CN1944408A - Process for preparing symmetric tetrachloro pyridine - Google Patents
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- CN1944408A CN1944408A CN 200610052255 CN200610052255A CN1944408A CN 1944408 A CN1944408 A CN 1944408A CN 200610052255 CN200610052255 CN 200610052255 CN 200610052255 A CN200610052255 A CN 200610052255A CN 1944408 A CN1944408 A CN 1944408A
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Abstract
The process of preparing symmetric tetrachloro pyridine includes the chlorination reaction of chloro pyridine containing 1-3 chlorine atoms and chlorine at 170-250 deg.c in the presence of iron powder or Lewis acid as catalyst for 8-48 hr. The preparation process uses chlorine in the liquid phase chlorination reaction to chlorinate chloropyridine, dichloropyridine, trichloropyridine, etc, and has single pass conversion rate up to 97 %, simple technological process, low production cost and excellent industrial application value.
Description
(1) technical field
The present invention relates to a kind of preparation method of symmetrical 4 chloro pyridine.
(2) background technology
The symmetry 4 chloro pyridine is called 2,3,5 again, and the 6-4 chloro pyridine has molecular structure as shown below:
Owing to have a plurality of electron withdrawing groups in its molecular structure, make that the chlorine on 2 has bigger reactive behavior and becomes a kind of pyridine derivate that has much commercial value, can be used for the synthetic of weedicide, mycocide and sterilant.Because symmetrical 4 chloro pyridine can be used as the important starting raw material that global marketing amount and sales volume occupy primary efficient, low toxicity, broad spectrum pesticide " Chlorpyrifos 94 ", up to now, the insider has done a large amount of research for the preparation of this chemical both at home and abroad, multiple preparation method has been proposed, press the difference of starting raw material, it is starting raw material with tribromo-acetyl thing and vinyl cyanide that these methods of conclude can be divided into following a few class (1), and (2) are that starting raw material (3) is a starting raw material with pyridine and chlorine with Perchloropyridine.
It is starting raw material that Chinese patent CN1421436 has introduced with Perchloropyridine, when inorganic ammonium salt exists, in solvent, become 4 chloro pyridine with zinc or iron powder reducing, because Perchloropyridine obtains with pyridine or polychlorinated pyridine and chlorine reaction, with directly make symmetrical 4 chloro pyridine with chlorine and compare with pyridine or polychlorinated pyridine, from raw material availability, obviously be uneconomic, this must cause production cost of products too high.It is the production technique that starting raw material is produced symmetrical 4 chloro pyridine that Chinese patent CN1421435 discloses with pyridine and chlorine, but the reaction product that obtains is the mixture of 4 chloro pyridine (about 60%) and Perchloropyridine (about 38%) or is the mixture of main component with the Perchloropyridine, also need to carry out reduction reaction and just can obtain 4 chloro pyridine, in addition, this preparation method's temperature of reaction too high (270-500 ℃) has also strengthened the difficulty of practical application.Chinese patent 1676516 has proposed to become methyl trichloroacetate with trichoro-aldehyde through the hydrogen peroxide oxidation resterification, obtains 2,4 with the vinyl cyanide addition then, 4-three chloro-4-cyano butyric acid methyl esters, and last cyclisation is a 4 chloro pyridine.Raw material in this technology is cheap and easy to get relatively, a kind of important method for preparing symmetrical 4 chloro pyridine of can yet be regarded as.But exist because of operational path is long and cause the total yield of symmetrical 4 chloro pyridine not high (81.21%), and the deficiency of content (93%) on the low side.
Because the existing regulation of country: forbid selling at home and use five kinds high malicious sterilants such as " acephatemets ".Relevant government department is recommended with " Chlorpyrifos 94 " substitute as the malicious sterilant of above-mentioned height simultaneously, thereby how to reduce the production cost of " Chlorpyrifos 94 ", has become the research focus of manufacturer.Clearly; this needs to reduce the manufacturing cost of " Chlorpyrifos 94 " starting raw material; and symmetrical 4 chloro pyridine one of the important starting raw material of " Chlorpyrifos 94 " just, therefore necessary development is a kind of more helps reducing the novel preparation method that symmetrical 4 chloro pyridine production cost more helps environment protection simultaneously again.
(3) summary of the invention
The object of the invention is to provide the preparation method of the symmetrical 4 chloro pyridine that a kind of technology is simple, cost is low, yield is high.
The preparation method of described symmetrical 4 chloro pyridine comprises the steps: that with iron powder or Lewis acid be catalyzer, contains the chloro-pyridine of 1～3 chlorine atom and chlorine and carries out chlorination reaction 8～48 hours in 170-250 ℃, and products therefrom is symmetrical 4 chloro pyridine.
Described chloro-pyridine can be any mixture one of following or more than two kinds: a chloropyridine, dichloropyridine, trichloropyridine, a described chloropyridine such as 2-chloropyridine, 3-chloropyridine etc., described dichloropyridine is as 2,6-dichloropyridine, 2,3-dichloropyridine, 3,5-dichloropyridine etc., described trichloropyridine is as 2,3,5-trichloropyridine, 2,3,6-trichloropyridine etc.Preferably, described chloro-pyridine is 2,6-dichloropyridine or 2, the mixture of 6-dichloropyridine and 2-chloropyridine.
Described catalyzer can be Lewis acids such as iron powder or iron(ic) chloride, iron bromide, zinc chloride, is preferably iron(ic) chloride; Catalyst consumption is generally the 2-6% of chloro-pyridine quality, is preferably 4-5%.
Temperature of reaction of the present invention is vital, if temperature of reaction is lower than 170 ℃, productivity is low, is unsuitable for industrial production substantially, if it is then wayward to be higher than 250 ℃ of reactions, by product increases.For the temperature that keeps reacting required, must consider the temperature of reaction heat-eliminating medium, all kinds of heat-eliminating mediums are all available, as water vapor, water, wet goods.
The pressure of described chlorination reaction is preferably gauge pressure 0-0.08Mpa.
Preferably, described chlorination reaction is carried out in three stages, wherein the chlorination temperature of fs, pressure are respectively 170-205 ℃, gauge pressure 0-0.045Mpa, the chlorination temperature of subordinate phase, pressure are respectively 205-220 ℃, gauge pressure 0-0.065Mpa, the chlorination temperature of phase III, pressure are respectively 220-250 ℃, gauge pressure 0-0.08Mpa, wherein the fs is corresponding to the low-conversion stage of symmetrical 4 chloro pyridine, subordinate phase is corresponding to the middle transformation efficiency stage of symmetrical 4 chloro pyridine, and the phase III is corresponding to the high conversion stage of symmetrical 4 chloro pyridine.
The transformation efficiency in above-mentioned each stage is decided according to particular case, and usually, low-conversion can be meant that below 30-40% high conversion is meant more than 60-80%, is middle transformation efficiency between low-conversion and the high conversion.
Chlorination reaction of the present invention can be carried out in single-stage reactor, also can carry out in how placed in-line staged reactor, is recycled fully in order to guarantee chlorine, and preferably, described chlorination reaction is carried out in placed in-line staged reactor.
Again preferably, described chlorination reaction is carried out in placed in-line three reactor: when reacting first, in placed in-line three reactors, drop into identical chloro-pyridine and catalyzer post-heating, control that the reaction conditions of chloro-pyridine and chlorine is 170-250 ℃, 0-0.08Mpa in each reactor, when the material in the A reactor reaches reaction end, emit the product in the A reactor, products therefrom is directly used in the next step or carries out refinement treatment; Then, the material in the second reactor is put into A reactor, the material in the three reactor is put into second reactor, drops into identical chloro-pyridine and catalyzer again in the three reactor of sky; In the reaction process, chlorine feeds from the one-level chlorinator, behind the chloro-pyridine absorption reaction in the one-level chlorinator, tail gas discharged enters the secondary chlorination device, chloro-pyridine in wherein unreacted chlorine and the secondary chlorination device carries out chlorination reaction, enters three grades of chlorinators from secondary chlorination device tail gas discharged, and the interior chloro-pyridine of wherein unreacted chlorine and three grades of chlorinators carries out chlorination reaction, be admitted to the absorption tower from three grades of chlorinator tail gas discharged through surge tank, water absorbs makes hydrochloric acid.
Further, chlorination reaction in the above-mentioned A reactor is carried out in three stages, the chlorination temperature of fs wherein, pressure is respectively 170-205 ℃, gauge pressure 0-0.045Mpa, the chlorination temperature of subordinate phase, pressure is respectively 205-220 ℃, gauge pressure 0-0.065Mpa, the chlorination temperature of phase III, pressure is respectively 220-250 ℃, gauge pressure 0-0.08Mpa, wherein the fs is corresponding to the low-conversion stage of symmetrical 4 chloro pyridine, subordinate phase is corresponding to the middle transformation efficiency stage of symmetrical 4 chloro pyridine, and the phase III is corresponding to the high conversion stage of symmetrical 4 chloro pyridine.
The preparation method of symmetrical 4 chloro pyridine of the present invention in order to make chloro-pyridine and catalyzer thorough mixing, generally will have stirring before logical chlorine.After this, reaction both can be carried out under logical chlorine bubbling, also can carry out under mechanical stirring.In order to keep activity of such catalysts, reaction needs to carry out under anhydrous condition.Reaction needs 8～48 hours usually.Reaction finishes, and obtains content up to the target product more than 97%, need not to purify, and promptly can be directly used in hydrolysis reaction.Also can obtain purified symmetrical 4 chloro pyridine by such as distillation or post-treating method commonly used such as recrystallization or extraction.
Preparation method of the present invention directly carries out the liquid phase chlorination reaction to the described mixture of chloro-pyridine such as a chloropyridine, dichloropyridine, trichloropyridine or above-mentioned chloro-pyridine that comprises with chlorine, can obtain per pass conversion up to the target product more than 97%, technology is simple, production cost is low, has great industrial utility value.
(4) embodiment
The invention will be further described below in conjunction with embodiment, but protection scope of the present invention is not limited to this.Except that transformation efficiency in the mole, the percentage among the embodiment is all in mass.
Embodiment 1
Toward placed in-line three agitator is housed all respectively, pressure warning unit, thermometer, Chlorination tube, drop into 2 in the corrosion resistant 1000ml reactor of condenser, 6-dichloropyridine 325.6g, 2-chloropyridine 90.8g, iron(ic) chloride 20g, when being heated to the material melting, drive agitator, continue to be heated to 170 ℃, begin to feed chlorine, keep the interior temperature and pressure of A reactor respectively about 200 ℃ and about 0.04Mpa, temperature and pressure in second reactor and the three reactor is about 200 ℃, 0.075Mpa about, and the suitable feed back speed of control, the tail gas of controlling simultaneously in the three reactor does not have unreacted chlorine.When the content of symmetrical 4 chloro pyridine in the material in the A reactor reaches 40%, keep other reaction conditions to remain unchanged, but will control the interior temperature and pressure of A reactor respectively about 215 ℃ and about 0.06Mpa; And when the content of symmetrical 4 chloro pyridine in the material in the A reactor reaches 80%, control the interior temperature and pressure of A reactor respectively about 240 ℃ and about 0.08Mpa, the material in A reactor reaches till the reaction end.Reaction finishes, and the logical chlorine time is 20.5 hours, commonly goes into chlorine 940g.When terminal point reaches, stop logical chlorine, emit reaction mixture material 671.1g from A reactor, wherein contain chlorination product 97.02%, the GC analysis revealed contains symmetrical 4 chloro pyridine 97.0%, 2,3,6-trichloropyridine 0.98%, Perchloropyridine 1.97%.Other chloropyridine 0.05%.The per pass conversion of symmetry 4 chloro pyridine is by the 2-chloropyridine and 2 that drops into, and the 6-dichloropyridine counts 97.06%.
Then, material in the second reactor is put into A reactor, again the material in the three reactor is put into second reactor, in three reactor, drop into 2 then, 6-dichloropyridine 325.6g, 2-chloropyridine 90.8g, iron(ic) chloride 20g, begin introduce chlorine gas to make reaction by above-mentioned same mode, till A reactor arrives reaction end, the feeding time is 14.5 hours, commonly go into chlorine 750g, obtain and last time similar reaction result from A reactor: promptly the reaction mixture material is 670.9g, wherein contains chlorination product 97.02%, the GC analysis revealed contains symmetrical 4 chloro pyridine 97.13%, 2,3,6-trichloropyridine 1.04%, Perchloropyridine 1.79%, other chloropyridine 0.04%.The per pass conversion of symmetry 4 chloro pyridine is by the 2-chloropyridine and 2 that drops into, and the 6-dichloropyridine counts 97.16%.
Embodiment 2
Equipment and feeding mode are with embodiment 1, but the initial charge in the reactor changes 2 into, 6-dichloropyridine 444g, iron trichloride 20g, operating method is with embodiment 1, when A reactor arrives reaction end, get final product reaction mixture material 670g, wherein contain chlorination product 97.01%.The GC analysis revealed contains symmetrical 4 chloro pyridine 97.24%, 2,3,6-trichloropyridine 0.89%, Perchloropyridine 1.78%, other chloropyridine 0.09%.The transformation efficiency of symmetry 4 chloro pyridine is 97.14%.
Embodiment 3
Equipment and feeding mode are with embodiment 1, but initial charge changes polychlorinated pyridine mixture 485.2g into and (contains 3-chloropyridine 7.06%, 2-chloropyridine 4.68%, 3,5-dichloropyridine 6.10%, 2,6-dichloropyridine 67.11%, 2 in the reactor, 3,5-trichloropyridine 9.39%, 2,3,6-trichloropyridine 5.66%), iron trichloride 22g, operating method is with embodiment 1, when A reactor arrives reaction end, get final product reaction mixture material 738.8g, wherein contain chlorination product 97.02%.The GC analysis revealed contains symmetrical 4 chloro pyridine 96.92%, 2,3,6-trichloropyridine 0.94%, Perchloropyridine 2.07%, other chloropyridine 0.07%.The transformation efficiency of symmetry 4 chloro pyridine is 97.01%.
Embodiment 4
Equipment and feeding mode are with embodiment 1, but the initial charge in the reactor changes 2 into, 6-dichloropyridine 344g, 2-chloropyridine 76.9g, iron powder 6.9g, operating method are with embodiment 1, when A reactor arrives reaction end, get final product reaction mixture material 671.2g, wherein contain chlorination product 97.02%.The GC analysis revealed contains symmetrical 4 chloro pyridine 97.05%, 2,3,6-trichloropyridine 1.05%, Perchloropyridine 1.79%, other chloropyridine 0.11%.The transformation efficiency of symmetry 4 chloro pyridine is 97.07%.
Embodiment 5
Building-up reactions is carried out in A reactor.Drop into 2 in A reactor, 6-dichloropyridine 414.4g, 2-chloropyridine 45.4g, iron(ic) chloride 21g, when being heated to the material melting, drive agitator, continue to be heated to 170 ℃, begin to feed chlorine, tail gas directly imports the water resorber.Keep the interior temperature and pressure of reactor respectively about 200 ℃ and about 0.04Mpa, when the content of symmetrical 4 chloro pyridine in the material in the reactor reached 35%, the temperature and pressure in the control A reactor was respectively about 215 ℃ and about 0.06Mpa; When the content of symmetrical 4 chloro pyridine in the material in the reactor reached 80%, about 240 ℃ and 0.08Mpa, the material in A reactor reached till the reaction end temperature and pressure of control in the A reactor respectively.Reaction finishes, and the logical chlorine time is 30.5 hours, when terminal point reaches, stops logical chlorine, gets reaction mixture material 715.2g, wherein contains chlorination product 97.06%.The GC analysis revealed contains symmetrical 4 chloro pyridine 97.13%, 2,3,6-trichloropyridine 0.84%, Perchloropyridine 1.84%, other chloropyridine 0.19%.The transformation efficiency of symmetry 4 chloro pyridine is 97.15%.
Claims (10)
1, a kind of preparation method of symmetrical 4 chloro pyridine, it is characterized in that comprising the steps: that with iron powder or Lewis acid be catalyzer, contain the chloro-pyridine of 1～3 chlorine atom and chlorine and carried out chlorination reaction 8～48 hours in 170-250 ℃, products therefrom is symmetrical 4 chloro pyridine.
2, the preparation method of symmetrical 4 chloro pyridine as claimed in claim 1 is characterized in that described chloro-pyridine is one of following or any mixture more than two kinds: a chloropyridine, dichloropyridine, trichloropyridine.
3, the preparation method of symmetrical 4 chloro pyridine as claimed in claim 2 is characterized in that described chloro-pyridine is 2, the 6-dichloropyridine.
4, the preparation method of symmetrical 4 chloro pyridine as claimed in claim 2 is characterized in that described chloro-pyridine is 2, the mixture of 6-dichloropyridine and 2-chloropyridine.
5, the preparation method of symmetrical 4 chloro pyridine as claimed in claim 1 is characterized in that described catalyzer is an iron(ic) chloride, and catalyst consumption is the 2-6% of chloro-pyridine quality.
6, the preparation method of symmetrical 4 chloro pyridine as claimed in claim 1, the pressure that it is characterized in that described chlorination reaction is gauge pressure 0-0.08Mpa.
7, the preparation method of symmetrical 4 chloro pyridine as claimed in claim 1, it is characterized in that described chlorination reaction carries out in three stages, the chlorination temperature of fs wherein, pressure is respectively 170-205 ℃, gauge pressure 0-0.045Mpa, the chlorination temperature of subordinate phase, pressure is respectively 205-220 ℃, gauge pressure 0-0.065Mpa, the chlorination temperature of phase III, pressure is respectively 220-250 ℃, gauge pressure 0-0.08Mpa, wherein the fs is corresponding to the low-conversion stage of symmetrical 4 chloro pyridine, subordinate phase is corresponding to the middle transformation efficiency stage of symmetrical 4 chloro pyridine, and the phase III is corresponding to the high conversion stage of symmetrical 4 chloro pyridine.
8,, it is characterized in that described chlorination reaction carries out in placed in-line staged reactor as the preparation method of the described symmetrical 4 chloro pyridine of one of claim 1～6.
9, the preparation method of symmetrical 4 chloro pyridine as claimed in claim 8, it is characterized in that described chlorination reaction carries out in placed in-line three reactor: when reacting first, in placed in-line three reactors, drop into identical chloro-pyridine and catalyzer post-heating, the reaction conditions of controlling chloro-pyridine and chlorine in each reactor is under 170-250 ℃, 0-0.08Mpa, when the material in the A reactor reaches reaction end, emit the product in the A reactor, products therefrom is directly used in the next step or carries out refinement treatment; Then, the material in the second reactor is put into A reactor, the material in the three reactor is put into second reactor, drops into identical chloro-pyridine and catalyzer again in the three reactor of sky; In the reaction process, chlorine feeds from the one-level chlorinator, behind the chloro-pyridine absorption reaction in the one-level chlorinator, tail gas discharged enters the secondary chlorination device, chloro-pyridine in wherein unreacted chlorine and the secondary chlorination device carries out chlorination reaction, enters three grades of chlorinators from secondary chlorination device tail gas discharged, and the interior chloro-pyridine of wherein unreacted chlorine and three grades of chlorinators carries out chlorination reaction, be admitted to the absorption tower from three grades of chlorinator tail gas discharged through surge tank, water absorbs makes hydrochloric acid.
10, the preparation method of symmetrical 4 chloro pyridine as claimed in claim 9, it is characterized in that the chlorination reaction in the described A reactor carries out in three stages, the chlorination temperature of fs wherein, pressure is respectively 170-205 ℃, gauge pressure 0-0.045Mpa, the chlorination temperature of second two-stage, pressure is respectively 205-220 ℃, gauge pressure 0-0.065Mpa, the chlorination temperature of phase III, pressure is respectively 220-250 ℃, gauge pressure 0-0.08Mpa, wherein the fs is corresponding to the low-conversion stage of symmetrical 4 chloro pyridine, subordinate phase is corresponding to the middle transformation efficiency stage of symmetrical 4 chloro pyridine, and the phase III is corresponding to the high conversion stage of symmetrical 4 chloro pyridine.
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102391176A (en) * | 2011-09-24 | 2012-03-28 | 廊坊北鑫化工有限公司 | Method for preparing 2-chloro-6-trichloromethylpyridine |
| CN103739543A (en) * | 2014-01-08 | 2014-04-23 | 盐城恒盛化工有限公司 | Preparation method of tetrachlorpyridine |
| CN104276998A (en) * | 2014-10-30 | 2015-01-14 | 天津河清化学工业有限公司 | Method for two-step synthesis of tetrachloropyridine by taking pyridine as raw material |
| CN105503516A (en) * | 2015-12-14 | 2016-04-20 | 山东凯盛新材料有限公司 | Continuous production technology and device for dichloro-m-xylene |
| CN107325046A (en) * | 2017-06-19 | 2017-11-07 | 南京大学 | The liquid phase chlorination method production technology and device of a kind of cyanopyridine of tetrachloro 2 |
| CN107790158A (en) * | 2017-10-11 | 2018-03-13 | 南京红太阳股份有限公司 | A kind of preparation method of loaded catalyst, synthetic method and 2,3,5,6 4 chloro pyridines |
| CN111620813A (en) * | 2020-07-07 | 2020-09-04 | 天津科技大学 | Method for continuously chlorinating and synthesizing tetrachloropyridine |
| CN113563153A (en) * | 2021-08-25 | 2021-10-29 | 中化学科学技术研究有限公司 | Method for preparing monochloro-o-xylene by continuous chlorination of o-xylene |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3538100A (en) * | 1968-03-15 | 1970-11-03 | Olin Corp | Process for preparing highly chlorinated pyridines |
| US4256894A (en) * | 1978-04-24 | 1981-03-17 | The Dow Chemical Company | Preparation of chlorinated pyridines |
-
2006
- 2006-06-30 CN CNB2006100522558A patent/CN100447133C/en not_active Expired - Fee Related
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102391176A (en) * | 2011-09-24 | 2012-03-28 | 廊坊北鑫化工有限公司 | Method for preparing 2-chloro-6-trichloromethylpyridine |
| CN103739543A (en) * | 2014-01-08 | 2014-04-23 | 盐城恒盛化工有限公司 | Preparation method of tetrachlorpyridine |
| CN104276998A (en) * | 2014-10-30 | 2015-01-14 | 天津河清化学工业有限公司 | Method for two-step synthesis of tetrachloropyridine by taking pyridine as raw material |
| CN105503516A (en) * | 2015-12-14 | 2016-04-20 | 山东凯盛新材料有限公司 | Continuous production technology and device for dichloro-m-xylene |
| CN105503516B (en) * | 2015-12-14 | 2018-03-23 | 山东凯盛新材料股份有限公司 | Between benzyl dichloride continuous production processes and device |
| CN107325046A (en) * | 2017-06-19 | 2017-11-07 | 南京大学 | The liquid phase chlorination method production technology and device of a kind of cyanopyridine of tetrachloro 2 |
| CN107790158A (en) * | 2017-10-11 | 2018-03-13 | 南京红太阳股份有限公司 | A kind of preparation method of loaded catalyst, synthetic method and 2,3,5,6 4 chloro pyridines |
| CN111620813A (en) * | 2020-07-07 | 2020-09-04 | 天津科技大学 | Method for continuously chlorinating and synthesizing tetrachloropyridine |
| CN113563153A (en) * | 2021-08-25 | 2021-10-29 | 中化学科学技术研究有限公司 | Method for preparing monochloro-o-xylene by continuous chlorination of o-xylene |
| CN113563153B (en) * | 2021-08-25 | 2024-01-23 | 中化学科学技术研究有限公司 | Method for preparing monochloro-ortho-xylene by continuous chlorination of ortho-xylene |
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