CN111233704B - Method for preparing 6-aminocapronitrile product - Google Patents
Method for preparing 6-aminocapronitrile product Download PDFInfo
- Publication number
- CN111233704B CN111233704B CN202010181800.3A CN202010181800A CN111233704B CN 111233704 B CN111233704 B CN 111233704B CN 202010181800 A CN202010181800 A CN 202010181800A CN 111233704 B CN111233704 B CN 111233704B
- Authority
- CN
- China
- Prior art keywords
- reaction
- aminocapronitrile
- acid
- caprolactam
- combination
- 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.)
- Active
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C253/00—Preparation of carboxylic acid nitriles
- C07C253/22—Preparation of carboxylic acid nitriles by reaction of ammonia with carboxylic acids with replacement of carboxyl groups by cyano groups
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C227/00—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton
- C07C227/22—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton from lactams, cyclic ketones or cyclic oximes, e.g. by reactions involving Beckmann rearrangement
Abstract
The invention relates to a method for preparing a 6-aminocapronitrile product, which comprises the following steps: a: uniformly mixing caprolactam, an acid solution and the like according to a certain proportion, adding the mixture into a reaction kettle, heating and stirring the mixture for reaction; b: after the caprolactam in the step A is reacted, removing low-boiling-point substances under reduced pressure, and recrystallizing to obtain 6-aminocaproic acid salt; c: b, uniformly mixing the 6-aminocaproate, the alcohol, the ammoniating agent, the dehydrating agent and the like obtained in the step B according to a certain proportion, adding the mixture into a reaction kettle, heating and stirring the mixture for reaction; d: and D, rectifying the reaction liquid obtained in the step C, separating and purifying to obtain the 6-aminocapronitrile. The method for preparing the 6-aminocapronitrile product has the advantages of high reaction conversion rate, high purity of the 6-aminocapronitrile product of more than 98 percent, mild reaction conditions and relatively simple preparation process.
Description
Technical Field
The invention relates to the technical field of preparation of aminonitrile, in particular to a method for preparing a 6-aminocapronitrile product.
Background
6-aminocapronitrile is an important chemical intermediate, the price is high, downstream products 1,6-hexamethylene diamine are obtained after hydrogenation, and 1,6-hexamethylene diamine is one of three nylon raw materials and can be used for producing nylon 66, nylon 610, hexamethylene diisocyanate and other large chemical products. The current production of 6-aminocapronitrile is mainly obtained by partial hydrogenation of 1,6-adiponitrile, as in patent CN1238334C, CN101309897B, or by hydrogenation of olefinic nitrile, as in patent NL812780. The patent of preparing 6-aminocapronitrile by using caprolactam as a raw material is less, and the patent CN107602416A mentions a technology of preparing 6-aminocapronitrile by using a caprolactam gas phase method, but the technology requires that the reaction temperature is more than 300 ℃, and the pressurization is performed, the reaction condition is harsh, and the technology is not suitable for large-scale industrialization; although patent CN107739318A mentions a caprolactam liquid-phase preparation process, the reaction conversion rate is low, and a large amount of nitrile solvent is used, which pollutes the environment.
Disclosure of Invention
The technical problem to be solved by the invention is a method for preparing a 6-aminocapronitrile product, which takes caprolactam as a raw material, and has the advantages of high reaction conversion rate, mild reaction conditions and relatively simple preparation process.
In order to solve the technical problems, the technical scheme adopted by the method for preparing the 6-aminocapronitrile product provided by the invention is as follows:
a process for preparing a 6-aminocapronitrile product comprising the steps of:
a: uniformly mixing caprolactam and an acidic solution, adding the mixture into a reaction kettle, heating and stirring the mixture to react;
b: after the caprolactam in the step A is reacted, distilling to remove low-boiling-point substances, and recrystallizing to obtain 6-aminocaproic acid salt;
c: b, uniformly mixing the 6-aminocaproate obtained in the step B with alcohol, an ammoniating agent and a dehydrating agent, and adding the mixture into a reaction kettle to be heated and stirred for reaction;
d: and D, carrying out reduced pressure rectification on the reaction liquid obtained in the step C, and separating and purifying to obtain the 6-aminocapronitrile.
Preferably, the acidic solution of step a is an aqueous solution of an organic acid, which is formic acid, acetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, or a combination thereof.
Preferably, in the step A, the mass ratio of the caprolactam to the acidic solution is 1 (1-100). Preferably, in the step A, the mass ratio of the caprolactam to the acidic solution is 1 (1-20).
Preferably, in step B, the solvent for recrystallization comprises a good solvent and a poor solvent, the volume ratio of the good solvent to the poor solvent is 1 (0.1-1), the good solvent is water, methanol, ethylene glycol or dimethylformamide or a combination thereof, and the poor solvent is petroleum ether, cyclohexane, toluene, p-xylene or butyl acetate or a combination thereof.
Further preferably, in step B, in the recrystallization process: the stirring speed is 150-200 r/min, and the cooling speed is 1-5 ℃/min.
Preferably, in step C, the alcohol is a diol which is ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,4-pentanediol, 1,5-pentanediol or a combination thereof.
Preferably, in step C, the ammoniating agent is ammonium oxalate, formamide, ammonium carbamate, or a combination thereof.
Preferably, in step C, the dehydrating agent is phosphorus oxychloride, phosphorus pentachloride, ethyl phosphate, trifluoroacetic anhydride, N-methyl-N-trimethylsilyl trifluoroacetamide, or a combination thereof.
Preferably, in the step C, the mass ratio of the 6-aminocaproate to the alcohol to the ammoniating agent to the dehydrating agent is 1 (1-10) to 1-8 to 0.01-0.1.
Preferably, in step D, the vacuum rectification conditions of the reaction solution are as follows: the bottom temperature of the vacuum rectification tower is 180-190 ℃, the vacuum degree is more than-0.095 MPa, when the top temperature of the rectification tower is 40-60 ℃, the low-boiling-point substances begin to be discharged, and when the top temperature of the rectification tower is 160-170 ℃, the 6-aminocapronitrile begins to be discharged.
The invention relates to a method for preparing 6-aminocapronitrile product by reacting caprolactam in liquid phase, which comprises the following steps:
wherein HX is aqueous solution of organic acid, and the aqueous solution of organic acid can be aqueous solution of one or more mixed acids of formic acid, acetic acid, methanesulfonic acid, benzenesulfonic acid and p-toluenesulfonic acid.
Wherein R is 1 An alkyl chain of 2~5 carbon atoms; NH (NH) 3 R 2 To be able to liftThe ammonia source for supplying ammonia gas can be one or a combination of more than two of ammonium oxalate, formamide and ammonium carbamate. Independently, R 2 Represents a non-amino group of the ammonia source material.
Compared with the prior art, the method for preparing the 6-aminocapronitrile product has the following advantages:
1. the method for preparing the 6-aminocapronitrile product takes caprolactam as a starting raw material, and 6-aminocapronitrile is prepared by reaction in a liquid phase in the absence of a catalyst.
2. Caprolactam is hydrolyzed in an acid solution to open a ring to form 6-aminocaproic acid salt, if the caprolactam is directly hydrolyzed without adding acid, the obtained 6-aminocaproic acid is unstable and easy to cyclize, the subsequent process is difficult to carry out, and the used acid is dissolved in water to enable the reaction to be in a homogeneous reaction, so that the salt forming reaction effect is better. The acidic aqueous solution needs to be excessive so as to ensure that the caprolactam is completely hydrolyzed, ring-opened and salified.
3. In the step B, the recrystallization has the advantages that the purity of the 6-aminocaproate can be greatly improved, a high-purity main raw material is provided for the reaction in the subsequent step C, and unnecessary side reactions are reduced.
4. In the step C, 6-aminocaproate and dihydric alcohol are subjected to esterification reaction, and hydroxyl-terminated dihydric alcohol is adopted, so that the reactivity of the alcohol is improved, the feeding amount of the alcohol is reduced, and the purification unit consumption is saved. The ammoniating agent is ammonium oxalate, formamide, ammonium carbamate or a combination thereof, can release ammonia to participate in ammoniation reaction after being heated and decomposed, and terminal amino groups in a molecular structure of the ammoniating agent can also participate in ammoniation reaction. The dehydrating agent is phosphorus oxychloride, phosphorus pentachloride, ethyl phosphate, trifluoroacetic anhydride, N-methyl-N-trimethylsilyl trifluoroacetamide or a combination thereof, and is used as the dehydrating agent for the ammoniated reaction product, so that the ammoniated product is subjected to dehydration reaction to generate 6-aminocapronitrile, and the ammoniated product is difficult to undergo dehydration reaction without adding the substances. The alcohol excess ensures that the 6-aminocaproate is completely esterified; the excess amination agent ensures complete amination of the esterification product.
Drawings
FIG. 1 is a nuclear magnetic spectrum (hydrogen spectrum) of a 6-aminocapronitrile product produced in the method for producing 6-aminocapronitrile according to example 1 of the present invention;
FIG. 2 is a nuclear magnetic detection diagram (carbon spectrum) of a 6-aminocapronitrile product produced in the method for producing 6-aminocapronitrile according to example 1 of the present invention;
FIG. 3 is a gas chromatographic examination of the 6-aminocapronitrile product produced in the process for producing 6-aminocapronitrile according to example 1 of the invention.
Detailed Description
Unless defined otherwise, technical terms used in the following examples have the same meanings as commonly understood by one of ordinary skill in the art to which the present invention belongs. The experimental reagents used in the following examples, unless otherwise specified, were all conventional biochemical reagents; the experimental methods are conventional methods unless otherwise specified.
Examples 1 to 5 below are examples of the preparation of 6-aminocapronitrile from caprolactam under laboratory conditions, the vacuum distillation conditions being typical distillation conditions in the laboratory, the glass column used in the laboratory having a height of 1.2m and an internal diameter of 24mm and the packing being a 3mm diameter Φ ring. The bottom temperature of the vacuum rectification tower is 180-190 ℃, the vacuum degree is more than-0.095 MPa, and when the top temperature of the rectification tower is 160-170 ℃, the 6-aminocapronitrile begins to be discharged.
Example 1
Uniformly mixing 10g of caprolactam and 100g of formic acid aqueous solution, adding the mixture into a reaction kettle A, stirring and heating at a stirring speed of 1000RPM, starting reflux reaction when the temperature is raised to 110 ℃, refluxing for 2h, discharging the reaction solution to a rectifying kettle C, distilling to remove low-boiling-point substances, transferring the rectifying kettle solution to a reaction kettle B, recrystallizing by using methanol-toluene (the volume ratio of the methanol to the toluene is 1. After the reaction is finished, the reaction liquid is rectified under reduced pressure, separated and purified to obtain the 6-aminocapronitrile with the purity of 98.3 percent and the product yield of 68.9 percent.
The vacuum rectification conditions of the 6-aminocapronitrile product in the example are as follows: the temperature of the rectifying still is 183 ℃, the top temperature is 161 ℃, the vacuum degree is-0.096 MPa, and 6-aminocapronitrile is distilled from the top of the rectifying still.
Example 2
Uniformly mixing 10g of caprolactam and 150g of formic acid aqueous solution, adding the mixture into a reaction kettle A, stirring and heating at a stirring speed of 1100RPM, starting reflux reaction when the temperature is raised to 112 ℃, discharging the reaction solution into a rectifying kettle C after refluxing for 1.5h, distilling to remove low-boiling-point substances, transferring the rectifying kettle liquid to a reaction kettle B, recrystallizing (at a stirring speed of 150 r/min and a cooling speed of 2 ℃/min) by using ethylene glycol-toluene (at a volume ratio of ethylene glycol to toluene of 1: 0.5) to obtain 6-aminocaproate solid, discharging the liquid in the kettle, adding 40g of ethylene glycol, 35g of ammonium oxalate and 0.5g of ethyl phosphate into the kettle, uniformly mixing, stirring and heating at a stirring speed of 1100RPM, performing reflux reaction at 150 ℃ for 5h, and discharging. After the reaction is finished, the reaction liquid is rectified under reduced pressure, separated and purified to obtain the 6-aminocapronitrile with the purity of 98.8 percent and the product yield of 70.5 percent.
The vacuum rectification conditions of the 6-aminocapronitrile product in the example are as follows: the temperature of the rectifying still is 189 ℃, the top temperature is 160 ℃, the vacuum degree is-0.095MPa, and 6-aminocapronitrile is distilled from the top of the rectifying still.
Example 3
Uniformly mixing 11g of caprolactam and 155g of acetic acid aqueous solution, adding the mixture into a reaction kettle A, stirring and heating at a stirring speed of 1200RPM, starting reflux reaction when the temperature is raised to 110 ℃, discharging the reaction solution to a rectifying kettle C after refluxing for 3 hours, distilling to remove low-boiling-point substances, transferring the rectifying kettle liquid to a reaction kettle B, recrystallizing (with a stirring speed of 190 r/min and a cooling speed of 3.5 ℃/min) by using methanol-p-xylene (with a volume ratio of methanol to p-xylene of 1: 0.8) to obtain 6-aminocaproate solid, discharging liquid in the kettle, adding 40g of ethylene glycol, 35g of formamide and 0.6g of ethyl phosphate into the kettle, uniformly mixing, stirring and heating at a stirring speed of 1200RPM, carrying out reflux reaction at 130 ℃ for 2 hours, and then discharging. After the reaction is finished, the reaction liquid is rectified under reduced pressure, separated and purified to obtain the 6-aminocapronitrile, the purity is 99.1 percent, and the product yield is 73 percent.
The vacuum rectification conditions of the 6-aminocapronitrile product in the example are as follows: the temperature of the rectifying still is 185 ℃, the top temperature is 162 ℃, the vacuum degree is-0.095MPa, and 6-aminocapronitrile is distilled from the top of the tower.
Example 4
Uniformly mixing 11g of caprolactam and 120g of methanesulfonic acid aqueous solution, adding the mixture into a reaction kettle A, stirring and heating at a stirring speed of 1100RPM, starting reflux reaction when the temperature is raised to 110 ℃, discharging the reaction solution to a rectifying kettle C after refluxing for 2 hours, distilling to remove low-boiling-point substances, transferring the rectifying kettle liquid to a reaction kettle B, recrystallizing (with a stirring speed of 190 r/min and a cooling speed of 4 ℃/min) by using methanol-cyclohexane (with a volume ratio of methanol to cyclohexane of 1: 0.4) to obtain 6-aminocaproate solid, discharging liquid in the kettle, adding 40g of 1, 3-propylene glycol, 35g of formamide and 0.5g of trifluoroacetic anhydride into the kettle, uniformly mixing, stirring and heating at a stirring speed of 1200RPM, and performing reflux reaction at 130 ℃ for 2.5 hours, and discharging. After the reaction is finished, the reaction liquid is rectified under reduced pressure, separated and purified to obtain the 6-aminocapronitrile with the purity of 98.1 percent and the product yield of 68.9 percent.
The vacuum rectification conditions of the 6-aminocapronitrile product in the example are as follows: the temperature of the rectifying still is 183 ℃, the top temperature is 162 ℃, the vacuum degree is-0.098MPa, and 6-aminocapronitrile is distilled from the top of the rectifying still.
Example 5
Uniformly mixing 10g of caprolactam and 145g of benzenesulfonic acid aqueous solution, adding the mixture into a reaction kettle A, stirring and heating at a stirring speed of 1100RPM, starting reflux reaction when the temperature is raised to 115 ℃, discharging the reaction solution to a rectifying kettle C after refluxing for 3 hours, distilling to remove low-boiling-point substances, transferring the rectifying kettle solution to a reaction kettle B, recrystallizing by using dimethylformamide-petroleum ether (the volume ratio of the dimethylformamide to the petroleum ether is 1: 0.8) (the stirring speed is 200 r/min, the cooling speed is 3 ℃/min) to obtain 6-aminocaproate solid, discharging the liquid in the kettle, adding 60g of 1, 4-butanediol, 50g of ammonium carbamate and 0.8g of phosphorus oxychloride into the kettle, stirring and heating after uniform mixing, stirring at a stirring speed of 1100RPM, performing reflux reaction at 120 ℃ for 2 hours, and discharging. After the reaction is finished, the reaction liquid is rectified under reduced pressure, separated and purified to obtain the 6-aminocapronitrile with the purity of 99.2 percent and the product yield of 66.8 percent.
The vacuum rectification conditions of the 6-aminocapronitrile product in the example are as follows: the temperature of the rectifying still and the top temperature are 186 ℃, the vacuum degree is-0.098MPa, and 6-aminocapronitrile is distilled from the top of the rectifying still and the top temperature is 160 ℃.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (6)
1. A process for preparing a 6-aminocapronitrile product, comprising the steps of:
a: caprolactam and an acid solution are uniformly mixed and then added into a reaction kettle to be heated and stirred for reaction, wherein the acid solution is an aqueous solution of an organic acid, the aqueous solution of the organic acid is formic acid, acetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid or a combination thereof, and the mass ratio of the caprolactam to the acid solution is 1 (1-100);
b: after the caprolactam in the step A is reacted, distilling to remove low-boiling-point substances, and recrystallizing to obtain 6-aminocaproic acid salt;
c: b, uniformly mixing the 6-aminocaproate obtained in the step B with alcohol, an ammoniating agent and a dehydrating agent, adding the mixture into a reaction kettle, heating and stirring the mixture to react, wherein the alcohol is dihydric alcohol which is ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,4-pentanediol, 1,5-pentanediol or a combination thereof, and the mass ratio of the 6-aminocaproate, the alcohol, the ammoniating agent and the dehydrating agent is 1 (1-10) to 0.01-0.1;
d: and D, rectifying the reaction liquid obtained in the step C under reduced pressure, separating and purifying to obtain the 6-aminocapronitrile.
2. The method of claim 1, wherein: in the step A, the mass ratio of caprolactam to the acid solution is 1 (1-20).
3. The method of claim 1, wherein: in the step B, the solvent for recrystallization comprises a good solvent and a poor solvent, the volume ratio of the good solvent to the poor solvent is 1 (0.1-1), the good solvent is water, methanol, glycol or dimethylformamide or a combination thereof, and the poor solvent is petroleum ether, cyclohexane, toluene, p-xylene or butyl acetate or a combination thereof.
4. The method of claim 1, wherein: in step C, the ammoniating agent is ammonium oxalate, formamide, ammonium carbamate, or a combination thereof.
5. The method of claim 1, wherein: in the step C, the dehydrating agent is phosphorus oxychloride, phosphorus pentachloride, ethyl phosphate, trifluoroacetic anhydride, N-methyl-N-trimethylsilyl trifluoroacetamide or a combination thereof.
6. The method of claim 1, wherein: in the step D, the vacuum rectification conditions of the reaction liquid are as follows: the bottom temperature of the vacuum rectification tower is 180-190 ℃, the vacuum degree is more than-0.095 MPa, when the top temperature of the rectification tower is 40-60 ℃, the low-boiling-point substances begin to be discharged, and when the top temperature of the rectification tower is 160-170 ℃, the 6-aminocapronitrile begins to be discharged.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010181800.3A CN111233704B (en) | 2020-03-16 | 2020-03-16 | Method for preparing 6-aminocapronitrile product |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010181800.3A CN111233704B (en) | 2020-03-16 | 2020-03-16 | Method for preparing 6-aminocapronitrile product |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111233704A CN111233704A (en) | 2020-06-05 |
| CN111233704B true CN111233704B (en) | 2023-01-06 |
Family
ID=70863545
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010181800.3A Active CN111233704B (en) | 2020-03-16 | 2020-03-16 | Method for preparing 6-aminocapronitrile product |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111233704B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111574400B (en) * | 2020-06-10 | 2022-11-25 | 江苏扬农化工集团有限公司 | Separation method of ammoniated and dehydrated product of caprolactam and synthesis method of hexamethylene diamine |
| CN114149331A (en) * | 2021-12-20 | 2022-03-08 | 昌德新材科技股份有限公司 | Method for preparing hexamethylene diamine |
| CN114195663A (en) * | 2021-12-20 | 2022-03-18 | 昌德新材科技股份有限公司 | Preparation method of 6-aminocaproic acid |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3131968A1 (en) * | 1981-08-13 | 1983-02-24 | Chemische Werke Hüls AG, 4370 Marl | METHOD FOR PRODUCING ALIPHATIC NITRILES |
| JP4024388B2 (en) * | 1998-06-25 | 2007-12-19 | 花王株式会社 | Method for producing aliphatic nitrile |
| US6812237B2 (en) * | 2000-05-15 | 2004-11-02 | Novartis Ag | N-substituted peptidyl nitriles as cysteine cathepsin inhibitors |
| JP2002284753A (en) * | 2001-03-23 | 2002-10-03 | Koei Chem Co Ltd | Method for manufacturing nitrile |
| JP2006182708A (en) * | 2004-12-28 | 2006-07-13 | Kao Corp | Manufacturing method of aliphatic nitrile |
| WO2012119941A1 (en) * | 2011-03-04 | 2012-09-13 | Prozymex A/S | Peptidyl nitrilcompounds as peptidase inhibitors |
| AR091858A1 (en) * | 2012-07-25 | 2015-03-04 | Sova Pharmaceuticals Inc | CISTATIONIN-g-LIASA INHIBITORS (CSE) |
| TWI591045B (en) * | 2012-08-03 | 2017-07-11 | 祥翊製藥股份有限公司 | Method for making 6-aminocaproic acid as active pharmaceutical ingredient |
| CN104945278A (en) * | 2015-06-04 | 2015-09-30 | 荆州和乐实业科技有限公司 | Malononitrile synthesis method |
| WO2020031201A1 (en) * | 2018-08-04 | 2020-02-13 | Msn Laboratories Private Limited, R&D Center | Improved process for the preparation of 6-aminohexanoic acid |
| CN109369430A (en) * | 2018-11-22 | 2019-02-22 | 沧州旭阳化工有限公司 | A method of preparing 6-aminocaprolc acid |
| CN110423201B (en) * | 2019-04-30 | 2022-07-12 | 郑州大学 | Method for synthesizing hexamethylene diamine by using caprolactam as raw material |
-
2020
- 2020-03-16 CN CN202010181800.3A patent/CN111233704B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN111233704A (en) | 2020-06-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111233704B (en) | Method for preparing 6-aminocapronitrile product | |
| CN111004148B (en) | Method for preparing 6-aminocapronitrile by gas phase method | |
| CN101648885B (en) | Amide dimer and preparation method thereof | |
| CN112079725A (en) | Method for producing hexamethylene diamine | |
| CN111978207A (en) | Method for synthesizing hexamethylene diamine key intermediate | |
| CN106674172B (en) | Method for preparing hexahydrophthalic anhydride | |
| CN113105363B (en) | Method for synthesizing 6-aminocapronitrile from cyclohexanone oxime in one step | |
| CN112661670A (en) | Method for preparing 1,6-hexamethylene dicarbamate in non-catalytic mode | |
| CN114702402B (en) | Synthetic method of fluoro-phenyl amino acid hydrochloride | |
| CN109721496B (en) | Synthetic method of 3-nitro-o-xylene | |
| CN111620771B (en) | Esterification-hydrolysis method lactic acid purification process flow based on catalytic reaction rectification coupling technology | |
| CN111153823B (en) | Method for preparing oxamide from dimethyl oxalate | |
| CN113292522A (en) | Method for preparing 5-hydroxymethylfurfural by catalyzing biomass sugar with organic acid | |
| CN111454172A (en) | Production method for preparing glutaronitrile by aminolysis of ester substance | |
| CN114315520A (en) | Method for separating and purifying high-carbon diol through low-temperature crystallization | |
| CN113024398A (en) | Preparation method of capsaicin and capsaicin prepared by using same | |
| CN112209839A (en) | Method for synthesizing 2, 2-difluoroethylamine by using high-boiling-point substance in R142b as raw material | |
| CN111471001B (en) | Preparation method of 4- [ (1R) -1-amino-2-hydroxyethyl ] -3-fluoro-benzonitrile | |
| CN115850090B (en) | Method for preparing 4,4' -diaminodiphenyl methane by graphene catalysis | |
| CN112279783B (en) | Method for preparing 3-hydroxypropionitrile under supercritical condition | |
| CN111285772B (en) | Synthesis method of tetramethyldiene triamine compound | |
| CN117051050A (en) | Novel method for preparing amide compounds by biocatalysis | |
| CN117820155A (en) | Preparation method of 4,4 '-diamino-2' -chloro-benzoylanilide | |
| CN113735721A (en) | Method for synthesizing 3-ethylamino-4-methylphenol | |
| CN116041200A (en) | Method for synthesizing N- (4-fluoroaniline) -2-hydroxy-N-isopropyl acetamide |
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 |