CN111718266A - Purification method and application of p-nitroaniline - Google Patents
Purification method and application of p-nitroaniline Download PDFInfo
- Publication number
- CN111718266A CN111718266A CN201910213131.0A CN201910213131A CN111718266A CN 111718266 A CN111718266 A CN 111718266A CN 201910213131 A CN201910213131 A CN 201910213131A CN 111718266 A CN111718266 A CN 111718266A
- Authority
- CN
- China
- Prior art keywords
- nitroaniline
- filtering
- water
- purified
- paranitroaniline
- 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
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/82—Purification; Separation; Stabilisation; Use of additives
- C07C209/84—Purification
Abstract
A method for purifying p-nitroaniline and application thereof comprise the following steps: (1) dissolving: adding p-nitroaniline into an oxygen-containing polar solvent, and stirring until the p-nitroaniline is completely dissolved; (2) and (3) filtering: adding a filter aid into the solution, and filtering, wherein a filter cake is the impurities such as tar in the p-nitroaniline and the filter aid, and a filtrate is the purified p-nitroaniline solution; (3) and (3) post-treatment: adding water into the purified paranitroaniline solution for rectification, and extracting the solvent from the tower top for recycling; and the suspension of water and p-nitroaniline is taken as the tower bottom, the suspension is filtered, the filter cake is the purified p-nitroaniline, and the filtrate is water and is recycled and reused. The paranitroaniline treated by the invention is bright yellow in appearance, small in smell and not pungent, and can be directly used for catalytic hydrogenation reaction, particularly for the reaction of a noble metal catalyst, so that the continuous application of the catalyst is realized, and the product quality reaches the standard.
Description
Technical Field
The invention relates to a method for purifying p-nitroaniline and application thereof, belonging to the technical field of chemical industry.
Background
P-nitroaniline, abbreviated as PNA, is an important organic synthetic raw material, and is mainly used for preparing azo dyes and p-phenylenediamine; in addition, p-nitroaniline is used to make antioxidants of p-phenylenediamine architecture such as antioxidants 33PD, 44PD, 77PD, and the like.
The antioxidant 33PD, 44PD and 77PD is synthesized by adopting a reductive alkylation process route of p-nitroaniline and ketone, the reductive alkylation is carried out by adopting a catalytic hydrogenation mode, and the catalyst generally adopts noble metals such as palladium and platinum, wherein the platinum effect is better. The noble metal catalyst has high price and low consumption, so the requirement on raw materials is extremely high. The p-nitroaniline is a product obtained by reacting p-nitrochlorobenzene with high-concentration ammonia water at 180 ℃ under 4.5MPa for 10 hours, a certain amount of tar is inevitably generated in the long-time high-temperature and high-pressure reaction process, and the tar is fatal to a noble metal catalyst, so that the catalyst can be quickly deactivated and cannot be used indiscriminately, the product quality is low, the catalyst cost is high, and the production is seriously influenced. Since commercially available p-nitroaniline, whether wet, dry or fine, or even chemically pure or analytically pure, contains the above-mentioned tar, catalytic hydrogenation using p-nitroaniline as a raw material, particularly, a reaction using a noble metal as a catalyst, requires purification of the p-nitroaniline as a raw material to remove the tar.
The storage is reported in research on preparation process of high-purity p-nitroaniline (modern chemical engineering, 2012, (3): 33-35), that the purity of the p-nitroaniline can reach 99.9%, and the analysis method adopts gas chromatography area normalization to calculate the purity of the p-nitroaniline, and no report about a treatment method of tar contained in the p-nitroaniline is found. Yuanjunxiu et al reported in patent CN102001952A a method for preparing high-purity paranitroaniline, which was prepared by this method, the purity of paranitroaniline was as high as 99.9%, and no description was given about the method for treating the tar oil contained in paranitroaniline.
Huarenqing in patent CN1111236A reports a preparation process of odorless paranitroaniline, which comprises adding paranitroaniline into methanol or ethanol, heating to reflux and maintaining for a certain time, adding water to precipitate paranitroaniline, separating paranitroaniline from solvent, and drying to obtain odorless paranitroaniline, wherein no treatment on tar contained in paranitroaniline is required.
Friendship and cheng in patent CN105061214B, a process for producing N, N' -di-sec-butyl-p-phenylenediamine is reported, wherein the description about the treatment of p-nitroaniline tar: butanone and paranitroaniline are put into a batching kettle according to the proportion of 1.3:1.2, heated to 120 ℃, stirred for 20 minutes to dissolve the materials, then activated carbon with the particle size of 100 meshes is put into the batching kettle, stirred for 5 to 10 minutes, filtered out by a plate frame filtering device, and adhered to a filtering plate frame under the pressure action of the activated carbon, so that the activated carbon can adsorb tar in raw materials passing through the plate frame. According to the method, firstly, butanone and p-nitroaniline are heated to 120 ℃ to dissolve the materials, the boiling point of butanone is 79.6 ℃ under normal pressure, in order to reach the temperature of 120 ℃, a batching kettle must be sealed and pressure-resistant, and the equipment investment is increased; secondly, because the filtration is carried out while the filtration is hot, the filters and corresponding pipelines must be subjected to omnibearing heat tracing, the p-nitroaniline is prevented from being separated out due to temperature reduction caused by improper heat preservation, the filters and the corresponding pipelines are blocked once the p-nitroaniline is separated out, the filtration operation is difficult to carry out, and the dredging is particularly difficult due to the 147 ℃ melting point of the p-nitroaniline, so that the operability of the method in actual production is not strong, and the treatment cost is increased.
Disclosure of Invention
The invention aims to provide a method for purifying p-nitroaniline, which is characterized in that a proper solvent is selected to dissolve the p-nitroaniline but not tar, so that the tar is filtered and separated, and the aim of purifying the p-nitroaniline is fulfilled.
The main technical scheme of the invention is as follows: the p-nitroaniline purification method comprises the following steps:
(1) dissolving: adding p-nitroaniline into an oxygen-containing polar solvent, and stirring until the p-nitroaniline is completely dissolved;
(2) and (3) filtering: adding a filter aid into the solution, and filtering, wherein a filter cake is the impurities such as tar in the p-nitroaniline and the filter aid, and a filtrate is the purified p-nitroaniline solution;
(3) and (3) post-treatment: adding water into the purified paranitroaniline solution for rectification, and extracting the solvent from the tower top for recycling; and the suspension of water and p-nitroaniline is taken as the tower bottom, the suspension is filtered, the filter cake is the purified p-nitroaniline, and the filtrate is water and is recycled and reused.
In the step (1), the oxygen-containing polar solvent may be ester such as ethyl acetate, methyl acetate, etc., or ketone such as acetone, butanone, 2-pentanone, cyclohexanone, 4-methyl-2-pentanone, 5-methyl-2-hexanone, etc., preferably ketone is used as the solvent.
In the step (1), the molar ratio of the paranitroaniline to the solvent is 1: (4-20).
In the step (2), the filter aid can be diatomite or activated carbon, and the mass ratio of the paranitroaniline to the filter aid is 1: 0.01 to 0.05.
And (3) in the step (2), adding the filter aid, stirring for 30-60 minutes at room temperature, and filtering.
The steps (1) and (2) are both carried out at room temperature.
In the step (3), the mass ratio of the paranitroaniline to the deionized water is 1: (2-5).
The invention has the advantages that: (1) compared with CN105061214B, the invention has the advantages that the paranitroaniline is dissolved and filtered under room temperature and normal pressure, the operation process of high temperature and pressure is avoided, the operation is simple and convenient, and the equipment investment is less; (2) by adding a certain amount of water during the rectification and the solvent recovery, on one hand, the method plays a role in washing inorganic salt such as NH carried in the paranitroaniline4Cl and the like, on the other hand, potential safety hazards caused by direct contact of p-nitroaniline and a heating surface (the inner wall of the reactor) due to continuous evaporation of the solvent are avoided, and finally, the discharging is convenient due to the existence of water; (3) the invention does not produce waste water, and the added water can be recycled for the next batch operation. The paranitroaniline treated by the method is bright yellow in appearance, small in smell and not pungent (is yellowish brown before treatment and pungent in smell), can be directly used for catalytic hydrogenation reaction, particularly for the reaction of a noble metal catalyst, realizes continuous application of the catalyst and standard product quality, and ensures that the production is smoothly carried out, so that the method has better application prospect.
Drawings
FIG. 1 is a schematic flow chart of a method according to an embodiment of the present invention.
Detailed Description
The process of the present invention is described in detail below with reference to examples.
The following example scheme refers to figure 1.
Example 1
75g of p-nitroaniline (industrial tide, content 93%) and 280g of acetone are added into a four-neck flask at the room temperature of 30 ℃, stirred and dissolved, and a large amount of black tar is arranged at the bottom of the flask. 1g of diatomaceous earth was then added, stirring was continued for 30 minutes, and then qualitative filter paper filtration was performed on the pad in a triangular glass funnel. After filtration, adding 200mL of distilled water into the filtrate, rectifying to recover acetone, cooling when the temperature is suddenly changed from 56.5 ℃ to 82 ℃ (the liquid temperature is about 100 ℃), filtering the kettle liquid, sleeving the mother liquid for the next batch of rectified acetone, and filtering a filter cake which is 86g of p-nitroaniline tide and is bright yellow crystal without pungent smell.
Example 2
75g of paranitroaniline (industrial tide, content 93%) and 300g of acetone are added into a four-neck flask at the room temperature of 20 ℃, stirred and dissolved, and a large amount of black tar is arranged at the bottom of the flask. 1.5g of diatomaceous earth was then added, stirring was continued for 30 minutes, and qualitative filter paper filtration was then performed on the pad in a triangular glass funnel. After filtration, adding 220mL of distilled water into the filtrate, rectifying to recover acetone, cooling when the temperature is changed from 56.5 ℃ to 82 ℃ (the liquid temperature is about 100 ℃), filtering the kettle liquid, sleeving the mother liquid for the next batch of rectified acetone, and filtering a filter cake which is 82g of p-nitroaniline wet product. Bright yellow crystal, no pungent smell.
Example 3
75g of p-nitroaniline (industrial tide, content 93%) and 350g of acetone are added into a four-neck flask at the room temperature of 8 ℃, stirred and dissolved, and a large amount of black tar is arranged at the bottom of the flask. 1.5g of activated charcoal was then added, stirring was continued for 30 minutes, and qualitative filter paper was then placed on a pad in a triangular glass funnel. After filtration, adding 250mL of distilled water into the filtrate, rectifying and recovering acetone, cooling when the temperature is suddenly changed from 56.5 ℃ to 82 ℃ (the liquid temperature is about 100 ℃), filtering the kettle liquid, sleeving the mother liquor for the next batch of rectified acetone, and filtering a filter cake which is 85g of p-nitroaniline wet product. Bright yellow crystal, no pungent smell.
Example 4
75g of p-nitroaniline (industrial tide, content 93%) and 315g of butanone are added into a four-neck flask at the room temperature of 28 ℃, stirred and dissolved, and a large amount of black tar is arranged at the bottom of the flask. 1g of diatomaceous earth was then added, stirring was continued for 30 minutes, and then qualitative filter paper filtration was performed on the pad in a triangular glass funnel. After filtration, adding 200mL of distilled water into the filtrate, recovering butanone by azeotropic distillation, cooling when the temperature suddenly changes from 73.5 ℃ (the azeotropic point of butanone and water) to 88 ℃ (the liquid temperature is about 100 ℃), filtering the kettle liquid, sleeving the mother liquid for the next batch of azeotropic distillation butanone, and filtering a filter cake which is 85g of paranitroaniline wet product and is bright yellow crystal without pungent smell.
Example 5
75g of p-nitroaniline (industrial tide, content 93%) and 360g of butanone are added into a four-neck flask at room temperature of 10 ℃, stirred and dissolved, and a large amount of black tar is arranged at the bottom of the flask. 1g of activated charcoal was then added, stirring was continued for 30 minutes, and then qualitative filter paper filtration was performed on the pad in a triangular glass funnel. After filtration, adding 200mL of distilled water into the filtrate, recovering butanone by azeotropic distillation, cooling when the temperature suddenly changes from 73.5 ℃ (the azeotropic point of butanone and water) to 88 ℃ (the liquid temperature is about 100 ℃), filtering the kettle liquid, sleeving the mother liquid for the next batch of azeotropic distillation butanone, and filtering a filter cake which is 82g of p-nitroaniline wet product and is bright yellow crystal without pungent smell.
Example 6
75g of p-nitroaniline (industrial moisture, content 93%) and 720g of 5-methyl-2-hexanone (MIAK for short) are added into a four-neck flask at the room temperature of 30 ℃, stirred and dissolved, and a large amount of black tar is arranged at the bottom of the flask. 2g of diatomaceous earth was then added, stirring was continued for 30 minutes, and then qualitative filter paper filtration was performed on the pad in a triangular glass funnel. After filtration, adding 200mL of distilled water into the filtrate, performing azeotropic distillation to recover 5-methyl-2-hexanone, cooling when the temperature is suddenly changed from 94.5 ℃ (the azeotropic point of 5-methyl-2-hexanone and water) to 99 ℃ (the liquid temperature is about 105 ℃), filtering the kettle liquid, sleeving the mother liquid for the next batch of azeotropic distillation of 5-methyl-2-hexanone, and filtering a filter cake which is 82g of p-nitroaniline tide and is bright yellow crystal without pungent smell.
Example 7
75g of paranitroaniline (industrial tide, content 93%) and 8400g of ethyl acetate are added into a four-neck flask at the room temperature of 25 ℃, stirred and dissolved, and a large amount of black tar is arranged at the bottom of the flask. 2g of activated charcoal was then added, stirring was continued for 30 minutes, and then qualitative filter paper filtration was performed on the pad in a triangular glass funnel. After filtration, adding 200mL of distilled water into the filtrate, recovering ethyl acetate by azeotropic distillation, cooling when the temperature is suddenly changed from 70.5 ℃ (the azeotropic point of ethyl acetate and water) to 99 ℃ (the liquid temperature is about 110 ℃), filtering the kettle liquid, sleeving the mother liquid for the next batch of azeotropic distillation ethyl acetate, and using a filter cake which is 84g of p-nitroaniline tide and is bright yellow crystal without pungent smell.
Example 8
The p-nitroaniline tide treated by the method described in example 1 was applied to the synthesis of antioxidant 44PD (N, N' -di-sec-butyl-p-phenylenediamine), and the application of the catalyst was examined.
Sequentially adding p-nitroaniline tide (PNA for short), butanone (MEK for short) and 3% Pt/C catalyst into an autoclave, wherein the ratio of ketoamine is 6: 1 (mol ratio), each over N2、H2After replacement, the pressure is increased to 3.2MPa, stirring is started, and the temperature is increased. The reaction temperature is maintained at 85-105 ℃, the reaction is carried out for about 2 hours under the hydrogen pressure of 3.2MPa, and the temperature is reduced to the room temperature. Releasing pressure, discharging, filtering, and applying a filter cake as a catalyst to the next pot; and (3) simply distilling the filtrate under normal pressure, slowly vacuumizing when the liquid temperature reaches 110 ℃, cooling to 50 ℃ (absolute pressure is 30-40 mmHg) when the liquid temperature reaches 140 ℃, and discharging after cooling. The product is obtained by collecting the bottom liquid, and concentrating, rectifying and recovering the bottom liquid.
The catalyst is used for 15 times, the conversion rate of the paranitroaniline is 100 percent, the average content of the product is 98.07 percent, the average yield is 97.12 percent, the activity of the catalyst is not reduced, and the catalyst can be continuously used, thereby achieving the aim of the invention.
Example 9
In contrast to example 8, p-nitroaniline was used without treatment for the synthesis of antioxidant 44PD under the same reaction conditions as in example 8.
As can be seen from the above table, the paranitroaniline is not purified, and the product quality is rapidly reduced after the catalyst is used indiscriminately, which indicates that the paranitroaniline contains impurities which poison the catalyst, so the paranitroaniline must be purified, and the catalyst can be used indiscriminately.
Example 10
At 5m3700kg of p-nitroaniline (industrial tide, content 93%) and 3000kg of acetone were added to a stainless steel reaction kettle with a stirrer, stirred at 25 ℃ to dissolve, 10kg of diatomaceous earth was then added, stirring was continued for 30 minutes, and then filtration was performed through a stainless steel sintered tube filter. After filtration, 2000kg of deionized water is added into the filtrate, acetone is recovered by rectification, when the temperature is suddenly changed from 56.5 ℃ to 82 ℃ (the liquid temperature is about 100 ℃), the temperature is reduced, the kettle liquid is filtered by a centrifugal machine, the mother liquor is used for next batch of rectified acetone, the filter cake is 850kg of p-nitroaniline moist product, and the filter cake is bright yellow crystal and has no pungent smell.
The p-nitroaniline tide product is applied to synthesizing an antioxidant 77PD (N, N' -bis (1, 4-dimethylpentyl) p-phenylenediamine), and the condition of using the catalyst is examined.
At 1.5m3Sequentially adding p-nitroaniline tide, 5-methyl-2-hexanone and 3% Pt/C catalyst into the autoclave, and respectively passing through N2、H2After replacement, the pressure is increased to 3.2MPa, stirring is started, and the temperature is increased. The reaction temperature is maintained at 85-145 ℃, the reaction is carried out for about 2-4 hours under the hydrogen pressure of 3.2MPa, and the temperature is reduced to the room temperature. Releasing pressure, discharging, filtering, and applying a filter cake as a catalyst to the next pot; and (3) simply distilling the filtrate under normal pressure, slowly vacuumizing when the liquid temperature reaches 120 ℃, cooling to 50 ℃ (absolute pressure is 30-40 mmHg) when the liquid temperature reaches 140 ℃, and discharging after cooling. The product is obtained by the distillation of the solvent,the upper layer liquid is directly applied and the lower layer liquid is collected and then concentrated, rectified and recycled.
Therefore, the antioxidant 77PD is synthesized in pilot plant production by adopting the method, the catalyst can be applied mechanically, and the product quality reaches the standard.
The scope of protection of the invention is not limited to the embodiments described above, but is within the scope of protection of all variants that can be derived by a person skilled in the art, as mentioned in the claims.
Claims (9)
1. A method for purifying p-nitroaniline is characterized by comprising the following steps:
(1) dissolving: adding p-nitroaniline into an oxygen-containing polar solvent, and stirring until the p-nitroaniline is completely dissolved to form a solution;
(2) and (3) filtering: adding a filter aid into the solution, and filtering, wherein a filter cake is impurities in the p-nitroaniline and the filter aid, and a filtrate is a purified p-nitroaniline solution;
(3) and (3) post-treatment: adding the purified paranitroaniline solution into deionized water for rectification, and extracting the solvent from the tower top for recycling; and the suspension of water and p-nitroaniline is taken as the tower bottom, the suspension is filtered, the filter cake is the purified p-nitroaniline, and the filtrate is water and is recycled and reused.
2. The method according to claim 1, wherein in the dissolving step (1), the oxygen-containing polar solvent is an ester or a ketone selected from the group consisting of ethyl acetate, methyl acetate, acetone, butanone, 2-pentanone, cyclohexanone, 4-methyl-2-pentanone, and 5-methyl-2-hexanone.
3. The method according to claim 1, wherein in the dissolving step (1), the molar ratio of p-nitroaniline to solvent is 1: (4-20).
4. The method according to claim 1, wherein in the step (2), the filter aid is selected from diatomite or activated carbon.
5. The method according to claim 1, wherein in the step (2) of filtering, the mass ratio of the p-nitroaniline to the filter aid is 1: 0.01 to 0.05.
6. The method according to claim 1, wherein in the step (3), the mass ratio of the p-nitroaniline to the deionized water is 1: (2-5).
7. The method of claim 1, wherein the steps of (1) dissolving and (2) filtering are performed at room temperature.
8. The method according to claim 1, wherein in the step (2), the filtration is carried out after adding the filter aid and stirring at room temperature for 30 to 60 minutes.
9. Use of the process for the purification of p-nitroaniline according to any one of claims 1-8, characterized in that the treated p-nitroaniline is used for the preparation of antioxidants of the 33PD, 44PD, 77PD p-phenylenediamine architecture.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910213131.0A CN111718266A (en) | 2019-03-20 | 2019-03-20 | Purification method and application of p-nitroaniline |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910213131.0A CN111718266A (en) | 2019-03-20 | 2019-03-20 | Purification method and application of p-nitroaniline |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111718266A true CN111718266A (en) | 2020-09-29 |
Family
ID=72562209
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910213131.0A Pending CN111718266A (en) | 2019-03-20 | 2019-03-20 | Purification method and application of p-nitroaniline |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111718266A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114349645A (en) * | 2020-10-13 | 2022-04-15 | 中石化南京化工研究院有限公司 | Method for purifying p-phenylenediamine and application thereof |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050177003A1 (en) * | 2002-02-06 | 2005-08-11 | Dominic Vanoppen | Method for the production of amines |
| CN101376623A (en) * | 2007-08-31 | 2009-03-04 | 中国石油天然气股份有限公司 | Method for separating methyl isobutyl ketone synthetic fluid |
| CN102992985A (en) * | 2012-12-21 | 2013-03-27 | 天津大学 | Method and device for separating and recycling butanone by three-tower pressure-variable rectification and heat integration |
| CN105061214A (en) * | 2015-08-05 | 2015-11-18 | 安徽威驰化工有限责任公司 | Production process of N,N'-di-sec-butyl-1,4-phenylenediamine |
-
2019
- 2019-03-20 CN CN201910213131.0A patent/CN111718266A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050177003A1 (en) * | 2002-02-06 | 2005-08-11 | Dominic Vanoppen | Method for the production of amines |
| CN101376623A (en) * | 2007-08-31 | 2009-03-04 | 中国石油天然气股份有限公司 | Method for separating methyl isobutyl ketone synthetic fluid |
| CN102992985A (en) * | 2012-12-21 | 2013-03-27 | 天津大学 | Method and device for separating and recycling butanone by three-tower pressure-variable rectification and heat integration |
| CN105061214A (en) * | 2015-08-05 | 2015-11-18 | 安徽威驰化工有限责任公司 | Production process of N,N'-di-sec-butyl-1,4-phenylenediamine |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114349645A (en) * | 2020-10-13 | 2022-04-15 | 中石化南京化工研究院有限公司 | Method for purifying p-phenylenediamine and application thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105435815B (en) | It is used to prepare the renovation process of the catalyst of adjacent methyl cyclohexanol | |
| CN101798271A (en) | Method for preparing (+/-)-norepinephrine | |
| CN111718266A (en) | Purification method and application of p-nitroaniline | |
| CN113861052A (en) | Preparation method of 2-amino-5-chlorobenzophenone | |
| CN101863840B (en) | Preparation method of 5-amino-6-methyl benzimidazolone | |
| CN101508701B (en) | Method for preparing glyphosate by oxidizing N-(Phosphonomethyl)iminodiacetic acid with active carbon as catalyst oxygen | |
| CN103193660B (en) | Synthetic method of 4-alkoxy phenylamine compound | |
| US9206099B2 (en) | Method for producing hydrogenated biphenol | |
| CN114230510B (en) | Collinear production process of hindered amine compound | |
| EP0421046B1 (en) | Process for producing highly pure 3,3',4,4' - biphenyltetra- carboxylic acid or dianhydride thereof | |
| CN112299999B (en) | Refining method of high-purity ethyl acetate | |
| CN111454172B (en) | Production method for preparing glutaronitrile by aminolysis of ester substances | |
| CN106957235B (en) | A kind of preparation method of tamoxifen | |
| CN112479824A (en) | Method for recovering crystallization mother liquor in production process of 4-chloro-3, 5-dimethylphenol | |
| CN108147988B (en) | Preparation method of lactam compound with high chiral purity | |
| CN106748830B (en) | A kind of preparation method of 3- amino-4-fluorophenol | |
| CN102180781B (en) | Method for extracting and producing high-purity xanthohumol from residues generated by extracting hops by carbon dioxide | |
| CN109438210B (en) | Preparation method of pivalic aldehyde | |
| US20240043364A1 (en) | Method for preparing 3,3',4,4'-dicyclohexyltetracarboxylic acid and method for treating acidic wastewater | |
| CN114436944B (en) | Synthesis method of ibrutinib intermediate | |
| CN103772224B (en) | Preparation method of D-threonine | |
| CN115536548B (en) | Environment-friendly synthesis method of intermediate | |
| CN106380439A (en) | A Pd/C reduction method adopting water as a solvent for preparing indole-2-carboxylic acid | |
| CN109535063B (en) | Process for extracting carbazole from anthracene oil by coupling separation method | |
| CN114349645A (en) | Method for purifying p-phenylenediamine and application thereof |
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 |