Method for preparing fluorochloropropane through addition method

Abstract

The invention discloses a method for preparing fluorochloropropane by an addition process, which comprises the following steps: under the action of an addition catalyst, dichloromethane, difluoromethane and fluorine-containing olefin with the general formula of CF2 = CR1R2 are subjected to liquid phase addition reaction to prepare fluorochloropropane with the general formula of CF3CR1R2CH2Cl, in the reaction process, the content of fluorine-containing olefin in a reaction system is monitored and controlled to be smaller than or equal to 5%, the addition catalyst is a mixed catalyst formed by metal fluoride, metal chloride and metal oxide, and metal is selected from group IIIA, IVB or VA metal elements. The method disclosed by the invention has the advantages of simple process flow, mild reaction conditions, easiness in product separation, high product purity, remarkably prolonged service life of the catalyst and the like.

Description

Technical Field

[0001] The present invention relates to the preparation of fluorochloropropanes, and particularly to a method for preparing fluorochloropropanes of the general formula CF3CR1R2CH2Cl by reacting fluorinated olefins CF2=CR1R2 with dichloromethane and difluoromethane under the action of a metal Lewis acid mixed catalyst. Background Art

[0002] 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 fluorinated fine chemicals, which can be used to prepare novel refrigerants HCFO-1224yd and HFO-1234yf through dehalogenation reactions, and thus have great application potential.

[0003] Currently, there are few relevant 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.

[0004] (I) Research on the Synthesis of 1-Chloro-3,3,3-trifluoropropane

[0005] Patent US2644845A discloses a preparation method of 1-chloro-3,3,3-trifluoropropane using 1,1,1-trifluoropropane and chlorine as raw materials through photochlorination. This preparation method has a simple process, but the product yield is relatively low. Under the irradiation of a 200W incandescent lamp and a reaction temperature of 110°C, the yield of 1-chloro-3,3,3-trifluoropropane is only 56%.

[0006] Patent CN1488614A discloses a two-step preparation method of 1-chloro-3,3,3-trifluoropropane, including: 1) under the action of ferric trichloride or a phosphate ester initiator, carbon tetrachloride and ethylene are used to prepare the intermediate 1,3,3,3-tetrachloropropane; 2) under the action of stannic chloride or titanium tetrachloride catalyst, anhydrous hydrogen fluoride liquid-phase fluorinates 1,3,3,3-tetrachloropropane to generate 1-chloro-3,3,3-trifluoropropane. This process route has low requirements for reaction equipment, low energy consumption, and easy separation and purification of products, but there is a problem of low raw material utilization rate. Under preferred conditions, the conversion rate of carbon tetrachloride is 75%, and the product yield in the fluorination step is only 65%.

[0007] Patent CN107162871A discloses a preparation method of 1-chloro-3,3,3-trifluoropropane by a two-step method. Using activated carbon as a catalyst and trifluoromethane as the starting material, a catalytic chlorination reaction occurs in a fixed-bed reactor to obtain the intermediate trifluorochloromethane. Then, trifluorochloromethane and ethylene undergo a telomerization reaction under the action of an iron-molybdenum catalyst to generate 1-chloro-3,3,3-trifluoropropane. The yield of this process route can reach 86%, but the intermediate product needs to go through purification steps such as alkali washing, drying, and extraction, with complex post-treatment. At the same time, the reaction temperature is relatively high, and the gas-phase chlorination temperature exceeds 300 °C.

[0008] (II) Research on the synthesis of 2,3-dichloro-1,1,1-trifluoropropane

[0009] Patent CN101168494A discloses a method for liquid-phase fluorination synthesis of 2,3-dichloro-1,1,1-trifluoropropane using 1,1,1,2,3-pentachloropropane as the raw material under the action of catalysts such as chromium fluoride, magnesium fluoride, and titanium fluoride. This process route is simple and the raw materials are easily available, but the product yield is relatively low. When reacting at a reaction temperature of 90 - 130 °C for 4 - 10 h, the product yield is only about 85%.

[0010] Patent CN10197936A discloses a preparation method of 2,3-dichloro-1,1,1-trifluoropropane using 1,1,1-trifluoropropene and chlorine as raw materials, under the irradiation of an ultraviolet lamp, in a tubular or autoclave reactor. The raw material conversion rate of this method reaches 95%, and the selectivity exceeds 90%, but it has high requirements for equipment and great harm to the human body.

[0011] (III) Research on the synthesis of 3-chloro-1,1,1,2-tetrafluoropropane

[0012] Patent WO2019003896A discloses a method for preparing 2-chloro-1,1,1,2-tetrafluoropropane and / or 3-chloro-1,1,1,2-tetrafluoropropane by liquid-phase photocatalytic chlorination reaction using 1,1,1,2-tetrafluoropropane as the raw material. This 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 the separation and purification difficult.

[0013] Patent CN115023490A discloses a preparation method of 3-chloro-1,1,1,2-tetrafluoropropane. Hydrogenation of 2,3,3,3-tetrafluoropropene is carried out under a palladium-carbon catalyst to obtain 1,1,1,2-tetrafluoropropane, and then it reacts with chlorine to obtain a mixture of HCFC-244bb, HCFC-244eb, and HCFC-234ea. Then, this mixture is distilled and purified to obtain 3-chloro-1,1,1,2-tetrafluoropropane, but this patent does not disclose the reaction conditions and reaction effects.

[0014] (4) Research on the Synthesis of 2,3-Dichloro-1,1,1,2-Tetrafluoropropane

[0015] Patents CN103524293A, CN105753638A, CN105777484A, etc. disclose a method for synthesizing 2,3-dichloro-1,1,1,2-tetrafluoropropane by two-step gas-phase and liquid-phase fluorination using a compound with the general formula CF 3-X Cl x CH 2-y Cl y CH 3-z Cl z as the starting material under the action of a fluorination catalyst. Under preferred conditions, the conversion rate of the raw material 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, the liquid-phase fluorination temperature is 110 - 150 °C, and the reaction process requires the combination of gas-phase fluorination and liquid-phase fluorination, with relatively high process difficulty. Moreover, the service life of the catalyst is not disclosed in this patent.

[0016] In summary, in the prior art, fluorochloropropane is synthesized by chlorination or fluorination, but the product yield is relatively low; or it is obtained through a two-step reaction, but the technical route is relatively complex, and the yield of the target product is not high either. The reaction conditions are harsh, and there are problems such as high difficulty in product separation and purification. Summary of the Invention

[0017] To solve the above technical problems, the present invention provides a method for preparing fluorochloropropane by an addition method, which has the advantages of simple process, mild reaction conditions, easy product separation, good product purity, and significantly improved catalyst life.

[0018] The object of the present invention is achieved by the following technical solutions:

[0019] A method for preparing fluorochloropropane by an addition method, the method comprising: under the action of an addition catalyst, dichloromethane, difluoromethane and a fluorinated olefin represented by Formula I are subjected to a liquid-phase addition reaction to obtain a fluorochloropropane represented by Structural Formula II, and the reaction formula is as follows:

[0020]

[0021] In the formula, R1 is selected from hydrogen or fluorine, and R2 is selected from hydrogen or chlorine;

[0022] The addition catalyst is a mixed catalyst formed by a metal fluoride, a metal chloride and a metal oxide, and the metal therein is selected from Group IIIA, Group IVB or Group VA metal elements. 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; and 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] Even more preferably, the metal in the metal fluoride, metal chloride, and metal oxide is the same metal.

[0029] In the addition catalyst of the present invention, fluorine, chlorine, and oxygen respectively come from the corresponding metal fluoride, metal chloride, and metal oxide. By changing the contents of the metal fluoride, metal chloride, and metal oxide in the addition catalyst, the contents of fluorine, chlorine, and oxygen elements in the addition catalyst can be adjusted.

[0030] 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 raw materials difluoromethane and dichloromethane to form active ions such as F-, CH2F + , Cl - , CH2Cl + etc. The addition reaction of halogenated hydrocarbons and halogenated olefins belongs to electrophilic addition. According to Markovnikov's rule and the electronegativity of charged groups, F - , CH2Cl +It can undergo a regioselective addition reaction with fluoroolefin compounds to obtain the addition product CF3CR1R2CH2Cl with high selectivity.

[0032] The fluoroolefins described in the present invention are selected from at least one of vinylidene fluoride (CF2=CH2F), vinylidene chloride (CF2=CHCl), trifluoroethylene (CF2=CHF), or trichloroethylene (CF2=CFCl), and their 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 fluorochloropropane described in the present invention, the ratio of raw materials, the ratio of raw materials to the addition catalyst, the reaction temperature, the reaction time, the feeding method, etc. will all affect the reaction results, especially have a greater impact on the catalyst life and the selectivity of the target product. Therefore,

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

[0035] Furthermore, the specific gravity of dichloromethane to the addition catalyst ≥ 2; when the specific gravity is less than 2, the liquid holdup in the reaction kettle is insufficient, and the reaction system cannot be effectively stirred, resulting in a decrease in the product yield. Preferably, the specific gravity of dichloromethane to the addition catalyst is 2 - 10; more preferably, the specific gravity of dichloromethane to the addition catalyst is 4 - 6.

[0036] The present invention has found through research that during the preparation of fluorochloropropane by the addition method, the raw material fluoroolefin is easily adsorbed on the active center of the catalyst and polymerizes, thereby preventing the contact between the reactants and the active center, resulting in a decrease in the catalyst activity and even deactivation of the catalyst. Therefore, in the reaction process of the present invention, the content of fluoroolefin in the reaction system is monitored, and the content of fluoroolefin is controlled ≤ 5%, preferably controlled ≤ 3%, more preferably controlled ≤ 1%; when the content of fluoroolefin in the reaction system > 5%, the active center of the catalyst will be gradually occupied by the fluoroolefin polymer, resulting in the gradual deactivation of the catalyst.

[0037] To maximize the limitation of the polymerization of fluorinated olefins at the active centers during the reaction process and further improve the service life of the catalyst, the fluorinated olefins in the present invention are continuously fed under pressure by a metering pump, and the continuous feeding rate mainly depends on the consumption rate of fluorinated olefins in the reaction system. To avoid the accumulation of fluorinated olefins in the reaction system, generally, the feeding rate of fluorinated olefins is 20 - 120 g / h, preferably 60 - 80 g / h. Once it is monitored that the content of fluorinated olefins in the reaction system > 5%, the feeding rate of fluorinated olefins is reduced. During the actual operation process, when the content of fluorinated olefins in the reaction system approaches 5% or reaches 5%, the feeding rate of fluorinated olefins can be appropriately reduced.

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

[0039] And

[0040] Wherein, is the molar amount of fluorinated olefins, is the molar amount of difluoromethane, is the molar amount of dichloromethane. During the actual reaction process, the fluorinated olefins are continuously fed. Once it is detected that the raw materials difluoromethane or dichloromethane in the reaction system are consumed up, the feeding of fluorinated olefins is immediately stopped. At this time, the total feeding amount of fluorinated olefins must satisfy the above relationship, so as to avoid the polymerization of excessive fluorinated olefins on the active centers and 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 fluorochloropropane of the present invention, after adding metal fluoride, metal chloride and metal oxide to a reactor (reaction kettle or tubular reactor) according to a certain ratio, dichloromethane is added to the reactor. Difluoromethane can be added to the reactor together with dichloromethane, or continuously introduced into the reactor, or mixed with fluorinated olefins to form a mixed gas and then continuously introduced into the reactor.

[0043] Or, the addition catalyst and dichloromethane are formed into a uniformly mixed material and then continuously introduced into the reactor, and difluoromethane and fluorinated olefins are respectively continuously introduced into this reactor or mixed and then continuously introduced into this reactor.

[0044] In the method for preparing fluorochloropropane of the present invention, any of the above-mentioned feeding methods can be adopted, as long as the continuous feeding of fluorinated olefins is ensured. Preferably, the addition catalyst is pre-filled into the reactor first, and then dichloromethane and difluoromethane are added, and the fluorinated olefins are continuously fed under pressure by a metering pump.

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

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

[0047] Since the saturated vapor pressures of difluoromethane and fluoroolefins are much greater than that of dichloromethane, dichloromethane mainly exists in a liquid state during the reaction process. Coupled with the fact that the fluorochloropropane produced by the addition reaction is a liquid, therefore, the addition process of the present invention is preferably a solvent-free reaction, and no other solvents need to be added during the reaction process, which can effectively reduce the separation steps of the product.

[0048] Specifically, the addition product after the reaction can be effectively separated from the addition catalyst and the reaction product by filtration. Among the reaction products, the boiling points of the target product CF3CR1R2CH2Cl and the by-product CF2ClCR1R2CH2Cl differ by 15 to 30 °C, and the target product with a purity ≥ 99.7% can be obtained by rectification or distillation.

[0049] The fluorochloropropane synthesized by the present invention, as a fluorine-containing intermediate, can obtain important fluoroolefins such as HFO-1243zf, HFO-1234yf, and HCFO-1224yd through a dehalogenation step.

[0050] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0051] 1. The present invention only needs one-step addition reaction to prepare fluorochloropropane, with a simple process flow, mild reaction conditions, and high product yield.

[0052] 2. The present invention monitors the content of fluoroolefins in the reaction system and coordinates the feed adjustment to inhibit the polymerization of fluoroolefins on the active centers, significantly improving the service life of the catalyst.

[0053] 3. The post-treatment operation of the ternary liquid-phase addition process of the present invention is simple, the products are easy to separate, and the product purity is high, which is very suitable for industrial application. Specific Embodiments

[0054] The present invention will be further described below in conjunction with 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 alternative solutions, improvement solutions, and equivalent solutions that may be included within the scope of the claims.

[0055] Example 1

[0056] This example presents a preparation method of 1-chloro-3,3,3-trifluoropropane, which includes the following steps:

[0057] Weigh 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 respectively and add them to the reaction kettle. After sealing the kettle cover, evacuate the reaction kettle, then use a sampler to add 225 g of dichloromethane into the kettle, and place the reaction kettle in a cooling circulation pump at -30°C for 30 min. After taking out the reaction kettle, continue to add 125 g of difluoromethane, and vinylidene fluoride is fed under pressure through a metering pump at a flow rate of 60 g / h for 5 h. After the feeding is completed, the above raw materials continue to react for 5 h at a reaction temperature of 30°C and a stirring speed of 300 rpm.

[0058] During the reaction process, record the changes in the reaction pressure and temperature in the kettle, and at the same time monitor the content of vinylidene fluoride in the reaction kettle. Specifically, take samples every 30 minutes and analyze them by gas chromatography. The results show that during the whole reaction process, the content of vinylidene fluoride in the reaction system ≤ 2.8%. After the reaction is completed, wait for the temperature in the reaction kettle to drop to room temperature, open the gas valve to collect the gas-phase materials (unreacted difluoromethane and a small amount of addition products), filter the liquid-phase materials in the reaction kettle, the solid part is the addition catalyst, and the filtrate is treated by distillation to obtain the target product 1-chloro-3,3,3-trifluoropropane with a purity of 99.7%.

[0059] Conduct chromatographic analysis on the liquid-phase materials and gas-phase materials of the addition reaction respectively, and calculate to obtain: the conversion rate of vinylidene fluoride is 96.2%, the selectivity of 1-chloro-3,3,3-trifluoropropane is 85.6%, the selectivity of by-product 1,3-dichloro-1,1-difluoropropane is 13.7%, and there are also a small amount of other by-products generated (qualitatively analyzed by GC-MS as isomers of 1-chloro-3,3,3-trifluoropropane).

[0060] Example 2

[0061] The operation of this example is the same as that of Example 1, with the only difference being that: first increase the feeding speed of vinylidene fluoride to 100 g / h for 1 h, then reduce the feeding speed of difluoromethane to 50 g / h for 4 h, and continue to stir and react for 5 h after the feeding is completed.

[0062] By monitoring the change in the content of vinylidene fluoride in the reactor during the reaction process, it was found that the content of vinylidene fluoride in the reactor gradually increased as the reaction proceeded. When the reaction time was 1 h, the content of vinylidene fluoride in the reaction system reached 4.1%. Subsequently, the feeding rate of vinylidene fluoride was reduced to 50 g / h, and the content of vinylidene fluoride in the reactor gradually decreased to 0.8%.

[0063] Chromatographic analysis was carried out on the liquid-phase and gas-phase materials of the addition reaction respectively, and it was calculated that: the conversion rate of vinylidene fluoride was 94.4%, the selectivity of 1-chloro-3,3,3-trifluoropropane was 83.5%, the selectivity of by-product 1,3-dichloro-1,1-difluoropropane was 15.8%, and there were also a small amount of other by-products generated. After qualitative analysis by GC-MS, they were isomers of 1-chloro-3,3,3-trifluoropropane. The purity of the 1-chloro-3,3,3-trifluoropropane product after rectification treatment reached 99.6%.

[0064] Example 3

[0065] The operation of this example was the same as that of Example 1, with the only difference being that: the feeding rate of vinylidene fluoride was first increased to 90 g / h for 2 h, and then the feeding rate of vinylidene fluoride was reduced to 40 g / h for 3 h. After the feeding was completed, stirring and reaction continued for 5 h.

[0066] By monitoring the change in the content of vinylidene fluoride in the reactor during the reaction process, it was found that the content of vinylidene fluoride in the reactor gradually increased as the reaction proceeded. When the reaction time was 2 h, the content of vinylidene fluoride reached 4.8%. Subsequently, the feeding rate of vinylidene fluoride was reduced to 40 g / h, and the content of vinylidene fluoride in the reactor gradually decreased to 1.3%.

[0067] Chromatographic analysis was carried out on the liquid-phase and gas-phase products of the addition reaction respectively, and it was calculated that: the conversion rate of vinylidene fluoride was 88.4%, the selectivity of 1-chloro-3,3,3-trifluoropropane was 79.3%, the selectivity of by-product 1,3-dichloro-1,1-difluoropropane was 19.7%, and there were also a small amount of other by-products generated. After qualitative analysis by GC-MS, they were isomers of 1-chloro-3,3,3-trifluoropropane. The purity of 1-chloro-3,3,3-trifluoropropane after rectification treatment reached 99.7%.

[0068] Example 4

[0069] The operation of this example was the same as that of Example 1, with the only difference being that: the addition catalyst was changed to 48.4 g (0.19 mol) of hafnium tetrafluoride anhydrous, 41.9 g (0.14 mol) of antimony pentachloride anhydrous and 12.2 g (0.12 mol) of aluminum oxide, and other conditions remained unchanged.

[0070] Chromatographic analysis was performed on the liquid and gas-phase materials of the addition reaction, and the following were calculated: the conversion rate of trifluoroethylene was 86.4%, the selectivity of 3,3-dichloro-1,1,1,2-tetrafluoropropane was 76.7%, the selectivity of by-product 1,3,3-trichloro-1,1,2-trifluoropropane was 23.0%, and a small amount of other by-products were formed, which were qualitatively analyzed by GC-MS as isomers of 3,3-dichloro-1,1,1,2-tetrafluoropropane.

[0071] Example 5

[0072] The operation of this example was the same as that of Example 1, except that: the addition catalyst was 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 remained unchanged.

[0073] Chromatographic analysis was performed on the liquid and gas-phase materials of the addition reaction, and the following were calculated: the conversion rate of trifluoroethylene was 76.1%, the selectivity of 3,3-dichloro-1,1,1,2-tetrafluoropropane was 69.8%, the selectivity of by-product 1,3,3-trichloro-1,1,2-trifluoropropane was 29.3%, and a small amount of other by-products were formed, which were qualitatively analyzed by GC-MS as isomers of 3,3-dichloro-1,1,1,2-tetrafluoropropane.

[0074] Example 6

[0075] The operation of this example was the same as that of Example 1, except that: the addition catalyst was 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 remained unchanged.

[0076] Chromatographic analysis was performed on the liquid and gas-phase materials of the addition reaction, and the following were calculated: the conversion rate of trifluoroethylene was 83.7%, the selectivity of 3,3-dichloro-1,1,1,2-tetrafluoropropane was 76.2%, the selectivity of by-product 1,3,3-trichloro-1,1,2-trifluoropropane was 23.2%, and a small amount of other by-products were formed, which were qualitatively analyzed by GC-MS as isomers of 3,3-dichloro-1,1,1,2-tetrafluoropropane.

[0077] Examples 7 - 12

[0078] The operation steps of Examples 7 - 12 were the same as those of Example 1, the only difference being that the mass of anhydrous aluminum trifluoride, anhydrous aluminum trichloride, and aluminum oxide in the mixed catalyst was changed to regulate the composition of fluorine, chlorine, and oxygen elements in the addition catalyst. The specific reaction results are shown in Table 1 below:

[0079] Table 1 Influence of Different Contents of Fluorine, Chlorine and Oxygen Elements in the Addition Catalyst on the Results of the Addition Reaction

[0080]

[0081]

[0082] Examples 13 - 28

[0083] The operation steps of Examples 13 - 28 are the same as those of Example 1, except that only the type of the metal cation of the addition catalyst is changed, the compositions of fluorine, chlorine and oxygen elements remain unchanged, and the reaction temperature is adjusted to match the catalyst activity. The specific reaction results are shown in Table 2 below:

[0084] Table 2 Influence of Different Metal Cations in the Addition Catalyst on the Effect of the Addition Reaction

[0085]

[0086] Examples 29 - 38

[0087] The operation steps of Examples 29 - 38 are the same as those of Example 1, except that: the reaction conditions are changed, where the feeding amount of the addition catalyst remains unchanged, the feeding rate of vinylidene fluoride remains unchanged, and the molar feeding ratio of difluoromethane to vinylidene fluoride remains unchanged. The specific reaction results are shown in Table 3 below:

[0088] Table 3 Results of the Addition Reaction under Different Reaction Conditions

[0089]

[0090] Examples 39 - 50

[0091] The operation steps of Examples 39 - 50 are the same as those of Example 1, except that: different fluorochloropropanes are prepared by changing the types of fluorinated olefins, and at the same time, the reaction temperature and the total reaction time are adjusted. The reaction results are shown in Table 4:

[0092] Table 4 Results of the Addition Reaction with Different Raw Materials

[0093]

[0094]

[0095] Examples 51 - 53

[0096] Examples 51 - 53 are respectively the experiments of applying the addition catalyst in the preparation process of 1 - chloro - 3,3,3 - trifluoropropane in Examples 1 - 3. The reaction results are shown in Table 5 below:

[0097] Table 5 Results of the Experiment of Applying the Catalyst under Different Contents of Vinylidene Fluoride

[0098]

[0099] Note: The number of reuse times in the table refers to the number of times the catalyst is repeatedly evaluated. The number of reuse times for the first use of the catalyst is 0, and the number of reuse times for the second use is 1.

[0100] Comparative Examples 1 - 6

[0101] The specific operation steps of Comparative Examples 1 - 6 are the same as those of Example 1, except that the addition catalyst is changed to anhydrous aluminum trifluoride, or anhydrous aluminum trichloride, or aluminum oxide, or any combination of two of anhydrous aluminum trifluoride, anhydrous aluminum trichloride, and aluminum oxide. The content of fluorine, chlorine, and oxygen elements in the addition catalyst is adjusted by changing the addition amount, and other reaction conditions remain unchanged. The reaction results are shown in Table 6 below:

[0102] Table 6 Reaction Effects of Catalysts with Different Element Contents

[0103]

[0104] Comparative Example 7

[0105] 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 addition amount of the addition catalyst is reduced to 1 g, the addition amount of raw material dichloromethane is increased to 600 g, the addition amount of raw material vinylidene fluoride is increased to 750 g, the addition amount of difluoromethane is increased to 200 g, and other conditions remain unchanged.

[0106] Chromatographic analysis was carried out on the liquid and gas phase materials of the addition reaction respectively, and it was calculated that: the conversion rate of vinylidene fluoride was only 8.9%, the selectivity of 1 - chloro - 3,3,3 - trifluoropropane was 43.5%, and the selectivity of by - product 1,3 - dichloro - 1,1 - difluoropropane was 55.8%.

[0107] Comparative Example 8

[0108] The specific operation of this comparative example is the same as that of Example 1, except that: the addition amount of dichloromethane is increased to 800 g, the addition amount of vinylidene fluoride is reduced to 20 g, the addition amount of difluoromethane is increased to 200 g, and other conditions remain unchanged.

[0109] Chromatographic analysis was carried out on the liquid and gas phase materials of the addition reaction respectively, and it was calculated that: the conversion rate 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%.

[0110] Comparative Example 9

[0111] The specific operation of this comparative example is the same as that of Example 1, except that: the raw material feeding method is changed. 300 g of vinylidene fluoride is pre-loaded in the reaction kettle, and dichloromethane and difluoromethane are fed through a metering pump. The feeding rate of dichloromethane is 45 g / h, and the feeding rate of difluoromethane is 25 g / h. The total feeding amounts are 225 g and 125 g respectively.

[0112] The liquid-phase material and gas-phase material of the addition reaction are respectively subjected to chromatographic analysis, and it is calculated that: the conversion rate of vinylidene fluoride is 48.5%, the selectivity of 1-chloro-3,3,3-trifluoropropane is 52.7%, and the selectivity of by-product 1,3-dichloro-1,1-difluoropropane is 46.4%.

[0113] Comparative Example 10

[0114] The specific operation of this comparative example is the same as that of Example 10, except that: the feeding rate of vinylidene fluoride is kept constant at 150 g / h, the feeding time is 2 h, and after the feeding is completed, stirring reaction is carried out for 7 h, and the catalyst reuse experiment is carried out under this reaction condition. The reaction results are shown in Table 7 below:

[0115] Table 7 Reaction results of catalyst reuse at different feeding rates

[0116]

Claims

1. A method for preparing fluorochloropropane by an addition method, characterized in that, The method includes: under the action of an addition catalyst, dichloromethane, difluoromethane and a fluorinated olefin represented by Formula I are prepared by a liquid-phase addition reaction to obtain a fluorochloropropane represented by 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 a metal fluoride, a metal chloride and a metal oxide, and the metal therein is selected from Group IIIA, Group IVB or Group VA metal elements.

2. The method for preparing fluorochloropropane according to claim 1, wherein: 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, wherein: 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 1-3, characterized in that: The metals in the metal fluoride, the metal chloride and the metal oxide are the same metal.

5. The method for preparing fluorochloropropane according to claim 4, wherein: 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.

6. The method for preparing fluorochloropropane according to claim 5, characterized in that: In the addition catalyst, the molar content of fluorine element is between 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 1-6, characterized in that: During the reaction process, monitor the content of the fluorinated olefin in the reaction system and control its content ≤ 5%.

8. The method for preparing fluorochloropropane according to claim 1, characterized in that: The fluorinated olefin is selected from at least one of vinylidene fluoride, chlorodifluoroethylene, trifluoroethylene or chlorotrifluoroethylene, 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, wherein: The molar ratio of dichloromethane to the fluorinated olefin is (0.5-2):

1.

10. The method for preparing fluorochloropropane according to claim 1, wherein: The specific gravity of dichloromethane to the addition catalyst is 2-10.

11. The method for preparing fluorochloropropane according to claim 1, wherein: During the addition reaction process, the total addition amount of the fluorinated olefin satisfies the following relationship: and Among them, 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, wherein: During the addition reaction process, the fluorinated olefin is continuously fed under pressure by a metering pump.

13. The method for preparing fluorochloropropane according to claim 12, wherein: When it is monitored that the content of the fluorinated olefin in the reaction system > 5% during the reaction process, reduce the feeding rate of the fluorinated olefin.

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

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

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