Catalyst for synthesizing (E / Z)-1, 2-difluoroethylene as well as preparation method and application thereof

Abstract

The invention relates to the technical field of preparation of fluorine-containing olefin catalysts, and discloses a catalyst for synthesizing (E / Z)-1, 2-difluoroethylene as well as a preparation method and application thereof. The catalyst is mainly obtained from a catalyst precursor, and the catalyst precursor comprises a main catalyst and a co-catalyst; the main catalyst is selected from any one or a combination of more of IIA group oxides, IIIA group oxides and VIB group oxides; the cocatalyst is selected from any one or a combination of more of VIII B group oxides; the preparation method of the catalyst comprises the following steps: pressing, drying and roasting the catalyst precursor, and activating with chlorofluorocarbon. When the catalyst is used for catalytically synthesizing (E / Z)-1, 2-difluoroethylene, the conversion rate of substrates (such as 1, 1, 2-trifluoroethane and R143) is high, the content of impurities in a product is low, and the selectivity of (E / Z)-1, 2-difluoroethylene is high; in addition, the catalyst has a longer service life.

Description

Technical Field

[0001] The present application relates to the technical field of preparing fluorine-containing olefin catalysts, and specifically to a catalyst for synthesizing (E / Z)-1,2-difluoroethylene, and a preparation method and application thereof. Background Art

[0002] E-1,2-difluoroethylene (E-HFO-1132) has a low boiling point, moderate flammability, and low toxicity, and is considered a potential substitute for HFCs refrigerants such as R410A. At the same time, the ODP value of 1,2-difluoroethylene is 0, and the GWP100 value is less than 2. Its molecular structure does not contain perfluoroalkyl groups, and it is not a PFAS substance. Its degradation products in the atmospheric environment do not contain trifluoroacetic acid (TFA), and it will not cause secondary pollution to the environment, meeting the requirements of the fifth-generation ODS substitute.

[0003] There are many existing methods for synthesizing (E / Z)-HFO-1132, including gas / liquid phase dehydrofluorination, thermal decomposition, isomerization, fluorine-chlorine exchange, dehalogenation and other routes. Among the various synthetic methods reported, the process of using 1,1,2-trifluoroethane (R143) as a raw material and gas phase dehydrofluorination to obtain (E / Z)-HFO-1132 has the potential for industrialization. The prior art discloses fluoride, oxide, and fluorine oxide catalysts based on metal chromium, aluminum, iron, nickel, and magnesium, and synthesizes (E / Z)-HFO-1132 by gas phase dehydrofluorination of R143. The conversion rate of R143 can reach more than 90%, the selectivity of E-HFO-1132 is about 30%, and the selectivity of Z-HFO-1132 is about 60%. It is worth noting that a certain amount of oxygen will also be added to the reaction, which is mainly to remove the carbon deposits produced during the reaction, thereby extending the service life of the catalyst. However, excess oxygen and carbon dioxide produced by the reaction with carbon will enter the crude product. In addition, according to public data reports, a variety of organic impurities including methane, trifluoromethane, vinylidene fluoride, fluoromethane, 1,1,1-trifluoroethane, etc. will be produced during the synthesis of HFO-1132. Therefore, multiple types of impurities coexist, and some impurities may have azeotropy, which is not conducive to the separation and purification of HFO-1132. Summary of the invention

[0004] The present application provides a catalyst for synthesizing (E / Z)-1,2-difluoroethylene, and a preparation method and application thereof. The catalyst uses one or more oxides of IIA, IIIA, and VIB as a main catalyst, and an oxide of Group VIIIB as a co-catalyst. The main catalyst and the co-catalyst are mixed in a specific ratio and then catalyzed by chlorofluorocarbons to obtain the obtained catalyst. The applicant has found that when the catalyst is used to catalyze the synthesis of (E / Z)-1,2-difluoroethylene, the conversion rate of the substrate (such as 1,1,2-trifluoroethane, R143) is high, the impurity content in the product is low, and the selectivity of (E / Z)-1,2-difluoroethylene is high. In addition, further research has found that the catalyst has a better service life, thereby greatly reducing the consumption of the catalyst in the catalytic reaction, thereby achieving the purpose of reducing costs.

[0005] This application involves the following:

[0006] A catalyst for synthesizing (E / Z)-1,2-difluoroethylene, wherein the catalyst is mainly obtained from a catalyst precursor, wherein the catalyst precursor comprises a main catalyst and a co-catalyst;

[0007] The main catalyst is selected from any one or more combinations of Group IIA oxides, Group IIIA oxides and Group VIB oxides;

[0008] The promoter is selected from any one or more combinations of Group VIII B oxides.

[0009] Wherein, the Group IIA oxides include magnesium oxide, barium oxide, calcium oxide; and / or,

[0010] The IIIA group oxide includes aluminum oxide and indium oxide; and / or,

[0011] The Group VIB oxides include chromium oxide, molybdenum oxide, and tungsten oxide; and / or,

[0012] The Group VIIIB oxides include nickel oxide and cobalt oxide.

[0013] Optionally, the main catalyst is selected from any one or more combinations of Group VIB oxides;

[0014] Preferably, the main catalyst comprises chromium oxide.

[0015] Optionally, the promoter comprises nickel oxide.

[0016] Optionally, the mass ratio of the main catalyst to the co-catalyst is 100:(0.05-50);

[0017] Preferably, the mass ratio of the main catalyst to the co-catalyst is 100:(5-40);

[0018] More preferably, the mass ratio of the main catalyst to the co-catalyst is 100:(10-30).

[0019] Optionally, the chlorofluorocarbon is selected from any one or more combinations of difluoromonochloromethane, difluorodichloromethane, monofluorodichloroethane, difluoromonochloroethane, dichloropentafluoropropane and 1-chloro-3,3,3-trifluoropropene.

[0020] A method for preparing the catalyst for synthesizing (E / Z)-1,2-difluoroethylene comprises: pressing, drying, calcining the catalyst precursor, and activating it with chlorofluorocarbon to obtain the catalyst.

[0021] Optionally, the calcination temperature is 250-400°C;

[0022] Preferably, the calcination temperature is 300-360°C.

[0023] Optionally, the activation temperature is 150-400°C;

[0024] Preferably, the activation temperature is 200-300°C.

[0025] Optionally, the drying temperature is 100-200°C.

[0026] A method for synthesizing (E / Z)-1,2-difluoroethylene comprises using the above catalyst or the catalyst prepared by the above preparation method.

[0027] Beneficial Effects

[0028] 1. The present application uses one or more oxides of IIA, IIIA, and VIB as main catalysts and Group VIIIB oxides as co-catalysts to prepare a metal fluoride chloride, which is used to catalyze 1,1,2-trifluoroethane (R143); the conversion rate of the catalyst for 1,1,2-trifluoroethane (R143) is in the range of 90-99%, the selectivity for E-HFO-1132 is about 33-40%, the selectivity for Z-HFO-1132 is about 57-60%, and the impurity content is significantly reduced (not more than 5%).

[0029] 2. The present application further selects appropriate main catalyst and co-catalyst, and further optimizes the mass ratio of the two to obtain a catalyst with better performance (in terms of the conversion rate of the catalyst to 1,1,2-trifluoroethane (R143), the selectivity to E-HFO-1132, the selectivity to Z-HFO-1132 and the impurity content when the catalyst is subjected to the catalytic reaction).

[0030] 3. The present application further optimizes the process parameters for preparing the catalyst, such as calcination temperature, activation temperature, etc., to obtain a catalyst with better performance (in terms of the conversion rate of the catalyst to 1,1,2-trifluoroethane (R143), selectivity to E-HFO-1132, selectivity to Z-HFO-1132 and impurity content when the catalyst is subjected to the catalytic reaction).

[0031] 4. The catalyst prepared by using chromium oxide and nickel oxide powder as raw materials and difluorochloromethane as catalysis in the present application has a significantly extended service life: after a service time of up to 100 hours, the catalyst still maintains good stability; for example, its reaction conversion rate for 1,1,2-trifluoroethane (R143) is only reduced by 2.5%, and its selectivity for HFO-1132 is only reduced by 4%, while the impurity content is not higher than 8%. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 . GC spectrum of the crude HFO-1132 product of Example 4.

[0033] Figure 2 GC spectrum of the HFO-1132 (E) product after purification of the crude HFO-1132 product of Example 4.

[0034] Figure 3 GC spectrum of the HFO-1132(Z) product after purification of the crude HFO-1132 product of Example 4. DETAILED DESCRIPTION

[0035] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in components' functions as the criterion for distinction.

[0036] As mentioned throughout the specification and claims, "including" or "comprising" is an open term and should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present application, but the description is for the purpose of the general principles of the specification and is not intended to limit the scope of the present application. The scope of protection of the present application shall be determined by the attached claims. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by ordinary technicians in the field to which the present disclosure belongs.

[0037] It should be understood that the embodiments of the present application described herein include "consisting of" and / or "consisting essentially of" embodiments. References to "about" a value or parameter herein include (and describe) variations to the value or parameter itself. For example, a description referring to "about X" includes a description of "X".

[0038] As used herein, reference to a "not" value or parameter generally means and describes an "except" value or parameter. For example, the method is not used to treat cancer type X, meaning that the method is used to treat cancers other than type X.

[0039] As used herein, the term "about XY" has the same meaning as "about X to about Y."

[0040] As used herein and in the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. It should also be noted that the claims may be drafted to exclude any optional elements. This statement is therefore intended to serve as antecedent basis for the use of exclusive terminology such as "only", "only" and the like in connection with the recitation of claim elements, or the use of a limitation of "no".

[0041] As used herein, the term "and / or" in phrases such as "A and / or B" is intended to include both A and B; A or B; A (alone); and B (alone). Similarly, as used herein, the term "and / or" in phrases such as "A, B, and / or C" is intended to include each of the following embodiments: A, B, and C; A, B, or C; A or C; A or B; B or C; A and C; A and B; B and C; A (alone); B (alone); and C (alone).

[0042] The present application provides a catalyst for synthesizing (E / Z)-1,2-difluoroethylene, wherein the catalyst is mainly obtained from a catalyst precursor, wherein the catalyst precursor comprises a main catalyst and a co-catalyst;

[0043] The main catalyst is selected from any one or more combinations of Group IIA oxides, Group IIIA oxides and Group VIB oxides.

[0044] In the present application, "XOClF-YOClF" is used to represent the catalyst finally prepared; "X" refers to the metal element of the main catalyst, "Y" refers to the metal element of the co-catalyst, and "XOClF" and "YOClF" do not directly represent the molecular formula of the obtained metal fluoride chloride, but only refer to the element composition contained in the metal fluoride chloride. For example, chromium oxide is used as the main catalyst and nickel oxide is used as the co-catalyst to prepare the catalyst by the method of the present application, and the catalyst finally obtained is recorded as CrOClF-NiOClF catalyst.

[0045] In some embodiments, the main catalyst is selected from Group IIA oxides; in some embodiments, the main catalyst is selected from Group IIIA oxides; in some embodiments, the main catalyst is selected from Group VIB oxides; in some embodiments, the main catalyst is selected from Group IIA oxides and Group IIIA oxides; in some embodiments, the main catalyst is selected from Group IIA oxides and Group VIB oxides; in some embodiments, the main catalyst is selected from Group IIIA oxides and Group VIB oxides; in some embodiments, the main catalyst is selected from Group IIA oxides, Group IIIA oxides and Group VIB oxides.

[0046] In some embodiments, the Group IIA oxides include but are not limited to magnesium oxide, barium oxide, and calcium oxide; in some embodiments, the Group IIA oxides are magnesium oxide, barium oxide, and calcium oxide. In some embodiments, the Group IIIA oxides include but are not limited to aluminum oxide and indium oxide; in some embodiments, the Group IIIA oxides are aluminum oxide and indium oxide. In some embodiments, the Group VIB oxides include but are not limited to chromium oxide, molybdenum oxide, and tungsten oxide; in some embodiments, the Group VIB oxides are chromium oxide, molybdenum oxide, and tungsten oxide. In some embodiments, the Group VIB oxides include but are not limited to nickel oxide and cobalt oxide; in some embodiments, the Group VIB oxides are nickel oxide and cobalt oxide.

[0047] In some embodiments, the main catalyst is selected from any one or more of magnesium oxide, barium oxide, calcium oxide, aluminum oxide, indium oxide, chromium oxide, molybdenum oxide, and tungsten oxide; in some preferred embodiments, the main catalyst is selected from any one or more of magnesium oxide, barium oxide, calcium oxide, aluminum oxide, and chromium oxide; in some embodiments, the main catalyst is magnesium oxide; in some embodiments, the main catalyst is calcium oxide; in some embodiments, the main catalyst is aluminum oxide; in some embodiments, the main catalyst is chromium oxide; in some embodiments, the main catalyst is barium oxide. In some embodiments, the main catalyst is mainly chromium oxide; wherein, "mainly" means at least 50wt%, at least 55wt%, at least 60wt%, at least 65wt%, at least 70wt%, at least 75wt%, at least 80wt%, at least 85wt%, at least 90wt%, at least 95wt%, at least 96wt%, at least 97wt%, at least 98wt%, at least 99wt%, at least 99.5wt%, at least 99.8wt%, at least 99.9wt% or 100wt% of the main catalyst is selected as chromium oxide; for example, 50wt%, 55wt%, 60wt%, 65wt%, 70wt%, 75wt%, 80wt%, 85wt%, 90wt%, 95wt%, 96wt%, 97wt%, 98wt%, 99wt%, 99.5wt%, 99.8wt%, 99.9wt% or 100wt% of the main catalyst is chromium oxide, and the remaining main catalyst can be, for example, optional magnesium oxide, barium oxide, calcium oxide, aluminum oxide or any combination thereof.

[0048] In some embodiments, the co-catalyst is selected from any one of nickel oxide and zirconium oxide or a combination of any proportion of the two. When the main catalyst is selected differently, the performance changes of the catalysts obtained by using nickel oxide and cobalt oxide as co-catalysts respectively do not show relatively consistent regularity. For example: Compared with the catalysts prepared from aluminum oxide and cobalt oxide, the catalysts prepared from aluminum oxide and nickel oxide have a higher conversion rate for 1,1,2-trifluoroethane (R143), a higher selectivity for (E / Z)-1,2-difluoroethylene, and a lower impurity content, that is, the coordination effect of nickel oxide is better (for example, refer to Example 1 and Example 2); Compared with the catalysts prepared from chromium oxide and cobalt oxide, the catalysts prepared from chromium oxide and nickel oxide have a higher conversion rate for 1,1,2-trifluoroethane (R143), a higher selectivity for (E / Z)-1,2-difluoroethylene, and a lower impurity content, that is, the coordination effect with nickel oxide is still better (for example, refer to Example 3 and Example 4); however, for example, compared with the catalyst made from magnesium oxide and cobalt oxide, the catalyst made from magnesium oxide and nickel oxide has a slightly lower conversion rate for 1,1,2-trifluoroethane (R143), a higher selectivity for (E / Z)-1,2-difluoroethylene, and a lower impurity content (for example, refer to Example 5 and Example 6); and for example, compared with the catalyst made from barium oxide and cobalt oxide, the catalyst made from barium oxide and nickel oxide has a higher conversion rate for 1,1,2-trifluoroethane (R143), but a slightly lower selectivity for (E / Z)-1,2-difluoroethylene and a slightly higher impurity content (for example, refer to Example 7 and Example 8).

[0049] In some embodiments, the mass ratio of the main catalyst to the co-catalyst is any ratio range within the range of 100:(0.05-50), 100:(1-45), 100:(5-50), 100:(5-45), 100:(5-40), 100:(5-35), 100:(5-30), 100:(10-30), 100:(15-25) or 100:(0.05-50); for example, it can be 100:0.05, 100:0.1, 100:0.5, 100:1, 100:2, 100:3, 100:4, 100:5, 100:7, 100:8, 100:9, 100:10 :10, 100:11, 100:12, 100:13, 100:14, 100:15, 100:16, 100:17, 100:18, 100:19, 100:20, 100:21, 100:22, 100:23, 100:24, 100:25, 100:26, 100:27, 100:28, 100:29, 100:30, 100:32, 100:34, 100:35, 100:37, 100:39, 100:40, 100:43, 100:45, 100:49, 100:50 or any ratio within the range of 100:(0.05-50). In some preferred embodiments, the mass ratio of the main catalyst to the co-catalyst is 100:(5-40) or any ratio range within the range thereof. In some more preferred embodiments, the mass ratio of the main catalyst to the co-catalyst is 100:(10-30) or any ratio range within the range thereof; within this ratio range, the performance of the catalyst obtained is more excellent. For example, the conversion rate of 1,1,2-trifluoroethane (R143) is in a relatively high range: 95.1-97.1%, even as high as 98%, 99%; for example, the selectivity for E-1,2-difluoroethylene is in the range of 36.5-38.1%, even as high as 39%, 40%; for example, the selectivity for Z-1,2-difluoroethylene is in the range of 58.2-59.8%, even as high as 60%, 62%; and the impurity content is as low as 3.2-3.8%, even lower than 2.8%, 2.5%.

[0050] In some embodiments, the chlorofluorocarbon is selected from any one or more combinations of difluorochloromethane, difluorodichloromethane, monochlorodifluoroethane, difluorochloroethane, dichloropentafluoropropane and 1-chloro-3,3,3-trifluoropropene; in some preferred embodiments, the chlorofluorocarbon is selected from any one or more combinations of monochlorodifluoroethane, difluorochloroethane, difluorochloromethane and dichloropentafluoropropane. For example, in some embodiments, the chlorofluorocarbon is monochlorodifluoroethane; in some embodiments, the chlorofluorocarbon is difluorochloroethane; in some embodiments, the chlorofluorocarbon is difluorochloromethane; in some embodiments, the chlorofluorocarbon is difluorochloromethane; in some embodiments, the chlorofluorocarbon is dichloropentafluoropropane. In some more preferred embodiments, the chlorofluorocarbon mainly includes difluorochloromethane. Wherein, "mainly" means that at least 50wt%, at least 55wt%, at least 60wt%, at least 65wt%, at least 70wt%, at least 75wt%, at least 80wt%, at least 85wt%, at least 90wt%, at least 95wt%, at least 96wt%, at least 97wt%, at least 98wt%, at least 99wt%, at least 99.5wt%, at least 99.8wt%, at least 99.9wt% or 100wt% of the chlorofluorocarbon is selected as difluorochloromethane; for example, 50wt%, 55wt%, 60wt%, 65wt%, 70wt%, 75wt%, 80wt%, 85wt%, 90wt%, 95wt%, 96wt%, 97wt%, 98wt%, 99wt%, 99.5wt%, 99.8wt%, 99.9wt% or 100wt% of the chlorofluorocarbon is difluorochloromethane, and the remaining chlorofluorocarbons can be, for example, optional monofluorodichloroethane, difluorochloroethane and dichloropentafluoropropane or any combination thereof.

[0051] The catalyst is obtained by pressing, drying, calcining and activating the catalyst precursor with chlorofluorocarbon.

[0052] The present application also provides a method for preparing a catalyst for synthesizing (E / Z)-1,2-difluoroethylene, comprising: pressing, drying, and calcining the catalyst precursor, and activating the catalyst with chlorofluorocarbon to obtain the catalyst.

[0053] In some embodiments, the catalyst precursor is a powder mixture.

[0054] In some embodiments, the pressing is to press the catalyst precursor into a granular shape to facilitate loading of materials and subsequent operations. When pressed into a granular shape, it can be pressed into any geometric state, for example, it can be a sphere, a cylinder, a cube, a cuboid, a truncated cone, a terrace, a triangular pyramid, a cone, etc. that can be easily thought of by a technician in the field; or it can also be any other three-dimensional shape. It is understandable that the present application does not have too many restrictions on the shape of the particles, as long as it can be easily loaded into the reaction equipment. In some embodiments, it is cylindrical. It should be noted that the particle size of the cylindrical particles is related to the size of the reaction equipment. If the content cavity of the reaction equipment is larger, the particle size of the particles can be larger; otherwise it is smaller. And those skilled in the art can appropriately adjust the particle size according to the size of the content cavity of the reaction equipment. For example, in some embodiments, the diameter of the inner cavity of the reaction device is 20-30 mm, and the diameter of the cylindrical particles can be any diameter range within the range of 3-15 mm, 3-12 mm, 3-10 mm, 3-8 mm, 3-5 mm or 3-15 mm; for example, it can be any diameter range within the range of 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm or 3-12 mm. In a specific embodiment, a fixed bed reaction device is used for the reaction, the reactor has an inner diameter of 25 mm and a length of 600 mm, the particles are cylindrical, the particle diameter is 3 mm, and the catalyst loading is 60 mL.

[0055] In some embodiments, the drying temperature is 100-200° C., 100-180° C., 100-160° C., 100-140° C., 100-120° C., or any temperature in the range of 100-200° C.; for example, 100° C., 105° C., 110° C., 115° C., 120° C., 125° C., 130° C., 135° C., 140° C., 145° C., 150° C., 155° C., 160° C., 165° C., 170° C., 175° C., 180° C., 185° C., 190° C., 195° C., 200° C., or any temperature in the range of 100-200° C. The change of drying temperature will not have a greater impact on the final result, mainly because the subsequent roasting temperature is much higher than the drying temperature, so even if it is not fully dried during drying, it will be further dried during roasting. Therefore, the drying temperature here is not completely limited to the range of 100-200°C; if the drying temperature is lower than 100°C, for example 50-100°C; for example, when drying at 95°C, 90°C, 85°C, 80°C, 75°C, 70°C, 65°C, 60°C, 55°C or 50°C, a longer drying time is required, and the drying time in the drying stage will be significantly extended, significantly reducing the efficiency. Therefore, from the perspective of processing efficiency, the drying process should be carried out at a higher drying temperature; but this does not absolutely mean that a drying temperature below 100°C cannot be used. If the drying temperature is higher than 200°C, for example 200-250°C, 200-300°C; further for example 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, 270°C, 275°C, 280°C, 285°C, 290°C, 295°C, 300°C, the drying temperature has little effect on the performance of the final catalyst, but a higher drying temperature will lead to significantly increased energy consumption and increased costs; however, this does not mean that drying temperatures higher than 200°C cannot be used.

[0056] In some embodiments, the calcination temperature is 250-400°C, 300-380°C, 300-360°C, 300-340°C, 300-320°C, or any temperature range within the range of 250-400°C; for example, the calcination temperature is 250°C, 255°C, 260°C, 265°C, 270°C, 275°C, 280°C, 285°C, 290°C, 295°C, 300°C, 305°C, 310°C, 315°C, 320°C, 325°C, 330°C, 335°C, 340°C, 345°C, 350°C, 355°C, 360°C, 365°C, 370°C, 375°C, 380°C, 385°C, 390°C, 395°C, 400°C, or any temperature within the range of 300-400°C. In some preferred embodiments, the calcination temperature is 300-360°C; within this temperature range, the performance of the obtained catalyst is more excellent. For example, the conversion rate of 1,1,2-trifluoroethane (R143) is in a relatively high range: 95.1-95.7%, even as high as 97%, 99%; for example, the selectivity for E-1,2-difluoroethylene is in the range of 37.2-37.6%, even as high as 38.5%, 40%; for example, the selectivity for Z-1,2-difluoroethylene is in the range of 58.6-59%, even as high as 60%, 62%; and the impurity content is as low as 3.2-3.8%, even lower than 3.0%, 2.8%. When the calcination temperature is increased, for example, 380°C or 400°C, the performance of the obtained catalyst is reduced, the selectivity for E-1,2-difluoroethylene is reduced, and the impurity content is increased; it may be that when the calcination temperature is higher than 380°C, the internal pore structure of the catalyst is affected, resulting in poor performance of the catalyst.

[0057] In some embodiments, the activation temperature is any temperature range within the range of 150-400°C, 200-400°C, 200-300°C, 150-250°C or 150-400°C; for example, the activation temperature is 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, 270°C, 275°C, 280°C, 285°C, 290°C, 295°C, 300°C, 305°C, 310°C, 315°C, 320°C, 325°C, 330°C, 335°C, 340°C, 345°C, 350°C, 355°C, 360°C, 365°C, 370°C, 375°C, 380°C, 385°C, 390°C, 395°C, 400°C or any temperature in the range of 150-400°C. In some preferred embodiments, the activation temperature is 200-300°C; within this temperature range, the obtained catalyst has better performance. For example, the conversion rate of 1,1,2-trifluoroethane (R143) is in a relatively high range: 95.1-96.7%, even as high as 97% and 99%; for example, the selectivity of E-1,2-difluoroethylene is in the range of 36.6-39.2%, even as high as 40% and 41%; for example, the selectivity of Z-1,2-difluoroethylene is in the range of 57.3-59.3%, even as high as 60% and 62%; and the impurity content is as low as 3.2-4.3%, even lower than 3.0% and 2.8%. When the activation temperature is increased, for example, 350℃ and 400℃, the performance of the obtained catalyst is reduced, the selectivity of E-1,2-difluoroethylene is reduced, and the impurity content is significantly increased (up to 21.9%); it may be that when the activation temperature is higher than 350℃, the elemental composition of the catalyst changes greatly, resulting in too many side reactions in the catalytic reaction, resulting in a significant increase in the impurity content.

[0058] When the catalyst of the present application is used for catalytic reaction, in some embodiments, the substrate of the catalytic reaction is 1,1,2-trifluoroethane (R143), and E-HFO-1132 and Z-HFO-1132 are obtained after catalysis. In the present application, it is more desirable to obtain more E-HFO-1132.

[0059] In some embodiments, when the catalytic reaction is carried out, the reaction temperature is any temperature range within the range of 200-500°C, 200-450°C, 250-400°C, 250-350°C or 200-500°C; for example, it can be 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, 270°C, 275°C, 280°C, 285°C, 290°C, 295°C, 300°C, 305°C, 310°C, 315°C ℃, 320℃, 325℃, 330℃, 335℃, 340℃, 345℃, 350℃, 355℃, 360℃, 365℃, 370℃, 375℃, 380℃, 385℃, 390℃, 395℃, 400℃, 405℃, 410℃, 415℃, 420℃, 425℃, 430℃, 435℃, 440℃, 445℃, 450℃, 455℃, 460℃, 465℃, 470℃, 475℃, 480℃, 485℃, 490℃, 495℃, 500℃ or any temperature in the range of 200-500℃.

[0060] In some embodiments, when the catalytic reaction is carried out, the reaction pressure (gauge pressure) is 0-0.2Mpa, 0.01-0.18Mpa, 0.05-0.16Mpa, 0.1-0.15Mpa, 0.12-0.14Mpa or any pressure range within the range of 0-0.2Mpa; for example, it can be 0Mpa, 0.01Mpa, 0.02Mpa, 0.03Mpa, 0.04Mpa, 0.05Mpa, 0.06Mpa, 0.07Mpa, 0.08Mpa, 0.09Mpa, 0.01Mpa, 0.02Mpa, 0.04Mpa, 0.06Mpa, 0.08Mpa, 0.1Mpa, 0.12Mpa, 0.14Mpa, 0.16Mpa, 0.18Mpa, 0.2Mpa or any pressure within the range of 0-0.2Mpa.

[0061] In some embodiments, when the catalytic reaction is carried out, the space velocity of the substrate is 1-1000h -1 , 10-900h -1 , 50-800h -1 , 80-700h -1 , 100-600h -1 , 120-500h -1 , 120-400h -1 , 140-300h -1 , 160-260h -1 or 1-1000h -1Any airspeed range within the range; for example, it can be 1h -1 , 20h -1 , 40h -1 、60h -1 , 80h -1 、100h -1 , 110h -1 , 120h -1 , 140h -1 , 150h -1 、160h -1 、170h -1 、180h -1 、190h -1 , 200h -1 、250h -1 、300h -1 、350h -1 , 400h -1 , 450h -1 , 500h -1 、600h -1 、700h -1 、800h -1 , 900h -1 、1000h -1 or 1-1000h -1 Any airspeed within the range.

[0062] The specific embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the specific embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0063] Example

[0064] Example 1

[0065] Weigh 100g of aluminum oxide and 10g of cobalt oxide powder, mix them evenly, press them into 3mm particles, dry them at 120°C to constant weight, and calcine them at 340°C. Add chlorodifluoromethane at 200°C to activate the catalyst. When the pH value of the tail gas stabilizes at 4-5, the activation end point is reached, and the AlOClF-CoOClF catalyst is obtained.

[0066] Example 2

[0067] Weigh 100 g of aluminum oxide and 10 g of nickel oxide powder, and synthesize the AlOClF-NiOClF catalyst according to the method of Example 1.

[0068] Example 3

[0069] 100 g of chromium oxide and 10 g of cobalt oxide powder were weighed, and a CrOClF-CoOClF catalyst was synthesized according to the method of Example 1.

[0070] Example 4

[0071] 100 g of chromium oxide and 10 g of nickel oxide powder were weighed, and a CrOClF-NiOClF catalyst was synthesized according to the method of Example 1.

[0072] Example 5

[0073] 100 g of magnesium oxide and 10 g of cobalt oxide powder were weighed, and the MgOClF-CoOClF catalyst was synthesized according to the method of Example 1.

[0074] Example 6

[0075] Weigh 100 g of magnesium oxide and 10 g of nickel oxide powder, and synthesize MgOClF-NiOClF catalyst according to the method of Example 1.

[0076] Example 7

[0077] 100 g of barium oxide and 10 g of cobalt oxide powder were weighed, and a BaOClF-CoOClF catalyst was synthesized according to the method of Example 1.

[0078] Example 8

[0079] 100 g of barium oxide and 10 g of nickel oxide powder were weighed, and a BaOClF-NiOClF catalyst was synthesized according to the method of Example 1.

[0080] Example 9

[0081] 100 g of calcium oxide and 10 g of cobalt oxide powder were weighed, and a CaOClF-CoOClF catalyst was synthesized according to the method of Example 1.

[0082] Example 10

[0083] 100 g of calcium oxide and 10 g of nickel oxide powder were weighed, and a CaOClF-NiOClF catalyst was synthesized according to the method of Example 1.

[0084] Application Examples

[0085] Application Example 1

[0086] The catalyst prepared in Example 1 was used as the evaluation catalyst and placed in a fixed window reaction device. The reaction temperature was set to 300°C, the reaction pressure was set to 0 MPa (gauge pressure), and the reaction space velocity of 1,1,2-trifluoroethane (R143) was set to 200 h -1 After the reaction product was treated with 10 wt% KOH solution to remove hydrogen fluoride (HF), the content of each component was analyzed by gas chromatography. The specific results are shown in Table 1. Among them, the GC spectrum of the crude HFO-1132 product of Example 4 is shown in Figure 1 The impurities are mainly difluoromethane, trifluoroethane, difluoroethane, chlorotrifluoroethylene and HFO-1132a; the GC spectrum of the HFO-1132 (E) product after the HFO-1132 crude product of Example 4 is as follows Figure 2 As shown, the GC spectrum of the HFO-1132 (Z) product after the purification of the crude HFO-1132 product of Example 4 is as follows Figure 3 shown.

[0087] Application Example 2-10

[0088] The difference between Application Examples 2-10 and Application Example 1 is that, when performing the reaction, catalysts prepared in different embodiments are selected respectively, as shown in Table 1 for details.

[0089] Table 1 Evaluation of catalyst reaction performance of Examples 1-10

[0090]

[0091] From the data in Table 1, it can be seen that the catalyst prepared in Example 4 has a conversion rate of 95.1% for 1,1,2-trifluoroethane (R143), a selectivity of 37.5% for E-HFO-1132, a selectivity of 59.3% for Z-HFO-1132, and a content of only 3.2% for other impurities. Whether in terms of substrate conversion rate, product selectivity or impurity content, it has shown excellent results.

[0092] Comparative Example 1

[0093] The difference between this comparative example and Example 4 is that 110 g of chromium oxide (without adding nickel oxide) was weighed and the CrOClF catalyst was synthesized according to the method of Example 1.

[0094] Examples 11-15

[0095] The difference between Examples 11-15 and Example 4 is that the weight ratio of chromium oxide to nickel oxide is different; specifically,

[0096] In Example 11, the weight ratio of chromium oxide to nickel oxide is 1:100;

[0097] In Example 12, the weight ratio of chromium oxide to nickel oxide is 5:100;

[0098] In Example 4, the weight ratio of chromium oxide to nickel oxide is 10:100;

[0099] In Example 13, the weight ratio of chromium oxide to nickel oxide is 15:100;

[0100] In Example 14, the weight ratio of chromium oxide to nickel oxide is 20:100;

[0101] In Example 15, the weight ratio of chromium oxide to nickel oxide is 30:100.

[0102] Application Examples 11-16

[0103] The only difference between Application Examples 11-16 and Application Example 4 is that, when performing the reaction, catalysts prepared in different embodiments (or comparative examples) are selected respectively, as shown in Table 2 for details.

[0104] Table 2 Comparison of reaction performance of catalysts prepared with different weight ratios of chromium oxide to nickel oxide

[0105]

[0106] From the data in Table 2, it can be seen that the weight ratio of chromium oxide to nickel oxide in the preparation of the catalyst has a great influence on the conversion rate of the catalytic reaction: when the weight ratio of chromium oxide to nickel oxide is lower than 10:100 (e.g., 1:100, 5:100), the conversion rate of the prepared catalyst to 1,1,2-trifluoroethane (R143) will be lower than 90%. When the content of nickel oxide is or higher than 10wt% (e.g., Example 4, Examples 13 to 15), the reaction conversion rate tends to be stable, the selectivity of HFO-1132 remains basically stable, and the impurity content is lower than 4%. In addition, it can be seen from the results of Application Example 11 that when preparing the catalyst, if only the main catalyst (such as chromium oxide) is used without selecting the co-catalyst (such as nickel oxide) to prepare the catalyst, the performance of the obtained catalyst is significantly reduced; specifically, the conversion rate of the prepared catalyst for 1,1,2-trifluoroethane (R143) will be as low as 12.4%, while the selectivity of E-HFO-1132 will be less than 30%, only 25.6%, and the impurity content will be as high as 7.2%.

[0107] Examples 16-20

[0108] The only difference between Examples 16-20 and Example 4 is that the drying temperature is different when preparing the catalyst; specifically, the drying temperature in Example 16 is 100°C;

[0109] In Example 4, the drying temperature is 120°C;

[0110] In Example 17, the drying temperature is 140°C;

[0111] In Example 18, the drying temperature is 160°C;

[0112] In Example 19, the drying temperature is 180°C;

[0113] In Example 20, the drying temperature is 200°C.

[0114] Application Examples 17-21

[0115] The only difference between Application Examples 17-21 and Application Example 4 is that, when performing the reactions, catalysts prepared in different embodiments are selected, as shown in Table 3.

[0116] Table 3 Comparison of reaction performance of catalysts prepared at different drying temperatures

[0117]

[0118] From the data in Table 3, it can be seen that the drying temperature has no significant effect on the reaction conversion rate and product selectivity of the catalyst. This may be mainly because the calcination temperature is 340°C, and the water that is not removed during the drying process is removed during calcination, so it has no obvious effect on the catalyst.

[0119] Examples 21-25

[0120] The only difference between Examples 21-25 and Example 4 is that the calcination temperature is different when preparing the catalyst; specifically, the calcination temperature in Example 21 is 300°C;

[0121] In Example 22, the calcination temperature is 320°C;

[0122] In Example 4, the calcination temperature is 340°C;

[0123] In Example 23, the calcination temperature is 360°C;

[0124] In Example 24, the calcination temperature is 380°C;

[0125] In Example 25, the calcination temperature is 400°C.

[0126] Application Example 22-26

[0127] The only difference between Application Examples 22-26 and Application Example 4 is that, when carrying out the reaction, catalysts prepared in different embodiments are selected respectively, as shown in Table 4 for details.

[0128] Table 4 Comparison of reaction performance of catalysts prepared at different calcination temperatures

[0129]

[0130] From the data in Table 4, it can be seen that when the calcination temperature is lower than 380°C during the preparation of the catalyst, the prepared catalyst has no significant effect on the reaction conversion rate of 1,1,2-trifluoroethane (R143) and the selectivity of the catalytic product. When the temperature is or higher than 380°C, the reaction conversion rate of 1,1,2-trifluoroethane (R143) decreases, and the selectivity of HFO-1132 also decreases, and the impurity content increases. This may be because the calcination temperature higher than 380°C affects the internal pore structure of the catalyst, resulting in changes in the reaction effect.

[0131] Examples 26-30

[0132] The only difference between Examples 26-30 and Example 4 is that the activation temperature is different when preparing the catalyst; specifically, the activation temperature in Example 26 is 150°C;

[0133] In Example 4, the activation temperature is 200°C;

[0134] In Example 27, the activation temperature is 250°C;

[0135] In Example 28, the activation temperature is 300°C;

[0136] In Example 29, the activation temperature is 350°C;

[0137] In Example 30, the activation temperature is 400°C.

[0138] Application Examples 27-31

[0139] The only difference between Application Examples 27-31 and Application Example 4 is that, when carrying out the reaction, catalysts prepared in different embodiments are selected respectively, as shown in Table 5 for details.

[0140] Table 5 Comparison of reaction performance of catalysts prepared at different activation temperatures

[0141]

[0142] From the data in Table 5, it can be seen that when the activation temperature is lower than 200°C during the preparation of the catalyst, the reaction conversion rate of the prepared catalyst for 1,1,2-trifluoroethane (R143) is significantly reduced, and the impurity content increases. When the temperature is higher than 300°C, the reaction conversion rate of the prepared catalyst for 1,1,2-trifluoroethane (R143) is high, but the selectivity for the product HFO-1132 decreases rapidly, and the impurity content increases significantly. This may be because the activation temperature is too high, which affects the elemental composition of the catalyst phase, resulting in a large number of side reactions during the dehydrofluorination reaction, resulting in an increase in the impurity content.

[0143] Examples 31-35

[0144] The difference between Examples 31-35 and Example 27 is that the specific selection of the activator is different when preparing the catalyst; specifically, the activator in Example 27 is difluorochloromethane;

[0145] In Example 31, the activating agent is dichlorodifluoromethane;

[0146] In Example 32, the activator is monofluorodichloroethane;

[0147] In Example 33, the activating agent is difluoromonochloroethane;

[0148] In Example 34, the activator is dichloropentafluoropropane;

[0149] In Example 35, the activating agent is 1-chloro-3,3,3-trifluoropropene.

[0150] Comparative Example 2

[0151] The only difference between Comparative Example 2 and Example 27 is that the specific selection of the activator when preparing the catalyst is different; specifically, the activator in Comparative Example 2 is anhydrous hydrogen fluoride.

[0152] Application Examples 32-37

[0153] The only difference between Application Examples 32-37 and Application Example 28 is that, when carrying out the reaction, catalysts prepared in different embodiments (or comparative examples) are selected respectively, as shown in Table 6 for details.

[0154] Table 6 Comparison of reaction performance of catalysts prepared with different activation agents

[0155]

[0156] From the data in Table 6, it can be seen that the influence on the reaction performance of the catalyst when preparing the catalyst with different activators is significant. The catalyst activated with difluoromonochloromethane (Example 27 / Application Example 28) has the highest reaction conversion rate and target product selectivity under the same reaction conditions, while the catalyst using other chlorofluorocarbons as activators has lower conversion rate and selectivity. It is worth noting that the catalyst activated with anhydrous hydrogen fluoride has the lowest reaction conversion rate and the highest impurity content. This shows that the catalytic effect of the catalyst containing chlorine and fluorine elements is better than that of the catalyst containing fluorine element alone.

[0157] Catalyst life test

[0158] Some catalysts were selected from the catalysts of the above implementation schemes for life testing, and the reaction conversion rates of 1,1,2-trifluoroethane (R143) after different service times were statistically analyzed. The specific results are shown in Table 7.

[0159] Table 7 Catalyst life evaluation

[0160]

[0161] From the data of Table 7, it can be seen that all catalysts have a phenomenon of gradually decreasing activity. In Examples 1-10, only the catalyst deactivation speed of Examples 3 and 4 is significantly slower, while the reaction conversion rate of other catalysts will all drop to less than 10% within 12h. It is worth noting that the deactivation rate of pure chromium fluoride catalyst (Comparative Example 2) is significantly faster than other catalysts, mainly due to the higher acidity of the chromium fluoride catalyst, which easily leads to olefin polymerization and thus affects catalyst activity. Based on the embodiment 27 catalyst optimized in Example 4, within the evaluation range of 100h, the catalyst maintains good stability, wherein the reaction conversion rate is only reduced by 2.5%, the HFO-1132 selectivity is reduced by 4%, and the impurity selectivity is not higher than 8%.

[0162] The description of the present disclosure is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the present disclosure to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present disclosure, and to enable those of ordinary skill in the art to understand the present disclosure and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A catalyst for synthesizing (E / Z)-1,2-difluoroethylene, wherein the catalyst is mainly obtained from a catalyst precursor, wherein the catalyst precursor comprises a main catalyst and a co-catalyst; The main catalyst is selected from any one or more combinations of Group IIA oxides, Group IIIA oxides and Group VIB oxides; The promoter is selected from any one or more combinations of Group VIII B oxides.

2. The catalyst according to claim 1, wherein the main catalyst comprises chromium oxide. The catalyst according to claim 1 , wherein the promoter comprises nickel oxide.

4. The catalyst according to claim 1, wherein the mass ratio of the main catalyst to the co-catalyst is 100:(0.05-50).

5. A method for preparing a catalyst for synthesizing (E / Z)-1,2-difluoroethylene as claimed in any one of claims 1 to 4, comprising: pressing, drying, calcining the catalyst precursor, and activating it with chlorofluorocarbon to obtain the catalyst.

6. The preparation method according to claim 5, wherein the chlorofluorocarbon is selected from any one or more combinations of difluoromonochloromethane, difluorodichloromethane, monofluorodichloroethane, difluoromonochloroethane, dichloropentafluoropropane and 1-chloro-3,3,3-trifluoropropene.

7. The preparation method according to claim 5, wherein the calcination temperature is 250-400°C.

8. The preparation method according to claim 5, wherein the activation temperature is 150-400°C.

9. The preparation method according to claim 5, wherein the drying temperature is 100-200°C.

10. A method for synthesizing (E / Z)-1,2-difluoroethylene, comprising using the catalyst according to any one of claims 1 to 4 or the catalyst prepared by the preparation method according to any one of claims 5 to 9.

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