CN101157637A - Method for preparing 3,4-dimethyl phenylhydrazine - Google Patents
Method for preparing 3,4-dimethyl phenylhydrazine Download PDFInfo
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- CN101157637A CN101157637A CNA2007101354766A CN200710135476A CN101157637A CN 101157637 A CN101157637 A CN 101157637A CN A2007101354766 A CNA2007101354766 A CN A2007101354766A CN 200710135476 A CN200710135476 A CN 200710135476A CN 101157637 A CN101157637 A CN 101157637A
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- dimethyl phenyl
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Abstract
The invention relates to a preparation method of 3, 4-dimethyl phenyl hydrazine. By using 3, 4-dimethylaniline as the initial raw material, the preparation method is capable of producing the 3, 4-dimethyl phenyl hydrazine after the diazotization reaction, the reduction reaction and hydrolysis, wherein, the reduction reaction which utilizes sodium metabisulfite as the reduction agent is carried out under the conditions that the temperature is 10 and 35 DEG C, and the PH value is 7 to 9. The 3, 4-dimethyl phenyl hydrazine produced by the preparation method of the invention has the advantages of high product purity and low production cost.
Description
Technical field
The present invention relates to a kind of 3, the preparation method of 4-dimethyl hydrazinobenzene.
Background technology
3, the 4-dimethyl hydrazinobenzene is a kind of important intermediate, especially a kind of medicine intermediate, prior art is with 3, the 4-xylidine is a raw material, through diazotization reaction, and the S-WAT reduction, hydrolysis, prepare 3, the synthetic method of 4-dimethyl hydrazinobenzene, long reaction time, generally need yield only to be 63-72%, and the production cost height.
Summary of the invention
It is a kind of 3 that technical problem to be solved by this invention provides, the preparation method of 4-dimethyl hydrazinobenzene, by this method obtain 3,4-dimethyl hydrazinobenzene product purity height, and production cost is low.
For solving above technical problem, the present invention adopts following technical scheme:
A kind of 3, the preparation method of 4-dimethyl hydrazinobenzene, with 3, the 4-xylidine is a starting raw material, through diazotization reaction, reduction reaction, hydrolysis prepares 3,4-dimethyl hydrazinobenzene, described reduction reaction are reductive agent with the Sodium Pyrosulfite, and at 10-35 ℃, pH carries out under the condition of 7-9.
The temperature of described reduction reaction is preferably 20 ℃, and pH is preferably 7.
Because the technique scheme utilization, the present invention compared with prior art has following advantage:
Adopt Sodium Pyrosulfite as reductive agent, shortened the reaction times greatly, generally only need half hour can reach reaction end, production cost is low, and the product purity height (greater than 98%) that makes.
Embodiment
Below the specific embodiment of the present invention is described:
In the 600ml beaker, add entry 150ml, stir, add 10N hydrochloric acid 57.5ml, 3,4-xylidine 24.2 grams treat 3, after the 4-xylidine all dissolves, slowly solution is cooled to below 0 ℃ or 0 ℃, slowly add sodium nitrite solution (being made into by 15 gram Sodium Nitrites and 30ml water), finish, regulation system pH is 1-2, about 5 ℃ of the temperature of control reaction system, react after 20 minutes, stopped reaction filters and the reservation yellow filtrate.
Add entry 250ml in the 1000ml beaker, stir adding Sodium Pyrosulfite 64 grams, sodium hydroxide 65 grams down, this moment, pH value of solution was 7, solution temperature is 35 ℃, treat that solution is cooled to 15 ℃ after, slowly above-mentioned filtrate is added, solution temperature is 20 ℃ when adding, and pH is 7, continues reaction 30 minutes, the reaction system to 80 of heating ℃ stirs, and slowly adds hydrochloric acid 172.5ml, continue to heat to 97-100 ℃, and after reacting 0.5 hour under this temperature, adding gac 8 grams, the decolouring after-filtration gets yellow filtrate.Cooling system to 10 ℃ is filtered and is kept filter cake and drying obtains product.It is 99.62% that high performance liquid chromatography is surveyed its purity.
Claims (2)
1. one kind 3, the preparation method of 4-dimethyl hydrazinobenzene, with 3, the 4-xylidine is a starting raw material, through diazotization reaction, reduction reaction, hydrolysis prepares 3, the 4-dimethyl hydrazinobenzene, it is characterized in that: described reduction reaction is reductive agent with the Sodium Pyrosulfite, and at 10-35 ℃, pH carries out under the condition of 7-9.
2. according to claim 1 a kind of 3, the preparation method of 4-dimethyl hydrazinobenzene is characterized in that: described reduction reaction is at 20 ℃, and pH carries out under 7 the condition.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007101354766A CN101157637A (en) | 2007-11-12 | 2007-11-12 | Method for preparing 3,4-dimethyl phenylhydrazine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007101354766A CN101157637A (en) | 2007-11-12 | 2007-11-12 | Method for preparing 3,4-dimethyl phenylhydrazine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101157637A true CN101157637A (en) | 2008-04-09 |
Family
ID=39305887
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2007101354766A Pending CN101157637A (en) | 2007-11-12 | 2007-11-12 | Method for preparing 3,4-dimethyl phenylhydrazine |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101157637A (en) |
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2007
- 2007-11-12 CN CNA2007101354766A patent/CN101157637A/en active Pending
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Open date: 20080409 |