CN101891634B - Method for purifying pendimethalin - Google Patents
Method for purifying pendimethalin Download PDFInfo
- Publication number
- CN101891634B CN101891634B CN 201010231419 CN201010231419A CN101891634B CN 101891634 B CN101891634 B CN 101891634B CN 201010231419 CN201010231419 CN 201010231419 CN 201010231419 A CN201010231419 A CN 201010231419A CN 101891634 B CN101891634 B CN 101891634B
- Authority
- CN
- China
- Prior art keywords
- pendimethalin
- reaction
- thiocyanate
- content
- purification
- 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
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a method for purifying pendimethalin, which comprises the following steps of: adding coarse product of pendimethalin, thiocyanate and hydrochloric acid into a reaction container according to a mass ratio of 7-10:1:3-5; performing reflux reaction at the temperature of between 75 and 81 DEG C for 6 to 15 hours under normal pressure, adding the thiocyanate again in the reaction process for continuous reaction until the content of N-nitrosamine compound is less than 10ppm, and taking an oil layer after the reaction is finished; and washing the oil layer with water, alkali and water in turn and controlling the temperature to between 60 and 90 DEG C under the vacuum condition for removing a solvent so as to obtain the pendimethalin. The method for purifying the pendimethalin has the advantages that: due to the existence of the aid thiocyanate, the speed of the reaction for removing the N-nitrosamine compound is high, and the content of the N-nitrosamine compound is less than 20ppm; because the reaction temperature is controlled at the reflux temperature, the method does not need to be operated under the pressure condition, and can reduce the operating difficulty and equipment requirement and improve the operating safety.
Description
Technical field
The present invention is a kind of method of purification of weedicide, is a kind of method of purification of pendimethalin specifically.
Background technology
Pendimethalin (Pendimethalin), its chemical name: N-(ethyl propyl)-3,4-dimethyl-2,6-dinitraniline; Be a kind of dinitroaniline herbicide, be applicable to annual gramineous weed and some broadleaf weeds.Because the herbicidal effect of pendimethalin product is good, safe, thereby has obtained to apply widely.
Current technology is starting raw material with 3,4-dimethyl nitrobenzene, through hydrogenating reduction, with propione carry out alkylated reaction, again through nitration reaction, take off nitroso-group reaction and make the product pendimethalin.In US Patent No. .Patent4136117, US Patent No. .Patent4621157, put down in writing the poisonous N-nitroso-group by product that to supervene in the nitration reaction process of this technique about 20%.In Adv.Cancer.Res.1967.10:163 (" forward position cancer research " 1967 October the 163rd page), put down in writing these N-nitrosamine compounds many animals have been had carcinogenesis.Soon in Nature .1970.225:21 (" nature " 21 phases of 225 volumes in 1970), be proved again these N-nitrosamine compounds subsequently human body is also had carcinogenesis.At " Chemical Analysis " .Vol.37.No.4., Apr.2001 put down in writing in (in the 4th phase of the 37th volume in April calendar year 2001 " Chemical Analysis ") because the N-nitrosamine compound that produces in this technique is difficult to volatilization, and in soil, be difficult for degraded, easily be trapped in the soil by plant absorbing; Thereby must remove the N-nitrosamine compound.The related scientific research mechanism of countries in the world and manufacturing enterprise all carried out research to this, US Patent No. .Patent5196585 etc. have introduced and have added the generation that sulphite, dithionate etc. are organized by product in the nitrifying process, but the content that adopts N-nitrosamine compound after the method is still more than 10%; US Patent No. 4136117 grades were reported under the condition of 80～82 ℃ of nitrated rear employing thionamic acid and 37.7% hydrochloric acid reaction 6 hours, and the content of N-nitrosamine compound can reach 0.1%; US Patent No. 5922915 grades are reported in the temperature to 170 that improves material under the existence of urea and nitrogen～180 ℃ of contents that can make the N-nitrosamine compound, but cause the decomposition of target product under the hot conditions, have reduced the purity of product pendimethalin; Adopt propione and concentrated hydrochloric acid and nitrated rear material reaction, 80～88 ℃ of temperature, pressure 1～2kg/cm in the US Patent No. 4391992
2Condition under can reduce the content of N-nitrosamine compound.But owing to require to reach this pressure under hydrochloric acid medium, the condition of equipment material is harsh, has increased the difficulty of operation and the security of operation.
In recent years, along with the reinforcement of the whole world to Consciousness of food security, the specification of quality of Pesticidal products is improved gradually, in fact the content's index of N-nitrosamine compound has become the main restraining factors of this production development and outlet in the pendimethalin product.Need a kind of new processing method that removes the N-nitrosamine compound in the pendimethalin product.
Summary of the invention
Goal of the invention: in order to overcome the deficiencies in the prior art, the object of the present invention is to provide a kind of simple to operate, safe, can fast eliminating the method for purification of pendimethalin of N-nitrosamine compound.
Technical scheme: in order to solve the problems of the technologies described above, the technical solution used in the present invention is: a kind of method of purification of pendimethalin, the method comprises the steps:
(1) feed intake: be 7～10 with pendimethalin crude product, thiocyanate-, hydrochloric acid according to mass ratio: 1: 3～5 drop in the reaction vessels;
(2) reaction: back flow reaction is 6～15 hours under 75～81 ℃, normal pressure, and reacting the content that detected the N-nitrosamine compound in 6～15 hours in the process, when being 100～200ppm, N-nitrosamine compound content adds thiocyanate-, this moment, the additional amount of thiocyanate-was 0.25～0.5 times of thiocyanate-add-on in the step (1), then continue reaction, until the content of N-nitrosamine compound is got oil reservoir after reaction finishes during less than 10ppm;
(3) make with extra care: the oil reservoir that obtains after step (2) reaction is finished after washing, alkali cleaning and washing, is controlled 60～90 ℃ of temperature and is carried out desolvation successively under vacuum condition, namely obtain described pendimethalin.
Described thiocyanate-is Sodium Thiocyanate 99 or ammonium thiocyanate.
Pendimethalin crude product described in the step (1) is for after nitrated and be dissolved in pendimethalin crude product in the ethylene dichloride solvent, and the weight content of ethylene dichloride solvent is 60% in the described pendimethalin crude product.
The mass concentration of hydrochloric acid is 25～35% described in the step (1).
Adopt liquid chromatography to follow the tracks of the content that detects the N-nitrosamine compound in the step (2).
In the step (3), vacuum tightness is-0.01MPa.
The present invention is take after nitrated and be dissolved in pendimethalin crude product in the ethylene dichloride solvent as raw material, in the presence of hydrochloric acid, removes the N-nitrosamine compound under the condition take thiocyanate-as auxiliary agent and prepares highly purified pendimethalin product.
Beneficial effect: compared with prior art, the present invention has the following advantages: because the existence of auxiliary agent thiocyanate-, the speed of response that removes the N-nitrosamine compound is very fast, can make the content of N-nitrosamine compound less than 20ppm; Because temperature of reaction is controlled at reflux temperature, need to not operate having under the condition of pressure, can reduce the requirement of operation easier and equipment, can increase operational security.
Embodiment
The present invention is further described below by specific embodiment; should be pointed out that for the person of ordinary skill of the art, under the prerequisite that does not break away from the principle of the invention; can also make some modification and improvement, these also should be considered as belonging to protection scope of the present invention.
Embodiment 1:
Be equipped with stir and the glass there-necked flask of heating unit in to add 0.25g pendimethalin crude product, 0.03g Sodium Thiocyanate 99,0.125g mass concentration be 31% hydrochloric acid refluxed 15 hours in 80 ℃, added the 0.01g Sodium Thiocyanate 99 in 8 hours reacting.Liquid chromatography is followed the tracks of the N-nitrosamine less than 10ppm, after reaction finishes oil reservoir through washing, alkali cleaning and again after the washing vacuum tightness for the condition of-0.01Mpa under the control temperature obtain the finished product pendimethalin less than 90 ℃ of desolvations, the mass content of described pendimethalin is that 96.7%, N-content of nitrosamines is less than 16ppm.
The pendimethalin crude product is for after nitrated and be dissolved in pendimethalin crude product in the ethylene dichloride solvent in the present embodiment, and the weight content of ethylene dichloride solvent is 60% in this pendimethalin crude product.
Embodiment 2:
Be equipped with stir and the glass there-necked flask of heating unit in to add 5g pendimethalin crude product, 0.71g Sodium Thiocyanate 99,2.13g mass concentration be 31% hydrochloric acid refluxed 15 hours in 80 ℃, added the 0.23g Sodium Thiocyanate 99 in 8 hours reacting.Liquid chromatography is followed the tracks of the N-nitrosamine less than 10ppm, and oil reservoir was through washing, alkali cleaning with wash the final vacuum degree again and obtain the finished product pendimethalin for 60～90 ℃ temperature desolvation under the-0.01Mpa after reaction finished.The mass content of described pendimethalin is that 96.2%, N-content of nitrosamines is less than 5ppm.
The pendimethalin crude product is for after nitrated and be dissolved in pendimethalin crude product in the ethylene dichloride solvent in the present embodiment, and the weight content of ethylene dichloride solvent is 60% in this pendimethalin crude product.
Embodiment 3:
Adding 40kg pendimethalin crude product, mass concentration and be 31% hydrochloric acid 12kg, Sodium Thiocyanate 99 4.0kg in the 100L reactor stirs in 75 ℃ and adds ammonium thiocyanate 1.6kg after refluxing 8 hours, N-nitrosamine compound content continues to reflux 7 hours between 100～200ppm at this moment.Liquid-phase chromatographic analysis N-content of nitrosamines is less than 10ppm, and reaction finishes.Be lower than 90 ℃ temperature vacuum tightness through control after the washing of routine, alkali cleaning, the washing and obtain the finished product pendimethalin for desolvation under the-0.01Mpa, the mass content of gained pendimethalin is 96.4%, and the N-content of nitrosamines is less than 10ppm.
Embodiment 4:
Adding 40kg pendimethalin crude product, mass concentration and be 31% hydrochloric acid 20kg, ammonium thiocyanate 4.0kg in the 100L reactor stirs in 81 ℃ and adds ammonium thiocyanate 1.0kg after refluxing 8 hours, N-nitrosamine compound content continues to reflux 7 hours between 100～200ppm at this moment.Liquid-phase chromatographic analysis N-content of nitrosamines is less than 10ppm, and reaction finishes.Be lower than through control after the washing of routine, alkali cleaning, the washing that desolvation obtains the finished product pendimethalin under 90 ℃ the temperature vacuum, the mass content of gained pendimethalin is that 96.2%, N-content of nitrosamines is less than 10ppm.
Embodiment 5: substantially the same manner as Example 1, difference is that the mass concentration of hydrochloric acid is 25%.
Embodiment 6: substantially the same manner as Example 2, difference is that the mass concentration of hydrochloric acid is 35%.
Claims (6)
1. the method for purification of a pendimethalin is characterized in that, the method comprises the steps:
(1) feed intake: be 7～10 with pendimethalin crude product, thiocyanate-, hydrochloric acid according to mass ratio: 1: 3～5 drop in the reaction vessels;
(2) reaction: back flow reaction is 6～15 hours under 75～81 ℃, normal pressure, and reacting the content that detected the N-nitrosamine compound in 6～15 hours in the process, when being 100～200ppm, N-nitrosamine compound content adds thiocyanate-, this moment, the additional amount of thiocyanate-was 0.25～0.5 times of thiocyanate-add-on in the step (1), then continue reaction, until the content of N-nitrosamine compound is got oil reservoir after reaction finishes during less than 10ppm;
(3) make with extra care: the oil reservoir that obtains after step (2) reaction is finished after washing, alkali cleaning and washing, is controlled 60～90 ℃ of temperature and is carried out desolvation successively under vacuum condition, namely obtain described pendimethalin.
2. the method for purification of a kind of pendimethalin according to claim 1 is characterized in that, described thiocyanate-is Sodium Thiocyanate 99 or ammonium thiocyanate.
3. the method for purification of a kind of pendimethalin according to claim 1, it is characterized in that, pendimethalin crude product described in the step (1) is for after nitrated and be dissolved in pendimethalin crude product in the ethylene dichloride solvent, and the weight content of ethylene dichloride solvent is 60% in the described pendimethalin crude product.
4. the method for purification of a kind of pendimethalin according to claim 1 is characterized in that, the mass concentration of hydrochloric acid is 25～35% described in the step (1).
5. the method for purification of a kind of pendimethalin according to claim 1 is characterized in that, adopts liquid chromatography to follow the tracks of the content that detects the N-nitrosamine compound in the step (2).
6. the method for purification of a kind of pendimethalin according to claim 1 is characterized in that, in the step (3), vacuum tightness is-0.01MPa.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010231419 CN101891634B (en) | 2010-07-20 | 2010-07-20 | Method for purifying pendimethalin |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010231419 CN101891634B (en) | 2010-07-20 | 2010-07-20 | Method for purifying pendimethalin |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101891634A CN101891634A (en) | 2010-11-24 |
| CN101891634B true CN101891634B (en) | 2013-04-03 |
Family
ID=43101011
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201010231419 Active CN101891634B (en) | 2010-07-20 | 2010-07-20 | Method for purifying pendimethalin |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101891634B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102701989B (en) * | 2012-05-24 | 2013-11-13 | 山东华阳农药化工集团有限公司 | Method for removing nitrosamine from dinitroaniline herbicides |
| CN105315162A (en) * | 2014-07-23 | 2016-02-10 | 江苏永安化工有限公司 | Novel method used for increasing pendimethlin purity |
| CN109320424B (en) * | 2017-07-31 | 2021-12-21 | 江苏永安化工有限公司 | Method for purifying pendimethalin |
| CN109970573B (en) * | 2019-05-17 | 2021-10-15 | 江苏永安化工有限公司 | Method for removing N-nitroso compound from pendimethalin |
| CN112379030A (en) * | 2020-11-18 | 2021-02-19 | 山东华阳农药化工集团有限公司 | Preparation method of N-nitroso pendimethalin standard sample and accurate determination method of nitrite in pendimethalin product |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5196585A (en) * | 1990-10-02 | 1993-03-23 | Dowelanco | Process for treating dinitroanilines with sulfite to reduce impurities and to reduce the ability to produce nitrosamines |
| CN101070287A (en) * | 2007-06-07 | 2007-11-14 | 吉化集团公司 | Process for removing N-nitroso-pendimethalin from pendimethialin |
-
2010
- 2010-07-20 CN CN 201010231419 patent/CN101891634B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5196585A (en) * | 1990-10-02 | 1993-03-23 | Dowelanco | Process for treating dinitroanilines with sulfite to reduce impurities and to reduce the ability to produce nitrosamines |
| CN101070287A (en) * | 2007-06-07 | 2007-11-14 | 吉化集团公司 | Process for removing N-nitroso-pendimethalin from pendimethialin |
Non-Patent Citations (1)
| Title |
|---|
| 刘庆文.二甲戊乐灵清洁工艺研究.《中国优秀硕士学位论文全文数据库（电子期刊）工程科技I辑》.2006,(第9期),B016-101. * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101891634A (en) | 2010-11-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101891634B (en) | Method for purifying pendimethalin | |
| CN102285891B (en) | Method for preparing arylamine by catalytic hydrogenation of aromatic nitro compound | |
| CN102225935B (en) | Manufacturing method of proPiconazole | |
| CN103626691B (en) | The preparation method of ZEN 90160 | |
| CN102180834B (en) | Preparation method for edaravone | |
| CN108069831B (en) | Method for synthesizing 2, 3-dimethyl-4-fluorophenol | |
| EP1857434B1 (en) | Method for producing xylylenediamine | |
| CN103130657A (en) | Synthetic method of 2-chloro-4-aminophenol | |
| CN101575269A (en) | Preparation method of aromatic methyl ether compound | |
| CN106565425B (en) | Method for recovering catechol and levodopa from levodopa mother liquor | |
| CN102898422A (en) | Method for preparing difenoconazole | |
| CN103113240B (en) | Process for directly synthesizing p-aminophenol through hydrogenation of nitrobenzene | |
| CN110683959B (en) | Synthetic method of 2,4, 6-trifluorobenzylamine | |
| CN106008378A (en) | Preparation method of benzotriazole ultraviolet light absorber | |
| CN108892618A (en) | A kind of preparation method and applications of pair of nitrobenzyl alcohol | |
| CN104230838B (en) | The preparation method of agricultural insecticide indoxacarb high purity key intermediate | |
| CN104496761A (en) | Bisphenol A preparation method | |
| CN106699522A (en) | Production process of high-quality trimethyl orthoacetate | |
| CN106083749A (en) | A kind of preparation method of Benzotriazole Ultraviolet Stabilizer | |
| JPS584750A (en) | Preparation of high purity aniline | |
| CN109053585B (en) | Synthetic method of triclabendazole | |
| CN104974061A (en) | Preparation method of balsalazide disodium | |
| CN103880717A (en) | Preparation method of bis(3-allyl-4-hydroxy phenyl) sulfone and derivative thereof | |
| CN106316861B (en) | A kind of method for preparing double benzene bacterium amine | |
| CN108069834A (en) | A kind of method that serialization prepares 3,4 ' dichloro-diphenyl ethers |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee |
Owner name: JIANGSU YONGAN CHEMICAL CO., LTD. Free format text: FORMER NAME: LIANSHUI YONGAN CHEMICAL CO., LTD. |
|
| CP03 | Change of name, title or address |
Address after: 223400 Zhu Zhen, Lianshui County, Jiangsu City, Huaian Province Patentee after: JIANGSU YONGAN CHEMICAL CO., LTD. Address before: 223400, Huaian City, Jiangsu province Lianshui County town of Lianshui Yongan Chemical Co., Ltd. Patentee before: Lianshui Yongan Chemical Co., Ltd. |