CN113461544B - Method for treating mixed liquid containing acetonitrile, triethylamine and water - Google Patents
Method for treating mixed liquid containing acetonitrile, triethylamine and water Download PDFInfo
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- CN113461544B CN113461544B CN202110706991.5A CN202110706991A CN113461544B CN 113461544 B CN113461544 B CN 113461544B CN 202110706991 A CN202110706991 A CN 202110706991A CN 113461544 B CN113461544 B CN 113461544B
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/82—Purification; Separation; Stabilisation; Use of additives
- C07C209/86—Separation
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C253/00—Preparation of carboxylic acid nitriles
- C07C253/32—Separation; Purification; Stabilisation; Use of additives
- C07C253/34—Separation; Purification
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Abstract
The invention relates to a method for processing a mixed solution containing acetonitrile, triethylamine and water, which comprises the steps of rectifying the mixed solution to obtain a first material containing the acetonitrile, the triethylamine and the water at the tower top, obtaining a second material containing the acetonitrile and the water at the tower bottom, carrying out azeotropic rectification on the first material and the cyclohexane to obtain a third material containing the cyclohexane, the acetonitrile, the water and the triethylamine at the tower top, obtaining a triethylamine product at the tower bottom, carrying out liquid-liquid extraction on the third material and the water to obtain a fifth material containing the water, the acetonitrile and the triethylamine at a heavy phase, obtaining a sixth material containing the cyclohexane and the triethylamine at a light phase, extracting the fifth material to carry out rectification to obtain a seventh material containing the azeotrope of the acetonitrile and the water at the tower top, and obtaining the water at the tower bottom. The invention can effectively treat the mixed liquid containing acetonitrile, triethylamine and water, and separate and recover the acetonitrile and triethylamine in the mixed liquid respectively, and is particularly suitable for the wastewater treatment in the pharmaceutical industry.
Description
Technical Field
The invention relates to a method for treating mixed liquid containing acetonitrile, triethylamine and water.
Background
Waste water containing acetonitrile and triethylamine is generated in the pharmaceutical industry, the acetonitrile and triethylamine in the waste water are good organic solvents and have high recovery value, but the acetonitrile, the water and the triethylamine form ternary azeotropic mixture, and the acetonitrile, the water and the triethylamine are difficult to separate by adopting a common method.
Disclosure of Invention
The invention mainly aims to separate the acetonitrile and the triethylamine from the mixed solution containing the acetonitrile, the triethylamine and water.
In order to achieve the above object, the present invention provides a method for treating a mixed solution containing acetonitrile, triethylamine and water, comprising the steps of:
rectifying the mixed solution in a first rectifying tower to obtain a first material containing acetonitrile, triethylamine and water at the tower top, obtaining a second material containing acetonitrile and water at the tower bottom,
the first material and cyclohexane are subjected to azeotropic distillation in a second rectifying tower to obtain a third material containing cyclohexane, acetonitrile, water and triethylamine at the tower top, a triethylamine product is obtained at the tower bottom,
performing liquid-liquid extraction on the third material and water in a liquid-liquid extraction tower to obtain a fifth material containing water, acetonitrile and triethylamine in a heavy phase, obtaining a sixth material containing cyclohexane and triethylamine in a light phase,
the fifth material is extracted and rectified in a third rectifying tower to obtain a seventh material containing azeotrope of acetonitrile and water at the tower top and water at the tower bottom,
and carrying out extractive distillation on the second material, the seventh material and ethylene glycol to obtain an acetonitrile product.
In some embodiments, the operating conditions of the first rectification column are: normal pressure, tower top temperature 63-70 deg.c, tower bottom temperature 72-82 deg.c and reflux ratio of 1-3.
In some embodiments, the first rectification column has an overhead temperature of 66.2 ℃, a bottoms temperature of 77.6 ℃, and a reflux ratio of 3.
In some embodiments, the operating conditions of the second rectification column are: normal pressure, tower top temperature of 50-60 deg.c, tower kettle temperature of 85-100 deg.c and reflux ratio of 1-4.
In some embodiments, the overhead temperature of the second rectification column is 53.6 ℃, the still temperature is 90.4 ℃, and the reflux ratio is 2.
In some embodiments, the liquid-liquid extraction column is operated at atmospheric pressure, an overhead temperature of 0 to 60 ℃, and a bottoms temperature of 0 to 60 ℃.
In some embodiments, the rectification by the third rectification column is batch rectification and the operating conditions of the third rectification column are: under normal pressure, the temperature of the top of the tower is 72-80 ℃, the temperature of the bottom of the tower is 98-105 ℃, the primary fraction of the third rectifying tower is an eighth material containing water, acetonitrile and triethylamine, the secondary fraction is the seventh material, and the eighth material reflows to the first rectifying tower for rectification.
In some embodiments, the third rectification column has an overhead temperature of 76.6 ℃ and a kettle temperature of 101.0 ℃.
In some embodiments, said sixth material is refluxed to a second rectification column for said azeotropic rectification.
In some embodiments, the water from the third distillation column bottoms is refluxed to the lle column.
The treatment method can effectively treat the mixed liquid containing the acetonitrile, the triethylamine and the water, and separate and recover the acetonitrile and the triethylamine in the mixed liquid respectively, and is particularly suitable for treating the wastewater in the pharmaceutical industry.
Drawings
FIG. 1 is a schematic diagram of a process for treating a mixture containing acetonitrile, triethylamine and water.
In the figure: 1. the method comprises the following steps of a first rectifying tower, 2, a second rectifying tower, 3, a liquid-liquid extraction tower, 4, a third rectifying tower, 5, an ethylene glycol extractive distillation system, 100, mixed liquor, 101, a first material, 102, a second material, 103, a third material, 104, a triethylamine product, 105, a fifth material, 106, a sixth material, 107a, an eighth material, 107b, a seventh material, 108, water, 200, cyclohexane and 300, wherein the first rectifying tower, the second rectifying tower, the third rectifying tower, the second rectifying tower, the mixed liquor, the first material, the second material, the 103, the third material, the 104, the triethylamine product, the 105, the fifth material, the 106, the sixth material, the 107a, the eighth material, the 107b, the seventh material, the 108, the water, the 200, and the 300.
Detailed Description
The rectifying tower in this embodiment includes not only the tower body, but also relevant corollary equipment and instrumentation systems, such as a relevant pump, a pipeline, a valve, a control system, etc., configured for the rectifying tower body to achieve rectification.
In the embodiment, the conveying of each material can be controlled by adopting pipelines, pumps, valves and control systems, and the temperature of the material can be adjusted by various heaters, heat exchangers and other equipment.
The extraction tower in this embodiment includes not only a tower body, but also relevant corollary equipment and instrumentation systems, such as relevant pumps, pipelines, valves, control systems, and the like, configured for the extraction tower in order to realize extraction split-phase extraction.
The contents in the present example are weight percentages unless otherwise specified.
The invention relates to a method for treating mixed liquid containing acetonitrile, triethylamine and water, which mainly comprises the following steps:
rectifying the mixed solution in a first rectifying tower to obtain a first material containing acetonitrile, triethylamine and water at the tower top, obtaining a second material containing acetonitrile and water at the tower bottom,
the first material and cyclohexane are subjected to azeotropic distillation in a second rectifying tower to obtain a third material containing cyclohexane, acetonitrile, water and triethylamine at the tower top, a triethylamine product is obtained at the tower bottom,
performing liquid-liquid extraction on the third material and water in a liquid-liquid extraction tower to obtain a fifth material containing water, acetonitrile and triethylamine in a heavy phase, obtaining a sixth material containing cyclohexane and triethylamine in a light phase,
the fifth material is extracted and rectified in a third rectifying tower to obtain a seventh material containing azeotrope of acetonitrile and water at the tower top, water is obtained at the tower bottom,
and carrying out extractive distillation on the second material, the seventh material and ethylene glycol to obtain an acetonitrile product.
The invention is further described with reference to the following figures and examples.
The mixed solution 100 subjected to the lock treatment in this example contains 68.57% of acetonitrile, 16.82% of triethylamine, 14.6% of water and 0.01% of toluene, and the mixed solution is conveyed to the first rectifying tower 1 through a pipeline for continuous rectification, wherein the feeding flow rate of the first rectifying tower is 1000kg/h, and the operating conditions of the first rectifying tower 1 are as follows: the atmospheric pressure, the overhead temperature 66.2 ℃, the bottom temperature 77.6 ℃, the reflux ratio 3, the first mass 101 containing 31.35% acetonitrile, 61.16% triethylamine, 7.45% water and 0.04% toluene, the top discharge at a flow rate of 275kg/h, the second mass 102 containing 82.69% acetonitrile and 17.31% water, the bottom discharge at a flow rate of 725kg/h.
The first material 101 and cyclohexane 200 are conveyed to a second rectifying tower 2 together through a pipeline for azeotropic rectification, the feeding flow rate of the first material is 275kg/h, the feeding flow rate of the cyclohexane is 500kg/h, and the operating conditions of the second rectifying tower 2 are as follows: the reaction conditions were normal pressure, the top temperature of 53.6 ℃ and the bottom temperature of 90.4 ℃, the reflux ratio was 0.2, the third material 103 containing 14.0% acetonitrile, 1.03% triethylamine, 81.56% cyclohexane and 3.34% water was discharged from the top of the second rectification column 2 at a flow rate of 613kg/h, and the triethylamine product 104 containing 99.9% triethylamine and 0.06% toluene was discharged from the bottom at a flow rate of 162kg/h, whereby high purity triethylamine was separated at the bottom of the second rectification column.
The third material 103 and water 300 enter the liquid-liquid extraction tower 3 together for extraction and phase separation, the feed flow of the third material is 613kg/h, the feed flow of the water is 300kg/h, and the operation conditions of the liquid-liquid extraction tower 3 are as follows: under normal pressure, the temperature at the top of the tower is 24.6 ℃, the temperature at the bottom of the tower is 54.5 ℃, most of acetonitrile in the third material is extracted by water to form a heavy phase, cyclohexane is enriched in a light phase, the light phase discharge of the liquid-liquid extraction tower is a sixth material 106 containing 98.7 percent of cyclohexane and 1.23 percent of triethylamine, the flow rate is 506kg/h, and the heavy phase discharge is a fifth material 105 containing 21.17 percent of acetonitrile, 0.03 percent of triethylamine, 0.07 percent of cyclohexane and 78.72 percent of water, the flow rate is 407kg/h.
The sixth material 106 contains 98.7% cyclohexane, and can be directly returned to the second rectifying tower 2 as an entrainer to perform azeotropic rectification with the first material 101.
The fifth material 105 is conveyed to a third rectifying tower 4 through a pipeline for intermittent rectification separation, and the operating conditions of the third rectifying tower are as follows: under the conditions that the tower top temperature is 76.6 ℃ and the tower bottom temperature is 101.0 ℃, the primary fraction at the tower top of the third rectifying tower is an eighth material 107a containing 81.16% of acetonitrile, 0.45% of triethylamine, 1.05% of cyclohexane and 17.35% of water, the eighth material 107a can reflux and enter the first rectifying tower 1 together with the mixed solution 100 for rectification, the secondary fraction after the primary fraction is a seventh material 107b containing 80.29% of acetonitrile and 19.71% of water, the material discharged from the tower bottom is pure water, and the water discharged from the tower bottom can be directly used as an extractant of the third material to return to the liquid-liquid extraction tower 3.
The second material and the seventh material are both a mixture of acetonitrile and water, and can be subjected to extractive distillation through an ethylene glycol extractive distillation system 5 in the prior art so as to obtain an acetonitrile product by separation.
The embodiments of the present invention are merely illustrative, and not restrictive, of the scope of the claims, and other substantially equivalent alternatives may occur to those skilled in the art and are within the scope of the present invention.
Claims (10)
1. A treatment method of mixed liquid containing acetonitrile, triethylamine and water is characterized by comprising the following steps:
rectifying the mixed solution in a first rectifying tower to obtain a first material containing acetonitrile, triethylamine and water at the tower top, obtaining a second material containing acetonitrile and water at the tower bottom,
the first material and cyclohexane are subjected to azeotropic distillation in a second rectifying tower to obtain a third material containing cyclohexane, acetonitrile, water and triethylamine at the tower top, a triethylamine product is obtained at the tower bottom,
performing liquid-liquid extraction on the third material and water in a liquid-liquid extraction tower to obtain a fifth material containing water, acetonitrile and triethylamine in a heavy phase, obtaining a sixth material containing cyclohexane and triethylamine in a light phase,
the fifth material is extracted and rectified in a third rectifying tower to obtain a seventh material containing azeotrope of acetonitrile and water at the tower top, water is obtained at the tower bottom,
and carrying out extractive distillation on the second material, the seventh material and ethylene glycol to obtain an acetonitrile product.
2. The process according to claim 1, characterized in that the operating conditions of the first rectification column are: normal pressure, tower top temperature 63-70 deg.c, tower bottom temperature 72-82 deg.c and reflux ratio of 1-3.
3. The process according to claim 2, wherein the first rectification column has a top temperature of 66.2 ℃, a bottom temperature of 77.6 ℃ and a reflux ratio of 3.
4. The process according to claim 1, characterized in that the operating conditions of the second rectification column are: normal pressure, tower top temperature of 50-60 deg.c, tower kettle temperature of 85-100 deg.c and reflux ratio of 1-4.
5. The process according to claim 4, wherein the second rectification column has an overhead temperature of 53.6 ℃, a bottom temperature of 90.4 ℃ and a reflux ratio of 2.
6. The process of claim 1, wherein the liquid-liquid extraction column is operated at atmospheric pressure, a head temperature of 0 to 60 ℃ and a bottom temperature of 0 to 60 ℃.
7. The process according to claim 1, wherein the rectification in the third rectification column is a batch rectification and the third rectification column is operated under the following conditions: under normal pressure, the temperature of the top of the tower is 72-80 ℃, the temperature of the bottom of the tower is 98-105 ℃, the primary fraction of the third rectifying tower is an eighth material containing water, acetonitrile and triethylamine, the secondary fraction is the seventh material, and the eighth material reflows to the first rectifying tower for rectification.
8. The process according to claim 7, wherein the third rectification column has an overhead temperature of 76.6 ℃ and a bottom temperature of 101.0 ℃.
9. The process of claim 1 wherein said sixth stream is refluxed to a second rectification column for said azeotropic rectification.
10. The process according to claim 1, wherein the water from the bottom of the third distillation column is refluxed to the lle column.
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| CN115850091A (en) * | 2022-12-30 | 2023-03-28 | 东华工程科技股份有限公司 | Method for separating acetonitrile, triethylamine and water by azeotropic distillation |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4308108A (en) * | 1979-03-28 | 1981-12-29 | Asahi Kasei Kogyo Kabushiki Kaisha | Process for purification of crude acetonitrile |
| US5876569A (en) * | 1998-06-29 | 1999-03-02 | Berg; Lloyd | Separation of methyl ethyl ketone from ethanol by extractive distillation |
| CN106349107A (en) * | 2016-08-24 | 2017-01-25 | 青岛科技大学 | Method and device for separating acetonitrile-triethylamine mixture through heterogeneous azeotropic rectification |
| CN108658785A (en) * | 2017-09-08 | 2018-10-16 | 杭州九清科技有限公司 | The separation method of difficult separation system containing triethylamine |
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| WO2005044783A2 (en) * | 2003-11-04 | 2005-05-19 | Lonza Ag | Acetonitrile recycling process |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4308108A (en) * | 1979-03-28 | 1981-12-29 | Asahi Kasei Kogyo Kabushiki Kaisha | Process for purification of crude acetonitrile |
| US5876569A (en) * | 1998-06-29 | 1999-03-02 | Berg; Lloyd | Separation of methyl ethyl ketone from ethanol by extractive distillation |
| CN106349107A (en) * | 2016-08-24 | 2017-01-25 | 青岛科技大学 | Method and device for separating acetonitrile-triethylamine mixture through heterogeneous azeotropic rectification |
| CN108658785A (en) * | 2017-09-08 | 2018-10-16 | 杭州九清科技有限公司 | The separation method of difficult separation system containing triethylamine |
Non-Patent Citations (1)
| Title |
|---|
| 萃取精馏分离丙酮-四氢呋喃的研究;刘岩等;《化学工程》;20121215(第12期);全文 * |
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