CN118253320A - Preparation process of 1, 1-difluoroethane dehydrofluorination catalyst - Google Patents
Preparation process of 1, 1-difluoroethane dehydrofluorination catalyst Download PDFInfo
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- 239000003054 catalyst Substances 0.000 title claims abstract description 52
- 238000002360 preparation method Methods 0.000 title claims abstract description 24
- NPNPZTNLOVBDOC-UHFFFAOYSA-N 1,1-difluoroethane Chemical compound CC(F)F NPNPZTNLOVBDOC-UHFFFAOYSA-N 0.000 title claims abstract description 19
- 238000005796 dehydrofluorination reaction Methods 0.000 title claims abstract description 19
- 229940051271 1,1-difluoroethane Drugs 0.000 title claims abstract description 18
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims abstract description 50
- 229910052751 metal Inorganic materials 0.000 claims abstract description 18
- 239000002184 metal Substances 0.000 claims abstract description 18
- 238000003756 stirring Methods 0.000 claims abstract description 9
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052731 fluorine Inorganic materials 0.000 claims abstract description 8
- 239000011737 fluorine Substances 0.000 claims abstract description 8
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- 238000006243 chemical reaction Methods 0.000 claims description 17
- 238000000034 method Methods 0.000 claims description 13
- KBJMLQFLOWQJNF-UHFFFAOYSA-N nickel(ii) nitrate Chemical compound [Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O KBJMLQFLOWQJNF-UHFFFAOYSA-N 0.000 claims description 11
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 claims description 10
- GPNDARIEYHPYAY-UHFFFAOYSA-N palladium(ii) nitrate Chemical compound [Pd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O GPNDARIEYHPYAY-UHFFFAOYSA-N 0.000 claims description 8
- 238000001035 drying Methods 0.000 claims description 5
- 238000000746 purification Methods 0.000 claims description 4
- 238000001914 filtration Methods 0.000 claims description 3
- 150000003839 salts Chemical class 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims 8
- 239000007789 gas Substances 0.000 description 26
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 24
- XUCNUKMRBVNAPB-UHFFFAOYSA-N fluoroethene Chemical compound FC=C XUCNUKMRBVNAPB-UHFFFAOYSA-N 0.000 description 17
- 230000003197 catalytic effect Effects 0.000 description 16
- 238000011084 recovery Methods 0.000 description 14
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 12
- 239000000463 material Substances 0.000 description 12
- 239000002253 acid Substances 0.000 description 11
- 229910052759 nickel Inorganic materials 0.000 description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 9
- 229910052799 carbon Inorganic materials 0.000 description 9
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- IRPGOXJVTQTAAN-UHFFFAOYSA-N 2,2,3,3,3-pentafluoropropanal Chemical compound FC(F)(F)C(F)(F)C=O IRPGOXJVTQTAAN-UHFFFAOYSA-N 0.000 description 3
- KLZUFWVZNOTSEM-UHFFFAOYSA-K Aluminum fluoride Inorganic materials F[Al](F)F KLZUFWVZNOTSEM-UHFFFAOYSA-K 0.000 description 3
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Abstract
The invention discloses a preparation process of a dehydrofluorination catalyst of 1, 1-difluoroethane, which comprises the following steps: and dropwise adding hydrofluoric acid into the metal solution under the condition of heating and stirring, continuously stirring after the dropwise adding is finished, adding hybridized metal, and purifying to obtain the metal hybridized fluorine-based catalyst.
Description
Technical Field
The invention relates to the field of catalyst synthesis, in particular to a preparation process of a dehydrofluorination catalyst for 1, 1-difluoroethane.
Background
The polyvinyl fluoride (PVF) has the lowest fluorine content and the lowest density in the fluoroplastic, is a thermoplastic resin with excellent comprehensive performance, and is also the lowest-cost variety in the fluoroplastic. The polyvinyl fluoride product has excellent corrosion resistance, wear resistance, self-lubricating property, dielectric property, excellent ultraviolet resistance, weather resistance and the like, and is mainly applied to the fields of solar back plates, atmosphere sampling bags, color steel plates, printing ink printing, space membrane materials, rock wool coating and the like.
According to the current economic development trend and the continuous progress of fluoropolymer processing technology, the consumption of the polyvinyl fluoride in the markets at home and abroad is steadily increasing. Vinyl Fluoride (VF) is the main raw material for preparing polyvinyl fluoride products, and with the continuous expansion of the application of polyvinyl fluoride products, the market demand of vinyl fluoride is also increasing.
The conventional fluoroethylene preparation method is 1, 1-difluoroethane dehydrofluorination (HF), and the technological method mainly comprises a thermokalite method, a high-temperature cracking method and a gas-phase catalytic (cracking) method.
The hot alkali method has the advantages that the process for removing the hydrogen fluoride under the alkaline condition does not need to use a catalyst, the phenomenon that the product yield is gradually reduced due to the deactivation of the catalyst can be avoided, but the 1, 1-difluoroethane and the alkali liquor/solid alkali are respectively in two phases, the contact is insufficient, the reaction time is long, the three wastes in the route are large, and the industrial production is difficult.
The high-temperature cracking process for removing hydrogen fluoride is a traditional process, because the 1, 1-difluoroethane has better thermal stability, the C-F bond cracking energy is high (522 kJ/mol), if a non-catalytic reaction is adopted, the cracking can only occur at a higher temperature, the energy consumption is high, the byproducts are more, and the reaction conditions and equipment requirements are harsh.
The gas phase catalytic (cracking) method is to carry out the reaction of removing HF by catalytic cracking of 1, 1-difluoroethane under the action of a catalyst, and has the most extensive research due to the technical advantages of the gas phase catalytic method, but the traditional catalyst has low catalytic life due to the strong Lewis acid site, is easy to deposit carbon or tuberculosis sites on the surface, and limits the industrial application of the traditional catalyst.
Disclosure of Invention
In order to solve the problems, the invention provides a preparation process of a1, 1-difluoroethane dehydrofluorination catalyst, which is used for preparing the catalyst, and the prepared metal hybridization fluorine-based catalyst has high catalytic conversion rate, strong stability and long service life.
The technical scheme of the invention is realized as follows:
the invention provides a preparation process of a1, 1-difluoroethane dehydrofluorination catalyst, which comprises the following steps: and (3) dropwise adding excessive hydrofluoric acid into the metal solution under the condition of heating and stirring, continuously stirring after the dropwise adding is finished, adding the hybridized metal, and purifying to obtain the metal hybridized fluorine-based catalyst.
Further, the metal solution is an aluminum nitrate solution.
Further, the molar ratio of hydrofluoric acid to aluminum nitrate is 16:3-4:1.
The beneficial effects of adopting above-mentioned scheme are: hydrofluoric acid reacts with aluminum nitrate to form aluminum fluoride, which has high catalytic activity for dehydrofluorination of 1, 1-difluoroethane. In combination with the gas-phase catalytic dehydrofluorination reaction of 1, 1-difluoroethane, the bond is broken into a reaction speed control step due to larger bond energy of C-F, and the abundant surface acid sites of the Lewis acid catalyst can effectively activate the C-F bond, which is an active center for HF removal reaction.
Further, the heating temperature is 10 to 40 ℃, preferably 15 to 35 ℃.
The beneficial effects of adopting above-mentioned scheme are: but different precipitation temperatures have a significant effect on the initial activity of the catalyst. The precipitation temperature is increased, the nucleation rate is increased, the generated crystal nucleus is increased, the precipitation with smaller particles tends to be generated, the specific surface area of the prepared aluminum fluoride is increased, and the initial activity of the catalyst is increased.
Further, the concentration of the hydrofluoric acid is 20-30 mol.L -1.
The beneficial effects of adopting above-mentioned scheme are: the higher the concentration of hydrofluoric acid used, the higher the supersaturation degree of the solution, the faster the nucleation rate, the more crystal nuclei are generated, the smaller the particles obtained to precipitate, the larger the specific surface area, and thus the activity is high.
Further, the hybrid metal is in the form of a metal salt, including nickel nitrate and protactinium nitrate.
Further, the molar ratio of the nickel nitrate to the aluminum nitrate is 4:9-4:3.
The beneficial effects of adopting above-mentioned scheme are: the traditional aluminum fluoride catalyst has strong Lewis acid sites, is easy to deposit carbon or tuberculosis sites on the surface, has low catalytic life and limits the industrial application. With the addition of nickel, the strong acid sites of the catalyst are converted into medium strong acid sites due to the interaction of nickel and acid sites on the surface of the catalyst, so that the carbon deposition effect is reduced, and the stability of the catalyst is improved. Meanwhile, nickel can effectively activate C-H bond, and metallic nickel can be considered to provide new active site, thereby improving catalytic activity.
Further, the molar ratio of the palladium nitrate to the nickel nitrate is 1:4-1:1.
The beneficial effects of adopting above-mentioned scheme are: although the acidity of the strong acid sites of the catalyst is reduced, a carbon deposition effect occurs. Palladium can react with carbon deposition to pyrolyze the carbon deposition, and acid sites are regenerated, so that the stability of the catalyst is further improved.
Further, the purification method is filtration and drying.
Further, the drying conditions are: 85-95 ℃ for 10-24h.
A catalyst prepared by a preparation process of a1, 1-difluoroethane dehydrofluorination catalyst.
Compared with the prior art: the beneficial effects of the invention are as follows:
1. because the bond energy of the C-F bond is larger, the bond is broken into a reaction speed control step, and the abundant surface acid sites of the Lewis acid catalyst can effectively activate the C-F bond, which is an active center for removing HF reaction.
2. The proper precipitation temperature and hydrofluoric acid concentration can obtain smaller particle size of the precipitation particles, and the prepared catalyst has larger specific surface area and higher activity.
3. The interaction between nickel and acid sites on the surface of the catalyst converts the strong acid sites of the catalyst into medium strong acid sites, so that the carbon deposition effect is reduced, and the stability of the catalyst is improved. Meanwhile, nickel can effectively activate C-H bond, and metallic nickel can be considered to provide new active site, thereby improving catalytic activity.
4. Palladium can react with carbon deposition to pyrolyze the carbon deposition, and acid sites are regenerated, so that the stability of the catalyst is further improved.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a process for refining and purifying fluoroethylene according to an embodiment of the present invention.
In the figure: a first vaporizer, a second vaporizer, a first gas heat exchanger, a second gas heat exchanger, a raw material preheater, a cracking furnace, a filter, a compressor, a post-condenser, a recovery tower 10 HF, a tail gas absorbing device 11, a high-pressure pump 12, a pre-preheater 13, a 14 152a circulating tower, a pre-cooler 15, a16 VF purifying tower, a tar tower 17, a 18 152a recovering tower and a gas collecting reactor 19.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Description of the reagent:
Hydrofluoric acid, aluminum nitrate, nickel nitrate, palladium nitrate, shanghai Ala Biochemical technologies Co., ltd.
Preparation example 1
Preparation of a metal hybridization fluorine-based catalyst: 168mL of 25 mol.L -1 hydrofluoric acid was added dropwise to 4L of an aluminum nitrate solution containing 191.7g of aluminum nitrate at a rate of 50mL min -1 at 25℃with stirring. After the completion of the dropwise addition, stirring was continued and 109.7g of nickel nitrate and 69.1g of palladium nitrate were added, stirring was performed for 5 hours, and then filtration and drying in an oven at 90℃were performed for 12 hours, to obtain the metal-hybridized fluorine-based catalyst.
Example 1
TABLE 1
| Project | Unit (B) | Content of |
| 1, 1-Difluoroethane (152 a) | wt% | Greater than 99.9 |
| Moisture content | ppmwt | Less than 25 |
| Acetylene (acetylene) | ppmvol | Less than 25 |
| Vinyl chloride | ppmvol | Less than 2.5 |
As shown in fig. 1, fresh raw materials (the material compositions are shown in table 1) and recycled materials were vaporized in a first vaporizer 1 and a second vaporizer 2, respectively, at a pressure of 1MPa and a temperature of 80 ℃.
After merging, the temperature is respectively increased to 130 ℃ and 180 ℃ through a first gas heat exchanger 3 and a second gas heat exchanger 4, then raw material pyrolysis gas is heated to 300 ℃ through a raw material preheater 5 and then is introduced into a pyrolysis furnace 6 for normal pressure catalytic pyrolysis, the pyrolysis furnace 6 is a single-channel multi-tube reactor, and the tube array is internally filled with the metal hybridization fluorine-based catalyst particles prepared in the preparation example 1, wherein the pyrolysis gas consists of 20.23% VF, 68.75%152a, 10.18% HF, 0.8% acetylene and a small amount of tar.
After solid impurities and part of tar are removed from pyrolysis gas through a filter 7, the pyrolysis gas enters a first gas heat exchanger 3 and a second gas heat exchanger 4 for heat recovery, the temperature is reduced to 210 ℃ after two-stage heat exchange, the temperature is reduced to normal temperature by a cooler before a machine, the pyrolysis gas is compressed by a compressor 8, the pressure after the compression is 0.8MPa, and the temperature is reduced to 17 ℃ after the pyrolysis gas is condensed by a condenser 9 after the machine.
The compressed and liquefied crude product enters an HF recovery tower 10 from pressure, a crude VF product obtained by separation at the top of the HF recovery tower 10 mainly comprises 152a, VF and acetylene, a condenser at the top of the HF recovery tower 10 discharges part of gas phase to a safe emptying recovery unit through temperature control, and the safe emptying recovery unit comprises a tail gas absorption device 11, wherein the gas phase mainly comprises acetylene, a few small-molecule noncondensable gases and purge gas.
The condenser distillate at the top of the HF recovery column 10 is pressurized to 2.65MPa by a high-pressure pump 12 and a pre-tower preheater 13, and is conveyed to a 152a circulating column 14 for rectification separation after being heated to 50 ℃, the 152a circulating column 14 is conveyed to the bottom to obtain 152a material with 99.5 mass percent purity, and the material is conveyed to a second vaporizer 2 as a circulating flow to be vaporized and then is combined with fresh raw material gas, and the top of the 152a circulating column 14 is obtained to obtain a crude product, wherein the crude product mainly comprises VF and acetylene.
152A, the material at the top of the circulating tower 14 enters a pre-tower cooler 15 to reduce the temperature to minus 10 ℃, then is introduced into a VF purifying tower 16 for purification, and the purified VF is discharged from the bottom of the VF purifying tower 16 and enters a storage tank for storage. The high-concentration acetylene is mainly obtained at the top of the VF purifying tower 16, and the material is diluted by the VF product and then is introduced into a gas collecting reactor 19.
The material at the bottom of the HF recovery column 10 is conveyed to a tar column 17 for separation, and the main components are 152a, HF and tar, the tar is separated from the bottom of the tar column 17, and 152a and HF are obtained from the top of the tar column.
The material from the top of the tar tower 17 enters a 152a recovery tower 18 for rectification, the HF product obtained from the bottom of the 152a recovery tower 18 is sent to an HF storage tank for storage, and the 152a obtained from the top of the 152a recovery tower 18 enters a compression unit for compression by a compressor 8 and then enters a separation device for recycling.
Acetylene from the top of the VF purification tower 16 and HF from the bottom of the 152a recovery tower 18 are subjected to catalytic reaction in a gas collecting reactor 19, the composition of the material at the outlet of the gas collecting reactor 19 is the same as that of pyrolysis gas, the material is VF, HF, acetylene and 152a respectively, and the products after the reaction are conveyed to the HF recovery tower 10 for separation.
Example 2
This example differs from example 1 in that the hydrofluoric acid addition described in preparation example 1 was 144mL.
The other parts are exactly the same as in example 1.
Example 3
This example differs from example 1 in that the hydrofluoric acid addition described in preparation example 1 was 192mL.
The other parts are exactly the same as in example 1.
Example 4
This example differs from example 1 in that the hydrofluoric acid concentration in preparation example 1 was 20 mol.L -1 and the addition amount was 210mL.
The other parts are exactly the same as in example 1.
Example 5
This example differs from example 1 in that the hydrofluoric acid concentration in preparation example 1 was 30 mol.L -1 and the addition amount was 140mL.
The other parts are exactly the same as in example 1.
Example 6
This example differs from example 1 in that the heating temperature described in preparation example 1 is 10 ℃.
The other parts are exactly the same as in example 1.
Example 7
This example differs from example 1 in that the heating temperature described in preparation example 1 is 40 ℃.
The other parts are exactly the same as in example 1.
Example 8
This example differs from example 1 in that the nickel nitrate described in preparation example 1 is 73.08g.
The other parts are exactly the same as in example 1.
Example 9
This example differs from example 1 in that the nickel nitrate described in preparation example 1 is 219.24g.
The other parts are exactly the same as in example 1.
Example 10
This example differs from example 1 in that the palladium nitrate described in preparation example 1 is 46.1g.
The other parts are exactly the same as in example 1.
Example 11
This example differs from example 1 in that the palladium nitrate described in preparation example 1 is 138.25g.
The other parts are exactly the same as in example 1.
Comparative example 1
This comparative example differs from example 1 in that the nickel nitrate described in preparation example 1 was 0g.
The other parts are exactly the same as in example 1.
Comparative example 2
This comparative example differs from example 1 in that the palladium nitrate described in preparation example 1 was 0g.
The other parts are exactly the same as in example 1.
Detection and results
The products were taken at 20, 50, 100h time points to calculate the catalytic conversion.
The results are shown in Table 2.
TABLE 2
| Project | Conversion at 20h (%) | 50H conversion (%) | Conversion at 100h (%) |
| Example 1 | 85 | 83 | 81 |
| Example 2 | 70 | 68 | 65 |
| Example 3 | 86 | 78 | 68 |
| Example 4 | 80 | 77 | 76 |
| Example 5 | 86 | 83 | 81 |
| Example 6 | 83 | 80 | 77 |
| Example 7 | 75 | 70 | 68 |
| Example 8 | 87 | 78 | 63 |
| Example 9 | 65 | 60 | 59 |
| Example 10 | 85 | 75 | 64 |
| Example 11 | 86 | 83 | 81 |
| Comparative example 1 | 70 | 55 | 54 |
| Comparative example 2 | 76 | 54 | 28 |
As is clear from examples 1 to 3 of Table 2, the catalytic conversion rate was increased with increasing the amount of hydrofluoric acid, because Ni was not completely converted to be bonded with hydrofluoric acid when hydrofluoric acid was less, and part remained, and Ni was fully reacted with increasing hydrofluoric acid, and part of palladium exerted pyrolytic carbon action, and NiF also exerted catalytic effect on the reaction, and the catalytic activity was increased, and the reaction conversion rate was increased and the stability was improved, and when the amount of hydrofluoric acid was continuously increased, the promotion effect on the content of strongly acidic sites, namely, the strongly acidic sites were increased, and the effect of nickel was reduced to some extent, resulting in an increase in initial activity, but a decrease in stability, due to the participation of more palladium.
As is clear from examples 1 and 4 to 5, as the concentration of hydrofluoric acid is increased from 20mol.L -1 to 25mol.L -1, the higher the concentration of hydrofluoric acid used, the higher the supersaturation degree of the solution, the faster the nucleation rate, the more nuclei are generated, and the smaller the particles obtained as precipitates and the larger the specific surface area. The catalyst with high specific surface area constructs good material transfer condition, is more beneficial to the contact between the raw material and the surface of the catalyst, improves the conversion rate, continuously improves the concentration of hydrofluoric acid to 30 mol.L -1, and does not obviously improve the conversion rate.
Examples 1 and 6-7 show that the precipitation temperature is increased from 10 ℃ to 25 ℃, the nucleation rate is increased along with the temperature increase, generated crystal nuclei are increased, small-particle precipitation tends to be generated, good mass transfer conditions are constructed by the catalyst with high specific surface area, the contact of raw materials and the surface of the catalyst is facilitated, and the conversion rate is improved. The temperature is further increased to 40 ℃, the solubility of the catalyst is increased, smaller precipitated particles are not easy to generate, and the conversion rate is reduced.
As is evident from examples 8 to 9 and comparative example 1, the initial catalytic activity was improved by the excessive palladium incorporation due to the reduced amount of nickel, but the stability was lowered, and the catalytic activity was lowered by the excessive nickel incorporation due to the large loss of the strongly acidic sites.
As is evident from examples 10-11 and comparative example 2, palladium can improve the stability of the catalyst in the synergy of nickel, and extend the service life of the catalyst, but without the synergy of nickel, the stabilizing effect will be reduced.
The foregoing is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art, who is within the scope of the present invention, should make equivalent substitutions or modifications according to the technical scheme of the present invention and the inventive concept thereof, and should be covered by the scope of the present invention.
Claims (9)
1. A preparation process of a1, 1-difluoroethane dehydrofluorination catalyst is characterized by comprising the following steps of: dropwise adding excessive hydrofluoric acid into the metal solution under the condition of heating and stirring for reaction, continuously stirring after the dropwise adding is finished, adding hybridized metal, and purifying to obtain the metal hybridized fluorine-based catalyst;
the metal solution is aluminum nitrate solution;
the hybrid metal is in the form of a metal salt, including nickel nitrate and palladium nitrate.
2. The process for preparing a catalyst for dehydrofluorination of 1, 1-difluoroethane as claimed in claim 1, wherein: the molar ratio of the hydrofluoric acid to the aluminum nitrate is 16:3-4:1.
3. The process for preparing a catalyst for dehydrofluorination of 1, 1-difluoroethane as claimed in claim 1, wherein: the molar ratio of the nickel nitrate to the aluminum nitrate is 4:9-4:3.
4. The process for preparing a catalyst for dehydrofluorination of 1, 1-difluoroethane as claimed in claim 1, wherein: the molar ratio of the palladium nitrate to the nickel nitrate is 1:4-1:1.
5. The process for preparing a catalyst for dehydrofluorination of 1, 1-difluoroethane as claimed in claim 1, wherein: the heating temperature is 10-40 ℃.
6. The process for preparing a catalyst for dehydrofluorination of 1, 1-difluoroethane as claimed in claim 1, wherein: the concentration of the hydrofluoric acid is 20-30 mol.L -1.
7. The process for preparing a catalyst for dehydrofluorination of 1, 1-difluoroethane as claimed in claim 1, wherein: the purification method is filtration and drying.
8. The process for preparing a catalyst for dehydrofluorination of 1, 1-difluoroethane as claimed in claim 7, wherein: the drying conditions are as follows: 85-95 ℃ for 10-24h.
9. A catalyst prepared by the process for preparing a1, 1-difluoroethane dehydrofluorination catalyst as claimed in any one of claims 1 to 8.
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| CN118253320A true CN118253320A (en) | 2024-06-28 |
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