CN113461482A - Process for the purification of aqueous dichloromethane - Google Patents
Process for the purification of aqueous dichloromethane Download PDFInfo
- Publication number
- CN113461482A CN113461482A CN202110705693.4A CN202110705693A CN113461482A CN 113461482 A CN113461482 A CN 113461482A CN 202110705693 A CN202110705693 A CN 202110705693A CN 113461482 A CN113461482 A CN 113461482A
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- Prior art keywords
- dichloromethane
- tower
- temperature
- phase separation
- aqueous
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- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 title claims abstract description 176
- 238000000034 method Methods 0.000 title claims abstract description 16
- 238000000746 purification Methods 0.000 title claims abstract description 7
- 239000000463 material Substances 0.000 claims abstract description 42
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 18
- 150000005846 sugar alcohols Polymers 0.000 claims abstract description 8
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 28
- 238000005191 phase separation Methods 0.000 claims description 24
- 238000010992 reflux Methods 0.000 claims description 12
- 229920005862 polyol Polymers 0.000 claims description 3
- 150000003077 polyols Chemical class 0.000 claims description 3
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 claims description 2
- 238000000605 extraction Methods 0.000 description 4
- 229960003022 amoxicillin Drugs 0.000 description 1
- LSQZJLSUYDQPKJ-NJBDSQKTSA-N amoxicillin Chemical compound C1([C@@H](N)C(=O)N[C@H]2[C@H]3SC([C@@H](N3C2=O)C(O)=O)(C)C)=CC=C(O)C=C1 LSQZJLSUYDQPKJ-NJBDSQKTSA-N 0.000 description 1
- 229960000723 ampicillin Drugs 0.000 description 1
- AVKUERGKIZMTKX-NJBDSQKTSA-N ampicillin Chemical compound C1([C@@H](N)C(=O)N[C@H]2[C@H]3SC([C@@H](N3C2=O)C(O)=O)(C)C)=CC=CC=C1 AVKUERGKIZMTKX-NJBDSQKTSA-N 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005237 degreasing agent Methods 0.000 description 1
- 239000013527 degreasing agent Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000004088 foaming agent Substances 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 231100000053 low toxicity Toxicity 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000006082 mold release agent Substances 0.000 description 1
- LSQZJLSUYDQPKJ-UHFFFAOYSA-N p-Hydroxyampicillin Natural products O=C1N2C(C(O)=O)C(C)(C)SC2C1NC(=O)C(N)C1=CC=C(O)C=C1 LSQZJLSUYDQPKJ-UHFFFAOYSA-N 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 239000012429 reaction media Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/38—Separation; Purification; Stabilisation; Use of additives
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/38—Separation; Purification; Stabilisation; Use of additives
- C07C17/383—Separation; Purification; Stabilisation; Use of additives by distillation
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Extraction Or Liquid Replacement (AREA)
Abstract
The invention relates to a method for purifying aqueous dichloromethane, which comprises the following steps: extracting and phase-separating the aqueous dichloromethane and the polyhydric alcohol in a phase-separating tank together to obtain a first material containing dichloromethane in a heavy phase, carrying out side-line rectification on the first material in a first rectifying tower, and obtaining a dichloromethane product in the side line. The purification method of the invention can further reduce and remove a small amount of water contained in the dichloromethane, thereby obtaining an industrial-grade dichloromethane product.
Description
Technical Field
The present invention relates to a process for the purification of aqueous dichloromethane.
Background
Dichloromethane has the advantages of good solubility and low toxicity, and can be used as reaction medium in pharmaceutical industry for preparing ampicillin, amoxicillin and cephalomycin. Besides, methylene chloride can be used as a coating solvent, a metal degreasing agent, a gas fume spray, a polyurethane foaming agent, a mold release agent, a paint remover and the like. Dichloromethane is slightly soluble in water and dichloromethane can form an azeotrope with a boiling point close to that of dichloromethane. The methylene dichloride waste liquid generated in the biological pharmacy industry is rectified, refined and phase-separated to obtain methylene dichloride recovery products which usually contain about 0.1 percent of water, the water content of qualified industrial methylene dichloride products is at least required to be lower than 0.06 percent, and the concentration of water which is slightly soluble in methylene dichloride is reduced from 0.1 percent to below 0.06 percent, which obviously cannot be realized by the conventional method.
Disclosure of Invention
The main purpose of the invention is to realize the separation of trace water contained in dichloromethane so as to further purify the dichloromethane.
In order to achieve the above object, the present invention provides a method for purifying aqueous dichloromethane, comprising the steps of:
extracting aqueous dichloromethane and polyalcohol in a phase separation tank for phase separation to obtain a first material containing dichloromethane in a heavy phase,
and the first material is subjected to side line rectification in a first rectifying tower, and a dichloromethane product is obtained at the side line.
In some embodiments, the light phase of the extractive phase separation is conducted to obtain a second material containing polyhydric alcohol and water, the second material is rectified in a second rectifying tower, a fifth material containing polyhydric alcohol is obtained in the tower bottom, and the fifth material is refluxed and is subjected to extractive phase separation together with the aqueous dichloromethane.
In some embodiments, the operating conditions of the second rectification column are: 101kPa, the tower top temperature is 70-75 ℃, the tower kettle temperature is 190-200 ℃, the reflux ratio is 1-4, and polyol is added.
In some embodiments, the second rectification column has an overhead temperature of 72.75 ℃, a bottoms temperature of 196.98 ℃, and a reflux ratio of 2.
In some embodiments, the operating conditions of the first rectification column are: under normal pressure, the temperature at the top of the tower is 35-40 ℃, the temperature at the bottom of the tower is 170-175 ℃, the reflux ratio is 0.2-3, a dichloromethane product is discharged from the lateral line of the first rectifying tower, the discharged material at the top of the tower is a third material containing dichloromethane and water, and the discharged material at the bottom of the tower is a fourth material containing glycol and dichloromethane.
In some embodiments, refluxing the third and fourth materials together with the aqueous dichloromethane performs the extractive phase separation.
In some embodiments, the first rectification column has an overhead temperature of 39.5 ℃, a kettle temperature of 172.6 ℃, and a reflux ratio of 0.5.
In some embodiments, the polyol is ethylene glycol.
The purification method of the invention can further reduce and remove a small amount of water contained in the dichloromethane, thereby obtaining a dichloromethane product.
Drawings
FIG. 1 is a schematic flow diagram of the purification of methylene chloride.
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, and the like, configured for the rectifying tower body to achieve rectification.
In this embodiment, the transportation of each material may be controlled by a pipeline, a pump, a valve, and a control system, and the temperature of the material may be adjusted by various heaters, heat exchangers, and other devices.
The phase separation tank in this embodiment is not limited to a strict tank body, and may be various devices for performing phase separation, such as a phase separation tower and a phase separation tank, and may further include related supporting devices and instrumentation systems, such as a related pump, a pipeline, an invention, and a control system, which are configured for the phase separation tank to perform phase separation.
The contents in the present example are weight percentages unless otherwise specified.
The method for purifying the aqueous dichloromethane mainly comprises the following steps:
extracting aqueous dichloromethane and polyalcohol in a phase separation tank for phase separation to obtain a first material containing dichloromethane in a heavy phase,
and the first material is subjected to side line rectification in a first rectifying tower, and a dichloromethane product is obtained at the side line.
The invention is further described with reference to the following figures and examples.
The aqueous dichloromethane treated in this example contains 99.9% of dichloromethane and 0.1% of water by weight, and the aqueous dichloromethane and ethylene glycol are fed into a phase separation tank together for extraction phase separation, wherein the flow rate of the aqueous dichloromethane is 1000kg/h, the flow rate of the ethylene glycol is 500kg/h, the light phase after extraction phase separation is a first material containing 99.8% of ethylene glycol, 0.2% of water and 0.1% of dichloromethane, the flow rate of the light phase is 495kg/h, the heavy phase is a second material containing 0.5% of ethylene glycol, 0.01% of water and 99.5% of dichloromethane, and the flow rate of the heavy phase is 1005 kg/h. The heavy phase and the light phase are treated separately.
Extracting a first material, rectifying the first material in a first rectifying tower to further refine the dichloromethane, wherein the flow rate of the first material is 1005kg/h, the operating conditions of the first rectifying tower are normal pressure, the tower top temperature is 39.5 ℃, the tower bottom temperature is 172.6 ℃, the reflux ratio is 0.5, the tower top discharge is a third material of 99.0% of dichloromethane and 1% of water, the flow rate is 10kg/h, the tower bottom discharge is a fourth material of 10% of ethylene glycol and 90% of dichloromethane, the flow rate is 55kg/h, the side line discharge is a dichloromethane product containing 99.99% of dichloromethane and 0.01% of water, and the flow rate is 940 kg/h. The third material discharged from the top of the tower and the fourth material discharged from the bottom of the tower can return to the phase separation tank to continue extraction phase separation.
And the second material is sent to a second rectifying tower for rectification, the flow rate is 495kg/h, the operating condition of the second rectifying tower is 101kPa, the tower top temperature is 72.75 ℃, the tower bottom temperature is 196.98 ℃, the reflux ratio is 2, the material discharged from the tower top is 99.5 percent of water and trace dichloromethane wastewater, the flow rate is 99kg/h, and the material discharged from the tower bottom is a fifth material of 99.99 percent of ethylene glycol and 0.01 percent of water, the flow rate is 396 kg/h. The fifth material can return to the phase separation tank to continuously participate in extraction phase 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 (8)
1. A method for purifying aqueous dichloromethane, characterized by comprising the steps of:
extracting aqueous dichloromethane and polyalcohol in a phase separation tank for phase separation to obtain a first material containing dichloromethane in a heavy phase,
and the first material is subjected to side line rectification in a first rectifying tower, and a dichloromethane product is obtained at the side line.
2. The method of claim 1, wherein the light phase of the extractive phase separation is separated to obtain a second material comprising polyhydric alcohol and water, the second material is rectified in a second rectification column, a fifth material comprising polyhydric alcohol is obtained in the bottom of the column, and the fifth material is refluxed and extracted together with the aqueous dichloromethane.
3. The method of purifying aqueous dichloromethane as claimed in claim 2, characterized in that the operating conditions of the second rectification column are: 10-101kPa, the tower top temperature is 50-100 ℃, the tower kettle temperature is 120-200 ℃, and the reflux ratio is 1-4.
4. The process for purifying aqueous dichloromethane as claimed in claim 2, wherein the second rectification column has an overhead temperature of 72.75 ℃, a bottom temperature of 196.98 ℃ and a reflux ratio of 2.
5. The process for the purification of aqueous dichloromethane according to claim 1 characterized in that the operating conditions of the first rectification column are: under normal pressure, the temperature at the top of the tower is 35-40 ℃, the temperature at the bottom of the tower is 100-175 ℃, the reflux ratio is 0.2-3, a dichloromethane product is discharged from the lateral line of the first rectifying tower, the discharged material at the top of the tower is a third material containing dichloromethane and water, and the discharged material at the bottom of the tower is a fourth material containing glycol and dichloromethane.
6. The process of claim 5 wherein the refluxing of the third and fourth materials is conducted in conjunction with the extractive phase separation of the aqueous dichloromethane.
7. The process of claim 5, wherein the first rectification column has an overhead temperature of 39.5 ℃, a bottom temperature of 172.6 ℃ and a reflux ratio of 0.5.
8. The process of claim 1, wherein the polyol is ethylene glycol.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110705693.4A CN113461482A (en) | 2021-06-24 | 2021-06-24 | Process for the purification of aqueous dichloromethane |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110705693.4A CN113461482A (en) | 2021-06-24 | 2021-06-24 | Process for the purification of aqueous dichloromethane |
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| Publication Number | Publication Date |
|---|---|
| CN113461482A true CN113461482A (en) | 2021-10-01 |
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|---|---|---|---|
| CN202110705693.4A Pending CN113461482A (en) | 2021-06-24 | 2021-06-24 | Process for the purification of aqueous dichloromethane |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103553868A (en) * | 2013-10-29 | 2014-02-05 | 安徽省郎溪县联科实业有限公司 | Method for recovering dichloromethane |
| CN207047127U (en) * | 2017-06-17 | 2018-02-27 | 安徽智新生化有限公司 | A kind of recovery device of chemical industry tail gas dichloromethane |
| CN109928861A (en) * | 2019-04-15 | 2019-06-25 | 新中天环保股份有限公司 | A kind of method of purification recycling methylene chloride from solvent slop |
-
2021
- 2021-06-24 CN CN202110705693.4A patent/CN113461482A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103553868A (en) * | 2013-10-29 | 2014-02-05 | 安徽省郎溪县联科实业有限公司 | Method for recovering dichloromethane |
| CN207047127U (en) * | 2017-06-17 | 2018-02-27 | 安徽智新生化有限公司 | A kind of recovery device of chemical industry tail gas dichloromethane |
| CN109928861A (en) * | 2019-04-15 | 2019-06-25 | 新中天环保股份有限公司 | A kind of method of purification recycling methylene chloride from solvent slop |
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Application publication date: 20211001 |
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