CN111848433A - Process for preparing 4-aminophenylacetamide - Google Patents
Process for preparing 4-aminophenylacetamide Download PDFInfo
- Publication number
- CN111848433A CN111848433A CN202010676355.8A CN202010676355A CN111848433A CN 111848433 A CN111848433 A CN 111848433A CN 202010676355 A CN202010676355 A CN 202010676355A CN 111848433 A CN111848433 A CN 111848433A
- Authority
- CN
- China
- Prior art keywords
- aminophenylacetamide
- temperature
- preparation
- parts
- reaction
- 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.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C231/00—Preparation of carboxylic acid amides
- C07C231/02—Preparation of carboxylic acid amides from carboxylic acids or from esters, anhydrides, or halides thereof by reaction with ammonia or amines
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C231/00—Preparation of carboxylic acid amides
- C07C231/22—Separation; Purification; Stabilisation; Use of additives
- C07C231/24—Separation; Purification
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a preparation method of 4-aminophenyl acetamide, which comprises the following steps: adding 1 part of p-aminophenylacetic acid and 4 parts of methanol into a reaction container, uniformly stirring, adding concentrated sulfuric acid for reaction, and recovering excessive methanol in the reaction container after the reaction is finished; after the methanol recovery is finished, adding 5-6 parts of crystallization solution into a reaction container, uniformly stirring, and then dropwise adding 10 parts of ammonia water under stirring, wherein the dropwise adding time of the ammonia water is controlled to be 9-11 hours; after the ammonia water is dropwise added, preserving heat for 13h, then cooling the reaction container to 7-9 ℃, continuously stirring until a large number of crystals appear in the kettle, and then continuously stirring for 2h to obtain a feed liquid; the method overcomes the defects of the prior art, has no residual solvent, ensures that the yield of the 4-aminophenylacetamide can reach more than 89 percent, has no discharge of waste liquid, and is relatively environment-friendly and safe.
Description
Technical Field
The invention relates to the technical field of 4-aminophenylacetamide, and particularly belongs to a preparation method of 4-aminophenylacetamide.
Background
The arylamine compound is an important organic intermediate in the field of fine chemical engineering, and is widely applied to the industries of medicines, pesticides, dyes, surfactants, chelating agents, textile auxiliaries, high polymer materials, food additives and the like. The corresponding aromatic amines are prepared industrially predominantly by reduction of aromatic nitro compounds. There are many methods for reducing aromatic nitro compounds to aromatic amines, including metal reduction, alkali sulfide reduction, metal hydride reduction, electrochemical reduction, photochemical reduction, catalytic hydrogenation, and the like. The 4-aminophenylacetamide is mainly applied to synthesis of medicines, dyes and food additives, so that the synthesis and research of the 4-aminophenylacetamide are of practical significance.
The cooling agent has large demand in the perfume industry, but the cooling agent synthesis routes are various, the raw materials required by each process method are different, 4-aminophenylacetamide is the main raw material of the novel cooling agent, 4-aminophenylacetamide in the prior synthesis technology is generated by nitration of mixed acid into p-nitroacetanilide, then reducing, neutralizing, crystallizing and drying the reaction liquid to obtain a finished product, adopting a hydrogenation dangerous process as a synthesis process, the method has the advantages of high requirement on equipment, poor applicability, low yield in unit time, great difficulty in subsequent purification and separation, and removal of partial by-products by a distillation process, so that the process steps are excessively complicated, the loss of solvent and feed liquid is large, the primary crystallization rate is low, repeated extraction and crystallization are performed, excessive waste liquid is caused, the cost is gradually increased, the profit margin is reduced, and the method is not beneficial to the current environment-friendly and economic harmonious development.
Disclosure of Invention
The invention aims to provide an environment-friendly and safe preparation method of 4-aminophenylacetamide, shorten the preparation time of the 4-aminophenylacetamide, reduce byproducts and improve the purity of the 4-aminophenylacetamide.
In order to solve the problems, the technical scheme adopted by the invention is as follows:
the preparation method of the 4-aminophenylacetamide comprises the following steps:
s1, adding 1 part of p-aminophenylacetic acid and 4 parts of methanol into a reaction container, uniformly stirring, adding concentrated sulfuric acid, heating to 50-55 ℃, reacting at constant temperature for 4 hours, and recovering excessive methanol in the reaction container after the reaction is finished;
s2, after the methanol recovery is finished, adding 5-6 parts of crystallization solution into the reaction container, uniformly stirring, then dropwise adding 10 parts of ammonia water under stirring, and controlling the dropwise adding time of the ammonia water to be 9-11 hours;
s3, after dropwise adding ammonia water, keeping the temperature for 13h, then cooling the reaction container to 7-9 ℃, continuing stirring until a large number of crystals appear in the kettle, and then continuing stirring for 2h to obtain a feed liquid;
s4, separating the crystals in the feed liquid to obtain wet crystallized materials, and drying the wet crystallized materials to obtain the 4-aminophenyl acetamide.
Preferably, the amount of concentrated sulfuric acid added in step S1 is 3 times that of p-aminophenylacetic acid.
Preferably, the step S1 is performed by adding concentrated sulfuric acid dropwise, and the temperature in the reaction vessel is controlled to 10-28 ℃ during the dropwise addition.
Preferably, 1.4 to 1.65 parts of methanol is recovered in step S1, and the temperature in the reaction vessel during the recovery process is 71 to 75 ℃.
Preferably, the temperature in the reaction vessel when 5 to 6 parts of the crystallization solution is added to the reaction vessel in step S2 is 30 ℃.
Preferably, the crystallization solution in step S2 is one of sodium chloride, calcium chloride, zinc chloride, and magnesium chloride aqueous solutions.
Preferably, the content of the solute in the crystallization solution is 30 to 40 wt%.
Preferably, the temperature in the reaction vessel during stirring and dropwise addition of 10 parts of aqueous ammonia in step S2 is 27 ℃.
The invention adopts p-aminophenylacetic acid, methanol and sulfuric acid, integrates esterification and acidification to form a sulfate raw material in one step, then adds sodium chloride aqueous solution, synthesizes a 4-aminophenylacetamide crude product by the process of dropping concentrated ammonia water, has short reaction time, no by-product and high utilization rate of the raw material, adopts no distillation process for subsequent purification, reduces energy consumption, does not adopt organic solvent, adds the sodium chloride aqueous solution for reaction at one time, simultaneously serves as crystallization solvent, is heated and then added into a crystallization kettle through a filtering device, can achieve crystallization, has short crystallization time, can be directly recycled after evaporating partial water of mother liquor, controls the complete crystallization temperature at 7 ℃, is particularly easy to dry, has no residue of the solvent after drying, well reduces cost, controls cost and enlarges profit space, the primary yield of the 4-aminophenylacetamide with the purity of more than 99 percent can reach more than 89 percent, and the waste liquid is not discharged and is relatively environment-friendly and safe.
Compared with the prior art, the invention has the following implementation effects:
1. the method has the advantages of simple raw materials, short reaction time, no by-product, mild control condition and one-step completion of esterification and acidification.
2. The method only needs to adopt common raw materials, avoids hydrogenation dangerous process, adopts one-pot reaction, has short steps, adopts water as a solvent for crystallization, and is economic and environment-friendly.
3. The method can obtain the finished product by one-time crystallization, has short crystallization time, low content of 4-aminophenylacetamide in the mother liquor, light color of the mother liquor, direct recycling, no need of distillation or ion exchange treatment, greatly improved yield of the finished product, unchanged product quality, simple operation, one-pot reaction and crystallization, and good economy.
4. The process method is easy to obtain the 4-aminophenylacetamide product with higher purity in the aspect of operation, does not use organic solvent, reduces the danger of industrial production, and has double meanings of economy and environmental protection.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
Firstly, weighing 20kg of p-aminophenylacetic acid and 80kg of methanol in a reaction kettle, starting stirring, and starting circulating water to enable the temperature in the reaction kettle to reach 22 ℃; then pumping 60kg of concentrated sulfuric acid into the head tank, dropwise adding sulfuric acid, keeping the temperature in the reaction kettle at 26 ℃ in the dropwise adding process, after the dropwise adding of the sulfuric acid is finished, extruding cooling water, heating by using steam, controlling the heating temperature at 55 ℃, and heating for 4 hours; starting water jet vacuum, keeping the vacuum at-0.08 Mpa, recovering 32kg of methanol, wherein the recovered methanol can be recycled, and keeping the temperature in the reaction kettle at 73 ℃; after recovery, starting circulating water to cool the reaction kettle to 30 ℃, adding 37kg of sodium chloride and 70kg of water into the reaction kettle, and stirring for 30 min; then 200kg of ammonia water is pumped into the head tank, and dropwise adding is started, wherein in the dropwise adding process, the temperature in the reaction kettle is controlled to be 27 ℃, and the dropwise adding is carried out for 10.5 hours; after the dropwise adding is finished, preserving the heat for 13 hours, after the heat preservation is finished, starting chilled water, controlling the temperature in the reaction kettle to be 7 ℃, stirring until a large number of crystals appear in the reaction kettle, and then continuing stirring for 2 hours to obtain a feed liquid; transferring the feed liquid into a centrifugal machine, starting centrifugal material throwing to obtain 23.2kg of wet crystal material, wherein mother liquor is yellowish, and recycling part of water from the mother liquor for reuse; drying the centrifuged wet crystal material in an oven at 50 ℃ under reduced pressure for 2h to obtain the 4-aminophenylacetamide with the purity of 99.1 percent, the dry product of white crystal with the weight of 18.6kg and the yield of 93 percent.
Example 2
Firstly, weighing 20kg of p-aminophenylacetic acid and 80kg of methanol in a reaction kettle, starting stirring, and starting circulating water to enable the temperature in the reaction kettle to reach 10 ℃; then pumping 60kg of concentrated sulfuric acid into the head tank, dropwise adding sulfuric acid, keeping the temperature in the reaction kettle at 20 ℃ in the dropwise adding process, after the dropwise adding of the sulfuric acid is finished, extruding cooling water, heating by using steam, controlling the heating temperature at 51 ℃, and heating for 4 hours; starting water jet vacuum, keeping the vacuum at-0.08 Mpa, recovering 31kg of methanol, recycling the recovered methanol for the next time, and keeping the temperature in the reaction kettle at 75 ℃; after recovery, starting circulating water to cool the reaction kettle to 30 ℃, adding 37kg of sodium chloride and 70kg of water into the reaction kettle, and stirring for 30 min; then 200kg of ammonia water is pumped into the head tank, and dropwise adding is started, wherein in the dropwise adding process, the temperature in the reaction kettle is controlled to be 27 ℃, and the dropwise adding is carried out for 9 hours; after the dropwise adding is finished, preserving the heat for 13 hours, after the heat preservation is finished, starting chilled water, controlling the temperature in the reaction kettle to be 7 ℃, stirring until a large number of crystals appear in the reaction kettle, and then continuing stirring for 2 hours to obtain a feed liquid; transferring the feed liquid into a centrifugal machine, starting centrifugal material throwing to obtain 24.7kg of crystal wet material, wherein the mother liquid is yellowish, and recycling part of water from the mother liquid for reuse; drying the centrifuged wet crystal material in an oven at 50 ℃ under reduced pressure for 2h to obtain the 4-aminophenylacetamide with the purity of 99.4 percent, the dry product of white crystal with the weight of 18.9kg and the yield of 94.5 percent.
Example 3
Firstly, weighing 20kg of p-aminophenylacetic acid and 80kg of methanol in a reaction kettle, starting stirring, and starting circulating water to enable the temperature in the reaction kettle to reach 17 ℃; then pumping 60kg of concentrated sulfuric acid into the head tank, dropwise adding sulfuric acid, keeping the temperature in the reaction kettle at 28 ℃ in the dropwise adding process, after the dropwise adding of the sulfuric acid is finished, extruding cooling water, heating by using steam, controlling the heating temperature at 51 ℃, and heating for 4 hours; starting water jet vacuum, keeping the vacuum at-0.08 Mpa, recovering 29.7kg of methanol, recycling the recovered methanol for the next time, and keeping the temperature in the reaction kettle at 71 ℃; after recovery, starting circulating water to cool the reaction kettle to 30 ℃, adding 40kg of calcium chloride and 70kg of water into the reaction kettle, and stirring for 30 min; then 200kg of ammonia water is pumped into the head tank, and dropwise adding is started, wherein in the dropwise adding process, the temperature in the reaction kettle is controlled to be 27 ℃, and the dropwise adding is carried out for 9 hours; after the dropwise adding is finished, preserving the heat for 13 hours, after the heat preservation is finished, starting chilled water, controlling the temperature in the reaction kettle to be 9 ℃, stirring until a large number of crystals appear in the reaction kettle, and then continuing stirring for 2 hours to obtain a feed liquid; transferring the feed liquid into a centrifugal machine, starting centrifugal material throwing to obtain 21.2kg of crystal wet material, wherein mother liquor is yellowish, and recycling part of water from the mother liquor for reuse; drying the centrifuged wet crystal material in an oven at 50 ℃ under reduced pressure for 2h to obtain the 4-aminophenylacetamide with the purity of 99.7 percent, the dry product of white crystal with the weight of 17.9kg and the yield of 89.5 percent.
Example 4
Firstly, weighing 20kg of p-aminophenylacetic acid and 80kg of methanol in a reaction kettle, starting stirring, and starting circulating water to enable the temperature in the reaction kettle to reach 4 ℃; then pumping 60kg of concentrated sulfuric acid into the head tank, dropwise adding sulfuric acid, keeping the temperature in the reaction kettle at 10 ℃ in the dropwise adding process, after the dropwise adding of the sulfuric acid is finished, extruding cooling water, heating by using steam, controlling the heating temperature at 54 ℃, and heating for 4 hours; starting water jet vacuum, keeping the vacuum at-0.08 Mpa, recovering 32.1kg of methanol, recycling the recovered methanol for the next time, and keeping the temperature in the reaction kettle at 75 ℃; after recovery, starting circulating water to cool the reaction kettle to 30 ℃, adding 35kg of magnesium chloride and 70kg of water into the reaction kettle, and stirring for 30 min; then 200kg of ammonia water is pumped into the head tank, and dropwise adding is started, wherein in the dropwise adding process, the temperature in the reaction kettle is controlled to be 27 ℃, and the dropwise adding is carried out for 10.5 hours; after the dropwise adding is finished, preserving the heat for 13 hours, after the heat preservation is finished, starting chilled water, controlling the temperature in the reaction kettle to be 7 ℃, stirring until a large number of crystals appear in the reaction kettle, and then continuing stirring for 2 hours to obtain a feed liquid; transferring the feed liquid into a centrifugal machine, starting centrifugal material throwing to obtain 25.7kg of crystal wet material, recovering part of water from the mother liquid, and reusing; drying the centrifuged wet crystal material in an oven at 50 ℃ under reduced pressure for 2h to obtain the 4-aminophenylacetamide with the purity of 99.6 percent, the dry product of white crystal with the weight of 19.1kg and the yield of 95.5 percent.
Example 5
Firstly, weighing 20kg of p-aminophenylacetic acid and 80kg of methanol in a reaction kettle, starting stirring, and starting circulating water to enable the temperature in the reaction kettle to reach 5 ℃; then pumping 60kg of concentrated sulfuric acid into the head tank, dropwise adding sulfuric acid, keeping the temperature in the reaction kettle at 15 ℃ in the dropwise adding process, after the dropwise adding of the sulfuric acid is finished, extruding cooling water, heating by using steam, controlling the heating temperature at 50 ℃, and heating for 4 hours; starting water jet vacuum, keeping the vacuum at-0.08 Mpa, recovering 32.1kg of methanol, recycling the recovered methanol for the next time, and keeping the temperature in the reaction kettle at 75 ℃; after recovery, starting circulating water to cool the reaction kettle to 30 ℃, adding 35kg of zinc chloride and 70kg of water into the reaction kettle, and stirring for 30 min; then 200kg of ammonia water is pumped into the head tank, and dropwise adding is started, wherein in the dropwise adding process, the temperature in the reaction kettle is controlled to be 27 ℃, and the dropwise adding is carried out for 11 hours; after the dropwise adding is finished, preserving the heat for 13 hours, after the heat preservation is finished, starting chilled water, controlling the temperature in the reaction kettle to be 7 ℃, stirring until a large number of crystals appear in the reaction kettle, and then continuing stirring for 2 hours to obtain a feed liquid; transferring the feed liquid into a centrifugal machine, starting centrifugal material throwing to obtain 23.4kg of wet crystal material, recovering part of water from the mother liquid, and reusing; drying the centrifuged wet crystal material in an oven at 50 ℃ under reduced pressure for 2h to obtain the 4-aminophenylacetamide with the purity of 99.7 percent, the dry product of white crystal with the weight of 18.5kg and the yield of 92.5 percent.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (8)
- A process for the preparation of 4-aminophenylacetamide, characterised by comprising the steps of:s1, adding 1 part of p-aminophenylacetic acid and 4 parts of methanol into a reaction container, uniformly stirring, adding concentrated sulfuric acid, heating to 50-55 ℃, reacting at constant temperature for 4 hours, and recovering excessive methanol in the reaction container after the reaction is finished;s2, after the methanol recovery is finished, adding 5-6 parts of crystallization solution into the reaction container, uniformly stirring, then dropwise adding 10 parts of ammonia water under stirring, and controlling the dropwise adding time of the ammonia water to be 9-11 hours;s3, after dropwise adding ammonia water, keeping the temperature for 13h, then cooling the reaction container to 7-9 ℃, continuing stirring until a large number of crystals appear in the kettle, and then continuing stirring for 2h to obtain a feed liquid;s4, separating the crystals in the feed liquid to obtain wet crystallized materials, and drying the wet crystallized materials to obtain the 4-aminophenyl acetamide.
- 2. The process for the preparation of 4-aminophenylacetamide according to claim 1, wherein: the amount of concentrated sulfuric acid added in step S1 is 3 times of that of p-aminophenylacetic acid.
- 3. The process for the preparation of 4-aminophenylacetamide according to claim 1, wherein: step S1, adding concentrated sulfuric acid for dropwise addition, and controlling the temperature in the reaction container to be 10-28 ℃ during dropwise addition.
- 4. The process for the preparation of 4-aminophenylacetamide according to claim 1, wherein: in step S1, 1.4-1.65 parts of methanol is recovered, and the temperature in the reaction vessel in the recovery process is 71-75 ℃.
- 5. The process for the preparation of 4-aminophenylacetamide according to claim 1, wherein: in step S2, the temperature in the reaction vessel is 30 ℃ when 5 to 6 parts of the crystallization solution is added to the reaction vessel.
- 6. The process for the preparation of 4-aminophenylacetamide according to claim 1, wherein: the crystallization solution in step S2 is one of sodium chloride, calcium chloride, zinc chloride, and magnesium chloride aqueous solutions.
- 7. The process for the preparation of 4-aminophenylacetamide according to claim 6, wherein: the content of solute in the crystallization solution is 30-40 wt%.
- 8. The process for the preparation of 4-aminophenylacetamide according to claim 1, wherein: in step S2, the temperature in the reaction vessel was 27 ℃ while stirring and dropping 10 parts of aqueous ammonia.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010676355.8A CN111848433B (en) | 2020-07-14 | 2020-07-14 | Process for preparing 4-aminophenylacetamide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010676355.8A CN111848433B (en) | 2020-07-14 | 2020-07-14 | Process for preparing 4-aminophenylacetamide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111848433A true CN111848433A (en) | 2020-10-30 |
| CN111848433B CN111848433B (en) | 2023-04-28 |
Family
ID=72983936
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010676355.8A Active CN111848433B (en) | 2020-07-14 | 2020-07-14 | Process for preparing 4-aminophenylacetamide |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111848433B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003051909A2 (en) * | 2001-12-19 | 2003-06-26 | Astrazeneca Ab | Process for the manufacture of pharmaceutically acceptable salts of a compound |
| CN1617881A (en) * | 2000-07-22 | 2005-05-18 | 阿斯特拉曾尼卡有限公司 | Chemical process |
| US20100272655A1 (en) * | 2009-04-27 | 2010-10-28 | Kathryn Anne Bardsley | Menthylcarboxamides and Their Use as Cooling Agents |
-
2020
- 2020-07-14 CN CN202010676355.8A patent/CN111848433B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1617881A (en) * | 2000-07-22 | 2005-05-18 | 阿斯特拉曾尼卡有限公司 | Chemical process |
| WO2003051909A2 (en) * | 2001-12-19 | 2003-06-26 | Astrazeneca Ab | Process for the manufacture of pharmaceutically acceptable salts of a compound |
| US20100272655A1 (en) * | 2009-04-27 | 2010-10-28 | Kathryn Anne Bardsley | Menthylcarboxamides and Their Use as Cooling Agents |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111848433B (en) | 2023-04-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107337618B (en) | Production method for simultaneously improving purity and yield of metformin hydrochloride | |
| CN106045879B (en) | Method for preparing cyanoacetic acid | |
| CN104788345A (en) | High-purity metformin hydrochloride preparation method | |
| CN111548291B (en) | Environment-friendly synthetic method of scorch retarder N-phenyl-N-trichloromethylthio benzenesulfonamide | |
| CN103435507A (en) | Preparation method of L-alpha-methyl-3,4-dihydroxyphenylalanine | |
| CN106905163A (en) | A kind of green synthesis process of 4,4 ' dinitro diphenyl ether | |
| CN102010354A (en) | Method for recycling dimethyl sulfoxide waste residue | |
| CN110818573B (en) | Preparation method of 3,3 '-dichloro-4, 4' -diaminodiphenylmethane | |
| CN102617335B (en) | Process for synthesizing p-tert-butylbenzoic acid | |
| CN111848433B (en) | Process for preparing 4-aminophenylacetamide | |
| CN109503343B (en) | Preparation method of photoinitiator 184 | |
| CN112707848A (en) | Preparation method of guanidine hydrochloride | |
| CN104355990B (en) | Method for recycling and mechanically using L- (+) -tartaric acid in D-ethyl ester production | |
| CN103539745B (en) | A kind of preparation method of secnidazole | |
| CN107473927B (en) | Preparation process of biphenyl dichlorobenzyl | |
| CN109574893A (en) | A kind of method of sodium thiocarbonate synthesis mercaptoethylamine hydrochloride | |
| CN110642774B (en) | Preparation method of 1,2,3, 6-tetrahydrophthalimide | |
| CN104262208A (en) | Method for combined production of o-benzaldehyde sulfonic acid sodium salt and o-chlorobenzoic acid | |
| CN110590564B (en) | Method for synthesizing 2, 4-dichloroaniline by continuous chlorination process | |
| CN109485070B (en) | Method for treating triazine ring sodium salt mother liquor slag | |
| JP2024505087A (en) | Method for ammonolysis of bromoalkanoic acids | |
| CN112939801A (en) | Process for synthesizing cooling agent | |
| CN107915343B (en) | Process wastewater treatment process in production process of pyrazolone series products | |
| CN109836344B (en) | Method for producing glycine by organic solvent | |
| CN112159016A (en) | Method for recovering and treating waste acid water generated in amantadine synthesis |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |