CN111592510A - Synthesis method of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride - Google Patents
Synthesis method of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride Download PDFInfo
- Publication number
- CN111592510A CN111592510A CN202010338410.2A CN202010338410A CN111592510A CN 111592510 A CN111592510 A CN 111592510A CN 202010338410 A CN202010338410 A CN 202010338410A CN 111592510 A CN111592510 A CN 111592510A
- Authority
- CN
- China
- Prior art keywords
- hexafluoroisopropenylidene
- catalyst
- diphthalic anhydride
- bis
- hexafluoropropane
- 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
- 150000008064 anhydrides Chemical class 0.000 title claims abstract description 18
- 238000001308 synthesis method Methods 0.000 title abstract description 6
- 239000003054 catalyst Substances 0.000 claims abstract description 27
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims abstract description 14
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 6
- 239000012954 diazonium Substances 0.000 claims abstract description 6
- 150000001989 diazonium salts Chemical class 0.000 claims abstract description 6
- 238000003786 synthesis reaction Methods 0.000 claims abstract description 6
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims abstract description 5
- 239000004202 carbamide Substances 0.000 claims abstract description 5
- 239000000741 silica gel Substances 0.000 claims abstract description 5
- 229910002027 silica gel Inorganic materials 0.000 claims abstract description 5
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 9
- ZXEKIIBDNHEJCQ-UHFFFAOYSA-N isobutanol Chemical compound CC(C)CO ZXEKIIBDNHEJCQ-UHFFFAOYSA-N 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 8
- 239000000047 product Substances 0.000 claims description 7
- 238000006722 reduction reaction Methods 0.000 claims description 7
- MSTZGVRUOMBULC-UHFFFAOYSA-N 2-amino-4-[2-(3-amino-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropan-2-yl]phenol Chemical compound C1=C(O)C(N)=CC(C(C=2C=C(N)C(O)=CC=2)(C(F)(F)F)C(F)(F)F)=C1 MSTZGVRUOMBULC-UHFFFAOYSA-N 0.000 claims description 6
- 239000002253 acid Substances 0.000 claims description 6
- 239000002609 medium Substances 0.000 claims description 6
- 238000007670 refining Methods 0.000 claims description 6
- 239000002904 solvent Substances 0.000 claims description 5
- DKPFZGUDAPQIHT-UHFFFAOYSA-N Butyl acetate Natural products CCCCOC(C)=O DKPFZGUDAPQIHT-UHFFFAOYSA-N 0.000 claims description 4
- FUZZWVXGSFPDMH-UHFFFAOYSA-N hexanoic acid Chemical compound CCCCCC(O)=O FUZZWVXGSFPDMH-UHFFFAOYSA-N 0.000 claims description 4
- 239000012046 mixed solvent Substances 0.000 claims description 4
- NSGXIBWMJZWTPY-UHFFFAOYSA-N 1,1,1,3,3,3-hexafluoropropane Chemical compound FC(F)(F)CC(F)(F)F NSGXIBWMJZWTPY-UHFFFAOYSA-N 0.000 claims description 3
- GIPUOAREKWRFMO-UHFFFAOYSA-N 4-[2-(3,4-dicyanophenyl)-1,1,1,3,3,3-hexafluoropropan-2-yl]benzene-1,2-dicarbonitrile Chemical compound C=1C=C(C#N)C(C#N)=CC=1C(C(F)(F)F)(C(F)(F)F)C1=CC=C(C#N)C(C#N)=C1 GIPUOAREKWRFMO-UHFFFAOYSA-N 0.000 claims description 3
- RXQNKKRGJJRMKD-UHFFFAOYSA-N 5-bromo-2-methylaniline Chemical compound CC1=CC=C(Br)C=C1N RXQNKKRGJJRMKD-UHFFFAOYSA-N 0.000 claims description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 3
- ACXJLVBZFVBFPI-UHFFFAOYSA-N CC(C(C(F)=C1F)=C(C(O)=O)C(C(O)=O)=C1F)=CC(C(F)=C1F)=C(C(O)=O)C(C(O)=O)=C1F Chemical compound CC(C(C(F)=C1F)=C(C(O)=O)C(C(O)=O)=C1F)=CC(C(F)=C1F)=C(C(O)=O)C(C(O)=O)=C1F ACXJLVBZFVBFPI-UHFFFAOYSA-N 0.000 claims description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims description 3
- 238000005915 ammonolysis reaction Methods 0.000 claims description 3
- 239000012736 aqueous medium Substances 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- 239000010949 copper Substances 0.000 claims description 3
- 239000012043 crude product Substances 0.000 claims description 3
- 238000006297 dehydration reaction Methods 0.000 claims description 3
- 238000001035 drying Methods 0.000 claims description 3
- 230000003301 hydrolyzing effect Effects 0.000 claims description 3
- 238000004806 packaging method and process Methods 0.000 claims description 3
- 239000002994 raw material Substances 0.000 claims description 3
- 150000003839 salts Chemical class 0.000 claims description 3
- 230000002194 synthesizing effect Effects 0.000 claims description 3
- 125000002887 hydroxy group Chemical group [H]O* 0.000 abstract description 6
- 230000009286 beneficial effect Effects 0.000 abstract description 5
- -1 3-amino-4-hydroxyphenyl Chemical group 0.000 abstract description 3
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 abstract description 3
- 238000005576 amination reaction Methods 0.000 abstract description 3
- 231100000572 poisoning Toxicity 0.000 abstract description 3
- 230000000607 poisoning effect Effects 0.000 abstract description 3
- 230000002035 prolonged effect Effects 0.000 abstract description 3
- 238000007086 side reaction Methods 0.000 abstract description 3
- 229910052717 sulfur Inorganic materials 0.000 abstract description 3
- 239000011593 sulfur Substances 0.000 abstract description 3
- 238000007333 cyanation reaction Methods 0.000 abstract description 2
- 150000003568 thioethers Chemical class 0.000 abstract description 2
- 238000006243 chemical reaction Methods 0.000 description 5
- QHHKLPCQTTWFSS-UHFFFAOYSA-N 5-[2-(1,3-dioxo-2-benzofuran-5-yl)-1,1,1,3,3,3-hexafluoropropan-2-yl]-2-benzofuran-1,3-dione Chemical compound C1=C2C(=O)OC(=O)C2=CC(C(C=2C=C3C(=O)OC(=O)C3=CC=2)(C(F)(F)F)C(F)(F)F)=C1 QHHKLPCQTTWFSS-UHFFFAOYSA-N 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 239000013067 intermediate product Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 206010057040 Temperature intolerance Diseases 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000008543 heat sensitivity Effects 0.000 description 1
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
- C07D307/77—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom ortho- or peri-condensed with carbocyclic rings or ring systems
- C07D307/87—Benzo [c] furans; Hydrogenated benzo [c] furans
- C07D307/89—Benzo [c] furans; Hydrogenated benzo [c] furans with two oxygen atoms directly attached in positions 1 and 3
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention belongs to the technical field of synthesis of 4,4- (hexafluoroisopropenylene) diphthalic anhydride, and particularly relates to a synthesis method of 4,4- (hexafluoroisopropenylene) diphthalic anhydride. In addition, the Pd/C catalyst is pretreated, and proper sulfides are added for pretreatment, so that the sulfur poisoning resistance of the catalyst is improved, the service life of the catalyst is prolonged, and the frequency of application of the catalyst is increased; adding an alumina-silica gel catalyst in the second step, so that 2, 2-bis (3-amino-4-hydroxyphenyl) molecules are adsorbed on the surface of the catalyst in a flat shape, and hydroxyl is closer to the surface of the catalyst, thereby being beneficial to the amination reaction of the hydroxyl; in the fourth step, a small amount of urea is added in the cyanation reaction to prevent the diazonium salt from being oxidized, variegated oil and other side reactions.
Description
Technical Field
The invention belongs to the technical field of synthesis of 4,4- (hexafluoroisopropylidene) diphthalic anhydride, and particularly relates to a synthesis method of 4,4- (hexafluoroisopropylidene) diphthalic anhydride.
Background
In the prior art, intermediate products are not easy to separate, for example, common reduction solvents are methanol, ethanol, ethyl acetate and the like, and because the solvents have higher solubility to the products and amino substances have heat sensitivity, the subsequent product separation is not easy, the yield is lower, more waste is generated, and the economic benefit is not good.
Disclosure of Invention
The invention provides a method for synthesizing 4,4- (hexafluoroisopropenylidene) diphthalic anhydride, which can solve the problems pointed out in the background technology.
A method for synthesizing 4,4- (hexafluoroisopropylidene) diphthalic anhydride comprises the following steps:
firstly, 2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane is used as a raw material, and is subjected to reduction reaction to obtain 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, wherein the reduction solvent is a mixed solvent of isobutanol and butyl acetate;
introducing ammonia gas into the 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane in a fixed bed for ammonolysis to obtain 2, 2-bis (3, 4-di-o-aminophenyl) hexafluoropropane;
thirdly, diazotizing ortho-diamino by using nitrosyl sulfuric acid in an acetic acid medium;
fourthly, reacting the diazonium salt with copper tetracyanoammine coordination salt in an aqueous medium to obtain 2, 2-bis (3, 4-dicyanophenyl) hexafluoropropane;
fifthly, hydrolyzing at high temperature in an acid medium to obtain 4,4' (hexafluoroisopropenyl) diphthalic acid,
and (3) carrying out alkaline low-temperature dehydration reaction on hexa-and 4,4' (hexafluoroisopropenylidene) diphthalic acid to obtain a crude product of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride, and finally carrying out refining, indoor refining, drying and packaging to obtain a finished product of the 4,4- (hexafluoroisopropenylidene) diphthalic anhydride.
Preferably, a Pd/C catalyst is added in the first step.
Preferably, the Pd/C catalyst is used for pretreatment, and sulfide is added for pretreatment.
Preferably, an alumina-silica gel catalyst is added in the second step.
Preferably, a small amount of urea is added in step four.
The reaction mechanism is as follows:
the reaction equation is as follows:
the invention has the beneficial effects that: the invention provides a synthesis method of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride, which has the advantages of easy separation of intermediate products, high yield, less waste and good economic benefit, adopts a mixed solvent of isobutanol and butyl acetate to reduce the solubility of the products, is beneficial to the separation of the products and has high yield. In addition, the Pd/C catalyst is pretreated, and proper sulfides are added for pretreatment, so that the sulfur poisoning resistance of the catalyst is improved, the service life of the catalyst is prolonged, and the frequency of application of the catalyst is increased; adding an alumina-silica gel catalyst in the second step, so that 2, 2-bis (3-amino-4-hydroxyphenyl) molecules are adsorbed on the surface of the catalyst in a flat shape, and hydroxyl is closer to the surface of the catalyst, thereby being beneficial to the amination reaction of the hydroxyl; in the fourth step, a small amount of urea is added in the cyanation reaction to prevent the diazonium salt from being oxidized, variegated oil and other side reactions.
Detailed Description
A specific embodiment of the present invention is described in detail below, but it should be understood that the scope of the present invention is not limited by the specific embodiment.
Example (b):
the synthesis method of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride provided by the embodiment of the invention comprises the following steps:
firstly, 2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane is used as a raw material, and is subjected to reduction reaction to obtain 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, wherein the reduction solvent is a mixed solvent of isobutanol and butyl acetate; in addition, the Pd/C catalyst is added and pretreated by proper sulfide, so that the sulfur poisoning resistance of the catalyst is improved, the service life of the catalyst is prolonged, and the number of times of application of the catalyst is increased.
Introducing ammonia gas into the 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane in a fixed bed for ammonolysis to obtain 2, 2-bis (3, 4-di-o-aminophenyl) hexafluoropropane; the alumina-silica gel catalyst is added, so that 2, 2-bis (3-amino-4-hydroxyphenyl) molecules are flatly adsorbed on the surface of the catalyst, and the hydroxyl is closer to the surface of the catalyst, which is beneficial to the amination reaction of the hydroxyl
Thirdly, diazotizing ortho-diamino by using nitrosyl sulfuric acid in an acetic acid medium;
fourthly, reacting the diazonium salt with copper tetracyanoammine coordination salt in an aqueous medium to obtain 2, 2-bis (3, 4-dicyanophenyl) hexafluoropropane; a small amount of urea is added in the cyanolysis reaction to prevent the diazonium salt from being oxidized, variegated oil and other side reactions.
Fifthly, hydrolyzing at high temperature in an acid medium to obtain 4,4' (hexafluoroisopropenyl) diphthalic acid,
and (3) carrying out alkaline low-temperature dehydration reaction on hexa-and 4,4' (hexafluoroisopropenylidene) diphthalic acid to obtain a crude product of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride, and finally carrying out refining, indoor refining, drying and packaging to obtain a finished product of the 4,4- (hexafluoroisopropenylidene) diphthalic anhydride.
The reaction mechanism is as follows:
the reaction equation is as follows:
the above disclosure is only for a few specific embodiments of the present invention, however, the present invention is not limited to the above embodiments, and any variations that can be made by those skilled in the art are intended to fall within the scope of the present invention.
Claims (5)
1. A method for synthesizing 4,4- (hexafluoroisopropenylidene) diphthalic anhydride, which is characterized by comprising the following steps: the method comprises the following steps:
firstly, 2-bis (3-nitro-4-hydroxyphenyl) hexafluoropropane is used as a raw material, and is subjected to reduction reaction to obtain 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, wherein the reduction solvent is a mixed solvent of isobutanol and butyl acetate;
introducing ammonia gas into the 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane in a fixed bed for ammonolysis to obtain 2, 2-bis (3, 4-di-o-aminophenyl) hexafluoropropane;
thirdly, diazotizing ortho-diamino by using nitrosyl sulfuric acid in an acetic acid medium;
fourthly, reacting the diazonium salt with copper tetracyanoammine coordination salt in an aqueous medium to obtain 2, 2-bis (3, 4-dicyanophenyl) hexafluoropropane;
fifthly, hydrolyzing at high temperature in an acid medium to obtain 4,4' (hexafluoroisopropenyl) diphthalic acid,
and (3) carrying out alkaline low-temperature dehydration reaction on hexa-and 4,4' (hexafluoroisopropenylidene) diphthalic acid to obtain a crude product of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride, and finally carrying out refining, indoor refining, drying and packaging to obtain a finished product of the 4,4- (hexafluoroisopropenylidene) diphthalic anhydride.
2. The process of claim 1 for the synthesis of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride, wherein: and adding a Pd/C catalyst in the first step.
3. The process of claim 2 wherein the synthesis of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride comprises: the Pd/C catalyst is used for pretreatment, and sulfide is added for pretreatment.
4. The process of claim 1 for the synthesis of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride, wherein: and adding an alumina-silica gel catalyst in the second step.
5. The process of claim 1 for the synthesis of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride, wherein: and adding a small amount of urea in the fourth step.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010338410.2A CN111592510A (en) | 2020-04-26 | 2020-04-26 | Synthesis method of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010338410.2A CN111592510A (en) | 2020-04-26 | 2020-04-26 | Synthesis method of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111592510A true CN111592510A (en) | 2020-08-28 |
Family
ID=72185470
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010338410.2A Pending CN111592510A (en) | 2020-04-26 | 2020-04-26 | Synthesis method of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111592510A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1432569A (en) * | 1997-03-12 | 2003-07-30 | 罗纳-普朗克农业公司 | Prepn process of pyrazole derivative |
| CN101481318A (en) * | 2009-03-02 | 2009-07-15 | 常州市阳光医药原料有限公司 | Method for preparing electronic grade 2,2-bis[(3-amino-4-hydroxy)phenyl]- hexafluoropropane |
| CN101492381A (en) * | 2009-03-06 | 2009-07-29 | 东华大学 | Method of preparing 2,2-di(3-amino-4-hydroxyl phenyl) hexafluoroacetore |
| CN109678826A (en) * | 2019-02-21 | 2019-04-26 | 浙江诺诚技术发展有限公司 | A kind of method that temperate condition prepares hexafluorodianhydride (6FDA) |
-
2020
- 2020-04-26 CN CN202010338410.2A patent/CN111592510A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1432569A (en) * | 1997-03-12 | 2003-07-30 | 罗纳-普朗克农业公司 | Prepn process of pyrazole derivative |
| CN101481318A (en) * | 2009-03-02 | 2009-07-15 | 常州市阳光医药原料有限公司 | Method for preparing electronic grade 2,2-bis[(3-amino-4-hydroxy)phenyl]- hexafluoropropane |
| CN101492381A (en) * | 2009-03-06 | 2009-07-29 | 东华大学 | Method of preparing 2,2-di(3-amino-4-hydroxyl phenyl) hexafluoroacetore |
| CN109678826A (en) * | 2019-02-21 | 2019-04-26 | 浙江诺诚技术发展有限公司 | A kind of method that temperate condition prepares hexafluorodianhydride (6FDA) |
Non-Patent Citations (2)
| Title |
|---|
| ARNOLD, DONALD R.等: "Substituent effects on benzyl radical hyperfine coupling (hfc) constants. Part 3. Comparison of the α-hfc for substituted benzyl radicals with the β-hfc for substituted cumyl radicals"", CANADIAN JOURNAL OF CHEMISTRY, vol. 63, no. 5, pages 1150 - 1155 * |
| 卢小逸;吴文良;张启明;董道敏;: "一种非离子型造影剂关键中间体――碘化物的合成", 浙江化工, vol. 42, no. 07, pages 14 - 16 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104447237B (en) | Process with methanol polyoxymethylene dimethyl ether | |
| CN111592510A (en) | Synthesis method of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride | |
| CN101492379A (en) | Synthesis of alkoxyl aniline | |
| CN111592511A (en) | Preparation process of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride | |
| CN111592512A (en) | Synthesis process of 4,4- (hexafluoroisopropenylidene) diphthalic anhydride | |
| CN113603580B (en) | Method for synthesizing methacrylic acid by decarboxylation of itaconic acid | |
| CN114196431A (en) | Method for catalytic oxidation desulfurization by extraction of cyclodextrin eutectic solvent | |
| CN106946800A (en) | A kind of synthetic method of (1H, the 3H) diketone of quinazoline 2,4 and its derivative | |
| KR100205465B1 (en) | Process for preparing cellulose esters by use of carboxylic acids | |
| CN110372545B (en) | Preparation method of high-purity gliclazide intermediate p-toluenesulfonylurea | |
| CN103121927B (en) | Preparation method of polymethoxymethylal | |
| CN101684182A (en) | Preparation method of polyimide film | |
| CN112812082B (en) | Method for preparing 2, 5-furan dicarbaldehyde by catalyzing fructose through two-step method | |
| CN106905173B (en) | Process for preparing aminobenzoic acid or esters thereof | |
| KR20200024577A (en) | Method of manufacturing bio-adipic acid derived from glucose | |
| CN108276261A (en) | Catalytic molecular oxygen aoxidizes the method for preparing 2- bromine Fluorenones in a kind of water phase | |
| CN111187240B (en) | Preparation method of 4, 4-diphenyl ether dianhydride | |
| CN110256323B (en) | Method for synthesizing indole from ethylene glycol and aniline prepared from coal | |
| CN109369915B (en) | Method for synthesizing polyimide | |
| CN100375751C (en) | Production method of prednisone hydrolysate | |
| CN109761841B (en) | Preparation process of spectrum-grade formamide | |
| CN1948267A (en) | Preparation method of 3,3'-dimethyl-4,4'-diamino dibenzyl methane | |
| CN117943117A (en) | Anti-aging agent and preparation method thereof, catalyst for preparing anti-aging agent and preparation method and application thereof | |
| CN114394897B (en) | Process for the preparation of esters in aqueous solvent systems | |
| CN115043777B (en) | Synthesis method of lignin-based quinoline derivative |
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 |