dichloromethane.

12. The method for preparing fluorochloropropane according to claim 1, characterized in that: During the addition reaction, the fluorinated olefin is continuously fed under pressure through a metering pump.

13. The method for preparing fluorochloropropane according to claim 12, characterized in that: When it is monitored during the reaction that the content of fluorine-containing olefin in the reaction system is greater than 5%, the feed rate of the fluorine-containing olefin is reduced.

14. The method for preparing fluorochloropropane according to claim 12, characterized in that: The addition reaction temperature is -20 to 100°C, and the reaction time is 4 to 20 hours.

15. The method for preparing fluorochloropropane according to claim 14, characterized in that: The addition reaction temperature is 0-80°C, and the reaction time is 6-15h.

16. A method for preparing fluorine-containing propylene, characterized in that: The preparation method comprises: (1) preparing a fluorochloropropane intermediate by the method described in any one of claims 1 to 15; (2) The fluorochloropropane intermediate is subjected to a dehydrochlorination reaction under the action of activated carbon or a metal alkali solution to prepare fluorinated propene.

17. The method for preparing fluorine-containing propylene according to claim 16, characterized in that: In step (1), a fluorochloropropane reaction solution is prepared by the method described in any one of claims 1 to 15, and the reaction solution is subjected to solid-liquid separation to remove the addition catalyst, and then distilled to obtain a fluorochloropropane intermediate.

18. The method for preparing fluorine-containing propylene according to claim 16, characterized in that: In step (2), the activated carbon catalyst is selected from fruit shell activated carbon, coal-based activated carbon or wood-based activated carbon.

19. The method for preparing fluorine-containing propylene according to claim 18, characterized in that: In step (2), the dehydrochlorination reaction temperature is 200-500°C.

20. The method for preparing fluorine-containing propylene according to claim 16, characterized in that: In step (2), the metal alkali solution is selected from at least one of sodium hydroxide solution, potassium hydroxide solution, sodium carbonate solution, potassium carbonate solution, sodium bicarbonate solution and potassium bicarbonate solution, and the mass concentration of the metal alkali solution is 5 to 60 wt%.

21. The method for preparing fluorine-containing propylene according to claim 20, characterized in that: In step (2), the fluorochloropropane intermediate is subjected to a dehydrochlorination reaction in the presence of a metal alkali solution and a quaternary ammonium salt to prepare fluorinated propylene, wherein the quaternary ammonium salt is selected from at least one of tetrabutylammonium bromide, tetramethylammonium hydroxide and tetramethylammonium chloride.

22. The method for preparing fluorinated propylene according to claim 20 or 21, characterized in that: In step (2), the molar ratio of the fluorochloropropane intermediate to the metal base is 1:(0.1-5), and the dehydrochlorination reaction temperature is 10-100°C.

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