CN102627531A - Method for producing acicular 2, 5-dimethylphenol by water melt crystallization - Google Patents
Method for producing acicular 2, 5-dimethylphenol by water melt crystallization Download PDFInfo
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- CN102627531A CN102627531A CN2011103184198A CN201110318419A CN102627531A CN 102627531 A CN102627531 A CN 102627531A CN 2011103184198 A CN2011103184198 A CN 2011103184198A CN 201110318419 A CN201110318419 A CN 201110318419A CN 102627531 A CN102627531 A CN 102627531A
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- xylenol
- sodium
- acid dimethyl
- dimethylphenol
- water
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Abstract
The invention discloses a method for producing 2,5-dimethylphenol by water melt crystallization, wherein p-xylene is used as a raw material. The production method provided by the invention comprises the following steps of: 1, mixing p-xylene with concentrated sulfuric acid to obtain 2,5-dimethyl benzene sulfonic acid; 2, adding sodium hydroxide into 2,5-dimethyl benzene sulfonic acid to obtain 2,5-sodiumdimethylbenzenesulfonate; 3, mixing 2,5-sodiumdimethylbenzenesulfonate with sodium hydroxide, and fully reacting to obtain an aqueous solution of 2,5-sodiumdimethylphenol; 4, letting sulfur dioxide enter into the aqueous solution of 2,5-sodiumdimethylphenol to obtain 2,5-dimethylphenol crude product; and 5, carrying out vacuum distillation on the 2,5-dimethylphenol crude product, mixing the product with water, stirring, cooling, followed by crystallization, and finally carrying out preliminary dehydration by a centrifuge and two-stage dehydration by a rotary vacuum dryer to obtain 2,5-dimethylphenol. By the adoption of the method, the production is safer and the production cost is reduced.
Description
Technical field
The present invention relates to a kind ofly 2, the working method of 5-xylenol relates in particular to a kind of aqueous fusion and melts crystallization production needle-like 2, the method for 5-xylenol.
Background technology
2, the 5-xylenol is used for synthesizing of dyestuff and pharmaceutical prod hypolipidemic gemfibrozil etc. mainly as organic synthesis intermediate; Its proterties is a white, needle-shaped crystals, has fresh and sweet fragrance and smoke cured smell, also has the Moschus breath after the dilution; Can be used for to be dissolved in organic flux such as ethanol, 75 ℃ of fusing points in bacon and the flavouring essence for tobacco; 210 ℃ of boiling points, specific density (d20/4 ℃) is 1.016.
Have 2 now, the production technique of 5-xylenol is such: p-Xylol and strong sulfuric acid response produce 2, the 5-acid dimethyl; Generate 2 with the sodium hydroxide reaction then, 5-acid dimethyl sodium generates 2 with the reaction of sodium hydroxide high temperature alkali fuse again; 5-xylenol sodium, 2,5-xylenol sodium and dilute sulphuric acid reacted 2; 5-xylenol bullion is that solvent carries out crystallization, drying obtains 2 through the distillation back with ethanol again, 5-dimethyl benzene phenolic product; Etoh solvent distillation recycling use.
Therefore existing production technique exists many deficiencies and defective because the product purification crystallization has adopted ethanol to make solvent:
1, product per ton will lose etoh solvent 300～350kg, and ethanol is volatile;
2, the recrystallization operation will hocket and heat up and the cooling operation, consume steam and water coolant, and product energy consumption is increased;
3, etoh solvent belongs to inflammable explosive article, and the essential safety degree of production line is reduced;
These are not enough and defective can make production cost increase, and the danger of presence of fire, blast is arranged in process of production.
Summary of the invention
The object of the invention just be to provide a kind of can address the above problem 2, the working method of 5-xylenol can make production safer, reduces production costs.
To achieve these goals, the technical scheme of the present invention's employing is such: a kind of aqueous fusion melts crystallization production needle-like 2, and the method for 5-xylenol is starting material with the p-Xylol, and its production stage is following:
1,, obtains 2, the 5-acid dimethyl to complete reaction with p-Xylol and the vitriol oil mixed with mol ratio 1:1;
2, toward the 1st the step obtain 2, add sodium hydroxide in the 5-acid dimethyl, react to pH=8～10, obtain 2,5-acid dimethyl sodium;
3, again with the 2nd step obtain 2,5-acid dimethyl sodium and sodium hydroxide is with the mixed of mol ratio 1:1.5-2.5, and is heated to 280～300 ℃ and makes it complete reaction, obtains 2, the aqueous solution of 5-xylenol sodium;
4, toward the 3rd the step obtain 2, feed sulfurous gas in the aqueous solution of 5-xylenol sodium, react to pH=3～4, obtain 2,5-xylenol bullion; Obtain S-WAT simultaneously;
5, with the 4th the step obtain 2; 5-xylenol bullion carries out underpressure distillation and obtains distillate; Then with distillate and water by volume 1:2-3 mix, and stir decrease temperature crystalline and become needle-like 2, the 5-xylenol is dispersed in the water; After obtain 2, the 5-xylenol after whizzer preliminary hydro-extraction and the dehydration of revolution vacuum drier two-stage.
Further, the 1st step was 3-4 hours with the reaction times in the 3rd step.
Further, the 3rd the step in 2,5-acid dimethyl sodium and sodium hydroxide are 1:2 with the mol ratio.
Further, the volume ratio 1:2.5 of distillate and water in the 5th step.
Compared with prior art, the invention has the advantages that: be raw material with the p-Xylol, obtain 2 through concentrated acid sulfonation, alkali neutralization, high temperature alkali fuse, four steps of acidifying; 5-xylenol bullion; Again with 2,5-xylenol bullion agitation and dropping water under molten state obtains acicular 2 as the direct crystallisation by cooling of dispersion agent, 5-dimethyl benzene phenolic product; Cancelled the use of etoh solvent; Improve the essential safety degree of production line, reduced production cost, stopped the influence that volatilization loss causes environment in the alcoholic acid use.
Embodiment
To combine accompanying drawing that the present invention is described further below.
Embodiment: a kind of aqueous fusion melts crystallization production needle-like 2, and the method for 5-xylenol is starting material with the p-Xylol, and its production stage is following:
1,, obtains 2, the 5-acid dimethyl to complete reaction with p-Xylol and the vitriol oil mixed with mol ratio 1:1; In the actually operating, p-Xylol is mixed in the sulfonation reaction still with the vitriol oil, and to make the reaction times be 3-4 hours.
2, toward the 1st the step obtain 2, add sodium hydroxide in the 5-acid dimethyl, react to pH=8～10, obtain 2,5-acid dimethyl sodium; With 2, the 5-acid dimethyl places neutralization reactor, toward 2, adds sodium hydroxide in the 5-acid dimethyl then.
3, again with the 2nd step obtain 2,5-acid dimethyl sodium and sodium hydroxide is with the mixed of mol ratio 1:1.5-2.5, and is heated to 280～300 ℃ and makes it complete reaction, obtains 2, the aqueous solution of 5-xylenol sodium; With 2,5-acid dimethyl sodium places alkali-melting vessel, and toward 2, the aqueous solution of 5-xylenol sodium adds sodium hydroxide, and heats 3-4 hours; As preferably, 2,5-acid dimethyl sodium and sodium hydroxide are 1:2 with the mol ratio.
4, toward the 3rd the step obtain 2, feed sulfurous gas in the aqueous solution of 5-xylenol sodium, react to pH=3～4, obtain 2,5-xylenol bullion; Obtain S-WAT simultaneously; This step is carried out in the acidifying still.
5, with the 4th step obtain 2,5-xylenol bullion carries out underpressure distillation and obtains distillate, then with distillate and water by volume 1:2-3 mix; And stir decrease temperature crystalline and become needle-like 2; The 5-xylenol is dispersed in the water, and wherein, the volume ratio of distillate and water is preferably 1:2.5; 2,5-xylenol bullion carries out underpressure distillation in still kettle and obtains distillate, distillate and mix the formation molten state with water at the washing crystallization kettle; After obtain 2, the 5-xylenol after whizzer preliminary hydro-extraction and the dehydration of revolution vacuum drier two-stage.
Concrete production process is following: the p-Xylol and the vitriol oil generated 2 in 3～4 hours with mol ratio 1:1 normal-temperature reaction in the sulfonation reaction still, and the 5-acid dimethyl reacts to pH=8～10 generations 2 with sodium hydroxide then; 5-acid dimethyl sodium, in alkali-melting vessel 2,5-acid dimethyl sodium and excessive nearly one times sodium hydroxide are heated to 280～300 ℃ of reactions and generated 2 in 3～4 hours in alkali-melting vessel; 5-xylenol sodium, 2, the aqueous solution of 5-xylenol sodium feeds SO 2 acidifying to pH=3～4; Generate 2; 5-xylenol bullion, 2,5-xylenol bullion carries out underpressure distillation; Distillate and water stir decrease temperature crystalline by 1:2.5 (volume ratio) and become needle-like 2; The 5-xylenol is dispersed in the water, after the dehydration of revolution vacuum drier two-stage, obtains 2,5-xylenol finished product again through the whizzer preliminary hydro-extraction.
The present invention is raw material with the p-Xylol, obtains 2,5-xylenol bullion through concentrated acid sulfonation, alkali neutralization, high temperature alkali fuse, four steps of acidifying; Again with 2,5-xylenol bullion agitation and dropping water under molten state obtains acicular 2 as the direct crystallisation by cooling of dispersion agent, 5-dimethyl benzene phenolic product; Cancelled the use of etoh solvent; Improve the essential safety degree of production line, reduced production cost, stopped the influence that volatilization loss causes environment in the alcoholic acid use.
Claims (4)
1. an aqueous fusion melts crystallization production needle-like 2, and the method for 5-xylenol is characterized in that: be starting material with the p-Xylol, its production stage is following:
1,, obtains 2, the 5-acid dimethyl to complete reaction with p-Xylol and the vitriol oil mixed with mol ratio 1:1;
2, toward the 1st the step obtain 2, add sodium hydroxide in the 5-acid dimethyl, react to pH=8～10, obtain 2,5-acid dimethyl sodium;
3, again with the 2nd step obtain 2,5-acid dimethyl sodium and sodium hydroxide is with the mixed of mol ratio 1:1.5-2.5, and is heated to 280～300 ℃ and makes it complete reaction, obtains 2, the aqueous solution of 5-xylenol sodium;
4, toward the 3rd the step obtain 2, feed sulfurous gas in the aqueous solution of 5-xylenol sodium, react to pH=3～4, obtain 2,5-xylenol bullion; Obtain S-WAT simultaneously;
5, with the 4th the step obtain 2; 5-xylenol bullion carries out underpressure distillation and obtains distillate; Then with distillate and water by volume 1:2-3 mix, and stir decrease temperature crystalline and become needle-like 2, the 5-xylenol is dispersed in the water; After obtain 2, the 5-xylenol after whizzer preliminary hydro-extraction and the dehydration of revolution vacuum drier two-stage.
2. aqueous fusion according to claim 1 melts crystallization production needle-like 2, and the method for 5-xylenol is characterized in that: the reaction times of the 1st step with the 3rd step is 3-4 hours.
3. aqueous fusion according to claim 1 melts crystallization production needle-like 2, and the method for 5-xylenol is characterized in that: the 3rd the step in 2,5-acid dimethyl sodium and sodium hydroxide are 1:2 with the mol ratio.
4. aqueous fusion according to claim 1 melts crystallization production needle-like 2, and the method for 5-xylenol is characterized in that: the volume ratio 1:2.5 of distillate and water in the 5th step.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011103184198A CN102627531A (en) | 2011-10-19 | 2011-10-19 | Method for producing acicular 2, 5-dimethylphenol by water melt crystallization |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011103184198A CN102627531A (en) | 2011-10-19 | 2011-10-19 | Method for producing acicular 2, 5-dimethylphenol by water melt crystallization |
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| CN102627531A true CN102627531A (en) | 2012-08-08 |
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| CN2011103184198A Pending CN102627531A (en) | 2011-10-19 | 2011-10-19 | Method for producing acicular 2, 5-dimethylphenol by water melt crystallization |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108047001A (en) * | 2017-12-07 | 2018-05-18 | 西北化工研究院 | A kind of method for synthesizing 2,5- xylenols |
| CN108530267A (en) * | 2018-01-19 | 2018-09-14 | 南通柏盛化工有限公司 | A kind of preparation method of 2,5- xylenols |
| CN115181039A (en) * | 2022-07-15 | 2022-10-14 | 宁夏天新药业有限公司 | Method for continuously producing 2, 5-dimethylbenzenesulfonic acid and application thereof, and 2, 5-dimethylbenzenesulfonic acid |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1201776A (en) * | 1998-05-29 | 1998-12-16 | 锦洲石化天元集团公司 | Synthesis of p-cresol by direct alkali fusion method from toluene-p-sulfonic acid |
-
2011
- 2011-10-19 CN CN2011103184198A patent/CN102627531A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1201776A (en) * | 1998-05-29 | 1998-12-16 | 锦洲石化天元集团公司 | Synthesis of p-cresol by direct alkali fusion method from toluene-p-sulfonic acid |
Non-Patent Citations (3)
| Title |
|---|
| 姚远等: "2, 5-二甲基苯酚的制备", 《中国医药工业杂志》 * |
| 汤卫平: "2, 5-二甲基苯酚的制备", 《化学试剂》 * |
| 郭泰兴等: "磺化-碱熔法苯酚装置的合理利用", 《氯碱工业》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108047001A (en) * | 2017-12-07 | 2018-05-18 | 西北化工研究院 | A kind of method for synthesizing 2,5- xylenols |
| CN108047001B (en) * | 2017-12-07 | 2021-02-23 | 西北化工研究院 | Method for synthesizing 2, 5-dimethylphenol |
| CN108530267A (en) * | 2018-01-19 | 2018-09-14 | 南通柏盛化工有限公司 | A kind of preparation method of 2,5- xylenols |
| CN115181039A (en) * | 2022-07-15 | 2022-10-14 | 宁夏天新药业有限公司 | Method for continuously producing 2, 5-dimethylbenzenesulfonic acid and application thereof, and 2, 5-dimethylbenzenesulfonic acid |
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Application publication date: 20120808 |