CN1268510A - 4-methylimidazole refining process - Google Patents
4-methylimidazole refining process Download PDFInfo
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- CN1268510A CN1268510A CN99113573A CN99113573A CN1268510A CN 1268510 A CN1268510 A CN 1268510A CN 99113573 A CN99113573 A CN 99113573A CN 99113573 A CN99113573 A CN 99113573A CN 1268510 A CN1268510 A CN 1268510A
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- methylimidazole
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Abstract
The present invention relates to a refining technology of r-methyl imidazole, it adopts reduced-pressure distillation and installs a stirrer in the distilling tower kettle and outside reflux at tower top, so that it reduces greatly the polymer content in tower kettle, and at the same time, the purity of 4-methylimidazole is raised.
Description
The present invention relates to the 4-methylimidazole process for refining, particularly about containing the process for refining that 4-methylimidazole, glyoxal ethyline, ammonium oxalate and water are raw material.
4-methylimidazole is important medicine intermediate, is mainly used in synthetic anti-ulcer medicament Cimitidine Type A/AB.The technology of producing 4-methylimidazole at present mainly contains following several: (a) adopt pyruvic aldehyde, formaldehyde and ammonium sulfate at pH value 1～3, the synthetic 4-methylimidazole of dehydration condensation more than 80 ℃, extract with isopropylcarbinol, the 4-methylimidazole recovery rate reaches 85～88%, but this technological reaction is restive, the poor product quality that makes can not be as the raw material of synthetic Cimitidine Type A/AB; (b) adopt formaldehyde, pyruvic aldehyde to synthesize 4-methylimidazole technology with the ammonium succinate dehydration condensation, the yield of this technology only about 60%, and post-processing step is many, the production cost height; (c) adopt the synthetic 4-methylimidazole of formaldehyde, pyruvic aldehyde and ammonium oxalate dehydration condensation.The good product quality that this technology obtains, and ammonium oxalate can be recycled, so production cost is lower.It is raw material that the clear 60-104072 of document has introduced with the ammonium oxalate aqueous solution, formaldehyde, pyruvic aldehyde, the water yield: pyruvic aldehyde is 4～30 (w/w), or adds pyruvic aldehyde in the aqueous solution of ammonium oxalate and formaldehyde; Or in the ammonium oxalate aqueous solution, add the mixed solution of pyruvic aldehyde and formaldehyde; Or add pyruvic aldehyde, formaldehyde and ammonium oxalate in the water simultaneously respectively.Its reaction times needs 2～5 hours, contains 4-methylimidazole, glyoxal ethyline and not reacted pyruvic aldehyde, ammonium oxalate, water and other light component in the resultant of reaction.Because the thermostability of 4-methylimidazole is relatively poor, under long-time hot conditions, easily decompose and the generation superpolymer.Therefore, in treating process, be difficult to obtain the highly purified 4-methylimidazole and the higher refining rate of recovery.Adopt the way of underpressure distillation in the document, 130～140 ℃ of tower still temperature, vacuum tightness are to separate above-mentioned raw materials under the 7 mmhg conditions, its product purity reaches 98.5%, but the openly not refining rate of recovery, promptly there are a large amount of superpolymer in superpolymer content data in the still in test confirms its still.
The objective of the invention is to exist overhead product purity high not enough in the above-mentioned document, exist a large amount of superpolymer to influence the shortcoming of the product purification rate of recovery in the still, a kind of new 4-methylimidazole process for refining is provided in order to overcome.It is low that this technology has in the tower still superpolymer content, thereby can effectively improve the characteristics of the 4-methylimidazole product purity and the refining rate of recovery.
The objective of the invention is to realize: a kind of process for refining of 4-methylimidazole by following technical scheme, raw material contains 4-methylimidazole, glyoxal ethyline, ammonium oxalate and water, in rectifying tower, carry out underpressure distillation, its tower still temperature is 130～170 ℃, tower top temperature is 63～160 ℃, vacuum tightness is 5～40 mmhg, and rectifying Tata still has whipping appts, the cat head external reflux.
The stirring velocity of tower still whipping appts is 50～150 rev/mins in the technique scheme, and the reflux ratio of cat head external reflux is 1～5.
Owing to whipping appts is set, improved the flow condition of material in the still among the present invention, improved mass transfer and heat transfer efficiency, made tower still inwall be difficult for forming high-polymer membrane, reduced the formation of superpolymer in the still, improved the refining rate of recovery of 4-methylimidazole at the tower still.Adopt the high vacuum reduced pressure distillation technique, greatly reduce the service temperature of rectifying tower, reduced the decomposition and the polymerization of product 4-methylimidazole, reached superpolymer content in the minimizing still equally, improve the purpose of the refining rate of recovery.Adopt cat head external reflux technology to improve the purity of product 4-methylimidazole effectively, obtained effect preferably.
The invention will be further elaborated below by embodiment.[embodiment 1]
Theoretical number of plates of rectifying tower is 16.Under vacuum tightness 5 mmhg, tower still agitator speed is 83 rev/mins, and the trim the top of column ratio is 1, and tower still temperature is 130 ℃, and tower top temperature is 63 ℃.Through operation, superpolymer content is 3.3% (weight) in the still, and the purity of cat head 4-methylimidazole product is 99.1%.[embodiment 2]
Theoretical number of plates of rectifying tower is 16.Under vacuum tightness 20 mmhg, tower still agitator speed is 83 rev/mins, and the trim the top of column ratio is 2, and tower still temperature is 142 ℃, and tower top temperature is 102 ℃.Through operation, superpolymer content is 3.4% (weight) in the still, and the purity of cat head 4-methylimidazole product is 99.3%.[embodiment 3]
Theoretical number of plates of rectifying tower is 16.Under vacuum tightness 40 mmhg, tower still agitator speed is 83 rev/mins, and the trim the top of column ratio is 5, and tower still temperature is 170 ℃, and tower top temperature is 160 ℃.Through operation, superpolymer content is 3.8% (weight) in the still, and the purity of cat head 4-methylimidazole product is 99.5%.[comparative example 1]
Theoretical number of plates of rectifying tower is 16.Under vacuum tightness 5 mmhg, the tower still does not have agitator, and cat head does not have external reflux, and tower still temperature is 130 ℃, and tower top temperature is 63 ℃.Through operation, superpolymer content is 15.8% (weight) in the still, and the purity of cat head 4-methylimidazole product is 98%.[comparative example 2]
Theoretical number of plates of rectifying tower is 16.Under vacuum tightness 5 mmhg, tower still agitator speed is 83 rev/mins, and cat head does not have external reflux, and tower still temperature is 130 ℃, and tower top temperature is 63 ℃.Through operation, superpolymer content is 3.1% (weight) in the still, and the purity of cat head 4-methylimidazole product is 97%.[comparative example 3]
Theoretical number of plates of rectifying tower is 16.Under vacuum tightness 5 mmhg, the tower still does not have agitator, and the trim the top of column ratio is 1, and tower still temperature is 130 ℃, and tower top temperature is 63 ℃.Through operation, superpolymer content is 15.8% (weight) in the still, and pure the rubbing of cat head 4-methylimidazole product is 99.0%.
Claims (3)
1, a kind of process for refining of 4-methylimidazole, raw material contains 4-methylimidazole, glyoxal ethyline, ammonium oxalate and water, in rectifying tower, carry out underpressure distillation, its tower still temperature is 130～170 ℃, tower top temperature is 63～160 ℃, vacuum tightness is 5～40 mmhg, it is characterized in that rectifying Tata still band whipping appts, the cat head external reflux.
2, according to the process for refining of the described 4-methylimidazole of claim 1, the stirring velocity that it is characterized in that tower still whipping appts is 50～150 rev/mins.
3, according to the process for refining of the described 4-methylimidazole of claim 1, the reflux ratio that it is characterized in that the cat head external reflux is 1～5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99113573 CN1092644C (en) | 1999-03-30 | 1999-03-30 | 4-methylimidazole refining process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99113573 CN1092644C (en) | 1999-03-30 | 1999-03-30 | 4-methylimidazole refining process |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1268510A true CN1268510A (en) | 2000-10-04 |
| CN1092644C CN1092644C (en) | 2002-10-16 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 99113573 Expired - Fee Related CN1092644C (en) | 1999-03-30 | 1999-03-30 | 4-methylimidazole refining process |
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| CN (1) | CN1092644C (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104496907A (en) * | 2015-01-07 | 2015-04-08 | 江苏沿江化工资源开发研究院有限公司 | Method for refining imidazole through combination of continuous reduced-pressure side stream rectification and roller crystallization |
| CN108794402A (en) * | 2018-07-16 | 2018-11-13 | 南京雪郎化工科技有限公司 | A kind of preparation method of 4-methylimidazole |
| CN110988175A (en) * | 2019-12-17 | 2020-04-10 | 南京正济医药研究有限公司 | Method for determining genotoxic impurity methylglyoxal in cimetidine |
-
1999
- 1999-03-30 CN CN 99113573 patent/CN1092644C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104496907A (en) * | 2015-01-07 | 2015-04-08 | 江苏沿江化工资源开发研究院有限公司 | Method for refining imidazole through combination of continuous reduced-pressure side stream rectification and roller crystallization |
| CN108794402A (en) * | 2018-07-16 | 2018-11-13 | 南京雪郎化工科技有限公司 | A kind of preparation method of 4-methylimidazole |
| CN110988175A (en) * | 2019-12-17 | 2020-04-10 | 南京正济医药研究有限公司 | Method for determining genotoxic impurity methylglyoxal in cimetidine |
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| Publication number | Publication date |
|---|---|
| CN1092644C (en) | 2002-10-16 |
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Granted publication date: 20021016 Termination date: 20100330 |