CN102020605A - Liquid catalytic method for preparation of 2,3,5,6-tetrachloropyridine at normal pressure - Google Patents
Liquid catalytic method for preparation of 2,3,5,6-tetrachloropyridine at normal pressure Download PDFInfo
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- CN102020605A CN102020605A CN2009100190039A CN200910019003A CN102020605A CN 102020605 A CN102020605 A CN 102020605A CN 2009100190039 A CN2009100190039 A CN 2009100190039A CN 200910019003 A CN200910019003 A CN 200910019003A CN 102020605 A CN102020605 A CN 102020605A
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Abstract
The invention relates to a liquid catalytic method for preparation of 2,3,5,6-tetrachloropyridine at normal pressure, comprising following steps: under condition of liquid phase and normal pressure, adding a proper amount of polymer chlorine transfer catalyst with pyridine and chlorine as initial raw materials, obtaining 2,3,5,6-tetrachloropyridine by direct chlorination of pyridine, after the completion of chlorination reaction, adjusting PH value to be 8 using sodium hydroxide, and then extracting pyridine chloride using methanol.
Description
Technical field
The present invention relates to a kind of liquid-phase normal-pressure catalytic preparation 2,3,5, the method for 6-4 chloro pyridine
Background technology
By 2,3,5, the 6-4 chloro pyridine is that raw material is synthetic 3,5, the 6-phenolate trichloropyridine, and again with 3,5, the 6-phenolate trichloropyridine is the intermediate synthetic pesticide, is one of important process route of several efficient, low-toxin farm chemicals of preparation.With 3,5, the 6-phenolate trichloropyridine be intermediate not only can synthesizing efficient, the weedicide TRICLOPYR ACID of low toxicity, and can synthesizing efficient, the sterilant Chlorpyrifos 94 and the chlorpyrifos_methyl of low toxicity, wide spectrum.
Up to now, lot of domestic and foreign expert is to 3,5, and 6-phenolate trichloropyridine synthetic carried out big quantity research, developed numerous synthetic methods.
Can be divided into two classes by the raw material division: (1) is starting raw material with trichoroacetic chloride and vinyl cyanide; (2) be starting raw material with pyridine and chlorine.
U.S. Pat 3,538,100 and Europe patent EP 0 005 064 A1 and Chinese patent CN 100447133C, CN 1421435 and CN1421436 to have introduced with pyridine and chlorine be the synthetic method of starting raw material; U.S. Pat 4,327,216, European patent 0 397281 A2 have introduced with trichoroacetic chloride and acetonitrile is that initial feed is synthetic.
Press operational path and divide, synthesize 3,5, the method for 6-phenolate trichloropyridine mainly contains following several:
1. with trichoroacetic chloride, vinyl cyanide addition, cyclization, the aromizing route of raw material
This kind technology is to carry out addition with trichoroacetic chloride and vinyl cyanide, and again through cyclisation, last aromizing generates phenolate trichloropyridine.At present, the domestic production Chlorpyrifos 94 is all used this technology, and there is following problem in this operational path:
(1). the water one-step synthesis is low because of cost in the Chlorpyrifos 94 synthesis technique, is accepted by most of enterprises in recent years.But this Technology produces a large amount of waste water, and 1 ton of sodium phenolate trichloropyridine of every production produces 20 tons of waste water, and intractability is big, causes serious environmental to pollute.The processing treatment of waste water and recycle are that the former medicine of Chlorpyrifos 94 enlarges the biggest obstacle of producing.
(2). raw materials used relating to: trichoroacetic chloride, vinyl cyanide, oil of mirbane, ethyl benzoate, toluene, caustic soda, cuprous chloride, cuprous cyanide, cuprous chloride composite catalyst etc.Generally be no more than 70% with the trichoroacetic chloride rate that collects, remaining raw material has mainly entered waste water, especially cuprous cyanide has severe toxicity, oil of mirbane, toluene also have very high toxicity, not only can cause serious even fatal harm to operator, and the pollution that prussiate causes can't effect a radical cure, and will leave troubles to the descendants.
2. the second operational path is the operational path of pyridine high-temp chlorination, reduction, hydrolysis
This method is to be main raw material with pyridine and chlorine, and pyridine generates Perchloropyridine through high-temp chlorination, generates 4 chloro pyridine through reduction again, after alkaline hydrolysis generates phenolate trichloropyridine.The existing abroad industrialization report of this technology is in our the domestic development that also is in.
(1) this technology is that pyridine carries out chlorination reaction under 330 ℃ of high temperature, and is high to the erosion resistance requirement of equipment, because under the condition of high temperature and chlorine existence, reactor material selects to have great limitation.
(2) product of reaction generation is the mixture of 4 chloro pyridine and Perchloropyridine.Need be with mol ratio (Perchloropyridine: be that a large amount of acetonitriles of 1: 35 are made solvent acetonitrile) when Perchloropyridine is reduced into 4 chloro pyridine, acetonitrile has the toxicity of multiple diseases such as kidney injuries such as causing proteinuria, stomachache, diarrhoea, and acetonitrile is volatile, causes environmental pollution easily.
3. the 3rd operational path is pyridine through light chlorination, high temperature, high pressure alkaline hydrolysis chloridization process again
Elder generation's light chlorination generates 2, the 6-dichloropyridine, and high temperature, highly pressured hydrolysis generate 6-chloro-2 hydroxy pyrimidine, chlorination more again.At present, this technology is all not good at home and abroad, and reason is as follows:
(1) the three-step reaction total conversion rate is no more than 42%, and a large amount of byproducts and polymkeric substance cause environmental pollution easily.
(2) hydrolysis under the High Temperature High Pressure strong alkaline condition has proposed high requirement equally to the material of equipment, and the volume of high-tension apparatus also is very limited simultaneously, and the large-scale production difficulty is bigger.
4. the chloro-pyridine with 1～3 chlorine atom is a raw material, is catalyzer with iron powder or Lewis acid, carries out chlorination reaction with chlorine at 170-250 ℃ in three reactor, to prepare 2,3,5, the 6-4 chloro pyridine, this all has detailed presentations in EP 0 005 064 A1 and CN 100447133C.Problem mainly is temperature of reaction height (170-250 a ℃), long reaction time (8-48 hour), high energy consumption.In addition, dichloropyridine, trichloropyridine, 4 chloro pyridine all have the character of distillation, and the purification ratio of product is difficulty.
Summary of the invention
The characteristics of technology of the present invention are as follows:
(1). technology is simple: this technology is oriented chlorination catalysis new synthetic process, is initial feed with pyridine and chlorine promptly, under liquid-phase normal-pressure, carries out the directional catalyzing chlorination, generates 2,3,5, the 6-4 chloro pyridine, lectotype selection is easy, and is easy and simple to handle, is fit to large-scale production.
(2). high conversion: 2,3,5 in the reaction mixture, the 6-4 chloro pyridine can reach 95%.
(3). cleaning procedure: this technology does not produce the three wastes, and " waste residue " of generation is inorganic salt sodium-chlor.
(4). water saving: in the whole process of preparation, water does not efflux, and recycles.
(5). polymkeric substance chloride shift catalyzer is a kind of my company's synthetic functional polymer compound, can activate in considerable time, regenerate.Use repeatedly.
Embodiment
Following examples will the invention will be further described.
Embodiment one
Routinely the four-hole bottle of 500ml is loaded onto agitator, thermometer, chlorine input pipe and reflux exchanger, reflux exchanger is suitable for reading to be connected with safety flack and chlorine absorption unit.
In four-hole bottle, add pure pyridine 158g, polymkeric substance chloride shift catalyzer 12g, oil bath under agitation adds thermal material to reflux state, slowly feeds chlorine, after carrying out 18 hours, reaction stops, filter out polymkeric substance chloride shift catalyzer, the sodium hydroxide with 20% is transferred PH=8, and the result is as follows through gas chromatographic analysis: in peak area, 2,3,5, the 6-4 chloro pyridine is 91.3%; 2,3, the 6-trichloropyridine is 2.6%; 2,3, the 5-trichloropyridine is 0.8%; 2, the 6-dichloropyridine is 1.2%; The pyridine that 2-chloropyridine 3.1% and unreacted are intact.
Embodiment two
Device is as embodiment one, and raw material consumption and reaction conditions are constant, only changes polymkeric substance chloride shift catalyst levels, and its consumption increases 5g, and the reaction times is 18 hours still, and analytical results is as follows: 2,3,5, and the 6-4 chloro pyridine is 95.1%; 2,3, the 6-trichloropyridine is 1.5%; 2,3, the 5-trichloropyridine is 0.6%; 2, the 6-dichloropyridine is 0.8%; 2-chloropyridine 1.1% and unreacted pyridine.
Embodiment three
Device is as embodiment one, and raw material consumption and reaction conditions are with embodiment two, and the reaction times extends to 24 hours, and analytical results is as follows: 2,3,5, and the 6-4 chloro pyridine is 95.4%; 2,3, the 6-trichloropyridine is 1.3%; 2,3, the 5-trichloropyridine is 0.4%; 2, the 6-dichloropyridine is 0.6%; 2-chloropyridine 0.9% and unreacted pyridine.
Claims (2)
1. liquid-phase normal-pressure catalytic preparation 2,3,5, the method for 6-4 chloro pyridine, it is characterized in that with pyridine and chlorine be initial feed, under an amount of polymkeric substance chloride shift catalyst action, under the liquid-phase normal-pressure condition, preparation 2 in 15～24 hours refluxes, 3,5, the method for 6-4 chloro pyridine.
2. liquid-phase normal-pressure catalytic preparation 2,3,5, the method for 6-4 chloro pyridine is characterized in that pyridine and chlorine are that initial feed is carried out in the reaction of pyridine chlorination, its catalyst for oriented chlorination is the functional high molecule material with chloride shift katalysis.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2009100190039A CN102020605A (en) | 2009-09-23 | 2009-09-23 | Liquid catalytic method for preparation of 2,3,5,6-tetrachloropyridine at normal pressure |
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| CN2009100190039A CN102020605A (en) | 2009-09-23 | 2009-09-23 | Liquid catalytic method for preparation of 2,3,5,6-tetrachloropyridine at normal pressure |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103554015A (en) * | 2013-11-21 | 2014-02-05 | 山东谦诚工贸科技有限公司 | Method for preparing mixture of 2,3,5,6-tetrachloropyridine and pentachloropyridine from 2,6-dichloropyridine |
| CN103739543A (en) * | 2014-01-08 | 2014-04-23 | 盐城恒盛化工有限公司 | Preparation method of tetrachlorpyridine |
-
2009
- 2009-09-23 CN CN2009100190039A patent/CN102020605A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103554015A (en) * | 2013-11-21 | 2014-02-05 | 山东谦诚工贸科技有限公司 | Method for preparing mixture of 2,3,5,6-tetrachloropyridine and pentachloropyridine from 2,6-dichloropyridine |
| CN103739543A (en) * | 2014-01-08 | 2014-04-23 | 盐城恒盛化工有限公司 | Preparation method of tetrachlorpyridine |
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Application publication date: 20110420 |