Method for preparing polyhalogenated hydrocarbon compound by addition method

Abstract

The invention discloses a method for preparing a polyhalogenated hydrocarbon compound by an addition process, which comprises the following steps: under the action of an addition catalyst, chloroform, monochlorodifluoromethane and fluorine-containing olefin with the general formula of CF2 = CR1R2 are subjected to liquid phase addition reaction to prepare polyhalogenated hydrocarbon with the general formula of CF3CR1R2CHCl2, in the reaction process, the content of fluorine-containing olefin in the reaction system is monitored and controlled to be less than or equal to 5%, and the addition catalyst is a mixed catalyst formed by metal fluoride, metal chloride and metal oxide. The method has the advantages of simple process flow, mild reaction conditions, high product yield, long service life of the catalyst and the like.

Description

Technical Field

[0001] The present invention relates to the preparation of polyhalohydrocarbon compounds, and particularly to a method for preparing polyhalohydrocarbon compounds by reacting fluoroolefin CF2=CR1R2 with chloroform and chlorodifluoromethane under the action of a metal Lewis acid mixed catalyst. Background Art

[0002] Polyhalohydrocarbon compounds such as 3,3-dichloro-1,1,1-trifluoropropane, 1,1,2-trichloro-3,3,3-trifluoropropane, 3,3-dichloro-1,1,1,2-tetrafluoropropane, and 2,3,3-trichloro-1,1,1,2-tetrafluoropropane are important fine chemicals and can be used to prepare novel refrigerants HCFO-1233zd and HCFO-1224yd through dehalogenation reactions, thus having great application potential.

[0003] Patent CN102964206A of Juhua Group discloses a method for preparing 3,3-dichloro-1,1,1-trifluoropropane. Under photocatalysis, 3-chloro-1,1,1-trifluoropropane and chlorine are mixed in a certain proportion and then subjected to chlorination reaction in a photocatalytic chlorination reactor. This synthesis process is simple and the reaction conditions are mild, but there is a trade-off relationship between the raw material conversion rate and the product selectivity, and the product yield is only 51.2% under the optimized conditions.

[0004] Patent CN101168494A discloses a method for synthesizing 3,3-dichloro-1,1,1-trifluoropropane by liquid-phase fluorination reaction using 1,1,1,3,3-pentachloropropane and anhydrous hydrogen fluoride as raw materials under the action of catalysts such as chromium fluoride, magnesium fluoride, and titanium fluoride. The product yield of this process route reaches 85%, but it has high requirements for equipment and relatively harsh operating conditions.

[0005] Currently, there is no dedicated research on the synthesis of 3,3-dichloro-1,1,1,2-tetrafluoropropane, 1,1,2-trichloro-3,3,3-trifluoropropane, and 2,3,3-trichloro-1,1,1,2-tetrafluoropropane, and they mostly exist as by-products with generally low selectivity. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides an addition method for preparing polyhalohydrocarbon compounds with a simple process flow, mild reaction conditions, high product yield, and long catalyst life.

[0007] The object of the present invention is achieved by the following technical solutions:

[0008] A method for preparing a polyhalogenated hydrocarbon compound by an addition method, the method comprising: under the action of an addition catalyst, chloroform, chlorodifluoromethane and a fluorinated olefin represented by the following formula I are subjected to a liquid-phase addition reaction to obtain a polyhalogenated hydrocarbon compound represented by the structural formula II, and the reaction formula is as follows:

[0009]

[0010] In the formula, R1 is selected from hydrogen or fluorine, and R2 is selected from hydrogen or chlorine;

[0011] 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.

[0012] 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, Ta2O, Ga2O3 or In2O3.

[0013] More preferably,

[0014] the metal fluoride is selected from at least one of AlF3, TiF4, SbF5, ZrF4 or HfF4;

[0015] the metal chloride is selected from at least one of AlCl3, TiCl4, SbCl5, ZrCl4 or HfCl4;

[0016] the metal oxide is selected from at least one of Al2O3, TiO2, Sb2O5, ZrO2 or HfO2.

[0017] Even more preferably, the metals in the metal fluoride, the metal chloride and the metal oxide are the same metal.

[0018] 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, the metal chloride and the metal oxide in the mixed catalyst, the contents of fluorine element, chlorine element and oxygen element in the addition catalyst are adjusted.

[0019] 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%.

[0020] The addition catalyst of the present invention can efficiently dissociate raw materials dichlorofluoromethane and chloroform to form active ions such as F-, CHClF + , Cl-, CHCl2 + etc. The addition reaction of halogenated hydrocarbon and halogenated olefin belongs to electrophilic addition. According to Markov's rule and the electronegativity of charged groups, F- and CHCl2 + can undergo a regioselective addition reaction with fluorinated olefins to obtain the addition product CF3CR1R2CHCl2 with high selectivity.

[0021] The fluorinated olefins of the present invention are selected from at least one of vinylidene fluoride (CF2=CH2), chlorodifluoroethylene (CF2=CHCl), trifluoroethylene (CF2=CHF), or chlorotrifluoroethylene (CF2=CFCl), and the corresponding polyhalogenated hydrocarbons are 1,1-dichloro-3,3,3-trifluoropropane (CF3CH2CHCl2), 1,1,2-trichloro-3,3,3-trifluoropropane (CF3CHClCHCl2), 3,3-dichloro-1,1,1,2-tetrafluoropropane (CF3CHFCHCl2), or 2,3,3-trichloro-1,1,1,2-tetrafluoropropane (CF3CFClCHCl2).

[0022] In the method for preparing polyhalogenated hydrocarbon compounds of the present invention, the ratio of raw materials, the ratio of raw materials to the addition catalyst, reaction temperature, reaction time, feeding mode, etc. will all affect the reaction result, especially have a greater impact on the catalyst life and the selectivity of the target product. Therefore,

[0023] In the method for preparing polyhalogenated hydrocarbon compounds of the present invention, the molar ratio of chloroform to fluorinated olefin is (0.5 - 1):1; preferably, the molar ratio of chloroform to fluorinated olefin is (0.5 - 0.8):1; more preferably, the molar ratio of chloroform to fluorinated olefin is (0.5 - 0.6):1.

[0024] Furthermore, the specific gravity of chloroform to the addition catalyst ≥ 3; when the specific gravity is less than 3, 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 chloroform to the addition catalyst is 3 - 12; more preferably, the specific gravity of chloroform to the addition catalyst is 6 - 10.

[0025] It has been found through research in the present invention that during the preparation of polyhalohydrocarbon compounds by the addition method, the fluorine-containing olefin in the raw materials is likely to adsorb on the active centers of the catalyst and polymerize, thereby preventing the contact between the reactants and the active centers, 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 fluorine-containing olefin in the reaction system is monitored, and the content of fluorine-containing olefin is controlled ≤ 5%, preferably the content of fluorine-containing olefin is controlled ≤ 3%, and more preferably the content of fluorine-containing olefin is controlled ≤ 1%; when the content of fluorine-containing olefin in the reaction system > 5%, the active centers of the catalyst will gradually be occupied by the polymers of fluorine-containing olefin, causing the catalyst to gradually deactivate.

[0026] To limit the polymerization of fluorine-containing olefin on the active centers during the reaction process to the greatest extent and further improve the service life of the catalyst, the fluorine-containing olefin in the present invention is fed continuously under pressure by a metering pump, and the continuous feeding rate mainly depends on the consumption rate of fluorine-containing olefin in the reaction system. To avoid the accumulation of fluorine-containing olefin in the reaction system, generally, the feeding rate of fluorine-containing olefin is 20 - 120 g / h, preferably 60 - 80 g / h. Once it is detected that the content of fluorine-containing olefin in the reaction system > 5%, the feeding rate of fluorine-containing olefin is reduced. In the actual operation process, when the content of fluorine-containing olefin in the reaction system is close to 5% or reaches 5%, the feeding rate of fluorine-containing olefin can be appropriately reduced.

[0027] Furthermore, to avoid the deactivation of the catalyst caused by the polymerization of fluorine-containing olefin on the active centers of the catalyst, the fluorine-containing olefin should react completely as much as possible. Therefore, the total addition amount of fluorine-containing olefin satisfies the following relationship:

[0028] And

[0029] Among them, is the molar amount of fluorine-containing olefin, is the molar amount of chloroform, is the molar amount of chlorodifluoromethane. During the actual reaction process, the fluorine-containing olefin is fed continuously. Once it is detected that the raw materials chlorodifluoromethane or chloroform in the reaction system are consumed completely, the feeding of fluorine-containing olefin is stopped immediately. At this time, the total feeding amount of fluorine-containing olefin must satisfy the above relationship, so as to avoid the polymerization of excessive fluorine-containing olefin on the active centers and affect the catalyst activity and service life.

[0030] The content of fluorine-containing olefin in the reaction system is mainly monitored by chromatographic analysis of the material composition.

[0031] In the method for preparing the polyhalohydrocarbon compound of the present invention, after adding metal fluoride, metal chloride and metal oxide to a reactor (reaction kettle or tubular reactor) in a certain ratio, chloroform is added to the reactor. Chlorodifluoromethane can be added to the reactor together with chloroform, or continuously introduced into the reactor, or mixed with fluorinated olefin to form a mixed gas and then continuously introduced into the reactor.

[0032] Alternatively, an addition catalyst and chloroform are formed into a uniformly mixed material and then continuously introduced into the reactor, and chlorodifluoromethane and fluorinated olefin are respectively continuously introduced into the reactor or mixed and then continuously introduced into the reactor.

[0033] In the method for preparing the polyhalohydrocarbon compound of the present invention, any of the above-mentioned feeding methods can be adopted, as long as continuous feeding of the fluorinated olefin is ensured. Preferably, the addition catalyst is pre-filled into the reaction kettle first, and then chloroform and chlorodifluoromethane are added, and the fluorinated olefin is continuously pressurized and fed through a metering pump.

[0034] In the method for preparing the polyhalohydrocarbon compound of the present invention, the reaction temperature is 0 to 100 °C, and the total reaction time is 5 to 20 h. Preferably, the reaction temperature is 20 to 80 °C, and the reaction time is 8 to 15 h; more preferably, the reaction temperature is 30 to 60 °C, and the reaction time is 8 to 12 h.

[0035] The reaction pressure of the present invention does not need to be controlled, as long as the reactor is sealed, which is determined by the saturated vapor pressure of chlorodifluoromethane in the reactor, generally about 1.5 MPa. During the reaction process, as chlorodifluoromethane is consumed, the reaction pressure gradually decreases.

[0036] Since the saturated vapor pressures of chlorodifluoromethane and fluorinated olefin are much greater than that of chloroform, chloroform mainly exists in a liquid form during the reaction process. Coupled with the fact that the polyhalohydrocarbon 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 product separation step.

[0037] The polyhalohydrocarbon synthesized by the present invention is used as a fluorine-containing intermediate, and important fluorinated olefins such as HCFO-1233zd, HCFO-1224yd and CFO-1214ya can be obtained through a dehalogenation step.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] 1. The present invention only needs one-step addition reaction to prepare the polyhalohydrocarbon, the process flow is simple, and the reaction conditions are mild and the product yield is high.

[0040] 2. By monitoring the content of fluoroolefins in the reaction system and coordinating the feed adjustment, the present invention inhibits the polymerization of fluoroolefins on the active centers, significantly improving the service life of the catalyst. Detailed Embodiments

[0041] 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, improved, and equivalent solutions that may be included within the scope of the claims.

[0042] Example 1

[0043] This example presents a preparation method of 3,3-dichloro-1,1,1,2-tetrafluoropropane, including the following steps:

[0044] Weigh 41.8 g (0.25 mol) of anhydrous zirconium tetrafluoride, 35.0 g (0.15 mol) of anhydrous zirconium tetrachloride, and 14.7 g (0.12 mol) of zirconium dioxide and add them to the reaction kettle. After sealing the kettle cover, evacuate the reaction kettle, then use a sampler to add 300 g of chloroform into the kettle, place the reaction kettle in a cooling circulation pump at -30°C for 30 minutes. After taking out the reaction kettle, continue to add 260 g of chlorodifluoromethane, and trifluoroethylene is fed under pressure through a metering pump at a flow rate of 80 g / h for 5 hours. After the feeding is completed, the above raw materials continue to react for 5 hours at a reaction temperature of 40°C and a stirring speed of 300 rpm.

[0045] During the reaction process, record the changes in the reaction pressure and temperature in the kettle, and simultaneously monitor the content of trifluoroethylene in the reaction kettle. Specifically, take samples every 30 minutes and analyze them by gas chromatography. The results show that throughout the reaction process, the content of trifluoroethylene in the reaction system ≤ 2.3%. 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 chlorodifluoromethane 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 obtained by rectification to get the target product 3,3-dichloro-1,1,1,2-tetrafluoropropane.

[0046] Perform chromatographic analysis on the liquid-phase and gas-phase materials of the addition reaction respectively, and calculate to obtain: the conversion rate of trifluoroethylene is 98.3%, the selectivity of 3,3-dichloro-1,1,1,2-tetrafluoropropane is 86.2%, the selectivity of by-product 1,3,3-trichloro-1,1,2-trifluoropropane is 12.9%, and there are also a small amount of other by-products generated (qualitatively analyzed by GC-MS as isomers of 3,3-dichloro-1,1,1,2-tetrafluoropropane).

[0047] Example 2

[0048] The operation of this example is the same as that of Example 1, except that: the feeding rate of trifluoroethylene is first increased to 160 g / h for 1 h, then the feeding rate of trifluoroethylene is decreased to 60 g / h for 4 h, and after the feeding is completed, the reaction is continued with stirring for 5 h.

[0049] By monitoring the change of the trifluoroethylene content in the reactor during the reaction, it is found that the trifluoroethylene content in the reactor gradually increases with the progress of the reaction. When the reaction time is 1 h, the trifluoroethylene content in the reaction system reaches 3.6%. Then the feeding rate of trifluoroethylene is decreased to 60 g / h, and the trifluoroethylene content in the reactor gradually decreases to 0.9%.

[0050] Chromatographic analysis is carried out on the liquid-phase and gas-phase materials of the addition reaction respectively, and it is calculated that: the conversion rate of trifluoroethylene is 93.8%, the selectivity of 3,3-dichloro-1,1,1,2-tetrafluoropropane is 81.3%, the selectivity of by-product 1,3,3-trichloro-1,1,2-trifluoropropane is 18.1%, and there are also a small amount of other by-products generated, which are qualitatively analyzed by GC-MS as isomers of 3,3-dichloro-1,1,1,2-tetrafluoropropane.

[0051] Example 3

[0052] The operation of this example is the same as that of Example 1, except that: the feeding rate of trifluoroethylene is first increased to 140 g / h for 2 h, then the feeding rate of trifluoroethylene is decreased to 40 g / h for 3 h, and after the feeding is completed, the reaction is continued with stirring for 5 h.

[0053] By monitoring the change of the trifluoroethylene content in the reactor during the reaction, it is found that the trifluoroethylene content in the reactor gradually increases with the progress of the reaction. When the reaction time is 2 h, the trifluoroethylene content reaches 4.6%. Then the feeding rate of trifluoroethylene is decreased to 15 g / h, and the trifluoroethylene content in the reactor gradually decreases to 1.1%.

[0054] Chromatographic analysis is carried out on the liquid-phase and gas-phase products of the addition reaction respectively, and it is calculated that: the conversion rate of trifluoroethylene is 86.9%, the selectivity of 3,3-dichloro-1,1,1,2-tetrafluoropropane is 77.5%, the selectivity of by-product 1,3,3-trichloro-1,1,2-trifluoropropane is 21.7%, and there are also a small amount of other by-products generated, which are qualitatively analyzed by GC-MS as isomers of 3,3-dichloro-1,1,1,2-tetrafluoropropane.

[0055] Example 4

[0056] The operation of this example is the same as that of Example 1, except that: the addition catalyst is changed to 41.8 g (0.24 mol) of anhydrous zirconium tetrafluoride, 28.4 g (0.17 mol) of anhydrous titanium tetrachloride and 13.1 g (0.08 mol) of gallium trioxide, and other conditions remain unchanged.

[0057] The liquid-phase and gas-phase materials of the addition reaction were respectively subjected to chromatographic analysis, and the following were obtained by calculation: the conversion rate of trifluoroethylene was 81.4%, the selectivity of 3,3-dichloro-1,1,1,2-tetrafluoropropane was 73.3%, the selectivity of by-product 1,3,3-trichloro-1,1,2-trifluoropropane was 26.1%, and a small amount of other by-products were formed. Through GC-MS qualitative analysis, they were isomers of 3,3-dichloro-1,1,1,2-tetrafluoropropane.

[0058] Example 5

[0059] The operation of this example was the same as that of Example 1, except that: the addition catalyst was changed to 24.8 g (0.20 mol) of anhydrous titanium tetrafluoride, 18.6 g (0.14 mol) of anhydrous aluminum trichloride, and 25.2 g (0.12 mol) of hafnium dioxide, and other conditions remained unchanged.

[0060] The liquid-phase and gas-phase materials of the addition reaction were respectively subjected to chromatographic analysis, and the following were obtained by calculation: the conversion rate of trifluoroethylene was 77.4%, the selectivity of 3,3-dichloro-1,1,1,2-tetrafluoropropane was 79.5%, the selectivity of by-product 1,3,3-trichloro-1,1,2-trifluoropropane was 19.6%, and a small amount of other by-products were formed. Through GC-MS qualitative analysis, they were isomers of 3,3-dichloro-1,1,1,2-tetrafluoropropane.

[0061] Examples 6 - 10

[0062] The operation steps of Examples 6 - 10 were the same as those of Example 1, except that: the mass of anhydrous zirconium tetrafluoride, anhydrous zirconium tetrachloride, and zirconium dioxide 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:

[0063] Table 1 Influence of different contents of fluorine, chlorine, and oxygen elements in the addition catalyst on the addition reaction results

[0064]

[0065] Examples 11 - 26

[0066] The operation steps of Examples 11 - 26 were the same as those of Example 1, except that: the type of metal cation in 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:

[0067] Table 2 Influence of different metal cations in the addition catalyst on the addition reaction effect

[0068]

[0069] Examples 27 - 34

[0070] The operation steps of Examples 27 - 34 are the same as those of Example 1, except that: the reaction conditions are changed. Among them, the feeding amount of the addition catalyst remains unchanged, the feeding rate of trifluoroethylene remains unchanged, and the molar feeding ratio of chlorodifluoromethane to trifluoroethylene remains unchanged. The specific reaction results are shown in Table 3 below:

[0071] Table 3 Addition reaction results under different reaction conditions

[0072]

[0073] Examples 35 - 44

[0074] The operation steps of Examples 35 - 44 are the same as those of Example 1, except that: different polyhalohydrocarbons 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:

[0075] Table 4 Addition reaction results of different raw materials

[0076]

[0077]

[0078] Examples 45 - 47

[0079] Examples 45 - 47 are respectively the addition catalyst reuse experiments in the preparation processes of 3,3 - dichloro - 1,1,1,2 - tetrafluoropropane in Examples 1 - 3. The reaction results are shown in Table 5 below:

[0080] Table 5 Results of catalyst reuse experiments under different trifluoroethylene contents

[0081]

[0082] Note: The reuse times in the table refer to the number of times the catalyst is repeatedly evaluated. The reuse time for the first use of the catalyst is 0, and the reuse time for the second use is 1.

[0083] Comparative Examples 1 - 3

[0084] The specific operation steps of Comparative Examples 1 - 3 are the same as those of Example 1, except that: the addition catalyst is changed to zirconium tetrafluoride anhydrous, or zirconium chloride anhydrous, or zirconium dioxide, or any combination of two of zirconium tetrafluoride anhydrous, zirconium chloride anhydrous, and zirconium dioxide. The contents of fluorine, chlorine, and oxygen elements in the addition catalyst are adjusted by changing the addition amount, and other reaction conditions remain unchanged. The reaction results are shown in Table 6 below:

[0085] Table 6 Addition reaction results of different catalysts

[0086]

[0087] Comparative Example 7

[0088] The specific operation of this comparative example is the same as that of Example 1, except that: the compositions of fluorine, chlorine and oxygen elements in the addition catalyst remain unchanged, the total addition amount of the addition catalyst is reduced to 1 g, the addition amount of raw material chloroform is increased to 700 g, the addition amount of raw material trifluoroethylene is increased to 850 g, the addition amount of dichlorofluoromethane is increased to 450 g, and other conditions remain unchanged.

[0089] 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 trifluoroethylene was only 3.4%, the selectivity of 3,3-dichloro-1,1,1,2-tetrafluoropropane was 16.7%, and the selectivity of by-product 1,3,3-trichloro-1,1,2-trifluoropropane was 83.1%.

[0090] Comparative Example 8

[0091] The specific operation of this comparative example is the same as that of Example 1, except that: the addition amount of chloroform is increased to 600 g, the addition amount of trifluoroethylene is reduced to 10 g, the addition amount of dichlorofluoromethane is increased to 400 g, and other conditions remain unchanged.

[0092] 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 trifluoroethylene was 99.9%, the selectivity of 3,3-dichloro-1,1,1,2-tetrafluoropropane was 35.2%, and the selectivity of by-product 1,3,3-trichloro-1,1,2-trifluoropropane was 64.4%.

[0093] Comparative Example 9

[0094] The specific operation of this comparative example is the same as that of Example 1, except that: the raw material feeding mode is changed. 400 g of trifluoroethylene is pre-filled in the reaction kettle, and chloroform and dichlorofluoromethane are fed by metering pumps. The feeding rate of chloroform is 60 g / h, the feeding rate of dichlorofluoromethane is 52 g / h, and the total feeding amounts are 300 g and 260 g respectively.

[0095] 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 trifluoroethylene was 71.9%, the selectivity of 3,3-dichloro-1,1,1,2-tetrafluoropropane was 72.2%, and the selectivity of by-product 1,3,3-trichloro-1,1,2-trifluoropropane was 27.1%.

[0096] Comparative Example 10

[0097] The specific operation of this comparative example is the same as that of Example 1, except that: the feeding rate of trifluoroethylene is kept constant at 200 g / h, the feeding time is 2 h, and stirring and reacting continue for 7 h after the feeding is completed, and the catalyst reuse experiment is carried out under this reaction condition. The reaction results are shown in Table 7 below:

[0098] Table 7 Catalyst reuse reaction results at different feeding rates

[0099]

Claims

1. A method for preparing polyhalogenated hydrocarbon compounds by an addition method, characterized in that, The method includes: under the action of an addition catalyst, chloroform, chlorodifluoromethane, and a fluorinated olefin represented by the following formula I are prepared into a polyhalogenated hydrocarbon compound represented by the structural formula II through a liquid-phase addition reaction, 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 a polyhalogenated hydrocarbon compound 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 a polyhalogenated hydrocarbon compound 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 a polyhalogenated hydrocarbon compound 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 a polyhalogenated hydrocarbon compound according to claim 1, characterized in that: 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 a polyhalogenated hydrocarbon compound according to claim 5, wherein: 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 a polyhalogenated hydrocarbon compound 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 a polyhalogenated hydrocarbon compound according to claim 1, wherein: The fluorinated olefin is selected from at least one of vinylidene fluoride, chlorodifluoroethylene, trifluoroethylene, or chlorotrifluoroethylene, and the polyhalogenated hydrocarbon compound is selected from at least one of 1,1-dichloro-3,3,3-trifluoropropane, 1,1,2-trichloro-3,3,3-trifluoropropane, dichloro-1,1,1,2-tetrafluoropropane, or 2,3,3-trichloro-1,1,1,2-tetrafluoropropane.

9. The method for preparing a polyhalogenated hydrocarbon compound according to claim 1, wherein: The molar ratio of chloroform to the fluorinated olefin is (0.5 - 1):

1.

10. The method for preparing a polyhalogenated hydrocarbon compound according to claim 1, wherein: The specific gravity of chloroform to the addition catalyst is 3 - 12.

11. The method for preparing a polyhalogenated hydrocarbon compound according to claim 1, wherein: During the addition reaction process, the total addition amount of the fluorinated olefin satisfies the following relationship: and Wherein, is the molar amount of fluorinated olefin, is the molar amount of chlorodifluoromethane, is the molar amount of chloroform.

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

13. The method for preparing a polyhalogenated hydrocarbon compound 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 a polyhalogenated hydrocarbon compound according to claim 12, characterized in that: The addition reaction temperature is 0 - 100 °C, and the reaction time is 5 - 20 h.

15. The method for preparing a polyhalogenated hydrocarbon compound according to claim 14, wherein: The addition reaction temperature is 20 - 80 °C, and the reaction time is 8 - 15 h.

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