CN111393386A - Preparation method of thiadiazole derivative - Google Patents
Preparation method of thiadiazole derivative Download PDFInfo
- Publication number
- CN111393386A CN111393386A CN202010397306.0A CN202010397306A CN111393386A CN 111393386 A CN111393386 A CN 111393386A CN 202010397306 A CN202010397306 A CN 202010397306A CN 111393386 A CN111393386 A CN 111393386A
- Authority
- CN
- China
- Prior art keywords
- reaction
- dmtd
- preparation
- formaldehyde
- dropwise adding
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D285/00—Heterocyclic compounds containing rings having nitrogen and sulfur atoms as the only ring hetero atoms, not provided for by groups C07D275/00 - C07D283/00
- C07D285/01—Five-membered rings
- C07D285/02—Thiadiazoles; Hydrogenated thiadiazoles
- C07D285/04—Thiadiazoles; Hydrogenated thiadiazoles not condensed with other rings
- C07D285/12—1,3,4-Thiadiazoles; Hydrogenated 1,3,4-thiadiazoles
- C07D285/125—1,3,4-Thiadiazoles; Hydrogenated 1,3,4-thiadiazoles with oxygen, sulfur or nitrogen atoms, directly attached to ring carbon atoms, the nitrogen atoms not forming part of a nitro radical
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
- C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
- C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
- C23F11/16—Sulfur-containing compounds
- C23F11/165—Heterocyclic compounds containing sulfur as hetero atom
Abstract
The invention discloses a preparation method of a thiadiazole derivative, which comprises the following steps: dropwise adding aliphatic amine substances into a formaldehyde solution of DMTD, and reacting for 2-5 h at 60-100 ℃ after dropwise adding; then, raising the reaction temperature by 10-50 ℃, and reacting for 2-5 h again; after the reaction is finished, reduced pressure distillation is carried out, and the thiadiazole derivative is obtained by filtration. The preparation method can safely and efficiently synthesize the dimercapto thiadiazole derivative, and the product is easy to purify and has clear appearance; when the specific raw materials are used, the oil solubility of the product is good; the product obtained by the invention can be used as a metal deactivator, and shows a better copper corrosion inhibition effect in a copper corrosion experiment.
Description
Technical Field
The invention relates to the technical field of lubricating oil additives, in particular to a preparation method of a thiadiazole derivative.
Background
The thiadiazole derivative has good ion complexing and adsorbing capacity on nonferrous metals such as copper and the like, plays roles in passivating metal surfaces and inhibiting metal corrosion, can be used as a metal deactivator of various industrial lubricating oil, engine lubricating oil ester, gear oil and the like, and also can be used as an antiwear agent; due to the excellent metal complexing effect of the thiadiazole derivative, the thiadiazole derivative shows good synergistic antioxidant performance when being used in combination with other antioxidants. Thiadiazole derivatives are also widely used in countries and regions such as the United states, Europe and the like, and various large lubricating oil companies across countries have metal deactivators and antiwear agents of the types, so that the products are widely favored in the lubricating industry. Domestic research on such products is also numerous, and many companies have already been put into commercial production.
The synthesis method of the dimercapto thiadiazole derivative is more, and when 2, 5 dimercapto-1, 3, 4 thiadiazole (DMTD) is used as a starting material for preparing the derivative, hydrogen peroxide is usually used as a coupling agent, and mercaptan is used as an alkylation precursor; the hydrogen peroxide has higher requirements on operation processes and equipment, and the processes have safety risks; mercaptan has a strong foul smell and causes great environmental pressure on production.
US3087932 discloses a preparation method of thiadiazole derivatives, which uses a water-soluble solvent system to prepare thiadiazole derivatives by reacting dimercaptothiadiazole, mercaptan and hydrogen peroxide under mild conditions; however, the method has the defects of low utilization rate of hydrogen peroxide and low sulfur content of the product, and the patent does not determine a preferable synthetic route and synthetic conditions.
CN104178246 discloses a preparation method of a thiadiazole derivative mixture, wherein a phase transfer catalyst is used, a halogen-containing reagent is required to separate the catalyst in the post-treatment process, the separation is difficult, and the problem of waste water discharge exists in the practical application; meanwhile, the obtained product is a mixture of the thiadiazole derivative and a byproduct, and the proportion of the byproduct can reach up to 30%.
In addition, there is a literature report (relationship between structure and performance of metal deactivator — zhangmeicheng — 1988), the disulfide bond exists in the molecular structure of the traditional T561, and the disulfide bond may be converted into active sulfur during use, which may increase surface corrosion of copper to some extent.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a preparation method of a thiadiazole derivative.
The invention discloses a preparation method of a thiadiazole derivative, which comprises the following steps:
dropwise adding aliphatic amine substances into a formaldehyde solution of DMTD, and reacting for 2-5 h at 60-100 ℃ after dropwise adding; then, raising the reaction temperature by 10-50 ℃, and reacting for 2-5 h again;
after the reaction is finished, reduced pressure distillation is carried out, and the thiadiazole derivative is obtained by filtration.
As a further improvement of the invention, the method specifically comprises the following steps:
adding DMTD and formaldehyde or DMTD, formaldehyde and a solvent into a reaction container, and stirring at normal temperature to disperse DMTD in a reaction system;
heating the reactor to 60-100 ℃, dropwise adding a fatty amine substance, and carrying out Mannich reaction for 2-5 h after dropwise adding; then, increasing the reaction temperature by 10-50 ℃, and performing Mannich reaction for 2-5 h;
after the reaction is finished, reduced pressure distillation is carried out, and the thiadiazole derivative is obtained by filtration.
As a further improvement of the invention, the solvent is water, alcohol, alkane or aromatic hydrocarbon, and the formaldehyde is aqueous formaldehyde solution or paraformaldehyde.
According to a further improvement of the invention, the solvent is ethanol, and the molar ratio of the formaldehyde to the DMTD is (2.0-3.5): 1.
As a further improvement of the invention, the structural formula of the fatty amine substance is as follows:
in the formula, R1And R2Is a hydrogen atom or a linear or branched alkane group or an aromatic hydrocarbon group having 4 to 20 carbon atoms, R1And R2Cannot be simultaneously hydrogen atoms.
According to a further improvement of the invention, the fatty amine substance is secondary amine or primary amine, and the molar ratio of the fatty amine substance to DMTD is (2.0-2.5): 1.
As a further improvement of the invention, when the metal deactivator is used as a metal deactivator for lubricating oil, R of the fatty amine substance1And R2The carbon atom of the radical is preferably 8 to 12 carbon atoms.
As a further improvement of the invention, the vacuum degree of the reduced pressure distillation is-0.09 to-0.099 Mpa, the temperature is 100 to 110 ℃, and the time is 1 to 2 hours.
Compared with the prior art, the invention has the beneficial effects that:
the preparation method can safely and efficiently synthesize the dimercapto thiadiazole derivative, and the product is easy to purify and has clear appearance; when the specific raw materials are used, the oil solubility of the product is good; the product obtained by the invention can be used as a metal deactivator, and shows a better copper corrosion inhibition effect in a copper corrosion experiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
The invention is described in further detail below:
the structural formula of the thiadiazole derivative is as follows:
in the formula, R1And R2Can be any straight-chain or branched alkane group or aromatic hydrocarbon group containing 4-20 carbon atoms, and can also be hydrogen atoms at the same time but not simultaneously.
The invention provides a preparation method of a thiadiazole derivative, which is characterized in that a Mannich reaction principle is used, fatty amine substances such as alkyl primary amine or secondary amine and the like, formaldehyde aqueous solution or paraformaldehyde and DMTD are used as raw materials, and the thiadiazole derivative is synthesized by a one-step method.
The preparation method comprises the following steps:
dropwise adding aliphatic amine substances into a formaldehyde solution of DMTD, and reacting at 60-100 ℃ for 2-5 h after dropwise adding is finished, wherein the first reaction stage is shown as the first reaction stage; then raising the reaction temperature by 10-50 ℃, and reacting for 2-5 hours again, which is a second reaction stage; after the reaction is finished, reduced pressure distillation is carried out, and the thiadiazole derivative is obtained by filtration.
The preparation method specifically comprises the following steps:
step 1, adding DMTD and formaldehyde or DMTD, formaldehyde and a solvent into a reaction container, and fully stirring in any stirring mode at normal temperature to fully disperse DMTD in a reaction system;
wherein the content of the first and second substances,
the selection requirements of the solvent of the invention are as follows: solvents which do not dissociate active hydrogen under the conditions of the first reaction and the second reaction and can meet the requirements of reaction temperature can be used as reaction solvents in the invention; for this purpose, the solvent of the present invention may be water, alcohol, alkane, or aromatic hydrocarbon, and the like, and the solvent is preferably a polar solvent having good solubility for DMTD, such as ethanol, and more preferably ethanol; the mass ratio of the solvent to the target product is (0-1.5): 1.
The formaldehyde in the invention is formaldehyde aqueous solution or paraformaldehyde, when the formaldehyde aqueous solution is used, the total molar amount of formaldehyde contained in the solution should meet the reaction requirement, and the concentration of the formaldehyde is not limited, but the concentration of the formaldehyde solution should be more than 10% in terms of reaction speed and cost. When paraformaldehyde is used, the reaction temperature should be increased to activate the paraformaldehyde and release formaldehyde capable of participating in the reaction; the amount of paraformaldehyde used should be calculated based on the amount of formaldehyde that can be released after the activation of paraformaldehyde. The molar ratio of formaldehyde to DMTD is (2.0-3.5): 1, and more preferably (2.3-3.5): 1.
Step 2, heating the solution in the reactor to 60-100 ℃, dropwise adding a fatty amine substance, and performing Mannich reaction for 2-5 hours at the temperature after dropwise adding; then, increasing the reaction temperature by 10-50 ℃, and performing Mannich reaction for 2-5 h;
wherein the content of the first and second substances,
the structural formula of the fatty amine substance is as follows:
in the formula, R1And R2Is a hydrogen atom or a linear or branched alkane group or an aromatic hydrocarbon group having 4 to 20 carbon atoms, R1And R2Cannot be at the same timeIs a hydrogen atom; r1And R2Other heteroatoms may be included in the group and do not affect the reaction of the present patent, but may adversely affect the properties of the final product, such as affecting the oil solubility of the product, thereby limiting the utility of the corresponding derivatives in the lubricating oil field. When the amine used is a primary amine, i.e., two hydrogen atoms are bonded to a nitrogen atom, cross-linking by-products may occur in the product, affecting product properties. The molar ratio of the amine to the DMTD is (2.0-2.5): 1, and the more preferable molar ratio is (2.0-2.05): 1;
further, when used as a metal deactivator for lubricating oils, R of aliphatic amine-based substances1And R2The carbon atom of the radical is preferably 8 to 12 carbon atoms.
Step 3, after the reaction is finished, carrying out reduced pressure distillation, removing unreacted raw materials and solvents in the reaction system, and filtering to obtain the thiadiazole derivative;
wherein the content of the first and second substances,
the vacuum degree of the reduced pressure distillation operation is-0.09 to-0.099 Mpa, the temperature is 100 to 110 ℃, and the time is 1 to 2 hours. Higher operating temperatures can reduce the time for distillation operations, but amines are more easily oxidized, and thus increasing the temperature can cause decomposition of the product and a change in appearance.
The invention has the advantages that:
the preparation method has the characteristics of mild synthesis conditions, safe process, easy separation of unreacted raw materials and the like, can safely and efficiently synthesize the dimercaptothiadiazole derivative, and has the advantages of easy purification of the product and clear appearance; the product obtained by the method can be used as a metal deactivator, the target product does not contain disulfide bonds, and the copper corrosion inhibitor shows a good copper corrosion inhibition effect in a copper corrosion experiment; when the alkyl of the raw material amine is equivalent to that of the T561 sold in the market, the oil solubility is good, the appearance of a copper sheet in a copper corrosion test (GB/T5096) can be improved, and the corrosion to copper is smaller than that of a traditional T561 product.
Examples
Example 1
The invention provides a preparation method of a thiadiazole derivative, which comprises the following steps:
adding 10g of dimercaptothiadiazole, 10g of ethanol and 4.0g of 30% formaldehyde into a clean three-neck flask with a stirring and heating device, and fully stirring; heating to 65 ℃, dropwise adding 26.0g of dodecylamine, and keeping the temperature for reaction for 2 hours after dropwise adding; then the temperature is increased to 80 ℃, and the reaction is continued for 4 hours. Distilling under reduced pressure (operation conditions of-0.095 Mpa, 100 deg.C, 1.5h), and filtering to obtain the final product. The content of the effective component of the finished product is 99.3 percent (by the content of sulfur, the content of the effective component of the post-attached finished product is measured by a method).
Attached: method for testing content of active ingredients in finished product
Detecting sulfur content S in product1Theoretical sulfur content S calculated from the molecular structure of the product2Then, then
The content of effective component in the finished product is S2/S1×100％。
Example 2
The invention provides a preparation method of a thiadiazole derivative, which comprises the following steps:
adding 10g of dimercaptothiadiazole, 10g of water and 6.0g of 30% formaldehyde into a clean three-neck flask with a stirring and heating device, and fully stirring; heating to 70 ℃, dropwise adding 33g of tridecylamine, and carrying out heat preservation reaction for 3h after dropwise adding; then heating to 100 ℃, and continuing to react for 2 h; distilling under reduced pressure (operation conditions of-0.095 Mpa, 100 deg.C, 1.5h), and filtering to obtain the final product. The content of effective components in the finished product is 99.1 percent (calculated by the content of sulfur).
Example 3
The invention provides a preparation method of a thiadiazole derivative, which comprises the following steps:
adding 10g of dimercaptothiadiazole, 15g of ethanol and 7.7g of polyformaldehyde into a clean three-neck flask with a stirring and heating device, and fully stirring; heating to 70 ℃, dropwise adding 33g of diisooctylamine, and reacting for 3 hours in a heat preservation manner after dropwise adding; then heating to 80 ℃, and continuing to react for 5 hours; distilling under reduced pressure (operation conditions of-0.095 Mpa, 100 deg.C, 1.5h), and filtering to obtain the final product. The content of effective components in the finished product is 99.5 percent (calculated by the content of sulfur).
Example 4
The invention provides a preparation method of a thiadiazole derivative, which comprises the following steps:
adding 10g of dimercaptothiadiazole, 10g of toluene and formaldehyde solution (30 percent) and 8g of dimercaptothiadiazole into a clean three-neck flask with a stirring and heating cooling device, and fully stirring; heating to 80 ℃, dropwise adding 37g of oleylamine, and carrying out heat preservation reaction for 2 hours after dropwise adding; then heating to 110 ℃, and continuing to react for 5 h; distilling under reduced pressure (operation conditions of-0.095 Mpa, 100 deg.C, 1.5h), and filtering to obtain the final product. The content of effective components in the finished product is 99.3 percent (calculated by the content of sulfur).
The finished product obtained in the above experimental example was blended with 150SN base oil at an addition of 0.1%, and then subjected to a copper corrosion experiment with reference to GB/T5096. Each finished product shows a good copper corrosion inhibition effect.
TABLE 1 copper corrosion inhibition Properties of different products
As can be seen from Table 1, the copper corrosion detection result of the thiadiazole derivative prepared according to the technical scheme provided by the invention is equivalent to the performance of a commercially available T561 product at 100 ℃; after the detection temperature is increased, the performance is superior to that of a T561 product sold in the market. The characteristic is attributed to that the target product of the patent does not contain disulfide bonds, and does not corrode the copper surface at high temperature.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (8)
1. A preparation method of thiadiazole derivatives is characterized by comprising the following steps:
dropwise adding aliphatic amine substances into a formaldehyde solution of DMTD, and reacting for 2-5 h at 60-100 ℃ after dropwise adding; then, raising the reaction temperature by 10-50 ℃, and reacting for 2-5 h again;
after the reaction is finished, reduced pressure distillation is carried out, and the thiadiazole derivative is obtained by filtration.
2. The preparation method according to claim 1, which specifically comprises:
adding DMTD and formaldehyde or DMTD, formaldehyde and a solvent into a reaction container, and stirring at normal temperature to disperse DMTD in a reaction system;
heating the reactor to 60-100 ℃, dropwise adding a fatty amine substance, and carrying out Mannich reaction for 2-5 h after dropwise adding; then, increasing the reaction temperature by 10-50 ℃, and performing Mannich reaction for 2-5 h;
after the reaction is finished, reduced pressure distillation is carried out, and the thiadiazole derivative is obtained by filtration.
3. The method according to claim 2, wherein the solvent is water, an alcohol, an alkane or an aromatic hydrocarbon, and the formaldehyde is an aqueous formaldehyde solution or paraformaldehyde.
4. The preparation method according to claim 3, wherein the solvent is ethanol, and the molar ratio of the formaldehyde to the DMTD is (2.0-3.5): 1.
5. The process according to claim 1 or 2, wherein the fatty amine-based substance has the formula:
in the formula, R1And R2Is a hydrogen atom or a linear or branched alkane group or an aromatic hydrocarbon group having 4 to 20 carbon atoms, R1And R2Cannot be simultaneously hydrogen atoms.
6. The preparation method according to claim 5, wherein the aliphatic amine substance is a secondary amine or a primary amine, and the molar ratio of the aliphatic amine substance to DMTD is (2.0-2.5): 1.
7. The method of claim 5, wherein the gold is used as a lubricantR of the fatty amine substance when being used as a deactivator1And R2The carbon atom of the radical is preferably 8 to 12 carbon atoms.
8. The method of claim 1 or 2, wherein the vacuum degree of the reduced pressure distillation is-0.09 MPa to-0.099 MPa, the temperature is 100 ℃ to 110 ℃, and the time is 1 h to 2 h.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010397306.0A CN111393386A (en) | 2020-05-12 | 2020-05-12 | Preparation method of thiadiazole derivative |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010397306.0A CN111393386A (en) | 2020-05-12 | 2020-05-12 | Preparation method of thiadiazole derivative |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111393386A true CN111393386A (en) | 2020-07-10 |
Family
ID=71426267
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010397306.0A Pending CN111393386A (en) | 2020-05-12 | 2020-05-12 | Preparation method of thiadiazole derivative |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111393386A (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2765289A (en) * | 1953-04-29 | 1956-10-02 | Standard Oil Co | Corrosion inhibitors and compositions containing the same |
| CN104649998A (en) * | 2013-11-25 | 2015-05-27 | 刘现梅 | 2,4-bi(N,N-dihydroxyisopropylaminomethylsulfo)-thiadiazole and preparation method thereof |
-
2020
- 2020-05-12 CN CN202010397306.0A patent/CN111393386A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2765289A (en) * | 1953-04-29 | 1956-10-02 | Standard Oil Co | Corrosion inhibitors and compositions containing the same |
| CN104649998A (en) * | 2013-11-25 | 2015-05-27 | 刘现梅 | 2,4-bi(N,N-dihydroxyisopropylaminomethylsulfo)-thiadiazole and preparation method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 高永建，等: "噻二唑及其衍生物的制备", 《化学研究》 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3796661A (en) | Sulfurized triisobutylene | |
| US3673090A (en) | Sulfurization of triisobutylene and products resulting therefrom | |
| IL126985A (en) | Fuel additives | |
| JPS62501014A (en) | Lubricating oils containing small amounts of phosphorus and sulfur | |
| US3597353A (en) | 4,5,6,7-tetrahydro-benzotriazole as metal deactivator | |
| US4348210A (en) | Novel process and product | |
| US5407592A (en) | Multifunctional additives | |
| EP2791292A1 (en) | Cross products and co-oligomers of phenylenediamines and aromatic amines as antioxidants for lubricants | |
| US2680094A (en) | Rust preventive oil composition | |
| US4966721A (en) | N-N'-dihydrocarbyl substituted phenylene diamine-derived condensation products as antioxidants and lubricant compositions | |
| EP0315293B1 (en) | Oxidation and corrosion resistant diesel engine lubricant | |
| US3843536A (en) | Metal-deactivated organic compositions and process therefor | |
| CN113512455B (en) | Lubricating oil composition for piston air compressor | |
| CN111393386A (en) | Preparation method of thiadiazole derivative | |
| US3225099A (en) | N-methyl-n-phenyl-n-(3,5-di-tertiary-butyl-4-hydroxybenzyl)amine | |
| WO2004024850A1 (en) | Process for the production of a fuel composition | |
| US3305483A (en) | Stabilized organic compositions | |
| US5569407A (en) | Additives for fuels and lubricants | |
| US2515908A (en) | Antioxidants for oils and oil compositions containing the same | |
| US2928876A (en) | Condensation products of n-substituted dialkylenetriamines and orthohydroxy aromatic carbonyls | |
| JPS60146862A (en) | N,1-disubstituted hydrazine carboxamide | |
| US5073279A (en) | Sulfur coupled hydrocarbyl derived mercaptobenzothiazole adducts as multifunctional antiwear additives and compositions containing same | |
| CN110194751B (en) | Preparation method of thiadiazole derivative | |
| CN113461626A (en) | Preparation method of benzotriazole derivative and metal passivator | |
| JPS6299484A (en) | Method for preventing corrosion of copper and composition containing specific thiazole corrosion inhibitor contacted with copper or to copper |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20200710 |