CN109912502A - A kind of method that pyridine liquid phase Light chlorimation prepares 2,6- dichloropyridine - Google Patents
A kind of method that pyridine liquid phase Light chlorimation prepares 2,6- dichloropyridine Download PDFInfo
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- CN109912502A CN109912502A CN201910165588.9A CN201910165588A CN109912502A CN 109912502 A CN109912502 A CN 109912502A CN 201910165588 A CN201910165588 A CN 201910165588A CN 109912502 A CN109912502 A CN 109912502A
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Abstract
Use 4-Chlorobenzotrifluoride for solvent the present invention relates to a kind of, 2- chloropyridine and chlorine are raw material, prepare the 2 of product purity >=99.0%, the production method of 6- dichloropyridine, using 2- chloropyridine, chlorine as starting material, 4-Chlorobenzotrifluoride is solvent, continuous feed carries out liquid phase chlorination reaction under 150 DEG C~200 DEG C temperature, ultraviolet lights, chlorated liquid is obtained, 2,6- dichloropyridine content >=97% in pyridinium chloride therein, chlorated liquid is by thick steaming, Crystallization Separation or rectification and purification process, 2, the 6- dichloropyridine of purity >=99.0% is obtained, yield is greater than 90%.Advantage: reaction generates 2,6- dichloropyridine selectivity height, and solvent is added and overcomes the susceptible to plugging problem of reaction unit exhaust pipe, reaction process is easy to control, is advantageously implemented industrialized production.
Description
Technical field
Use 4-Chlorobenzotrifluoride for solvent the present invention relates to a kind of, 2- chloropyridine and chlorine are raw material, and it is pure to prepare product
The production method of the 2,6- dichloropyridine of degree >=99.0%.
Background technique
2,6- dichloropyridines are important industrial chemicals, can produce a variety of fine chemical products by 2,6- dichloropyridine,
It is widely used in medicine, filed of daily-use chemical industry and Novel insecticidal pesticide etc..
2,6- dichloropyridine is the raw material for producing 2,3,5,6- 4 chloro pyridine, trichloro pyridyl sodium alcoholate, 2,3- dichloropyridine.Three
Chloropyridine sodium alkoxide is the key intermediate for producing novel pesticide chlopyrifos, and 2,3- dichloropyridines are production novel pesticide chlorine worms
The key intermediate of benzamide.
The existing main synthetic method of 2,6- dichloropyridines has: pyridine solution gas phase light chlorination process, obtained main production
Object is 2- chloropyridine and 2,6- dichloropyridine mixture, and 2,6- dichloropyridine ratios are generally 10% or so, and chloride material needs logical
It crosses the series of steps such as neutralization, thick steaming and rectifying and isolates and purifies 2,6- dichloropyridine, generate a large amount of waste water and abraum salt, three wastes disposition
It is at high cost.
2- chloropyridine liquid phase light chlorination process, the conversion ratio about 96% of 10 hours 2- chloropyridine liquid of this method, 2,6- dichloropyridines
Yield about 93%, since pyridinium chloride easily distils, the material that distils with reaction end gas enters exhaust pipe, cold in the duct
But solid is sublimated into, exhaust pipe is blocked, causes production that cannot continue.
Summary of the invention
Purpose of design: avoiding the shortcoming in background technique, designs a kind of new method for preparing 2,6- dichloropyridine, should
New method can fundamentally overcome the pyridine liquid for the disadvantages of reaction mass distillation blocking exhaust pipe is deposited in existing preparation method
The method that phase Light chlorimation prepares 2,6- dichloropyridine.
Design scheme: in order to realize above-mentioned purpose of design.1, the present invention uses 4-Chlorobenzotrifluoride for the design of solvent, is
One of technical characteristic of the invention.The purpose of this design is: solvent steam raising at the reaction temperatures, and distillation material one
It rises and enters exhaust pipe with reaction end gas, be condensed into liquid in the duct, the pyridinium chloride for sublimating into solid is dissolved, is entered
Gas-liquid separator, it is ensured that reaction end gas pipeline is unimpeded.2, the present invention uses 4-Chlorobenzotrifluoride for the design of solvent, is the present invention
One of technical characteristic.The purpose of this design is: solvent gasifies at the reaction temperatures since pyridine chlorination is exothermic reaction
Evaporation, takes away reaction heat in time, avoids chlorination reaction system from overheating, keeps reaction process easily controllable, be advantageously implemented industrialization
Production.
Technical solution: a kind of method of 2- chloropyridine liquid phase Light chlorimation preparation 2,6- dichloropyridine, with 2- chloropyridine, chlorine
For starting material, 4-Chlorobenzotrifluoride etc. is solvent, and Continuous Liquid Phase chlorine is carried out under 150 DEG C~200 DEG C temperature, ultraviolet lights
Change reaction, obtains chlorated liquid, 2,6- dichloropyridine content >=97% in pyridinium chloride therein.Chlorated liquid is by thick steaming, crystallization
The purification process such as separation or rectifying, obtain 2, the 6- dichloropyridine of purity >=99.0%, yield 93%.
Compared with the background technology, the present invention, reaction generates 2,6- dichloropyridine selectivity height, and solvent is added and overcomes reaction
The susceptible to plugging problem of device exhaust pipeline, reaction process is easy to control, is advantageously implemented industrialized production.
Specific embodiment
A kind of 2- chloropyridine liquid phase Light chlorimation preparation process is as follows: solvent is previously added in optical chlorinating reaction device, heating rises
Temperature opens the ultraviolet lamp of optical chlorinating reaction device to 150 DEG C, and chlorine is passed through optical chlorinating reaction device, while by 2- chloropyridine, three
The solution pump that methyl fluoride trichloro-benzenes is made into proportion is added to optical chlorinating reaction device, carries out Continuous Liquid Phase chlorination under light illumination
Reaction controls 150 DEG C~200 DEG C of reaction temperature, and reacting rear material overflows to reaction collection, goes slightly to steam distillation.Tail gas warp
Aqueous alkali discharges after absorbing.
Chlorination reaction liquid steams separating tar through thick, and simple distillation point is separated through rectifying again, obtains 2, the 6- bis- of purity >=99.0%
Chloropyridine or the filtering of simple distillation lease making crystallisation by cooling, filter cake rectifying remove solvent, obtain 2, the 6- dichloro pyrrole of purity >=99.0%
Pyridine, filtrate, which directly covers, uses lower batch reaction, or passes through rectificating method recycling design and portioned product, 2,6- dichloropyridine yields
93%。
Embodiment 1: a kind of method of 2- chloropyridine liquid phase Light chlorimation preparation 2,6- dichloropyridine, with 2- chloropyridine and chlorine
For starting material, using trifluoromethyl dichloro-benzenes as solvent, make that 2- chlorine gives a tongue-lashing pyridine and chlorine is carried out continuously chlorine under the irradiation of ultraviolet light
Change reaction, obtained 2- chloropyridine chlorated liquid.
In the present embodiment, the weight proportion of 2- chloropyridine and solvent is 1: 0.1~4.When originating chlorination reaction, chlorination is reacted
It is previously added a certain amount of solvent in reactor, heats to 150 DEG C or more, is then continuously passed through chlorine, while continuous drop
Add the solution of the 2- chloropyridine and solvent prepared in proportion, controls reaction temperature in the range of 150 DEG C~200 DEG C, reaction solution
Continuous discharge is to chlorination collection or crude steam kettle.Originate chlorination reaction when solvent adding amount be reactor volume 10%~
80%, the inventory of chlorine is 0.62~1 times of 2- chloropyridine weight.Ultraviolet lighting wavelength is the ultraviolet source of 254~400nm
Or blue-light source.Solvent includes but is not limited to trifluoromethyl monochloro-benzene, trifluoromethyl dichloro-benzenes, trifluoromethyl trichloro-benzenes.
It reacts chlorated liquid and steams separating tar through thick, simple distillation point is separated through rectifying again, obtains 2, the 6- bis- of purity >=99.0%
Chloropyridine.
2- chloropyridine liquid phase Light chlorimation prepares 2,6- dichloropyridine condition test data
。
Embodiment 2: liquid phase Light chlorimation method described in above-described embodiment can also be implemented using discontinuous method.
For example:
Example 1:
1, into 500ml overflow flask be added 100g(about 62.5ml) trifluoromethyl trichloro-benzenes be bottom material, opened after being warming up to 150 DEG C
Begin logical chlorine 630ml/min, opens ultraviolet lamp.
2, start that 91% 2- chloropyridine trifluoromethyl trichlorobenzene solution is added dropwise, control rate of addition is 2.6ml/min, with anti-
Should carry out temperature can be gradually increasing, and the final reaction temperature that controls is at 160~200 DEG C.
3, reaction solution, which rises to after overflow port, begins with reaction solution and flows out to 2000ml receiving flask, continues that 91% 2- chlorine pyrrole is added dropwise
Pyridine trifluoromethyl trichlorobenzene solution, until solution (2- chloropyridine 1750g, trifluoromethyl trichloro-benzenes 175g) is added dropwise.
4, the reaction solution of taking-up is evaporated under reduced pressure after reaction, until being steamed without obvious fraction.Raffinate is tar,
Weighing.
5, steam fraction heating melting, then under stiring slow cooling to 10 DEG C hereinafter, 10 DEG C or less continue keep the temperature stir
1h is mixed until product filters after being sufficiently precipitated.
6, filter cake rectifying removes solvent, obtains 2, the 6- dichloropyridine product of purity >=99.0%.Filtrate, which directly covers, uses
Lower batch reaction.
2- chloropyridine liquid phase Light chlorimation prepares the experimental test data of 2,6- dichloropyridine (different temperatures)
。
Example 2:
1, into 500ml overflow flask be added 100g(about 62.5ml) trifluoromethyl trichloro-benzenes be bottom material, opened after being warming up to 150 DEG C
Begin logical 520~840ml/min of chlorine, opens ultraviolet lamp.
2, start that 91% 2- chloropyridine trifluoromethyl trichlorobenzene solution is added dropwise, control rate of addition is 2.6ml/min, with anti-
Should carry out temperature can be gradually increasing, and the final reaction temperature that controls is at 190 DEG C.
3, reaction solution, which rises to after overflow port, begins with reaction solution and flows out to 2000ml receiving flask, continues that 91% 2- chlorine pyrrole is added dropwise
Pyridine trifluoromethyl trichlorobenzene solution, until solution (2- chloropyridine 1750g, trifluoromethyl trichloro-benzenes 175g) is added dropwise.
4, the reaction solution of taking-up is evaporated under reduced pressure after reaction, until being steamed without obvious fraction.Raffinate is tar,
Weighing.
5, simple distillation divides rectifying removing solvent and other components, obtains 2, the 6- dichloropyridine product of purity >=99.0%.
2- chloropyridine liquid phase Light chlorimation prepares the experimental test data of 2,6- dichloropyridine (different amount of chlorine)
。
Example 3:
1, into 500ml overflow flask be added 100g(about 62.5ml) trifluoromethyl trichloro-benzenes be bottom material, opened after being warming up to 150 DEG C
Begin logical chlorine 630ml/min, opens ultraviolet lamp.
2, start that 91% 2- chloropyridine trifluoromethyl trichlorobenzene solution is added dropwise, control rate of addition is 2.6~9.6ml/
Min, carrying out temperature with reaction can be gradually increasing, and the final reaction temperature that controls is at 100 DEG C.
3, reaction solution, which rises to after overflow port, begins with reaction solution and flows out to 2000ml receiving flask, 20~91% 2- chloropyridines three
Methyl fluoride trichlorobenzene solution, until solution (2- chloropyridine 1750g, 175~7000g of trifluoromethyl trichloro-benzenes) is added dropwise.
Other operating procedures are the same as example 2.
2- chloropyridine liquid phase Light chlorimation prepares the experimental test data of 2,6- dichloropyridine (various concentration)
。
It is to be understood that: although above-described embodiment retouches mentality of designing of the invention detailed text of contrasting
It states, but these verbal descriptions, only the simple text of mentality of designing of the present invention is described, rather than to mentality of designing of the present invention
Limitation, any combination, increase or modification without departing from mentality of designing of the present invention falls within the protection scope of the present invention.
Claims (7)
1. a kind of method of 2- chloropyridine liquid phase Light chlorimation preparation 2,6- dichloropyridine, it is characterised in that: with 2- chloropyridine, chlorine
For starting material, 4-Chlorobenzotrifluoride is solvent, and continuous feed carries out liquid phase under 150 DEG C~200 DEG C temperature, ultraviolet lights
Chlorination reaction obtains chlorated liquid, 2,6- dichloropyridine content >=97% in pyridinium chloride therein, and chlorated liquid is by thick steaming, knot
Crystalline substance separation or rectification and purification process, obtain 2, the 6- dichloropyridine of purity >=99.0%, and yield is greater than 90%.
2. the method for liquid phase 2- chloropyridine Light chlorimation preparation 2,6- dichloropyridine according to claim 1, it is characterised in that:
Solvent is first added in the optical chlorinating reaction device, heats to reaction temperature, is passed through chlorine, while 2- being continuously added dropwise in proportion
The mixed solution of chloropyridine and solvent, reaction solution continuous overflow to chlorination collection.
3. solvent according to claim 1, it is characterised in that: solvent for use is trifluoromethyl monochloro-benzene, trifluoromethyl two
Chlorobenzene, trifluoromethyl trichloro-benzenes.
4. the method for 2- chloropyridine liquid phase Light chlorimation preparation 2,6- dichloropyridine according to claim 1, it is characterised in that:
The ultraviolet light uses wavelength for the ultraviolet source of 254~365nm or blue-light source.
5. the method for 2- chloropyridine liquid phase Light chlorimation preparation 2,6- dichloropyridine according to claim 1, it is characterised in that:
Described: reaction temperature is between 150 DEG C~200 DEG C.
6. chlorination reaction according to claim 2, it is characterised in that: 2- chloropyridine, solvent, chlorine feed ratio by weight
It is 1: 0.1~4: 0.62~1.
7. the method for 2- chloropyridine liquid phase Light chlorimation preparation 2,6- dichloropyridine according to claim 1, it is characterised in that:
The liquid phase Light chlorimation method can also be implemented using discontinuous method.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112174878A (en) * | 2020-10-04 | 2021-01-05 | 浙江埃森化学有限公司 | Method and device for preparing 2, 6-dichloropyridine by stepwise photochlorination of pyridine |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6475469A (en) * | 1987-09-18 | 1989-03-22 | Tosoh Corp | Production of 2,6-dichloropyridine |
| JPH01226874A (en) * | 1988-03-07 | 1989-09-11 | Tosoh Corp | Continuous production of 2,6-dichloropyridine |
| CN109134355A (en) * | 2018-10-30 | 2019-01-04 | 浙江埃森化学有限公司 | A kind of method that pyridine liquid phase Light chlorimation prepares 2,6- dichloropyridine |
-
2019
- 2019-03-05 CN CN201910165588.9A patent/CN109912502A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6475469A (en) * | 1987-09-18 | 1989-03-22 | Tosoh Corp | Production of 2,6-dichloropyridine |
| JPH01226874A (en) * | 1988-03-07 | 1989-09-11 | Tosoh Corp | Continuous production of 2,6-dichloropyridine |
| CN109134355A (en) * | 2018-10-30 | 2019-01-04 | 浙江埃森化学有限公司 | A kind of method that pyridine liquid phase Light chlorimation prepares 2,6- dichloropyridine |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112174878A (en) * | 2020-10-04 | 2021-01-05 | 浙江埃森化学有限公司 | Method and device for preparing 2, 6-dichloropyridine by stepwise photochlorination of pyridine |
| CN112174878B (en) * | 2020-10-04 | 2023-05-26 | 浙江埃森化学有限公司 | Method and device for preparing 2, 6-dichloropyridine by fractional photochlorination of pyridine |
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Application publication date: 20190621 |