CN107986962B - Method for recovering acetoacetates from acetoacetates distillation residues - Google Patents
Method for recovering acetoacetates from acetoacetates distillation residues Download PDFInfo
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- CN107986962B CN107986962B CN201711336190.4A CN201711336190A CN107986962B CN 107986962 B CN107986962 B CN 107986962B CN 201711336190 A CN201711336190 A CN 201711336190A CN 107986962 B CN107986962 B CN 107986962B
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- acetoacetic ester
- acetoacetate
- acetoacetates
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/30—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group
- C07C67/317—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by splitting-off hydrogen or functional groups; by hydrogenolysis of functional groups
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/52—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation
- C07C67/54—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation by distillation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/584—Recycling of catalysts
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- Organic Chemistry (AREA)
- Crystallography & Structural Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Abstract
The invention relates to a method for recovering acetoacetates from acetoacetates distillation residues, which comprises the following steps: adding corresponding alcohol and a catalyst accounting for 0.1-5% of the weight of the acetoacetic ester distillation residues into the acetoacetic ester distillation residues, and refluxing for 2-8 h; after the reaction is finished, the low boiling point is removed under reduced pressure, the qualified acetoacetic ester product is obtained by rectification, and the residual high boiling point is used as a catalyst for application. Converting the waste residue into corresponding acetoacetic ester, improving the reaction yield, wherein the conversion yield of dehydroacetic acid is 74-90%; acetic acid enters a low ester distillation head for recovery in an acetate mode, and the acetic acid byproduct in the synthesis of the acetoacetic ester is effectively utilized; the method greatly reduces the discharge amount of waste residues, does not generate waste water, saves energy, reduces emission, and has certain environmental protection benefit and social benefit.
Description
Technical Field
The invention belongs to the technical field of chemical residue recovery, and particularly relates to a method for recovering acetoacetates from acetoacetates distillation residues.
Background
Acetoacetic esters (such as methyl acetoacetate, ethyl acetoacetate or tert-butyl acetoacetate) need distillation and rectification purification after reaction preparation, and the acetoacetic ester distillation residues left after purification contain acetoacetic ester, acetic acid, dehydroacetic acid and the like, have the characteristics of large smell, high acidity, small combustion heat value and the like, and are very difficult to completely treat.
The method for recycling the acetoacetate distillation residue is few, and besides the conventional incineration, a method for treating and preparing dehydroacetic acid is also available.
Adding an alkaline aqueous solution into the acetoacetic ester distillation residue for neutralization, stirring and layering; the acetoacetic ester distillation residue is residue obtained by rectifying methyl acetoacetate, ethyl acetoacetate or tert-butyl acetoacetate; separating out an upper organic phase, adding a certain amount of sodium bicarbonate, heating to 180-210 ℃ and reacting for 1-5 hours; continuously introducing water vapor into the reaction solution after the reaction is finished, and condensing and collecting crystals carried out along with the water vapor after the water vapor is distilled; drying the collected crystals to obtain dehydroacetic acid.
This method has the following disadvantages:
1. the yield is low, and is only 30-70%;
2. a large amount of waste water is generated, the COD of the waste water is as high as hundreds of thousands, and the treatment is not easy;
3. the dehydroacetic acid processed by the method has small yield, is difficult to scale and is difficult to process and sell.
Disclosure of Invention
The invention aims to provide a method for recovering acetoacetic esters from acetoacetic ester distillation residues, which solves the problems of low conversion rate and difficult wastewater treatment.
The technical scheme adopted by the invention for solving the technical problems is as follows: a process for recovering acetoacetates from an acetoacetates distillation residue comprising the steps of:
1) adding corresponding alcohol and a catalyst accounting for 0.1-5% of the weight of the acetoacetic ester distillation residues into the acetoacetic ester distillation residues, and refluxing for 2-8 h;
2) after the reaction is finished, decompressing to remove low boiling point, and rectifying to obtain the qualified acetoacetic ester product.
Specifically, the acetoacetic ester distillation residue is a rectification high-boiling residue of methyl acetoacetate, ethyl acetoacetate or tert-butyl acetoacetate.
Specifically, the mass content of the acetoacetic esters in the acetoacetic ester distillation residues is 20-45%, the high boiling point of the acetoacetic ester distillation residues is dehydroacetic acid, and the mass content of the dehydroacetic acid is 35-45%.
Specifically, the molar ratio of the addition amount of the corresponding alcohol to the dehydroacetic acid content in the acetoacetate distillation residue is 2.1-3.5: 1.
Specifically, the corresponding alcohol is methanol, ethanol or tert-butyl alcohol, the alcohol corresponding to methyl acetoacetate is methanol, the alcohol corresponding to ethyl acetoacetate is ethanol, and the alcohol corresponding to tert-butyl acetoacetate is tert-butyl alcohol.
Specifically, the catalyst is one or more of concentrated sulfuric acid, p-toluenesulfonic acid and Lewis acid catalysts.
The main reaction equation of the present invention is as follows:
wherein R is methyl, ethyl or tert-butyl.
The mass content of the acetoacetic ester in the acetoacetic ester distillation residue is 20-45%, the acetoacetic ester distillation residue is not damaged in the reaction and can be recovered in rectification; the acidity of the acetoacetic ester distillation residue is 5-20% by acetic acid, corresponding acetate is obtained after reaction, and low-boiling recovery is carried out; the mass content of the acetoacetic esters in the high boiling point of the acetoacetic ester distillation residue is 20-45%, the mass content of the rest is 35-45%, the dehydroacetic acid can generate corresponding acetoacetic esters through the reaction, and the finished product is obtained through rectification.
The method has simple process and convenient control, can convert the waste residue into corresponding acetoacetic esters, improves the reaction yield, and ensures that the conversion yield of the dehydroacetic acid is 74-90 percent; the product after reaction is a product corresponding to the corresponding waste residue, so that the problem of subsequent sale is avoided; acetic acid enters a low ester distillation head for recovery in an acetate mode, and the acetic acid byproduct in the synthesis of the acetoacetic ester is effectively utilized; the method greatly reduces the discharge amount of waste residues, does not generate waste water, saves energy, reduces emission, and has certain environmental protection benefit and social benefit.
Detailed Description
The following are specific examples of the present invention and further describe the technical solutions of the present invention, but the scope of the present invention is not limited to these examples. All changes, modifications and equivalents that do not depart from the spirit of the invention are intended to be included within the scope thereof.
Example 1
300g of methyl acetoacetate residue (methyl acetoacetate content 42%, dehydroacetic acid content 43%), 2.5g of concentrated sulfuric acid and 51.6g of methanol were added to the flask, the mixture was stirred at elevated temperature, refluxed for 2 hours, refluxed, and then distilled at reduced temperature under reduced pressure, and the front fraction was cut off to obtain 284.6g of a finished product having a purity of 99.98% and a yield of 89.03% (calculated as the dehydroacetic acid content in the residue, and calculated according to the following equation (284.6-300 × 0.42)/(300.43/168 × 116) ═ 2) ═ 89.03%.
Example 2
300g of an ethyl acetoacetate residue (20% of ethyl acetoacetate), 4g of p-toluenesulfonic acid and 65.6g of ethanol were added to the flask, the mixture was stirred at elevated temperature, refluxed for 5 hours, refluxed, and then subjected to reduced-temperature reduced-pressure distillation, and the front fraction was cut off to obtain 208.2g of a finished product with a purity of 99.95% and a yield of 84.00% (calculated as the content of dehydroacetic acid in the residue, and calculated according to the following equation (208.2-300: 0.20)/(300: 0.38/168: 130: 2): 84.00%.
Example 3
300g of an ethyl acetoacetate residue (45% of ethyl acetoacetate content, 35% of dehydroacetic acid content), 0.3g of a Lewis acid catalyst and 86.3g of ethanol were added to the flask, the mixture was stirred at a high temperature and refluxed for 4 hours, the reflux was completed, the temperature and the pressure were reduced, and the distillate was cut off to obtain 297.5g of a finished product having a purity of 99.96% and a yield of 81.00% (calculated as the dehydroacetic acid content in the residue, and calculated according to the following equation (297.5.5-300: 0.45)/(300: 0.35/168: 130: 2): 81.00%.
Example 4
300g of t-butyl acetoacetate residue (35% of t-butyl acetoacetate and 45% of dehydroacetic acid), 15g of concentrated sulfuric acid and 208.1g of t-butyl alcohol are added into a flask, the mixture is heated and stirred, refluxed for 8 hours, and then the reflux is finished, the temperature is reduced, the pressure is reduced, the distillate is cut off to obtain 295.0g of finished product, the purity is 99.23%, the yield is 74.83%, and the yield is calculated according to the content of dehydroacetic acid in the residue and is 74.83% according to the following equation (295.0-300 x 0.35)/(300.45/168 x 158 2).
Claims (2)
1. A method for recovering acetoacetates from an acetoacetate distillation residue is characterized by comprising the following steps:
1) adding corresponding alcohol and a catalyst accounting for 0.1-5% of the weight of the acetoacetic ester distillation residues into the acetoacetic ester distillation residues, and refluxing for 2-8 h; the mass content of the acetoacetic esters in the acetoacetic ester distillation residues is 20-45%, the high boiling point of the acetoacetic ester distillation residues is dehydroacetic acid, and the mass content of the dehydroacetic acid is 35-45%; the catalyst is one or more of concentrated sulfuric acid, p-toluenesulfonic acid and Lewis acid catalyst; the acetoacetic ester distillation residue is rectification high-boiling residue of methyl acetoacetate, ethyl acetoacetate or tert-butyl acetoacetate, the alcohol corresponding to methyl acetoacetate is methanol, the alcohol corresponding to ethyl acetoacetate is ethanol, and the alcohol corresponding to tert-butyl acetoacetate is tert-butyl alcohol.
2) After the reaction is finished, decompressing to remove low boiling point, and rectifying to obtain the qualified acetoacetic ester product.
2. The method for recovering acetoacetates from an acetoacetate distillation residue as claimed in claim 1, wherein the molar ratio of the corresponding alcohol added to the amount of dehydroacetic acid in the acetoacetate distillation residue after purification is 2.1-3.5: 1.
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CN113045417B (en) * | 2019-12-29 | 2023-04-07 | 南通醋酸化工股份有限公司 | Process for producing acetoacetic ester by catalytic method |
CN112409165A (en) * | 2020-11-06 | 2021-02-26 | 山东汇海医药化工有限公司 | Method for recovering ethyl acetoacetate distillation head |
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CN103554073B (en) * | 2013-11-01 | 2015-10-21 | 山东汇海医药化工有限公司 | A kind of method utilizing acetoacetic ester distillation residue to prepare dehydro-acetic acid |
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Denomination of invention: A method for recovering acetoacetate from acetoacetate distillation residue Effective date of registration: 20211130 Granted publication date: 20200908 Pledgee: Dongying Hekou District sub branch of China Post Savings Bank Co.,Ltd. Pledgor: SHANDONG HUIHAI PHARMACEUTICAL& CHEMICAL Co.,Ltd. Registration number: Y2021980013568 |