CN113200816A - Hydroxypivalaldehyde hydrogenation process - Google Patents
Hydroxypivalaldehyde hydrogenation process Download PDFInfo
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- CN113200816A CN113200816A CN202110530598.5A CN202110530598A CN113200816A CN 113200816 A CN113200816 A CN 113200816A CN 202110530598 A CN202110530598 A CN 202110530598A CN 113200816 A CN113200816 A CN 113200816A
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- hydrogenation
- reaction
- catalyst
- hydroxypivalaldehyde
- bed layer
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- 238000005984 hydrogenation reaction Methods 0.000 title claims abstract description 51
- JJMOMMLADQPZNY-UHFFFAOYSA-N 3-hydroxy-2,2-dimethylpropanal Chemical compound OCC(C)(C)C=O JJMOMMLADQPZNY-UHFFFAOYSA-N 0.000 title claims description 10
- 239000003054 catalyst Substances 0.000 claims abstract description 35
- 238000006243 chemical reaction Methods 0.000 claims abstract description 33
- 238000009903 catalytic hydrogenation reaction Methods 0.000 claims abstract description 9
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 6
- 239000001257 hydrogen Substances 0.000 claims abstract description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 10
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 7
- 239000010949 copper Substances 0.000 claims description 7
- 229910052802 copper Inorganic materials 0.000 claims description 7
- -1 hydroxyl pivalic aldehyde Chemical compound 0.000 claims description 6
- 239000002826 coolant Substances 0.000 claims description 5
- 238000001816 cooling Methods 0.000 claims description 5
- 239000011344 liquid material Substances 0.000 claims description 4
- 239000012295 chemical reaction liquid Substances 0.000 claims description 3
- UKVIEHSSVKSQBA-UHFFFAOYSA-N methane;palladium Chemical group C.[Pd] UKVIEHSSVKSQBA-UHFFFAOYSA-N 0.000 claims description 3
- 238000005516 engineering process Methods 0.000 claims description 2
- SLCVBVWXLSEKPL-UHFFFAOYSA-N neopentyl glycol Chemical compound OCC(C)(C)CO SLCVBVWXLSEKPL-UHFFFAOYSA-N 0.000 abstract description 9
- 238000002156 mixing Methods 0.000 abstract description 8
- 239000007788 liquid Substances 0.000 abstract description 6
- 230000000694 effects Effects 0.000 abstract description 2
- 230000005484 gravity Effects 0.000 abstract description 2
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 12
- 239000000047 product Substances 0.000 description 9
- AMIMRNSIRUDHCM-UHFFFAOYSA-N Isopropylaldehyde Chemical compound CC(C)C=O AMIMRNSIRUDHCM-UHFFFAOYSA-N 0.000 description 8
- GETQZCLCWQTVFV-UHFFFAOYSA-N trimethylamine Chemical compound CN(C)C GETQZCLCWQTVFV-UHFFFAOYSA-N 0.000 description 8
- 239000000463 material Substances 0.000 description 6
- 239000000203 mixture Substances 0.000 description 4
- 238000006482 condensation reaction Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- YYKMQUOJKCKTSD-UHFFFAOYSA-N 2,2-bis(hydroxymethyl)butanal Chemical compound CCC(CO)(CO)C=O YYKMQUOJKCKTSD-UHFFFAOYSA-N 0.000 description 1
- ZJCCRDAZUWHFQH-UHFFFAOYSA-N Trimethylolpropane Chemical compound CCC(CO)(CO)CO ZJCCRDAZUWHFQH-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229920005862 polyol Polymers 0.000 description 1
- 150000003077 polyols Chemical class 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 150000005846 sugar alcohols Polymers 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
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Classifications
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/132—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group
- C07C29/136—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH
- C07C29/14—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH of a —CHO group
- C07C29/141—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH of a —CHO group with hydrogen or hydrogen-containing gases
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention provides a hydroxytetravaleraldehyde hydrogenation process, which comprises the steps of mixing hydroxytetravaleraldehyde and hydrogen in a hydrogenation reactor for catalytic hydrogenation reaction to generate neopentyl glycol; the catalyst bed layer in the hydrogenation reactor is split into a plurality of sections of reaction beds, and a heat exchanger is arranged between every two beds. According to the invention, the catalyst bed layer is split into the multiple sections of reaction beds, and the heat exchangers are arranged among the beds, so that the reaction of each catalyst bed layer is ensured to be carried out under the condition close to the optimal temperature, the product yield is improved by 0.7-1.3%, and the effect is obvious; the multi-section bed design reduces the damage of gravity to the catalyst at the lower part and prolongs the service life of the catalyst; the liquid back mixing is reduced, the reaction driving force is improved, and the total conversion rate is improved.
Description
Technical Field
The invention belongs to the technical field of neopentyl glycol synthesis, and particularly relates to a hydroxytetravaleraldehyde hydrogenation process.
Technical Field
The technology for preparing polyol by catalytic hydrogenation is more and more concerned by people due to environmental friendliness, high product yield and excellent quality, and the processes of preparing neopentyl glycol by hydrogenating hydroxypivalaldehyde and preparing trimethylolpropane by hydrogenating 2, 2-dimethylolbutyraldehyde are reported in succession. Most of hydrogenation catalysts are palladium carbon catalysts and copper catalysts, and fixed bed reactors are adopted.
The reaction is generally carried out at 100-160 ℃ and 3.0-4.0 MPa, and is a strong exothermic reaction, and the control of the reaction temperature is the most key parameter for ensuring the conversion rate, improving the product selectivity and prolonging the service life of the catalyst. At present, the conventional method for preparing polyhydric alcohol by a hydrogenation method to build a device and controlling the temperature of a reactor bed layer is to adopt external circulation to obtain heat, namely, liquid phase discharging of the reactor is circulated by a pump, and the liquid phase discharging and the raw material liquid are returned to the reactor together after being cooled by external heat exchange.
Because a fixed bed reactor is adopted, in order to ensure the conversion rate, the catalyst bed layer is higher, and the external circulation heat taking mode is equivalent to an adiabatic bed compared with the catalyst bed layer, the bed layer temperature is gradually increased along with the reaction, the maximum temperature rise can reach more than 30 ℃, and the overhigh temperature rise influences the selectivity of the reaction, so that the byproducts are increased, the product yield is reduced, and the service life of the catalyst is influenced.
Disclosure of Invention
In order to solve the technical problems, the invention provides a hydroxytetravaleraldehyde hydrogenation process, which comprises the steps of mixing hydroxytetravaleraldehyde with hydrogen, carrying out catalytic hydrogenation reaction in a hydrogenation reactor, wherein a mixture obtained by the catalytic hydrogenation reaction contains neopentyl glycol; the catalyst bed in the hydrogenation reactor is split into a plurality of sections of reaction beds according to the actual temperature rise gradient, and an intersegmental heat taking facility, namely a heat exchanger, is arranged among the beds. And introducing a cooling medium into the heat exchanger, and cooling the reaction liquid entering the next bed layer.
The heat exchanger is of an internal (such as a coil pipe type or a tube array type) or external structure.
The hydrogenation catalyst is a palladium carbon catalyst and/or a copper catalyst; further, it is a copper-based catalyst.
The hydrogenation reaction temperature is 100-160 ℃, and the reaction pressure is 3.6-4.2 MPaG.
The method also comprises the steps that the liquid material at the bottom of the reactor is pressurized by a circulating pump, then is cooled by an external circulation heat collector and returns to the hydrogenation reactor, and the temperature rise of each bed layer is controlled within 5-10 ℃ in a mode of combining internal heat collection and external heat collection.
The hydrogenation reaction temperature is 100-160 ℃, and the reaction pressure is 3.6-4.2 MPaG.
And rectifying and separating the obtained mixture to obtain the neopentyl glycol.
The beneficial effects of the invention are mainly embodied in the following three aspects:
firstly, the catalyst bed layer is split into a plurality of sections of reaction beds, and an intersegmental heat taking facility is arranged among the bed layers, so that the reaction of each catalyst bed layer is ensured to be carried out under the condition of approximate optimal temperature, the reaction condition is improved, the product yield is improved by 0.7-1.3%, and the effect is obvious.
Secondly, because the height of the catalyst bed layer is greatly reduced, the damage of gravity to the catalyst at the lower part is reduced, the service life of the catalyst is prolonged, the service life of the copper-based hydroxyl pivalic aldehyde hydrogenation catalyst is prolonged to more than 2 years from 1 to 1.5 years at present, and the production cost is greatly reduced.
Thirdly, in the traditional hydrogenation bed temperature control, in order to reduce the bed temperature rise, the flow of the external circulation material needs to be increased, which inevitably causes a great amount of back mixing of the material, the raw material liquid is diluted by the hydrogenation product, the reaction driving force is reduced, and the conversion rate is reduced. And by setting interstage cooling, the liquid back mixing quality can be reduced by 20-30%, the reaction driving force is improved, and the improvement of the total conversion rate is facilitated.
Drawings
FIG. 1 is a schematic diagram of a hydrogenation reaction and gas-liquid separation process.
Wherein, 1 is hydrogenation feed (hydroxyl pivalaldehyde + fresh hydrogen), 2 is a hydrogenation reactor, 3 is a cooling medium, 4 is a heat exchanger, 5 is a hydrogenation catalyst bed, 6 is a mixture obtained by catalytic hydrogenation reaction, 7 is an external circulation return material, 8 is an external circulation pump, and 9 is an external circulation heat collector.
Detailed Description
Example 1
A hydroxyl pivalic aldehyde hydrogenation process comprises the steps of mixing hydroxyl pivalic aldehyde with fresh hydrogen to obtain hydrogenation feed 1, carrying out catalytic hydrogenation reaction in a hydrogenation reactor 2 as shown in figure 1, wherein a catalyst bed layer 5 in the hydrogenation reactor 2 is a three-section reaction bed, a heat exchanger 4 is arranged between each bed layer, a cooling medium 3 is introduced into the heat exchanger 4, and a reaction liquid entering the next bed layer is cooled, wherein the heat exchanger 4 is of a built-in (coil pipe type or tube type) or external structure, the inlet temperature of the cooling medium is 65-70 ℃, the outlet temperature is 70-75 ℃, and the hydrogenation catalyst is a copper catalyst (the CuO content is more than or equal to 35%); and pressurizing the liquid material at the bottom of the hydrogenation reactor 2 by a circulating pump 8, cooling by an external circulation heat collector 9 to obtain an external circulation return material 7, and returning to the hydrogenation reactor 2. And (3) sending the mixture 6 obtained by catalytic hydrogenation reaction into a subsequent system, rectifying and separating to remove high and low boiling point impurities to obtain a qualified neopentyl glycol product, wherein the hydrogenation reaction temperature is 110 +/-5 ℃, and the reaction pressure is 4.2 MPaG. By means of the combination of internal and external heat extraction, the temperature rise of each bed layer is controlled to be 5 ℃, and the liquid back-mixing quality can be reduced by 25% compared with that of the traditional hydrogenation process. Compared with the traditional hydrogenation process, the yield of the neopentyl glycol product is improved by 1.06%, and the conversion rate is improved by 1.2%.
The hydroxyl pivalic aldehyde is obtained by condensation reaction of isobutyraldehyde and formaldehyde under the condition that trimethylamine is used as a catalyst, wherein the molar ratio of the isobutyraldehyde to the formaldehyde to the trimethylamine is 1.04: 1: 0.02, the reaction temperature is 68-72 ℃, and the pressure is 0.2-0.5 MPaG.
Example 2
The same procedure as in example 1, except that the hydrogenation temperature was 160. + -. 5 ℃ and the reaction pressure was 3.6 MPaG. Compared with the traditional hydrogenation process, the yield of the neopentyl glycol product is improved by 0.84%, and the conversion rate is improved by 0.91%.
Comparative example 1 conventional hydrogenation process
Mixing hydroxyl pivalaldehyde and fresh hydrogen, carrying out catalytic hydrogenation reaction in a hydrogenation reactor, pressurizing a liquid material at the bottom of the hydrogenation reactor by a circulating pump, cooling by an external circulation cooler to obtain an external circulation return material, and returning the external circulation return material into the hydrogenation reactor; the hydrogenation catalyst is a copper catalyst (the CuO content is more than or equal to 35%); the hydrogenation reaction temperature is 120 +/-30 ℃, and the reaction pressure is 4.2 MPaG. The yield of neopentyl glycol product was 97% and the conversion 98.4%.
The hydroxyl pivalic aldehyde is obtained by condensation reaction of isobutyraldehyde and formaldehyde under the condition that trimethylamine is used as a catalyst, wherein the molar ratio of the isobutyraldehyde to the formaldehyde to the trimethylamine is 1.04: 1: 0.02, the reaction temperature is 68-72 ℃, and the pressure is 0.2-0.5 MPaG.
Claims (5)
1. A hydro-technology for hydroxyl pivalic aldehyde is characterized in that: the method comprises the steps that hydroxyl pivalaldehyde and hydrogen are mixed in a hydrogenation reactor (2) to carry out catalytic hydrogenation reaction, a hydrogenation catalyst bed layer (5) in the hydrogenation reactor (2) is split into a plurality of sections of reaction beds according to actual temperature rise gradient, a heat exchanger (4) is arranged among the bed layers, and a cooling medium (3) is introduced into the heat exchanger (4) to cool reaction liquid entering the next bed layer.
2. The process of claim 1, wherein the hydrogenation of hydroxypivalaldehyde comprises: the heat exchanger (4) is of an internal or external structure.
3. The process of claim 1, wherein the hydrogenation of hydroxypivalaldehyde comprises: the hydrogenation catalyst is palladium carbon catalyst and/or copper catalyst.
4. The process of claim 1, wherein the hydrogenation of hydroxypivalaldehyde comprises: the method also comprises pressurizing the liquid material at the bottom of the hydrogenation reactor (2) by a circulating pump (8), cooling by an external circulation heat collector (9) and returning to the hydrogenation reactor (2).
5. The process of claim 1, wherein the hydrogenation of hydroxypivalaldehyde comprises: the hydrogenation reaction temperature is 100-160 ℃, and the reaction pressure is 3.6-4.2 MPaG.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110530598.5A CN113200816A (en) | 2021-05-15 | 2021-05-15 | Hydroxypivalaldehyde hydrogenation process |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110530598.5A CN113200816A (en) | 2021-05-15 | 2021-05-15 | Hydroxypivalaldehyde hydrogenation process |
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| CN113200816A true CN113200816A (en) | 2021-08-03 |
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| CN202110530598.5A Pending CN113200816A (en) | 2021-05-15 | 2021-05-15 | Hydroxypivalaldehyde hydrogenation process |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115069268A (en) * | 2022-08-02 | 2022-09-20 | 山东鲁新设计工程有限公司 | Catalyst for preparing neopentyl glycol by high pressure method |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1286673A (en) * | 1997-12-30 | 2001-03-07 | 奈斯特化学公司 | Process for preparation of neopentyl glycol |
| CN102304021A (en) * | 2011-07-06 | 2012-01-04 | 上海焦化有限公司 | Method for preparing neopentyl glycol |
| CN102311313A (en) * | 2011-07-06 | 2012-01-11 | 上海焦化有限公司 | Neopentyl glycol preparation method utilizing catalytic hydrogenation by copper zinc aluminium catalyst |
| CN103351277A (en) * | 2013-06-28 | 2013-10-16 | 万华化学集团股份有限公司 | Neopentyl glycol preparation method |
| CN107540521A (en) * | 2016-06-29 | 2018-01-05 | 中国石油化工股份有限公司 | The method of hydroxy pivalin aldehyde Hydrogenation neopentyl glycol |
| CN108067164A (en) * | 2016-11-17 | 2018-05-25 | 中国石油化工股份有限公司 | A kind of hydrogenation reactor and hydrogenation technique |
| CN108067163A (en) * | 2016-11-17 | 2018-05-25 | 中国石油化工股份有限公司 | Hydrogenation reactor and hydrogenation technique |
| CN112537998A (en) * | 2020-12-18 | 2021-03-23 | 上海翼湍科技有限责任公司 | Process for producing neopentyl glycol by continuous catalytic hydrogenation |
-
2021
- 2021-05-15 CN CN202110530598.5A patent/CN113200816A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1286673A (en) * | 1997-12-30 | 2001-03-07 | 奈斯特化学公司 | Process for preparation of neopentyl glycol |
| CN102304021A (en) * | 2011-07-06 | 2012-01-04 | 上海焦化有限公司 | Method for preparing neopentyl glycol |
| CN102311313A (en) * | 2011-07-06 | 2012-01-11 | 上海焦化有限公司 | Neopentyl glycol preparation method utilizing catalytic hydrogenation by copper zinc aluminium catalyst |
| CN103351277A (en) * | 2013-06-28 | 2013-10-16 | 万华化学集团股份有限公司 | Neopentyl glycol preparation method |
| CN107540521A (en) * | 2016-06-29 | 2018-01-05 | 中国石油化工股份有限公司 | The method of hydroxy pivalin aldehyde Hydrogenation neopentyl glycol |
| CN108067164A (en) * | 2016-11-17 | 2018-05-25 | 中国石油化工股份有限公司 | A kind of hydrogenation reactor and hydrogenation technique |
| CN108067163A (en) * | 2016-11-17 | 2018-05-25 | 中国石油化工股份有限公司 | Hydrogenation reactor and hydrogenation technique |
| CN112537998A (en) * | 2020-12-18 | 2021-03-23 | 上海翼湍科技有限责任公司 | Process for producing neopentyl glycol by continuous catalytic hydrogenation |
Non-Patent Citations (2)
| Title |
|---|
| 夏蓉晖等: "3―羟基丙醛加氢固定床催化剂的研究", 《金山油化纤》 * |
| 王剑等: "新戊二醇的合成", 《上海化工》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115069268A (en) * | 2022-08-02 | 2022-09-20 | 山东鲁新设计工程有限公司 | Catalyst for preparing neopentyl glycol by high pressure method |
| CN115069268B (en) * | 2022-08-02 | 2024-05-14 | 山东鲁新设计工程股份有限公司 | Catalyst for preparing neopentyl glycol by high-pressure method |
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