CN108623516B - Method for improving color of aminopyralid - Google Patents
Method for improving color of aminopyralid Download PDFInfo
- Publication number
- CN108623516B CN108623516B CN201710178678.2A CN201710178678A CN108623516B CN 108623516 B CN108623516 B CN 108623516B CN 201710178678 A CN201710178678 A CN 201710178678A CN 108623516 B CN108623516 B CN 108623516B
- Authority
- CN
- China
- Prior art keywords
- aminopyralid
- product
- color
- solution
- improving
- 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
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
- C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
- C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
- C07D213/60—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D213/78—Carbon atoms having three bonds to hetero atoms, with at the most one bond to halogen, e.g. ester or nitrile radicals
- C07D213/79—Acids; Esters
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
- C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
- C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
- C07D213/60—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D213/78—Carbon atoms having three bonds to hetero atoms, with at the most one bond to halogen, e.g. ester or nitrile radicals
- C07D213/79—Acids; Esters
- C07D213/803—Processes of preparation
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a method for improving the color of aminopyralid, and aims to solve the problems that 4-amino-3, 6-dichloropyridine-2-formic acid prepared by the conventional method through electrolytic dechlorination is brownish red in appearance, and a product with light color and high purity needs to be subjected to very complicated purification processes such as repeated crystallization and the like. The invention adds oxidant into the aminopyralid sodium salt or aminopyralid potassium salt water solution, and then the obtained precipitate is filtered after acidification, thus obtaining the purified product. Compared with the existing aminopyralid separation method, the method has the advantages of simple operation, short process flow, less generated wastewater amount, capability of obviously reducing the purification cost of aminopyralid and obvious improvement significance and application value. Meanwhile, experimental results show that the invention can be used for preparing light red to white products, the content of the product is more than 96%, the product has higher purity, the product separation is simpler, the application value is higher, and the invention is worthy of large-scale popularization and application.
Description
Technical Field
The invention relates to the field of chemical engineering, in particular to the field of organic synthesis, and specifically relates to a method for improving the color of aminopyralid. The invention essentially provides a method for purifying aminopyralid, which can purify the aminopyralid so as to prepare a product with lighter color and higher purity, can greatly simplify the production process and operation, reduces the purification cost of the aminopyralid, and has obvious progress significance and higher application value.
Background
WO01/51468 discloses the use of aminopyralid as herbicides. Meanwhile, synthetic methods of aminopyralid are disclosed in patents CN1394241 and CN 101522628.
The existing synthesis method of aminopyralid is to take 4-amino-3, 5, 6-trichloropyridine-2-formic acid as raw material and to obtain the aminopyralid through electrolytic dechlorination.
Disclosure of Invention
However, the applicant found in the actual production process: 4-amino-3, 5, 6-trichloropyridine-2-formic acid is taken as a raw material, electrolysis, acidification and crystallization are carried out, the obtained 4-amino-3, 6-dichloropyridine-2-formic acid is brownish red in appearance, and products with lighter color and higher purity can be obtained only by complicated purification processes such as repeated crystallization, so that the production cost of the high-purity aminopyralid is greatly increased. Therefore, it is highly desirable to find a simple and inexpensive purification method to overcome the above problems.
The invention aims to: aiming at the problems that 4-amino-3, 5, 6-trichloropyridine-2-formic acid is adopted as a raw material, the appearance of the 4-amino-3, 6-dichloro pyridine-2-formic acid prepared by electrolytic dechlorination is brownish red, and the complicated purification process such as repeated crystallization is needed to obtain a product with lighter color and higher purity, the method for improving the color of the aminopyralid is provided. The invention adds oxidant into the aminopyralid sodium salt or aminopyralid potassium salt water solution, and then the obtained precipitate is filtered after acidification, thus obtaining the purified product. Compared with the existing aminopyralid separation method, the method has the advantages of simple operation, short process flow, less generated wastewater amount, capability of obviously reducing the purification cost of aminopyralid and obvious improvement significance and application value. Meanwhile, experimental results show that the invention can be used for preparing light red to white products, the content of the product is more than 96%, the product has higher purity, the product separation is simpler, the application value is higher, and the invention is worthy of large-scale popularization and application.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method of improving the color of aminopyralid comprising the steps of:
(1) adding oxidant into the aminopyralid sodium salt water solution or aminopyralid potassium salt water solution to obtain a first solution
(2) Acidifying the first solution, generating a precipitate in the acidified first solution to obtain a second solution, and filtering the second solution to obtain the precipitate, namely the product.
In the step 1, aminopyralid to be purified is used as a raw material to prepare a aminopyralid sodium salt aqueous solution or a aminopyralid potassium salt aqueous solution.
Based on the aminopyralid sodium salt or the aminopyralid potassium salt, the molar amount of the oxidant is 1-20% of the molar amount of the aminopyralid sodium salt or the aminopyralid potassium salt.
Preferably, the molar amount of the oxidizing agent is 3-5% of the molar amount of the aminopyralid sodium salt or the aminopyralid potassium salt.
The pH value of the aminopyralid sodium salt aqueous solution or the aminopyralid potassium salt aqueous solution is 5.0-13.0.
The oxidant is one or more of a gas oxidant and an aqueous solution oxidant.
The oxidant is one or more of hydrogen peroxide, sodium hypochlorite and chlorine.
In the step 2, the first solution is acidified to a pH value of 1-3, and precipitates are generated in the acidified first solution.
In the step 2, the first solution is acidified to a pH of 1.
At present, after electrolysis and acidification are carried out by the existing method, the obtained aminopyralid has brownish red appearance, difficult product separation and high impurity content, which affects the quality of original drugs, and the product with lighter color and higher purity needs to be subjected to very complicated purification processes such as repeated crystallization, which leads to great increase of production cost.
In order to solve the problem that the production cost is greatly increased due to the fact that a complicated purification process is required when picloram with light color and high purity is prepared, the applicant carries out a large number of researches and exploration experiments. In the experimental process, the inventor finds that the decolorizing effect cannot be realized by the conventional decolorizing agent such as activated carbon, but the inventor quite unexpectedly finds that: the addition of certain oxidizing substances to the aqueous alkali metal aminopyralid solution can greatly improve the color and quality of the final product. The applicant speculates that this may be due to the presence of intermediate states in the reaction process (electrolytic dechlorination), which is the presence of these substances, giving the product a dark brownish red colour.
Through the above unexpected findings, the inventors tried a large amount of oxidizing substances, and in general, the addition of an oxidizing agent would achieve a desirable effect, and finally obtained the technical solution of the present application, namely, provided a method for improving the color of aminopyralid, which belongs to the field of organic synthesis. In the scheme, an oxidant is added into a sodium or potassium aminopyralid aqueous solution, and then the obtained precipitate is filtered after acidification, so that light red or white aminopyralid solid can be obtained.
Further, the method comprises the following steps: adding an oxidant into the aqueous solution of the aminopyralid sodium salt or the aminopyralid potassium salt, acidifying, and filtering the obtained precipitate to obtain the product. Compared with the existing separation and purification method, the method has the advantages of simple operation, short process flow, less generated wastewater amount, capability of obviously reducing the purification cost of aminopyralid and obvious improvement significance and application value. Meanwhile, the experimental result shows that the invention can be used for preparing light red to white products, the content is more than 96 percent, the purity is higher, and the product separation is simpler.
The molar amount of the oxidant is 1-20% of the molar amount of the aminopyralid (i.e. the molar amount of the oxidant is 1-20 mol%, preferably 3-5 mol% of the molar amount of the aminopyralid) based on the aminopyralid. Generally, increasing the amount of oxidizing agent used gives better product appearance, but doing so increases purification costs and loses more product.
Meanwhile, in the step 1, in order to ensure the solubility of aminopyralid in the mother liquor, the pH value should be kept within the range of 5-13, the lower the temperature is, the higher the pH value is required, and the preferable pH value range is 7-8. In the invention, the aminopyralid sodium salt aqueous solution or the aminopyralid potassium salt aqueous solution prepared by an electrolytic method can be used as a raw material, and the aminopyralid to be purified can also be used as a raw material (the aminopyralid is prepared into the aminopyralid sodium salt aqueous solution or the aminopyralid potassium salt aqueous solution and then is operated), so that the further purification of the aminopyralid is realized.
The oxidizing agent may be one or more of a gaseous oxidizing agent (including but not limited to chlorine, ozone), a water-soluble oxidizing agent (including but not limited to hydrogen peroxide, hypochlorite). Generally, the effect of an equivalent amount of water-soluble oxidizing agent is less likely to be achieved by a gaseous oxidizing agent due to the reaction phase interface. Therefore, the oxidizing agent is preferably one or more of hydrogen peroxide, sodium hypochlorite, chlorine gas, and peracetic acid. More preferably, the oxidizing agent is hydrogen peroxide or sodium hypochlorite.
Preferably, in step 2, the first solution is acidified to pH 1, and the resulting precipitate is filtered. The pH value of the first solution is adjusted to be strong acid, which is beneficial to the precipitation of aminopyralid precipitate.
Through practical application, the invention can prepare products with light red to white, the content is more than 96 percent, and the purity is higher.
In conclusion, the invention provides a simple and cheap purification scheme, which can realize the high-efficiency purification of aminopyralid, and the purified product has a light red to white appearance and the content of more than 96 percent. Compared with the prior art, the method has the advantages of simple operation, short process flow, less generated wastewater amount, capability of obviously reducing the purification cost of aminopyralid, simple and feasible whole purification process, obvious energy-saving and emission-reduction and environment-friendly effects, obvious progress significance and application value, and large-scale popularization and application value.
Detailed Description
All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.
Any feature disclosed in this specification may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.
Example 1
After the electrolytic dechlorination reaction is finished, mother liquor of 4-amino-3, 5, 6-trichloropyridine-2-formic acid electrolytic dechlorination is obtained, the pH value of the mother liquor is adjusted to 7-8, namely, sodium salt solution of aminopyralid (namely, sodium salt solution of aminopyralid) is obtained, then 600g of the sodium salt solution (the content of 4-amino-3, 6-dichloropyridine-2-formic acid is 10%) is added into a 2L reaction bottle, oxidant (the specific type and the dosage are shown in the following table 1) is added, the mixture is acidified to the pH value of 1, filter pressing is carried out, aminopyralid is obtained, then drying is carried out, the solid is obtained, the yield is calculated, and various indexes are measured (shown in the following table 1).
Table 1 measurement results of example 1
| Serial number | Oxidizing agent | Dosage of | Content of product% | Impurity A% | Yield/g | Product index |
| 1 | Without adding | - | 95 | 0.50 | 55.4 | Brownish red, amorphous |
| 2 | Activated carbon | 3g | 95 | 0.50 | 55.2 | Brownish red, amorphous |
| 3 | 30% hydrogen peroxide | 1.6g(5％mol) | 97 | 0.02 | 55.0 | Off-white color |
| 4 | 30% hydrogen peroxide | 3.2g(10％mol) | 97 | 0.01 | 55.1 | Off-white color |
| 5 | Sodium hypochlorite 10% | 11g(5％mol) | 97 | 0.02 | 54.7 | Off-white color |
| 6 | Sodium hypochlorite 10% | 2.2g(1％mol) | 97 | 0.06 | 54.7 | Light red |
| 7 | Chlorine gas | 1g(5％mol) | 96 | 0.03 | 55.1 | Off-white color |
| 8 | Peroxyacetic acid | 1g(5％mol) | 96 | 0.05 | 55.0 | Off-white color |
The experimental results show that: the invention adopts hydrogen peroxide and sodium hypochlorite which have good effects, and the yield is approximately equivalent; similar results can be achieved with chlorine gas, but at a higher cost.
For the electrolytic dechlorination reaction, CN1394241 and CN101522628 can be referred to, and are not described herein again.
Example 2
100 g of brownish red 92% aminopyralid (namely the mass percentage content is 92%) is dissolved in a sodium hydroxide solution to ensure that the pH value of the system is 7.5, 20g of 10% sodium hypochlorite aqueous solution is added into the solution, then the solution is stirred for 1 hour, then hydrochloric acid is used for acidification until the pH value of the system is 1.0, and then the solution is centrifuged and dried to obtain 93 g of off-white aminopyralid (the content is 96%) solid.
The experimental results show that: the method can be used for purifying the brown red aminopyralid, has a good effect, can meet the requirements of industrial, large-scale and batch production, and has a good application prospect.
Aminopyralid is a herbicide technical product and can be prepared from 4-amino-3, 5, 6-trichloropyridine-2-formic acid through an electrolytic reaction. The aminopyralid in the electrolytic reaction system generates side reaction to generate a substance with dark brown-red color, the aminopyralid product is separated out after the reaction is finished and is acidified by hydrochloric acid, and then the finished product is obtained by filter pressing and drying. Due to the influence of impurities, the appearance of the finished product is brownish red or dark red solid, the product is difficult to separate, the content of the impurities is high, and the quality of the original medicine is influenced.
The invention provides a new purification scheme, so that the product is separated from a reaction system, the appearance of the product is white-like to light red, the impurity content is reduced by more than 80%, the product separation is relatively simpler, and the quality of the original medicine is higher. Meanwhile, the time results show that: the oxidant is added into the neutral reaction liquid, the neutral reaction liquid is evenly stirred and then reacts for a period of time, generally 1 to 2 hours, at the temperature of between 10 and 80 ℃, impurities are reduced to be below 0.10 percent, and the color of the solution is lightened. The solution is acidified, filter-pressed and dried to obtain a finished product of aminopyralid. The whole process is conventional operation, the engineering realization difficulty is low, and the method has high application value and application prospect.
The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.
Claims (7)
1. A method for improving the color of aminopyralid is characterized by comprising the following steps:
(1) adding an oxidant into a aminopyralid sodium salt aqueous solution or a aminopyralid potassium salt aqueous solution to obtain a first solution; the oxidant is one or more of hydrogen peroxide, sodium hypochlorite, chlorine and peroxyacetic acid;
(2) acidifying the first solution, generating a precipitate in the acidified first solution to obtain a second mixture, and filtering the second mixture to obtain the precipitate, namely the product.
2. The method for improving the color of aminopyralid according to claim 1, wherein in step 1, the aminopyralid to be purified is used as a raw material to prepare an aqueous solution of a sodium salt of aminopyralid or an aqueous solution of a potassium salt of aminopyralid.
3. The method for improving the color of aminopyralid according to claim 1 or 2, wherein the molar amount of the oxidizing agent is 1-20% of the molar amount of the sodium or potassium aminopyralid, based on the sodium or potassium aminopyralid.
4. The method for improving the color of aminopyralid according to claim 3, wherein the oxidant is used in a molar amount of 3-5% of the molar amount of the sodium or potassium aminopyralid.
5. The method for improving the color of aminopyralid according to any one of claims 1, 2 and 4, wherein the pH value of the aqueous solution of the sodium salt of aminopyralid or the potassium salt of aminopyralid is 5.0-13.0.
6. The method for improving the color of aminopyralid according to any one of claims 1, 2 and 4, characterized in that in the step 2, the first solution is acidified to a pH value of 1-3, and precipitates are generated in the acidified first solution.
7. The method for improving the color of aminopyralid according to claim 6, wherein in step 2, the first solution is acidified to a pH of 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710178678.2A CN108623516B (en) | 2017-03-23 | 2017-03-23 | Method for improving color of aminopyralid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710178678.2A CN108623516B (en) | 2017-03-23 | 2017-03-23 | Method for improving color of aminopyralid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108623516A CN108623516A (en) | 2018-10-09 |
| CN108623516B true CN108623516B (en) | 2020-08-04 |
Family
ID=63707373
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710178678.2A Active CN108623516B (en) | 2017-03-23 | 2017-03-23 | Method for improving color of aminopyralid |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108623516B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1816526A (en) * | 2003-07-02 | 2006-08-09 | 巴斯福股份公司 | In-situ treatment of pyridine-2,3-dicarboxylic acid esters with an oxidizing agent |
| CN105461622A (en) * | 2015-12-24 | 2016-04-06 | 山东埃森化学有限公司 | Method for preparing 4-amino-3,6-dichloropicolinic acid by reducing 4-amino-3,5,6-trichloropicolinic acid |
| CN105803481A (en) * | 2016-03-22 | 2016-07-27 | 浙江埃森化学有限公司 | Method for preparing 4-amidogen-3,6-dichloropyridine-2-formic acid by means of catalytic electrolysis |
-
2017
- 2017-03-23 CN CN201710178678.2A patent/CN108623516B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1816526A (en) * | 2003-07-02 | 2006-08-09 | 巴斯福股份公司 | In-situ treatment of pyridine-2,3-dicarboxylic acid esters with an oxidizing agent |
| CN105461622A (en) * | 2015-12-24 | 2016-04-06 | 山东埃森化学有限公司 | Method for preparing 4-amino-3,6-dichloropicolinic acid by reducing 4-amino-3,5,6-trichloropicolinic acid |
| CN105803481A (en) * | 2016-03-22 | 2016-07-27 | 浙江埃森化学有限公司 | Method for preparing 4-amidogen-3,6-dichloropyridine-2-formic acid by means of catalytic electrolysis |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108623516A (en) | 2018-10-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108341776B (en) | Process for synthesizing chloroquinate | |
| CN102633686A (en) | Preparation method of peramivir | |
| CN102250261B (en) | New method for producing iron dextran | |
| CN108191688A (en) | A kind of method synthesized and crystallize D-VB5 calcium | |
| CN109678744B (en) | Method for continuously preparing glycine | |
| US8680329B2 (en) | Process for preparation of α-ketoglutaric acid | |
| CN104817468B (en) | A kind of preparation method of glycine | |
| CN108623516B (en) | Method for improving color of aminopyralid | |
| CN105837432A (en) | Novel preparation method of 3,5-dichlorobenzoyl chloride | |
| CN101781264A (en) | Production method of 1-methyl-5-mercapto-1,2,3,4-tetrazole | |
| CN106349108B (en) | A kind of isolation and purification method of cyanoacetic acid | |
| CN110590719A (en) | Green method for preparing 2-furoic acid | |
| CN105085469B (en) | A kind of preparation method of the carboxylic acid of 5 chlorothiophene 2 | |
| CN110372528B (en) | Method for purifying valine | |
| CN105175316B (en) | A kind of method for preparing laxative picosulfate sodium | |
| CN112898225A (en) | Synthesis method of 1, 2-benzisothiazolin-3-ketone | |
| CN108423692B (en) | Method for purifying and refining sodium chloride by using waste salt generated in vitamin C production | |
| CN104513151B (en) | A kind of method extracting high purity butylene diacid from succinate fermentation liquid | |
| CN102020576A (en) | High-purity glutamic acid and preparation method thereof | |
| CN103087018A (en) | Preparation method of erythorbic acid | |
| CN112142727B (en) | Imazapyr methyl intermediate and preparation method and application thereof | |
| CN112625463B (en) | Salting-out refining method for synthetic edible pigment | |
| CN107652195A (en) | A kind of preparation method of 1 amino cyclopropanecarboxylic acid | |
| CN111153853B (en) | Preparation method of 2-chloronicotinic acid | |
| CN107778226B (en) | A kind of purification process of 4- amino -3,6- dichloropyridine -2- formic acid |
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 |