CN1948263A - Preparation method of 2,3,5,6-tetrafluoro benzoic acid - Google Patents
Preparation method of 2,3,5,6-tetrafluoro benzoic acid Download PDFInfo
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- CN1948263A CN1948263A CN 200510086604 CN200510086604A CN1948263A CN 1948263 A CN1948263 A CN 1948263A CN 200510086604 CN200510086604 CN 200510086604 CN 200510086604 A CN200510086604 A CN 200510086604A CN 1948263 A CN1948263 A CN 1948263A
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Abstract
The present invention relates to a method for preparing 2,3,5,6-tetrafluorobenzoic acid. Said method is characterized by that under the catalytic action of acidic catalyst it can make 2,3,5,6-tetrafluoro-1,4-xylylene nitrile be hydrolyzed, its reaction temperature is 125-165 deg.C, and its reaction time is 3-6 h.
Description
Technical field
The present invention relates to a kind of synthetic method of organic compound, specifically, the present invention relates to a kind of 2,3,5, the synthetic method of 6-tetrafluorobenzoic aid.
Background technology
2,3,5, the 6-tetrafluorobenzoic aid is the very important intermediate of synthetic pyrethroid insecticide-transfluthrin, and it has good insecticidal effect, and low to the toxicity of human body, therefore can be widely used in the synthetic of agricultural chemicals, medicine, liquid crystal material and photochromics.
At present, 2,3,5, the synthetic method of 6-tetrafluorobenzoic aid mainly contains following several:
(1) with the pentafluorobenzoic acid be raw material, add zinc powder, in potassium hydroxide solution, carry out defluorinate and obtain 2,3,5,6-tetrafluorobenzoic aid, its yield are 81.3%.Above-mentioned defluorinate process can also be in sodium carbonate solution, carries out hydrogenation reaction and make 2,3 in the presence of palladium/carbon, 5, the thick product of 6-tetrafluorobenzoic aid, this thick product obtains described product with sodium sulphite and chlorine/water aftertreatment, wherein only contains the raw material of 0.05% weight.
(2) be raw material with 4-trifluoromethyl benzoyl fluoride, obtain 2,3 through chlorination, 5,6-tetrachloro-4-trifluoromethyl benzoyl chloride, its yield 83%, it and Potassium monofluoride carry out the fluorine exchange then, obtain 2,3,5,6-tetrachloro-4-trifluoromethyl benzoyl fluoride gets 2 through hydrolysis and decarboxylic reaction again, 3,5,6-tetrachloro-4-trifluoromethylbenzene, its yield 72%, then 2,3,5, hydrolysis obtains 2 in 6-tetrachloro-4-trifluoromethylbenzene and 20% oleum, 3,5,6-tetrafluoro-phenylformic acid.
(3) hydrolysis 2,3,5,6 tetrafluoros-1 under alkaline condition, the 4-benzene dicarbonitrile.Because when alkali concn is too low, 2,3,5,6 tetrafluoros-1, the 4-benzene dicarbonitrile is not hydrolyzed, and alkali concn the phenomenon that glass flask is corroded occurs when too high, so hydrolysate is polluted.
In addition, following method is disclosed: 2,3 among the GB2122190,5,6-tetrafluoro-1,4-benzene dicarbonitrile and Glacial acetic acid, the vitriol oil were 175 ℃ of following reflux 3 hours, and the cooling back is poured this mixture in the water into, use extracted with diethyl ether then, obtain 2,3,5 after adding anhydrous magnesium sulfate drying, filtration, rotary distillation again, 6-tetrafluoro-1, the 4-phthalic acid.Resulting 2,3,5,6-tetrafluoro-1,4-phthalic acid and N, dinethylformamide or polarity nonionic solvent mixture heating up to 70 such as (as N,N-DIMETHYLACETAMIDE, glycol dimethyl ether, tetramethylene sulfone) ℃ reaction 4 hours, be cooled to 20 ℃ again, add water and be cooled to 5 ℃.Precipitated solid is filtered, is washed and be dry, and its filtrate is distilled under vacuum, contain in the resultant product 98% 2,3,5, the 6-tetrafluorobenzoic aid.But this method need consume more materials, so this method be uneconomical, but also can pollutes environment through operations such as repeatedly filtration, dryings.
Summary of the invention
The technical problem that solves
The purpose of this invention is to provide a kind ofly 2,3,5, the synthetic method of 6-tetrafluorobenzoic aid, this method have that synthetic route is short, reaction conditions is gentle, with low cost and rate of recovery advantages of higher purity height.
Technical scheme
Generate acid amides during the nitrile hydrolysis earlier, the latter continues hydrolysis and generates carboxylic acid.The hydrolysis of nitrile is carried out under alkalescence or solution or acid catalysis.When the ratio of acid or alkali and water and temperature are suitable, will and then take off carboxylic acid on one side, obtain the monocarboxylic acid compound.
The invention provides a kind ofly 2,3,5, the synthetic method of 6-tetrafluorobenzoic aid is characterized in that this method is included in an acidic catalyst and exists down, 2,3,5, and 6-tetrafluoro-1,4-benzene dicarbonitrile were hydrolyzed under temperature 125-165 ℃ 3-6 hour.
In more detail, this method may further comprise the steps:
(1) 2,3,5,6-tetrafluoro-1,4-benzene dicarbonitrile be with after an acidic catalyst and distilled water mix, under agitation reflux 3-6 hour;
(2) after reflux finishes, with this reaction mixture cool to room temperature, more this reaction mixture is poured in the distilled water lentamente, with extraction agent extraction three times, isolating organic layer merges again;
(3) organic phase of He Binging is carried out drying with siccative, removes by filter siccative then, and its organic phase boils off solvent earlier under normal pressure, under reduced pressure boils off remaining acetic acid again, then oven dry;
(4) Hong Gan organic phase is used decolorizing with activated carbon again, and recrystallization obtains the target product crystal of white then.
In above-mentioned method, described an acidic catalyst is selected from one or more in the following material: Glacial acetic acid, the vitriol oil or concentrated hydrochloric acid;
The volume ratio of described an acidic catalyst and distilled water is 10: 1～2: 1;
Described 2,3,5,6-tetrafluoro-1, the volume ratio of 4-benzene dicarbonitrile and described an acidic catalyst are 1: 5～1: 10.
Described extraction agent is a kind of or is selected from the extraction agent of ether, di-n-butyl ether, t-butyl methyl ether, Di Iso Propyl Ether, ethyl acetate or toluene; Its extraction conditions is:
The extraction agent thinner is an ether;
Extractant concentration 100%;
Extraction phase was than 5: 3;
Extraction temperature: room temperature;
Extraction mode: reaction mixture cool to room temperature, pour into this reaction mixture in the distilled water lentamente again, pour this aqueous solution into separating funnel, add extraction agent then in separating funnel, vibration shakes up, and tells organic phase and water, then water is being refunded separating funnel, add extraction agent again, totally 3 times, each (water: organic phase) of comparing 5: 3 that adds;
Described siccative is selected from one or more in the following material: CaCl
2, MgSO
4, Na
2SO
4, CaSO
4
In above-mentioned method, described 2,3,5,6-tetrafluoro-1, the 4-benzene dicarbonitrile is to use 2,3,5,6-tetrachloro-1, the 4-benzene dicarbonitrile makes, and 2,3,5,6-tetrachloro-1,4-benzene dicarbonitrile are directly to buy from ALDRICH company to obtain.
This method also comprises a decolouring step, adds a kind of material that is selected from ether, di-n-butyl ether, t-butyl methyl ether, Di Iso Propyl Ether, ethyl acetate or the toluene during decolouring.The purpose that adds described material is to dissolve 2,3,5, and the 6-tetrafluorobenzoic aid makes gac bring into play adsorption.
This method also comprises re-crystallization step, its recrystallization condition: distill out the most of material in decolorization under normal pressure, add sherwood oil then with 2,3,5, the 6-tetrafluorobenzoic aid is precipitated out, and dries after the filtration, thereby obtains crystal.
Positively effect
Provided by the invention 2,3,5,6-tetrafluoro-1,4-benzene dicarbonitrile preparation method's the rate of recovery improves about more than 10% than traditional method.In addition, the inventive method has been saved some reactions steps that traditional method adopted, so synthetic route is short, do not need to add metal or metal salt catalyst, the reaction conditions gentleness,, like this, this method is more simple and feasible,, the prices of raw and semifnished materials of use are also cheap, target product can reach very high purity, is suitable for large-scale industrial production.
Embodiment
Further set forth the present invention below in conjunction with specific embodiment.Should be understood that these embodiment only to be used to the present invention is described and be not used in restriction protection scope of the present invention.
Embodiment 1:
In the two-mouth bottle of the 25ml that is equipped with prolong, agitator and thermometer, the 1g2 that packs into, 3,5,6 tetrafluoros-1,4-benzene dicarbonitrile, the 5ml vitriol oil, 5ml Glacial acetic acid and 1ml distilled water, heating under agitation reaches 155 ℃ of reflux temperatures, back flow reaction 4 hours, stopped reaction then, cool to room temperature, again this reaction solution mixture is poured in the 50ml distilled water, divide with the 100ml ether to extract for three times, isolating organic phase adds CaCl after merging again
2Drying is filtered, and boils off ether under normal pressure, under reduced pressure boils off unnecessary catalyzer again, oven dry.With ether and activated carbon decolorizing, and recrystallization (50 ℃ of most of ether that distill out in decolorization under normal pressure, cooling causes room temperature, add sherwood oil 20ml then with 2,3,5, the 6-tetrafluorobenzoic aid is precipitated out, and after the filtration filter residue is dried, thereby obtains white crystal).The rate of recovery is: 87.7%, and product purity is: 98%.
Embodiment 2:
In the two-mouth bottle of the 25ml that is equipped with prolong, agitator and thermometer, put into 2,3 of 1g, 5,6 tetrafluoros-1, the vitriol oil of 4-benzene dicarbonitrile, 5ml and the distilled water of 1ml, heating under agitation reaches 125 ℃ of reflux temperatures, back flow reaction 6 hours, stopped reaction then, cool to room temperature, again this reaction solution mixture is poured in the distilled water of 50ml, divide three extractions with the 100ml di-n-butyl ether, isolating organic phase adds MgSO after merging again
4Drying is filtered, and steams di-n-butyl ether under normal pressure, under reduced pressure steams unnecessary catalyzer again, oven dry.With di-n-butyl ether and activated carbon decolorizing, and recrystallization (145 ℃ of most of di-n-butyl ethers that distill out in decolorization under normal pressure, cooling causes room temperature, add the 20ml sherwood oil then with 2,3,5, the 6-tetrafluorobenzoic aid is precipitated out, and after the filtration filter residue is dried, thereby obtains white crystal).The rate of recovery is: 80.9%, and product purity is: 96%.
Embodiment 3:
Be equipped with prolong, in the two-mouth bottle of the 25ml of agitator and thermometer, put into 2 of 1g, 3,5,6 tetrafluoros-1, the 4-benzene dicarbonitrile, the Glacial acetic acid of 5ml and the distilled water of 1ml, heating under agitation reaches 165 ℃ of reflux temperatures, back flow reaction 3 hours, stopped reaction then, cool to room temperature, again this reaction solution mixture is poured in the distilled water of 50ml, divide three extractions with 100ml ether and t-butyl methyl ether, isolating organic phase adds the calcium chloride drying after merging again, filter, under normal pressure, steam ether and t-butyl methyl ether, under reduced pressure steam unnecessary catalyzer, oven dry.Use activated carbon decolorizing, and recrystallization (65 ℃ of most of ether and t-butyl methyl ether that distill out in decolorization under normal pressure, cooling causes room temperature, add the 20ml sherwood oil then with 2,3,5, the 6-tetrafluorobenzoic aid is precipitated out, and after the filtration filter residue is dried, thereby obtains white crystal).The rate of recovery is: 82.7%, and product purity is: 95%.
Embodiment 4:
In the two-mouth bottle of the 25ml that is equipped with prolong, agitator and thermometer, put into 2,3 of 1g, 5,6 tetrafluoros-1, the concentrated hydrochloric acid of 4-benzene dicarbonitrile, 6ml and the distilled water of 1ml, heating under agitation reaches 145 ℃ of reflux temperatures, back flow reaction 5 hours, stopped reaction then, cool to room temperature, again this reaction solution mixture is poured in the distilled water of 50ml, divide three extractions with the 100ml Di Iso Propyl Ether, isolating organic phase adds Na after merging again
2SO
4Drying is filtered, and steams Di Iso Propyl Ether under normal pressure, under reduced pressure steams unnecessary catalyzer, oven dry.With Di Iso Propyl Ether and activated carbon decolorizing, and recrystallization (70 ℃ of most of materials that distill out in decolorization under normal pressure, cooling causes room temperature, add the 20ml sherwood oil then with 2,3,5, the 6-tetrafluorobenzoic aid is precipitated out, and after the filtration filter residue is dried, thereby obtains white crystal).The rate of recovery is: 77.4%, and product purity is: 96%.
Embodiment 5:
In the two-mouth bottle of the 25ml that is equipped with prolong, agitator and thermometer, put into 2,3 of 1g, 5,6 tetrafluoros-1, the distilled water of the concentrated hydrochloric acid of 4-benzene dicarbonitrile, 7ml, the Glacial acetic acid of 3ml and 1ml, heating under agitation reaches 160 ℃ of reflux temperatures, back flow reaction 4.5 hours, stopped reaction then, cool to room temperature, again this reaction solution mixture is poured in the distilled water of 50ml, divide three extractions with the 100ml ethyl acetate, isolating organic phase adds calcium chloride and MgSO after merging again
4Drying is filtered, and steams ethyl acetate under normal pressure, under reduced pressure steams unnecessary catalyzer, oven dry.With ethyl acetate and activated carbon decolorizing, and recrystallization (80 ℃ of most of ethyl acetate that distill out in decolorization under normal pressure, cooling causes room temperature, add the 20ml sherwood oil then with 2,3,5, the 6-tetrafluorobenzoic aid is precipitated out, and after the filtration filter residue is dried, thereby obtains white crystal).The rate of recovery is: 76.2%, and product purity is: 96%.
Embodiment 6:
In the two-mouth bottle of the 25ml that is equipped with prolong, agitator and thermometer, put into 2,3 of 1g, 5,6 tetrafluoros-1, the distilled water of the vitriol oil of 4-benzene dicarbonitrile, 5ml, the concentrated hydrochloric acid of 5ml and 1ml, heating under agitation reaches 130 ℃ of reflux temperatures, back flow reaction 5.5 hours, stopped reaction then, cool to room temperature, again this reaction solution mixture is poured in the distilled water of 50ml, divide three extractions with 100ml toluene, isolating organic phase adds CaSO after merging again
4Drying is filtered, and steams toluene under normal pressure, under reduced pressure steams unnecessary catalyzer, oven dry.Use activated carbon decolorizing, and recrystallization (85 ℃ of most of toluene that distill out in decolorization under normal pressure, cooling causes room temperature, adds sherwood oil 20ml then with 2,3,5, the 6-tetrafluorobenzoic aid is precipitated out, and after the filtration filter residue is dried, thereby obtains white crystal).The rate of recovery is: 85.8%, and product purity is: 95%.
Claims (9)
1, a kind of 2,3,5, the preparation method of 6-tetrafluorobenzoic aid is characterized in that this method is included in an acidic catalyst and exists down, 2,3,5, and 6-tetrafluoro-1,4-benzene dicarbonitrile were hydrolyzed under temperature 125-165 ℃ 3-6 hour.
2, preparation method according to claim 1 is characterized in that this method may further comprise the steps:
(1) 2,3,5,6-tetrafluoro-1,4-benzene dicarbonitrile be with after an acidic catalyst and distilled water mix, under agitation reflux 3-6 hour;
(2) after reflux finishes, with this reaction mixture cool to room temperature, more this reaction mixture is poured in the distilled water lentamente, with extraction agent extraction three times, isolating organic layer merges again;
(3) organic phase of He Binging is carried out drying with siccative, removes by filter siccative then, and its organic phase boils off solvent earlier under normal pressure, under reduced pressure boils off remaining acetic acid again, then oven dry;
(4) Hong Gan organic phase is used decolorizing with activated carbon again, and recrystallization obtains the target product crystal of white then.
3, preparation method according to claim 1 and 2 is characterized in that described an acidic catalyst is selected from one or more in the following material: Glacial acetic acid, the vitriol oil, concentrated hydrochloric acid.
4, preparation method according to claim 1 and 2, the volume ratio that it is characterized in that described an acidic catalyst and distilled water is 10: 1～2: 1.
5, preparation method according to claim 1 and 2, when it is characterized in that reacting 2,3,5,6-tetrafluoro-1, the volume ratio of 4-benzene dicarbonitrile and an acidic catalyst are 1: 5～1: 10.
6, preparation method according to claim 1 and 2 is characterized in that describedly 2,3,5, and 6-tetrafluoro-1,4-benzene dicarbonitrile be by 2,3,5,6-tetrachloro-1, and the 4-benzene dicarbonitrile makes.
7, preparation method according to claim 2 is characterized in that described extraction agent is one or more extraction agents that are selected from ether, di-n-butyl ether, t-butyl methyl ether, Di Iso Propyl Ether, ethyl acetate or toluene.
8, preparation method according to claim 2 is characterized in that described siccative is selected from one or more in the following material: CaCl
2, MgSO
4, Na
2SO
4, CaSO
4
9, preparation method according to claim 2 adds the material that one or more are selected from ether, di-n-butyl ether, t-butyl methyl ether, Di Iso Propyl Ether, ethyl acetate or toluene when it is characterized in that decolouring.
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| Application Number | Priority Date | Filing Date | Title |
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| CNB2005100866043A CN100560558C (en) | 2005-10-13 | 2005-10-13 | A kind of 2,3,5, the preparation method of 6-tetrafluorobenzoic aid |
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| CNB2005100866043A CN100560558C (en) | 2005-10-13 | 2005-10-13 | A kind of 2,3,5, the preparation method of 6-tetrafluorobenzoic aid |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109438234A (en) * | 2018-12-21 | 2019-03-08 | 浙江中欣氟材股份有限公司 | A kind of synthetic method of the fluoro- 4- methoxy benzyl alcohol of 2,3,5,6- tetra- |
| CN110437056A (en) * | 2019-07-17 | 2019-11-12 | 浙江华基生物技术有限公司 | The method of preparation of industrialization 2,3,4,5 tetra fluoro benzoic acid |
-
2005
- 2005-10-13 CN CNB2005100866043A patent/CN100560558C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109438234A (en) * | 2018-12-21 | 2019-03-08 | 浙江中欣氟材股份有限公司 | A kind of synthetic method of the fluoro- 4- methoxy benzyl alcohol of 2,3,5,6- tetra- |
| CN109438234B (en) * | 2018-12-21 | 2020-04-21 | 浙江中欣氟材股份有限公司 | Synthetic method of 2,3,5, 6-tetrafluoro-4-methoxymethyl benzyl alcohol |
| CN110437056A (en) * | 2019-07-17 | 2019-11-12 | 浙江华基生物技术有限公司 | The method of preparation of industrialization 2,3,4,5 tetra fluoro benzoic acid |
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| CN100560558C (en) | 2009-11-18 |
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Granted publication date: 20091118 Termination date: 20121013 |