CN103193686B - Esterification method for preparing azodicarbonic acid - Google Patents
Esterification method for preparing azodicarbonic acid Download PDFInfo
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- CN103193686B CN103193686B CN201310150201.5A CN201310150201A CN103193686B CN 103193686 B CN103193686 B CN 103193686B CN 201310150201 A CN201310150201 A CN 201310150201A CN 103193686 B CN103193686 B CN 103193686B
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Abstract
The invention discloses a method for preparing dialkyl azodicarbonic acid. The method comprises the steps of: mixing dimethyl azodicarbonic acid or diethyl azodicarbonic acid with sodium alkoxide solution, heating and reacting for 1-24h, and carrying out transesterification reaction between the dimethyl azodicarbonic acid or diethyl azodicarbonic acid and alcohol under the catalytic action of the sodium alkoxide; after the reaction is completed, regulating the pH value of the solution to 6-8, extracting an organic phase for 2-3 times with dichloromethane, combining the organic phases, drying for 8-12h with anhydrous sodium sulfate, and then performing reduced pressure distillation or recrystallization to obtain dialkyl azodicarbonic acid ROOCN=NCOOR, wherein R is alkyl containing 2-16 carbon atoms. According to the method, the dimethyl azodicarbonic acid or diethyl azodicarbonic acid is selected as raw materials, and is easily available; and the production cost is low, the economy is good, and pollution to the environment does not exist; the method for preparing the dialkyl azodicarbonic acid through esterification is simple to operate, short in process route, mild in reaction conditions, and high in yield, as well as suitable for industrialized development.
Description
Technical field
The present invention relates to a kind of method of azoformic acid dialkyl of preparation formula ROOCN=NCOOR representative.
Background technology
Azoformic acid dialkyl be one roughly the same time with the compound of azo and carboxyl functional group, relatively common are azo acid dimethyl ester (DMAD), diethyl azodiformate (DEAD), diisopropyl azodiformate (DIAD), azoformic acid dibenzyl ester (DBAD).Azoformic acid dialkyl is owing to having unique electronics and structural performance, reagent as a kind of multifunction is widely used in organic synthesis, particularly in the ammonification of the ammonification of Mitsunobu reaction, carbonyl compound, unsaturated hydrocarbon and heterogeneous ring compound synthetic, has very important effect.Azodiformate can also be served as oxygenant, for the dehydrogenation oxidation reaction of alcohol, amine.In addition, azoformic acid dialkyl is the important intermediate of a class and catalyzer, is widely used in the foaming of medicine intermediate, foamed polymer and the field of radical initiator.Its main application has the following aspects: (1), can synthesis of indole, the derivative of pyrrole etc. aspect medicine intermediate, for suppressing the generation of Phospholipid hydrolase, and sterilization and treatment and prevent diabetes, arteriosclerosis; (2), aspect catalyzer, except can be used as the catalyzer of polymkeric substance, can also serve as the radical initiator of synthetic thermoplastic synthon; (3) during as the whipping agent of foamed polymer, discharge the residual of gas as long as the viscosity characteristics of this polymkeric substance meets to expand or have after fusing, just can foam.
Azo acid dimethyl ester can be by A.Rodgman and G.F.Wright at J.Org.Chem, 18, the method proposing in 481-482 (1953) is synthetic, diethyl azodiformate can be by people such as Rabjohn at Organic Syntheses, 28,59 and the people such as Kauer at Organic Syntheses, collective volume IV, the method proposing in 411-415 (1963) is synthetic.Its synthetic method is as follows: first the chloro-formic ester of theoretical amount half is added drop-wise in the ethanolic soln of hydrazine hydrate and stirs for some time, maintain the temperature at below 20 DEG C, then drip remaining methyl-chloroformate and sodium hydrogen carbonate solution continues to react half an hour simultaneously, through suction filtration, washing, the dry white solid hydrazono-dioctyl phthalate dialkyl that obtains, productive rate is 81%～85%, above-mentioned product is stirred with water mixing machinery under condition of ice bath with methylene dichloride, slowly drip concentrated nitric acid oxidation, obtain product through washing, drying and other steps, productive rate is 70%～80%.But the method is taking chloro-formic ester and hydrazine hydrate as raw material, environmental pollution is serious, and expensive, environment is also had to very large pollution with the waste gas and waste liquid that nitric acid oxidation produces; In the method, the first step easily generates and replaces the by product carbazates of a side in addition, is difficult to separate, and is easily oxidized by nitric acid and makes next step separation more difficult.
In U.S.Patent No.3192196, the people such as Frederic D.Vidal has proposed the novel method of oxidation hydrazono-compound: a certain amount of nitrogen peroxide is passed into glacial acetic acid solution, is heated to 85 DEG C, now in reaction solution, have bubble to emerge.Take a morsel in this solution immigration there-necked flask, add wherein the glacial acetic acid solution of hydrazono-compound, after dropwising, the acetum of remaining nitrogen peroxide is joined in reaction flask, continue to be heated to 90～95 DEG C, keep 10min, then isolate azoformic acid dialkyl, washing, dry, final yield is more than 76%.This method provides cost savings to a certain extent, and the severe degree of reaction slows down to some extent, but easily produces a large amount of nitrogenous compounds, and environment is had to larger pollution.
In U.S.Patent No.3488342, the people's such as above-mentioned A.Rodgman method has been made improvement by Chester S.sheppard: the not treated chlorine that directly passes into fast of reaction product in chloro-formic ester and the hydrazine hydrate aqueous solution at sodium carbonate carries out next step oxidizing reaction, obtain target product, productive rate approximately 90% through extraction.This method is made solvent with water and is carried out the first step reaction compared with front one, reduce the by product of one-sided replacement, improve reaction yield, but, the method is still taking chloro-formic ester and hydrazine hydrate as raw material, and in second step, using chlorine instead is the danger that oxygenant has increased reaction, and the more difficult control of reaction end, and environment is also had to very large pollution.
Above traditional technology route, selects the material such as chloro-formic ester, hydrazine hydrate to make raw material, and these materials are not only expensive, and toxicity is large; Oxidising process need to be used the materials such as toxicity is large or corrodibility is strong concentrated nitric acid, nitrogen oxide, chlorine.Building-up process is seriously polluted, does not meet the standard of Modern Green Chemistry.
Summary of the invention
For above-mentioned prior art, for overcoming deficiency of the prior art, the invention provides a kind of method of preparing azoformic acid dialkyl.
The present invention is achieved by the following technical solutions:
A kind of method of preparing azoformic acid dialkyl: azo acid dimethyl ester or diethyl azodiformate mix with alcohol sodium solution, reacting by heating 1～24h, under the katalysis of sodium alkoxide, azo acid dimethyl ester or diethyl azodiformate and alcohol generation transesterification reaction; After having reacted, regulator solution pH value to 6～8, by dichloromethane extraction organic phase 2～3 times, merge organic phase, anhydrous sodium sulfate drying 8～12h, then through underpressure distillation or recrystallization, obtains azoformic acid dialkyl ROOCN=NCOOR, wherein, R is that alkyl (when reaction raw materials is azo acid dimethyl ester) or the R that contains 2～16 carbon atoms is the alkyl (when reaction raw materials is diethyl azodiformate) that contains 3～16 carbon atoms.
Reaction formula following (taking reaction raw materials as example as azo acid dimethyl ester):
Wherein, R is C
2～C
16.
Described sodium alkoxide is corresponding sodium alkoxide in prepared azoformic acid dialkyl, and for example preparing the sodium alkoxide that diethyl azodiformate is corresponding is sodium ethylate, and preparing the sodium alkoxide that azoformic acid dipropyl is corresponding is sodium propylate.That is: sodium alkoxide structural formula is RONa, and R is the alkyl that contains 2～16 carbon atoms.
Correspondingly, described alcohol is corresponding alcohol in prepared azoformic acid dialkyl, and for example preparing the alcohol that diethyl azodiformate is corresponding is ethanol, and preparing the alcohol that azoformic acid dipropyl is corresponding is propyl alcohol.That is: alcohol structural formula is ROH, and R is the alkyl that contains 2～16 carbon atoms.
The consumption of described sodium alkoxide is: 1%～20%mol, that is: the sodium alkoxide of 0.01～0.2mol for every 1mol azo acid dimethyl ester or diethyl azodiformate.Preferably, be 3%～8%mol.
Described sodium alkoxide can be commercially available product, also can make by oneself in laboratory, and self-control method in laboratory is: sodium Metal 99.5 is dropped in excessive alcohol, and sodium Metal 99.5 obtains alcohol sodium solution after dissolving.
Described azo acid dimethyl ester or diethyl azodiformate can be commercially available azo acid dimethyl ester or diethyl azodiformate, can be also laboratory self-control.
Temperature when described reacting by heating is according to the boiling point of various alcohol difference to some extent, and scope is 0～300 DEG C, preferably 80～200 DEG C.
Described regulator solution pH value material used is hydrochloric acid or sulfuric acid, and each scope solubility all can.
Being operating as of described underpressure distillation: first low-boiling compound (120 DEG C following) normal pressure is steamed, and then carry out underpressure distillation and obtain azoformic acid dialkyl.
Being operating as of described recrystallization: first alcohol is steamed, obtain white solid, then use ethyl acetate-sherwood oil mixture (the two volume ratio is 1:1～10) to carry out recrystallization.
The present invention is with azo acid dimethyl ester CH
3oOCN=NCOOCH
3or diethyl azodiformate CH
3cH
2oOCN=NCOOCH
2cH
3make azoformic acid dialkyl ROOCN=NCOOR through transesterification reaction.
The present invention is transesterification reaction, and contriver uses basic catalyst (sodium alkoxide), thus the carrying out of impelling reaction, improve the yield of reaction, through test of many times screening, the catalytic amount of the sodium alkoxide that contriver selects is 1%～20%mol, further optimize reaction, the amount of determining catalyzer is 3%～8%mol.1mol azo acid dimethyl ester carries out the alcohol that transesterify needs 2mol in theory, and in experiment, it is solvent that contriver selects alcohol, and the amount of alcohol is greatly excessive, is conducive to the raising of product yield; In experiment, the temperature of reaction is most important, is not only determining the yield of reaction, more has great relation with the reaction times, tested screening, and the definite optimal reaction temperature of contriver is 80～200 DEG C.
The invention has the beneficial effects as follows:
(1) to select azo acid dimethyl ester or diethyl azodiformate be raw material in the present invention, and raw material is easy to get, and production cost is low, good economy performance, and environmentally safe;
(2) azoformic acid dialkyl is prepared in transesterify of the present invention, and simple to operate, operational path is short, reaction conditions gentleness, and yield is high;
(3) product synthesis technique of the present invention is suitable for industrialized developing.
Embodiment
Below in conjunction with embodiment, the present invention is further illustrated.Should be noted that following explanation is only in order to explain the present invention, does not limit its content.
The reagent that following content relates to all can be bought acquisition by market.
The preparation of embodiment 1 diisopropyl azodiformate
In tri-mouthfuls of round-bottomed flasks of 250mL that magneton agitator, 25mL constant pressure funnel and rectifier unit are housed; add 100mL Virahol; under nitrogen protection; add 0.46g(0.02mol) sodium Metal 99.5; after sodium Metal 99.5 dissolves completely; drip 14.60g azo acid dimethyl ester, under reflux state, react 24h, to not having methyl alcohol to steam stopped reaction.10% hydrochloric acid (massfraction for reaction solution, being neutralized to pH value down together) is 7, by dichloromethane extraction organic phase 3 times, merge organic phase, anhydrous sodium sulfate drying spend the night (10h), steam unreacted isopropanol recovering, underpressure distillation, obtaining burgundy diisopropyl azodiformate 16.52g(yield is 81.8%).
1HNMR(CDCl
3,300MHz)δ(ppm):5.33-5.43(2H,m,CH)；1.55-1.57(12H,d,CH
3)。
IR(cm
-1):2955.61,2872.77(C-H)；1764.23(C=O)。
The preparation of embodiment 2 azoformic acid diisoamyl esters
In tri-mouthfuls of round-bottomed flasks of 250mL that magneton agitator, 25mL constant pressure funnel and rectifier unit are housed; add 100mL primary isoamyl alcohol; under nitrogen protection; add 0.46g(0.02mol) sodium Metal 99.5; after sodium Metal 99.5 dissolves completely; drip 14.60g azo acid dimethyl ester, under reflux state, react 16h, to not having methyl alcohol to steam stopped reaction.It is 7 that reaction solution is neutralized to pH value with 10% hydrochloric acid soln, uses dichloromethane extraction organic phase 3 times, merges organic phase, anhydrous sodium sulfate drying spend the night (10h), steam unreacted isopropylcarbinol and reclaim, underpressure distillation, obtaining orange red azoformic acid diisoamyl ester 21.91g(yield is 85.2%).
1HNMR(CDCl
3,300MHz)δ(ppm):4.13(4H,t,CH
2)；1.39-1.64(6H,m,CH,CH
2)；
0.87-0.93(12H,m,CH
3)；
IR(cm
-1):2954.60,2870.65(C-H)；1786.72(C=O)。
The preparation of embodiment 3 azoformic acid two cyclohexyls
In tri-mouthfuls of round-bottomed flasks of 250mL that magneton agitator, 25mL constant pressure funnel and rectifier unit are housed; add 100mL hexalin; under nitrogen protection; add 0.46g(0.02mol) sodium Metal 99.5; after sodium Metal 99.5 dissolves completely; drip 14.60g azo acid dimethyl ester, under reflux state, react 12h, to not having methyl alcohol to steam stopped reaction.It is 6 that reaction solution is neutralized to pH value with 10% hydrochloric acid soln, by dichloromethane extraction organic phase 3 times, merge organic phase, anhydrous sodium sulfate drying spend the night (8h), steaming unreacted hexalin reclaims, with ethyl acetate-sherwood oil mixture (the two volume ratio is 1:5) recrystallization, obtaining faint yellow solid azoformic acid two cyclohexyl 22.63g(yields is 80.1%).Mp=70～71 DEG C (72 DEG C of literature values).
1HNMR(CDCl
3,300MHz)δ(ppm):5.80(2H,s,CH)；1.17-1.72(20H,m,CH
2)。
IR(cm
-1):2983.04,2924.19(C-H)；1786.85(C=O)。
The preparation (azo acid dimethyl ester is raw material) of embodiment 4 azoformic acid didecyl esters
In tri-mouthfuls of round-bottomed flasks of 250mL that magneton agitator, 25mL constant pressure funnel and rectifier unit are housed; add 100mL nonylcarbinol; under nitrogen protection; add 0.46g(0.02mol) sodium Metal 99.5; after sodium Metal 99.5 dissolves completely; drip 14.60g azo acid dimethyl ester, in 200 DEG C of oil baths, react 10h, to not having methyl alcohol to steam stopped reaction.It is 8 that reaction solution is neutralized to pH value with 10% hydrochloric acid soln, by dichloromethane extraction organic phase 3 times, merge organic phase, anhydrous sodium sulfate drying spend the night (12h), underpressure distillation, obtaining orange red thick liquid azoformic acid didecyl ester 34.31g(yield is 86.3%).
1HNMR(CDCl
3,300MHz)δ(ppm):4.12(4H,t,CH
2)；1.64-1.69（4H,m,CH
2）；
1.54-1.56(4H,m,CH
2)；1.26(24H,m,CH
2)0.86-0.90(6H,t,CH
3)。
IR(cm
-1):2923.77,2854.81(C-H)；1774.21(C=O)。
The preparation (diethyl azodiformate is raw material) of embodiment 5 azoformic acid didecyl esters
In tri-mouthfuls of round-bottomed flasks of 250mL that magneton agitator, 25mL constant pressure funnel and rectifier unit are housed; add 100mL nonylcarbinol; under nitrogen protection; add 0.46g(0.02mol) sodium Metal 99.5; after sodium Metal 99.5 dissolves completely; drip 17.40g diethyl azodiformate, in 200 DEG C of oil baths, react 10h, to not having ethanol to steam stopped reaction.It is 7 that reaction solution is neutralized to pH value with 10% hydrochloric acid soln, by dichloromethane extraction organic phase 3 times, merge organic phase, anhydrous sodium sulfate drying spend the night (10h), underpressure distillation, obtaining orange red thick liquid azoformic acid didecyl ester 34.13g(yield is 85.8%).
1HNMR(CDCl
3,300MHz)δ(ppm):4.12(4H,t,CH
2)；1.64-1.69（4H,m,CH
2）；
1.54-1.56(4H,m,CH
2)；1.26(24H,m,CH
2)0.86-0.90(6H,t,CH
3)。
IR(cm
-1):2923.77,2854.81(C-H)；1774.21(C=O)。
The preparation of embodiment 6 azoformic acid two (16) alkyl esters
In tri-mouthfuls of round-bottomed flasks of 250mL that magneton agitator, 25mL constant pressure funnel and rectifier unit are housed; add 120g hexadecanol; after heating for dissolving; under nitrogen protection; add 0.23g(0.01mol) sodium Metal 99.5, after sodium Metal 99.5 dissolves completely, drip 7.30g azo acid dimethyl ester; in 200 DEG C of oil baths, react 6h, to not having methyl alcohol to steam stopped reaction.It is 7 that reaction solution is neutralized to pH value with 10% hydrochloric acid soln, by dichloromethane extraction organic phase 3 times, merge organic phase, anhydrous sodium sulfate drying spend the night (10h), steaming unreacted hexadecanol reclaims, with ethyl acetate-sherwood oil mixture (the two volume ratio is 1:2) recrystallization, obtaining faint yellow solid azoformic acid hexacosyl ester 25.10g(yield is 88.6%).Mp=37-39 DEG C (38 DEG C of literature values).
1HNMR(CDCl
3,300MHz)δ(ppm):4.41(4H,t,CH
2);1.86(4H,m,CH
2)；1.51(4H,m,CH
2)；
1.26-1.43(48H,m,(CH
2)
12)；0.89(6H,m,CH
3)。
IR(cm
-1):2914.87,2847.59(C-H)；1769.47(C=O)。
Although above-mentioned, the specific embodiment of the present invention is described; but not limiting the scope of the invention; on the basis of technical scheme of the present invention, those skilled in the art do not need to pay various amendments that creative work can make or distortion still in protection scope of the present invention.
Claims (1)
1. prepare the method for azoformic acid dialkyl for one kind, it is characterized in that: azo acid dimethyl ester or diethyl azodiformate mix with alcohol sodium solution, reacting by heating 1～24h, under the katalysis of sodium alkoxide, formic acid dimethyl ester or diethyl azodiformate and alcohol generation transesterification reaction; After having reacted, regulator solution pH value to 6～8, by dichloromethane extraction organic phase 2～3 times, merge organic phase, anhydrous sodium sulfate drying 8～12h, then through underpressure distillation or recrystallization, obtains azoformic acid dialkyl ROOCN=NCOOR, wherein, R is the alkyl that contains 2～16 carbon atoms;
Described sodium alkoxide is corresponding sodium alkoxide in prepared azoformic acid dialkyl, and the structural formula of sodium alkoxide is RONa, and R is the alkyl that contains 2～16 carbon atoms; Correspondingly, described alcohol is corresponding alcohol in prepared azoformic acid dialkyl, and the structural formula of alcohol is ROH, and R is the alkyl that contains 2～16 carbon atoms;
The consumption of described sodium alkoxide is: 1%～20%mol;
Temperature range when described reacting by heating is 0～300 DEG C;
Described regulator solution pH value material used is hydrochloric acid or sulfuric acid;
Being operating as of described underpressure distillation: first low-boiling compound is steamed, and then carry out underpressure distillation and obtain azoformic acid dialkyl;
Being operating as of described recrystallization: first alcohol is steamed, obtain white solid, then carry out recrystallization with ethyl acetate-sherwood oil mixture, the two volume ratio of ethyl acetate and sherwood oil is 1:1～10.
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| GB873597A (en) * | 1959-01-05 | 1961-07-26 | Wallace & Tiernan Inc | Manufacture of azo compounds |
| JP4092739B2 (en) * | 1996-09-27 | 2008-05-28 | 和光純薬工業株式会社 | Novel process for producing azoester compounds |
| FR2788517B1 (en) * | 1999-01-15 | 2001-03-16 | Atochem Elf Sa | PROCESS FOR THE PREPARATION OF AZOIMINOETHERS AND ESTERS OF AZOCARBOXYLIC ACIDS, AND NOVEL MIXED ESTERS OF AZOCARBOXYLIC ACIDS |
| CN101481326A (en) * | 2008-12-12 | 2009-07-15 | 青岛润兴光电材料有限公司 | Preparation of 2,2'-azodiisobutyrate |
| CN101717348B (en) * | 2009-12-03 | 2012-05-23 | 常州南京大学高新技术研究院 | Synthesis method of diisopropyl azodiformate |
| CN102898328B (en) * | 2012-10-26 | 2014-12-24 | 山东师范大学 | Synthesis method of diethyl azodicarboxylate and intermediate of diethyl azodicarboxylate |
| CN102898327B (en) * | 2012-10-26 | 2014-12-03 | 山东师范大学 | Synthesis method for dimethyl azodicarboxylate and intermediate thereof |
| CN103012215B (en) * | 2013-01-22 | 2014-02-19 | 山东师范大学 | Azo dodecanedioic acid dialkyl ester preparation method |
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