CN114213282A - Acetonitrile recovery method containing acid acetonitrile waste solvent - Google Patents
Acetonitrile recovery method containing acid acetonitrile waste solvent Download PDFInfo
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- CN114213282A CN114213282A CN202111572793.0A CN202111572793A CN114213282A CN 114213282 A CN114213282 A CN 114213282A CN 202111572793 A CN202111572793 A CN 202111572793A CN 114213282 A CN114213282 A CN 114213282A
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- acetonitrile
- fraction
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- waste solvent
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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
Abstract
The invention discloses a recycling method of an acid acetonitrile-containing waste solvent, which adopts tri-n-butylamine to neutralize acid in the acid acetonitrile-containing waste solvent, does not generate water in the process, does not need to carry out rectification for many times, can obtain high-purity and qualified-quality acid-free acetonitrile only by once rectification, has simpler operation process and easier operation, saves a large amount of energy, saves the recovery cost, improves the utilization rate of the acetonitrile, greatly shortens the treatment time, and saves a large amount of manpower and material resources.
Description
Technical Field
The invention relates to the field of chemical industry, in particular to a method for recycling an acid acetonitrile-containing waste solvent, which can directly carry out a series of treatments to obtain recyclable acetonitrile with qualified quality.
Background
Acetonitrile is a widely used solvent, has good solvent performance, is infinitely soluble in water and alcohol, is an important chemical raw material, can generate typical nitrile reaction, and is widely applied to the fields of pharmacy, petrochemical industry and fine chemical industry. The waste acetonitrile solvent usually contains hydrochloric acid, a small amount of water and partial impurities, the direct discharge can harm the environment and cause pollution, the waste of raw materials can be caused, the recovery of acetonitrile can reduce the cost and avoid waste, and the environmental pollution is avoided.
However, since the waste acetonitrile solvent contains hydrochloric acid, the recovery by a conventional method causes corrosion of equipment, and it is extremely easy to distill off the acid together and difficult to separate, the resultant waste acetonitrile solvent containing acid is generally difficult to handle.
At present, inorganic bases such as sodium hydroxide, potassium carbonate and the like are mostly added for neutralization in the existing recovery method of acid-containing acetonitrile, and then the acetonitrile is recovered through multiple times of rectification.
In the existing technical scheme for neutralizing acid in acetonitrile, alkali and acid contained in waste acetonitrile are added for neutralization reaction to generate water, the acetonitrile is easy to generate amide under the conditions of acid or alkali and water, water is generated in the neutralization reaction, the acetonitrile and the water are subjected to azeotropic distillation, multiple times of rectification is needed for separation, so that a large amount of energy is consumed in the separation mode, the treatment period is long, the purity of the obtained acetonitrile is not high, and how to provide a method for separating and purifying the acetonitrile from the acid-containing acetonitrile is called a technical problem which needs to be solved urgently in the industry.
Disclosure of Invention
In order to solve the technical problems, the invention provides a method for recovering high-purity acetonitrile from acid acetonitrile-containing wastewater more simply.
The technical scheme of the invention is realized as follows: a method for recovering acetonitrile from an acid acetonitrile-containing waste solvent comprises the steps of adding the acid acetonitrile-containing waste solvent into a reaction kettle, adding a proper amount of tri-n-butylamine to make the acetonitrile waste solvent alkalescent, slowly heating to reflux, keeping the reflux for 3-5 hours, cooling, filtering, rectifying, and removing front fractions to obtain high-purity acetonitrile.
The technical scheme of the invention is as follows:
the acetonitrile recovery method of the acid acetonitrile-containing waste solvent comprises the following steps:
(1) adding tri-n-butylamine into the waste solvent containing the acid acetonitrile, adjusting the pH to 7-8, and stirring for a period of time to ensure that the pH is unchanged in the process;
(2) heating the solution obtained in the step (1) for refluxing, ensuring that acid contained in the waste solvent can completely react with tri-n-butylamine, cooling to room temperature, filtering, taking filtrate, separating and precipitating part of insoluble substances, and simultaneously ensuring that the subsequent recovery process is safer and more reliable;
(3) rectifying the reacted filtrate obtained in the step (2), and carrying out total reflux for 2-3 hours;
(4) starting to collect a fraction at 76-80 ℃, wherein the fraction is a front fraction;
(5) continuously heating, and collecting 80 ℃ fraction which is middle fraction;
(6) continuously heating, and collecting 81 ℃ fraction which is a post fraction;
(7) after the reaction is finished, the purity of the obtained middle distillate and the purity of the obtained rear distillate are both more than 99 percent, the moisture is less than 0.05 percent, the obtained acetonitrile is high-purity acetonitrile, subsequent experiments can be carried out, and qualified products can be obtained.
Compared with the prior art, the method for recovering acetonitrile from the waste solvent containing the acetonitrile has the following beneficial effects:
the method is different from the conventional method for treating the waste solvent containing the acid acetonitrile, and because the acetonitrile and the water are subjected to azeotropic distillation, the water generated in the conventional recovery method is separated by multiple times of rectification, but the separation method needs to consume a large amount of energy, the treatment period is long, the purity of the obtained acetonitrile is not high, and the method perfectly solves the problem. The tri-n-butylamine is adopted to neutralize the acid in the waste solvent containing the acid acetonitrile, and no water is generated in the process. Therefore, the method is different from the conventional method for treating the waste solvent containing the acid acetonitrile, does not need to carry out rectification for many times, can obtain the acid-free acetonitrile with high purity and qualified quality by only carrying out rectification for one time, has simpler operation process and easier operation, saves a large amount of energy, saves the recovery cost, improves the utilization rate of the acetonitrile, greatly shortens the treatment time, and saves a large amount of manpower and material resources.
Detailed Description
The advantageous effects of the present invention will now be further described by the following examples, which should be understood as being for illustrative purposes only and not limiting the scope of the present invention, and that changes and modifications apparent to those of ordinary skill in the art in light of the present invention are also included within the scope of the present invention.
The acidity of the waste solvent containing acid acetonitrile generated in a certain production workshop is about 0.01 percent by taking the waste solvent containing acid acetonitrile as a treatment object.
Example 1:
(1) adding an acid acetonitrile-containing waste solvent into a reaction kettle, adding a proper amount of tri-n-butylamine, adjusting the pH to 7-8, and stirring for 1-2 hours;
(2) slowly heating to a reflux state, and keeping reflux for 3 hours;
(3) cooling, and performing precision filtration to remove insoluble substances;
(4) transferring the filtrate into a rectifying still, slowly heating to a reflux state, and carrying out total reflux for 2-3 hours;
(5) starting rectification, and adjusting the reflux ratio to be 10: 1;
(6) heating to gas phase temperature of 76 deg.C, collecting front distillate, stopping collecting at 80 deg.C, and detecting acetonitrile purity, acidity and water content in front distillate;
(7) continuously collecting the fraction discharged at 80 ℃ as middle fraction;
(8) continuously collecting the fraction discharged at the temperature of 81 ℃ into a post fraction;
(9) and combining the middle fraction and the later fraction to obtain the recovered acetonitrile, and detecting the purity, acidity and moisture of the acetonitrile by using a sample.
Example 2:
(1) adding an acid acetonitrile-containing waste solvent into a reaction kettle, adding a proper amount of tri-n-butylamine, adjusting the pH to 7-8, and stirring for 1-2 hours;
(2) slowly heating to a reflux state, and keeping refluxing for 4 hours;
(3) cooling, and performing precision filtration to remove insoluble substances;
(4) transferring the filtrate into a rectifying still, slowly heating to a reflux state, and carrying out total reflux for 2-3 hours;
(5) starting rectification, and adjusting the reflux ratio to be 10: 1;
(6) heating to gas phase temperature of 76 deg.C, collecting front distillate, stopping collecting at 80 deg.C, and detecting acetonitrile purity, acidity and water content in front distillate;
(7) continuously collecting the fraction discharged at 80 ℃ as middle fraction;
(8) continuously collecting the fraction discharged at the temperature of 81 ℃ into a post fraction;
(9) and combining the middle fraction and the later fraction to obtain the recovered acetonitrile, and detecting the purity, acidity and moisture of the acetonitrile by using a sample.
Example 3:
(1) adding an acid acetonitrile-containing waste solvent into a reaction kettle, adding a proper amount of tri-n-butylamine, adjusting the pH to 7-8, and stirring for 1-2 hours;
(2) slowly heating to a reflux state, and keeping reflux for 5 hours;
(3) cooling, and performing precision filtration to remove insoluble substances;
(4) transferring the filtrate into a rectifying still, slowly heating to a reflux state, and carrying out total reflux for 2-3 hours;
(5) starting the rectification and adjusting the reflux ratio to be 10:1
(6) Heating to gas phase temperature of 76 deg.C, collecting front distillate, stopping collecting at 80 deg.C, and detecting acetonitrile purity, acidity and water content in front distillate;
(7) continuously collecting the fraction discharged at 80 ℃ as middle fraction;
(8) continuously collecting the fraction discharged at the temperature of 81 ℃ into a post fraction;
(9) and combining the middle fraction and the later fraction to obtain the recovered acetonitrile, and detecting the purity, acidity and moisture of the acetonitrile by using a sample.
Respectively carrying out gas chromatography detection on the raw material acid acetonitrile-containing waste solvent and the acetonitrile produced in the examples 1-3, and simultaneously carrying out residual detection on the tri-n-butylamine on the acetonitrile produced in the examples 1-3, so as to obtain the following data:
the data show that the treatment method can obtain high-purity acetonitrile, and meanwhile, the energy consumption is less, and the treatment method is simpler.
It should be understood that the above experimental examples are only examples for clearly illustrating the present invention, and are not intended to limit the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
Claims (4)
1. The acetonitrile recovery method of the waste solvent containing the acid acetonitrile comprises the following steps:
(1) adding tri-n-butylamine into the waste solvent containing the acid acetonitrile, adjusting the pH to 7-8, and stirring for a period of time to ensure that the pH is unchanged in the process;
(2) heating the solution obtained in the step (1) for refluxing to ensure that acid and tri-n-butylamine completely react, cooling to room temperature, filtering to obtain filtrate,
(3) rectifying the reacted filtrate obtained in the step two;
(4) starting to collect a fraction at 76-80 ℃, wherein the fraction is a front fraction;
(5) continuously heating, and collecting 80 ℃ fraction which is middle fraction;
(6) continuously heating, and collecting 81 ℃ fraction which is a post fraction;
(7) after the reaction is finished, the obtained middle distillate and the obtained later distillate are the recovered high-purity acetonitrile.
2. The recycling method according to claim 1, wherein the reflux of the step (2) is maintained for 3 to 5 hours.
3. The recovery method according to claim 1, wherein the step (3) is refluxed for 2 to 3 hours.
4. The recovery method according to claim 1, wherein the purity of the fraction and the post-fraction in the step (7) are both 99% or more and the moisture content is 0.05% or less.
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| CN202111572793.0A CN114213282A (en) | 2021-12-21 | 2021-12-21 | Acetonitrile recovery method containing acid acetonitrile waste solvent |
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| CN202111572793.0A CN114213282A (en) | 2021-12-21 | 2021-12-21 | Acetonitrile recovery method containing acid acetonitrile waste solvent |
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4328075A (en) * | 1979-12-10 | 1982-05-04 | Standard Oil Company | Removal of cyanides from acetonitrile |
| JPH0525112A (en) * | 1991-07-16 | 1993-02-02 | Asahi Chem Ind Co Ltd | Purification of acetonitrile |
| JPH1025272A (en) * | 1996-07-09 | 1998-01-27 | Asahi Chem Ind Co Ltd | Purification of acetonitrile |
| JP2006124311A (en) * | 2004-10-28 | 2006-05-18 | Sumitomo Chemical Co Ltd | Method for producing anhydrous acetonitrile |
| CN101171233A (en) * | 2005-05-10 | 2008-04-30 | 旭化成化学株式会社 | High-purity acetonitrile and process for producing the same |
| JP2011098931A (en) * | 2009-11-09 | 2011-05-19 | Neos Co Ltd | Method for purifying acetonitrile |
| CN104203909A (en) * | 2012-03-26 | 2014-12-10 | 旭化成化学株式会社 | Method for purifying acetonitrile |
| CN107935887A (en) * | 2017-12-21 | 2018-04-20 | 上海应用技术大学 | A kind of preparation method of gradient level acetonitrile |
| CN111960966A (en) * | 2020-09-14 | 2020-11-20 | 永华化学股份有限公司 | Preparation method of chromatographic grade acetonitrile |
-
2021
- 2021-12-21 CN CN202111572793.0A patent/CN114213282A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4328075A (en) * | 1979-12-10 | 1982-05-04 | Standard Oil Company | Removal of cyanides from acetonitrile |
| JPH0525112A (en) * | 1991-07-16 | 1993-02-02 | Asahi Chem Ind Co Ltd | Purification of acetonitrile |
| JPH1025272A (en) * | 1996-07-09 | 1998-01-27 | Asahi Chem Ind Co Ltd | Purification of acetonitrile |
| JP2006124311A (en) * | 2004-10-28 | 2006-05-18 | Sumitomo Chemical Co Ltd | Method for producing anhydrous acetonitrile |
| CN101171233A (en) * | 2005-05-10 | 2008-04-30 | 旭化成化学株式会社 | High-purity acetonitrile and process for producing the same |
| JP2011098931A (en) * | 2009-11-09 | 2011-05-19 | Neos Co Ltd | Method for purifying acetonitrile |
| CN104203909A (en) * | 2012-03-26 | 2014-12-10 | 旭化成化学株式会社 | Method for purifying acetonitrile |
| CN107935887A (en) * | 2017-12-21 | 2018-04-20 | 上海应用技术大学 | A kind of preparation method of gradient level acetonitrile |
| CN111960966A (en) * | 2020-09-14 | 2020-11-20 | 永华化学股份有限公司 | Preparation method of chromatographic grade acetonitrile |
Non-Patent Citations (1)
| Title |
|---|
| 任士伟等: ""乙腈精制工艺的应用分析"", 《石油与天然气化工》, vol. 25, no. 3, pages 122 - 127 * |
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