A catalyst for synthesizing (E / Z)-1,2-difluoroethylene, a preparation method thereof, and an application thereof

Abstract

This application relates to the technical field of catalysts for preparing fluorinated olefins, and discloses a catalyst for synthesizing (E / Z)-1,2-difluoroethylene, its preparation method and application. The catalyst is mainly obtained from a catalyst precursor, and the catalyst precursor includes a main catalyst and a promoter; the main catalyst is selected from any one or a combination of oxides of Group IIA, Group IIIA, and Group VIB; the promoter is selected from any one or a combination of oxides of Group VIII B; the preparation method of the catalyst includes: pressing, drying, calcining the catalyst precursor, and activating it with chlorofluorocarbon to obtain the catalyst. When this catalyst is used in the catalytic synthesis of (E / Z)-1,2-difluoroethylene, it has a high conversion rate of the substrate (such as 1,1,2-trifluoroethane, R143), a low impurity content in the product, and a high selectivity for (E / Z)-1,2-difluoroethylene; in addition, this catalyst has a longer service life.

Description

Technical Field

[0001] This application relates to the technical field of catalysts for preparing fluorinated olefins, and specifically relates to a catalyst for synthesizing (E / Z)-1,2-difluoroethylene, its preparation method and application. Background Art

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

[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 reported synthesis methods, the process of using 1,1,2-trifluoroethane (R143) as the raw material and obtaining (E / Z)-HFO-1132 by gas-phase dehydrofluorination has the potential for industrialization. In the prior art, fluoride, oxide, and fluorinated oxide catalysts based on metals such as chromium, aluminum, iron, nickel, and magnesium are disclosed, and (E / Z)-HFO-1132 is synthesized 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 should be noted that a certain amount of oxygen is also added in this reaction, mainly to remove the carbon deposition generated during the reaction process, thereby prolonging the service life of the catalyst. However, excessive oxygen and the carbon dioxide generated by the reaction with carbon will enter the crude product. In addition, according to the reported public information, various organic impurities such as methane, trifluoromethane, vinylidene fluoride, fluoromethane, and 1,1,1-trifluoroethane will be generated during the synthesis of HFO-1132. Therefore, multiple types of impurities coexist, and some impurities may form azeotropes, 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, a preparation method thereof, and an application thereof. The catalyst uses one or more oxides of Group IIA, Group IIIA, and Group VIB as the main catalyst and an oxide of Group VIII as the co-catalyst. After mixing the main catalyst and the co-catalyst in a specific ratio and catalyzing with chlorofluorocarbons, the obtained catalyst is a metal fluorochloride. The applicant has found that when it catalyzes the synthesis of (E / Z)-1,2-difluoroethylene, it has a high conversion rate of the substrate (such as 1,1,2-trifluoroethane, R143), a low impurity content in the product, and a high selectivity for (E / Z)-1,2-difluoroethylene. In addition, further research has found that the catalyst has a better service life, which can greatly reduce the consumption of the catalyst in the catalytic reaction and achieve the purpose of cost reduction.

[0005] The present application relates to the following:

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

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

[0008] The co-catalyst is selected from any one or a combination of oxides of Group VIII.

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

[0010] The oxides of Group IIIA include aluminum oxide and indium oxide; and / or,

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

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

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

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

[0015] Optionally, the co-catalyst includes 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 cocatalyst is 100:(10 - 30).

[0019] Optionally, the chlorofluorocarbon is selected from any one or a combination of dichlorofluoromethane, dichlorodifluoromethane, 1,1-dichloro-2,2,2-trifluoroethane, 1,1-dichloro-1-fluoroethane, 1,2-dichloro-1,1,2,2-tetrafluoropropane, and 1-chloro-3,3,3-trifluoropropene.

[0020] A method for preparing the catalyst for synthesizing (E / Z)-1,2-difluoroethylene as described above, comprising: pressing, drying, calcining the catalyst precursor, and activating it with a 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, which includes using the catalyst as described above or the catalyst prepared by the preparation method as described above.

[0027] Beneficial effects

[0028] 1. In this application, a metal fluorochloride is prepared using one or more oxides of IIA, IIIA, and VIB as the main catalyst and an oxide of group VIII B as the cocatalyst, and it is used to catalyze 1,1,2-trifluoroethane (R143); the conversion rate of the catalyst to 1,1,2-trifluoroethane (R143) is in the range of 90 - 99%, its selectivity to E-HFO-1132 is about 33 - 40%, its selectivity to Z-HFO-1132 is about 57 - 60%, and the impurity content is significantly reduced (not higher than 5%).

[0029] 2. In this application, the main catalyst and the cocatalyst are further selected appropriately, and the mass ratio between the two is further optimized to obtain a catalyst with better performance (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 it is used in a catalytic reaction.

[0030] 3. The present application further optimizes the process parameters during the preparation of the catalyst, such as the calcination temperature, activation temperature, etc., to obtain a catalyst with better performance (including 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) during the catalytic reaction.

[0031] 4. The catalyst prepared by catalytically reacting dichlorofluoromethane with chromium oxide and nickel oxide powders as raw materials has a significantly extended service life: after a service time of up to 100 h, the catalyst still maintains good stability; for example, the reaction conversion rate of the catalyst to 1,1,2-trifluoroethane (R143) only decreases by 2.5%, the selectivity to HFO-1132 only decreases by 4%, and the impurity content is not higher than 8%. Description of the Drawings

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

[0033] Figure 2 . GC chromatogram of the purified HFO-1132(E) product of the crude HFO-1132 product of Example 4.

[0034] Figure 3 . GC chromatogram of the purified HFO-1132(Z) product of the crude HFO-1132 product of Example 4. Detailed Description of the Invention

[0035] It should be noted that certain terms 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. The specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of components as the criterion for distinction.

[0036] As mentioned throughout the specification and claims, "comprising" or "including" is an open-ended term and should be interpreted as "including but not limited to". The subsequent description in the specification is for the purpose of describing the preferred embodiments of the present application, but the description is for the general principle of the specification and is not used to limit the scope of the present application. The protection scope of the present application shall be determined by the scope defined by the appended claims. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present disclosure belongs.

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

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

[0039] As used herein, the term "about X - Y" 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. Thus, this statement is intended as a basis for antecedent use in connection with the recitation of claim elements with exclusive terms such as "only", "solely", etc., or the use of a limitation of "not".

[0041] As used herein, the term "and / or" in a phrase 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 a phrase 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, which is mainly obtained from a catalyst precursor containing a main catalyst and a co-catalyst.

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

[0044] In the present application, the finally prepared catalyst is represented by "XOClF - YOClF"; where "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 fluorochloride, but only refer to the elemental composition contained in the metal fluorochloride. For example, when chromium oxide is used as the main catalyst and nickel oxide is used as the co-catalyst, and the catalyst is prepared by the method of the present application, the finally obtained catalyst is denoted as the 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 VIII B oxides include, but are not limited to, nickel oxide and cobalt oxide; in some embodiments, the Group VIII B 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, the meaning of "mainly" is 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 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, optionally magnesium oxide, barium oxide, calcium oxide, aluminum oxide or any combination thereof.

[0048] In some embodiments, the cocatalyst is selected from any one or a combination of any proportions of nickel oxide and zirconium oxide. When the main catalyst is selected differently, using nickel oxide and cobalt oxide as cocatalysts respectively, the performance changes of the prepared catalysts do not show relatively consistent regularity. For example: compared with the catalyst prepared from alumina and cobalt oxide, the catalyst prepared from alumina and nickel oxide has a higher conversion rate of 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 catalyst prepared from chromium oxide and cobalt oxide, the catalyst prepared from chromium oxide and nickel oxide has a higher conversion rate of 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 prepared from magnesium oxide and cobalt oxide, the catalyst prepared from magnesium oxide and nickel oxide has a slightly lower conversion rate of 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 prepared from barium oxide and cobalt oxide, the catalyst prepared from barium oxide and nickel oxide has a higher conversion rate of 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 cocatalyst is 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 any proportional range within 100:(0.05 - 50); for example, specifically 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, 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 proportion within 100:(0.05 - 50). In some preferred embodiments, the mass ratio of the main catalyst to the cocatalyst is 100:(5 - 40) or any proportional range within it. In some more preferred embodiments, the mass ratio of the main catalyst to the cocatalyst is 100:(10 - 30) or any proportional range within it; within this proportional range, the performance of the prepared catalyst is more excellent. For example, the conversion rate of 1,1,2 - trifluoroethane (R143) is within a relatively high range: 95.1 - 97.1%, and even as high as 98%, 99%; for example, the selectivity for E - 1,2 - difluoroethylene is within the range of 36.5 - 38.1%, and even as high as 39%, 40%; for example, the selectivity for Z - 1,2 - difluoroethylene is within the range of 58.2 - 59.8%, and even as high as 60%, 62%; while the impurity content is as low as within the range of 3.2 - 3.8%, and even lower than 2.8%, 2.5%.

[0050] In some embodiments, the chlorofluorocarbon is selected from any one or a combination of more than one of chlorodifluoromethane, dichlorodifluoromethane, 1,1-dichloro-1-fluoroethane, 1,1-difluoro-1-chloroethane, 1,2-dichloro-1,1,2,2,3-pentafluoropropane, and 1-chloro-3,3,3-trifluoropropene; in some preferred embodiments, the chlorofluorocarbon is selected from any one or a combination of more than one of 1,1-dichloro-1-fluoroethane, 1,1-difluoro-1-chloroethane, chlorodifluoromethane, and 1,2-dichloro-1,1,2,2,3-pentafluoropropane. For example, in some embodiments, the chlorofluorocarbon is 1,1-dichloro-1-fluoroethane; in some embodiments, the chlorofluorocarbon is 1,1-difluoro-1-chloroethane; in some embodiments, the chlorofluorocarbon is chlorodifluoromethane; in some embodiments, the chlorofluorocarbon is 1,2-dichloro-1,1,2,2,3-pentafluoropropane. In some more preferred embodiments, the chlorofluorocarbon mainly comprises chlorodifluoromethane. Herein, the meaning of "mainly" is that at least 50 wt%, at least 55 wt%, at least 60 wt%, at least 65 wt%, at least 70 wt%, at least 75 wt%, at least 80 wt%, at least 85 wt%, at least 90 wt%, at least 95 wt%, at least 96 wt%, at least 97 wt%, at least 98 wt%, at least 99 wt%, at least 99.5 wt%, at least 99.8 wt%, at least 99.9 wt%, or 100 wt% of the chlorofluorocarbon is selected as chlorodifluoromethane; for example, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, 95 wt%, 96 wt%, 97 wt%, 98 wt%, 99 wt%, 99.5 wt%, 99.8 wt%, 99.9 wt%, or 100 wt% of the chlorofluorocarbon is chlorodifluoromethane, and the remaining chlorofluorocarbons can be, for example, optionally 1,1-dichloro-1-fluoroethane, 1,1-difluoro-1-chloroethane, and 1,2-dichloro-1,1,2,2,3-pentafluoropropane or any combination thereof.

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

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

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

[0054] In some embodiments, the pressing is to press the catalyst precursor into granular form to facilitate the loading of materials for subsequent operations. When pressing into granular form, it can be pressed into any geometric shape, such as spherical, cylindrical, cubic, cuboid, frustum of a cone, trapezoidal frustum, triangular pyramid, cone, etc., which are easily conceivable by those skilled in the art; or it can also be any other three-dimensional shape. It can be understood that the present application does not impose excessive restrictions on the shape of the particles, as long as they 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 inner cavity of the reaction equipment is larger, the particle size of the particles can be larger; conversely, it can be smaller. And those skilled in the art can appropriately adjust the particle size according to the size of the inner cavity of the reaction equipment. For example, in some embodiments, the inner cavity diameter of the reaction equipment is 20 - 30 mm, then the diameter of the cylindrical particles can be any diameter range within 3 - 15 mm, 3 - 12 mm, 3 - 10 mm, 3 - 8 mm, 3 - 5 mm or 3 - 15 mm; for example, it can be 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 any diameter range within 3 - 12 mm. In a specific embodiment, a fixed-bed reaction device is used for the reaction, the inner diameter of the reactor is 25 mm, the length is 600 mm, the particles are cylindrical, the particle size is 3 mm, and the catalyst loading is 60 mL.

[0055] In some embodiments, the drying temperature is any temperature range within 100 - 200 °C, 100 - 180 °C, 100 - 160 °C, 100 - 140 °C, 100 - 120 °C or 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 within 100 - 200 °C. The change in the drying temperature will not have a greater impact on the final result. The main reason is that the subsequent calcination temperature is much higher than the drying temperature. Therefore, even if it is not fully dried during drying, it will be further dried during calcination. 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, such as 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, so 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; however, this does not absolutely mean that a drying temperature lower than 100 °C cannot be used. If the drying temperature is higher than 200 °C, such as 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, this drying temperature has little impact on the performance of the finally prepared catalyst, but the higher drying temperature will bring a significantly increased energy consumption and increase the cost; however, this does not indicate that a drying temperature higher than 200 °C cannot be used.

[0056] In some embodiments, the calcination temperature is any temperature range within 250 - 400 °C, 300 - 380 °C, 300 - 360 °C, 300 - 340 °C, 300 - 320 °C or 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 300 - 400 °C. In some preferred embodiments, the calcination temperature is 300 - 360 °C; within this temperature range, the prepared catalyst has more excellent performance. For example, the conversion rate of 1,1,2 - trifluoroethane (R143) is within a relatively high range: 95.1 - 95.7%, even up to 97%, 99%; for example, the selectivity for E - 1,2 - difluoroethylene is within the range of 37.2 - 37.6%, even up to 38.5%, 40%; for example, the selectivity for Z - 1,2 - difluoroethylene is within the range of 58.6 - 59%, even up to 60%, 62%; while the impurity content is as low as within the range of 3.2 - 3.8%, even lower than 3.0%, 2.8%. When the calcination temperature is increased, such as 380 °C, 400 °C, the performance of the prepared catalyst decreases, the selectivity for E - 1,2 - difluoroethylene decreases and the impurity content increases; 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 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 within the range of 150 - 400 °C. In some preferred embodiments, the activation temperature is 200 - 300 °C; within this temperature range, the prepared catalyst has more excellent 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%, 99%; for example, the selectivity for E - 1,2 - difluoroethylene is in the range of 36.6 - 39.2%, even as high as 40%, 41%; for example, the selectivity for Z - 1,2 - difluoroethylene is in the range of 57.3 - 59.3%, even as high as 60%, 62%; while the impurity content is as low as in the range of 3.2 - 4.3%, even lower than 3.0%, 2.8%. When the activation temperature is increased, such as using 350 °C, 400 °C, the performance of the prepared catalyst is reduced, the selectivity for E - 1,2 - difluoroethylene is decreased, and the impurity content is significantly increased (up to 21.9%); it may be that when the activation temperature is higher than 350 °C, there are significant changes in the elemental composition of the catalyst, resulting in too many side reactions in the catalytic reaction and a significant increase in the impurity content.

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

[0059] In some embodiments, when performing the catalytic reaction, the reaction temperature is any temperature range within 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 °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, 405 °C, 410 °C, 415 °C, 420 °C, 425 °C, 430 °C, 435 °C, 440 °C, 445 °C, 450 °C, 455 °C, 460 °C, 465 °C, 470 °C, 475 °C, 480 °C, 485 °C, 490 °C, 495 °C, 500 °C, or any temperature within the range of 200 - 500 °C.

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

[0061] In some embodiments, when performing the catalytic reaction, the space velocity of the substrate is 1 - 1000 h -1 、10 - 900 h -1 、50 - 800 h -1 、80 - 700 h -1 、100 - 600 h -1 、120 - 500 h -1 、120 - 400 h -1 、140 - 300 h -1 、160 - 260 h -1 or 1 - 1000 h -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] Specific embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although specific embodiments of the present application are shown in the 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 so that the present application can be more thoroughly understood and the scope of the present application can be fully conveyed to those skilled in the art.

[0063] Embodiment

[0064] Example 1

[0065] Weigh 100 g of alumina and 10 g of cobalt oxide powder, mix them evenly and press them into 3 - mm particles, dry them at 120°C until constant weight, and calcine them at 340°C. Pass dichlorofluoromethane over the catalyst at 200°C for activation treatment. Wait until the pH value of the tail gas stabilizes at 4 - 5, which is the end point of activation, to obtain the AlOClF - CoOClF catalyst.

[0066] Example 2

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

[0068] Example 3

[0069] Weigh 100 g of chromium oxide and 10 g of cobalt oxide powder, and synthesize the CrOClF-CoOClF catalyst according to the method of Example 1.

[0070] Example 4

[0071] Weigh 100 g of chromium oxide and 10 g of nickel oxide powder, and synthesize the CrOClF-NiOClF catalyst according to the method of Example 1.

[0072] Example 5

[0073] Weigh 100 g of magnesium oxide and 10 g of cobalt oxide powder, and synthesize the MgOClF-CoOClF catalyst 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 the MgOClF-NiOClF catalyst according to the method of Example 1.

[0076] Example 7

[0077] Weigh 100 g of barium oxide and 10 g of cobalt oxide powder, and synthesize the BaOClF-CoOClF catalyst according to the method of Example 1.

[0078] Example 8

[0079] Weigh 100 g of barium oxide and 10 g of nickel oxide powder, and synthesize the BaOClF-NiOClF catalyst according to the method of Example 1.

[0080] Example 9

[0081] Weigh 100 g of calcium oxide and 10 g of cobalt oxide powder, and synthesize the CaOClF-CoOClF catalyst according to the method of Example 1.

[0082] Example 10

[0083] Weigh 100 g of calcium oxide and 10 g of nickel oxide powder, and synthesize the CaOClF-NiOClF catalyst according to the method of Example 1.

[0084] Application Example

[0085] Application Example 1

[0086] Using the catalyst prepared in Example 1 as the evaluation catalyst, place it in a fixed-bed reaction device, set the reaction temperature to 300 °C, the reaction pressure to 0 MPa (gauge pressure), and the reaction space velocity of 1,1,2-trifluoroethane (R143) to 200 h -1 , after removing hydrogen fluoride (HF) from the reaction product with a 10 wt% KOH solution, analyze the content of each component with a gas chromatograph. The specific results are shown in Table 1. Among them, the GC chromatogram of the crude HFO-1132 product in Example 4 is shown in Figure 1 , and its impurities are mainly difluoromethane, trifluoroethane, difluoroethane, trifluorochloroethylene, and HFO-1132a; the GC chromatogram of the purified HFO-1132 (E) product from the crude HFO-1132 product in Example 4 is as shown in Figure 2 , and the GC chromatogram of the purified HFO-1132 (Z) product from the crude HFO-1132 product in Example 4 is as shown in Figure 3 .

[0087] Application Examples 2 - 10

[0088] The difference between Application Example 2-10 and Application Example 1 is only that when carrying out the reaction, the catalysts prepared in different examples are selected respectively, as shown in Table 1 specifically.

[0089] Table 1 Evaluation of the catalytic reaction performance of the catalysts in 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 1,1,2-trifluoroethane (R143) as high as 95.1%, the selectivity of E-HFO-1132 is 37.5%, the selectivity of Z-HFO-1132 is 59.3%, and the content of other impurities is only 3.2%. Whether from the substrate conversion rate, product selectivity or impurity content, it shows 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) is weighed, and the CrOClF catalyst is synthesized according to the method of Example 1.

[0094] Examples 11 - 15

[0095] The difference between Examples 11-15 and Example 4 is only 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 difference between Application Examples 11 - 16 and Application Example 4 is only that different catalysts prepared from different Examples (or Comparative Examples) are selected during the reaction. See Table 2 for details.

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

[0105]

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

[0107] Examples 16 - 20

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

[0109] The drying temperature in Example 4 is 120 °C;

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

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

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

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

[0114] Application Examples 17 - 21

[0115] The difference between Application Examples 17-21 and Application Example 4 was only that different catalysts prepared in different examples were selected during the reaction. Specifically, see Table 3.

[0116] Table 3 Comparison of the 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 had little effect on the reaction conversion rate and the selectivity of each product of this catalyst. This may be mainly because the calcination temperature was 340 °C in all cases, and the water that was not removed during the drying process was removed during calcination, so there was no obvious effect on the catalyst.

[0119] Examples 21 - 25

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

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

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

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

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

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

[0126] Application Examples 22 - 26

[0127] The difference between Application Examples 22-26 and Application Example 4 was only that different catalysts prepared in different examples were selected during the reaction. Specifically, see Table 4.

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

[0129]

[0130] As can be seen from the data in Table 4, when the calcination temperature is lower than 380 °C during the preparation of the catalyst, the reaction conversion rate of the prepared catalyst to 1,1,2-trifluoroethane (R143) and the selectivity to the catalytic product are not significantly affected. When the temperature is 380 °C or higher, the reaction conversion rate of 1,1,2-trifluoroethane (R143) decreases, and at the same time, 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 difference between Examples 26-30 and Example 4 is only that the activation temperature is different during the preparation of the catalyst; specifically, the activation temperature in Example 26 is 150 °C;

[0133] The activation temperature in Example 4 is 200 °C;

[0134] The activation temperature in Example 27 is 250 °C;

[0135] The activation temperature in Example 28 is 300 °C;

[0136] The activation temperature in Example 29 is 350 °C;

[0137] The activation temperature in Example 30 is 400 °C.

[0138] Application Examples 27 - 31

[0139] The difference between Application Examples 27-31 and Application Example 4 is only that different catalysts prepared in different examples are selected during the reaction, as shown in Table 5 specifically.

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

[0141]

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

[0143] Examples 31 - 35

[0144] Examples 31 - 35 differ from Example 27 only in that the specific selection of the activator is different when preparing the catalyst; specifically, the activator in Example 27 is chlorodifluoromethane;

[0145] The activator in Example 31 is dichlorodifluoromethane;

[0146] The activator in Example 32 is 1,1 - dichloro - 2 - fluoroethane;

[0147] The activator in Example 33 is 1,1 - difluoro - 2 - chloroethane;

[0148] The activator in Example 34 is 1,1,2 - trichloro - 1,2,2 - trifluoropropane;

[0149] The activator in Example 35 is 1 - chloro - 3,3,3 - trifluoropropene.

[0150] Comparative Example 2

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

[0152] Application Examples 32 - 37

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

[0154] Table 6 Comparison of the reaction performance of catalysts prepared with different activators

[0155]

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

[0157] Lifetime Test of the Catalyst

[0158] Select some catalysts from the catalysts of the above embodiments for life testing, and count the reaction conversion rates of 1,1,2 - trifluoroethane (R143) after different service times. The specific results are shown in Table 7.

[0159] Table 7 Catalyst Life Evaluation

[0160]

[0161] As can be seen from the data in Table 7, all catalysts show a phenomenon of gradually decreasing activity. Among Examples 1 - 10, only the catalysts in Examples 3 and 4 have a significantly slower deactivation rate, while the reaction conversion rates of other catalysts will drop below 10% within 12 h. It is worth noting that the deactivation rate of the pure chromium fluoride catalyst (Comparative Example 2) is significantly faster than that of other catalysts, which is mainly due to the relatively high acidity of the chromium fluoride catalyst, which easily leads to olefin polymerization and thus affects the catalyst activity. Based on the optimization of Example 4, the catalyst of Example 27 maintained good stability within the evaluation range of 100 h, with the reaction conversion rate only decreasing by 2.5%, the selectivity of HFO - 1132 decreasing by 4%, and the impurity selectivity not exceeding 8%.

[0162] The description of the present disclosure has been given for purposes of illustration and description, and is not intended to be exhaustive or to limit the present disclosure to the forms disclosed. Many modifications and variations are obvious to those of ordinary skill in the art. The examples were chosen and described in order to better explain the principles of the present disclosure and its practical application, and to enable those of ordinary skill in the art to understand the present disclosure and design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A method for preparing a catalyst for synthesizing (E / Z)-1,2-difluoroethylene, comprising: pressing, drying, and calcining a catalyst precursor, and activating it with chlorofluorocarbon to obtain a catalyst; The catalyst precursor comprises a main catalyst and a co-catalyst; The main catalyst is chromium oxide; The promoter is nickel oxide and / or cobalt oxide; The chlorofluorocarbon is chlorodifluoromethane; The calcination temperature is 250-360°C; The activation temperature is 200-300°C.

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

3. The preparation method according to claim 1, wherein the drying temperature is 100-200°C.

4. A catalyst for synthesizing (E / Z)-1,2-difluoroethylene, wherein the catalyst is prepared by the preparation method according to any one of claims 1 to 3.

5. A method for synthesizing (E / Z)-1,2-difluoroethylene, comprising using a catalyst prepared by the preparation method according to any one of claims 1 to 3 or the catalyst according to claim 4.

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