CN111592469A - Method for recovering DMAC (dimethylacetamide) residual liquid in sucralose production - Google Patents
Method for recovering DMAC (dimethylacetamide) residual liquid in sucralose production Download PDFInfo
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- CN111592469A CN111592469A CN202010439442.1A CN202010439442A CN111592469A CN 111592469 A CN111592469 A CN 111592469A CN 202010439442 A CN202010439442 A CN 202010439442A CN 111592469 A CN111592469 A CN 111592469A
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C231/00—Preparation of carboxylic acid amides
- C07C231/12—Preparation of carboxylic acid amides by reactions not involving the formation of carboxamide groups
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C231/00—Preparation of carboxylic acid amides
- C07C231/22—Separation; Purification; Stabilisation; Use of additives
- C07C231/24—Separation; Purification
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C273/00—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
- C07C273/18—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of substituted ureas
- C07C273/189—Purification, separation, stabilisation, use of additives
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/41—Preparation of salts of carboxylic acids
- C07C51/412—Preparation of salts of carboxylic acids by conversion of the acids, their salts, esters or anhydrides with the same carboxylic acid part
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
- C07C51/44—Separation; Purification; Stabilisation; Use of additives by change of 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
Abstract
The invention relates to a method for recovering DMAC residual liquid in sucralose production, which comprises the following steps: rectifying and recovering DMF to generate DMAC residual liquid, adding the residual liquid into a reaction kettle, adding sodium hydroxide into the reaction kettle for neutralization reaction, distilling until the residual liquid is dry, obtaining powdery sodium acetate in the reaction kettle, continuously pumping the distilled and condensed mixed solution which does not contain acid DMAC, water and tetramethylurea into a dehydration tower for dehydration, obtaining a mixture of anhydrous DMAC and tetramethylurea at the bottom of the tower, entering the mixture into a rectifying tower, obtaining a high-purity DMAC product through condensation at the top of the tower, obtaining a tetramethylurea solution with the content of up to 60% at the bottom of the tower, and further recovering and separating the tetramethylurea. The process is simple, the residual liquid is further treated to recover valuable DMAC in the residual liquid, the amount of the residual liquid at the bottom of the tower is reduced, the difficulty in recovering the residual liquid is reduced, the solvent recovery efficiency is improved, the energy consumption is saved, the production cost is greatly reduced, and the pollution is reduced.
Description
Technical Field
The invention belongs to a method for treating a solvent in a sucralose production process in the technical field of chemical industry, and particularly relates to a method for recovering DMAC (dimethylacetamide) residual liquid in sucralose production.
Background
Sucralose is a fresh sweetener, the sweetness of which is 800 times of that of sucrose, and the sweetness of which is pure and similar to that of sucrose, and sucralose is not absorbed by human body, has no bioaccumulation and high safety, so that the sucralose industry is rapidly developed in this year, production enterprises are gradually increased, and the yield is continuously improved. DMF is used as a solvent in a large amount in the production process of sucralose, the use amount of DMF is increased along with the improvement of yield, the problem of DMF recovery of the solvent is inevitably existed in the current production process, DMF containing acetic acid is inevitably generated in the recovery process, and DMF needs to be treated and recovered, and the latest treatment process is to add dimethylamine to produce DMAC by adopting a reaction rectification method and recover DMF at the same time. But in the process of DMAC rectification, because the acid reaction is incomplete and the system contains tetramethylurea which is a byproduct in the chlorination section, the rectification tower can discharge a large amount of residual liquid which needs to be treated as dangerous waste, the prior art is to add the residual liquid into a reaction kettle according to the amount containing acetic acid with equal molar ratio to carry out neutralization reaction, steam is opened to carry out distillation after the reaction temperature is not increased, after the solvent is distilled to be dry, the residual dry powdery sodium acetate in the reaction kettle can be directly sold as a byproduct, the mixed solution containing no acid DMAC, water and tetramethylurea after distillation and condensation is continuously pumped into a dehydration tower to be dehydrated, partial reflux is extracted after the top of the dehydration tower is subjected to secondary condensation, the mixture of anhydrous DMAC and tetramethylurea at the bottom of the tower enters the rectification tower, partial reflux is extracted at the top of the tower through condensation, and a high-purity DMAC product is obtained, the tetramethylurea solution with the content as high as 60 percent is obtained at the bottom of the tower and then further recycled and separated. The process is simple, the residual liquid is further treated to recover valuable DMAC in the residual liquid, the amount of the residual liquid at the bottom of the tower is reduced, the difficulty in recovering the residual liquid is reduced, the solvent recovery efficiency is improved, the energy consumption is saved, the production cost is greatly reduced, and the pollution is reduced.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a method for recovering DMAC (dimethylacetamide) residual liquid in sucralose production, which has the advantages of simple operation, high efficiency, high recovery rate and low cost.
In order to achieve the purpose of the invention, the invention adopts the following technical scheme:
a recovery method of DMAC residual liquid in sucralose production comprises the steps of sending acid-containing DMF recovered in sucralose production to a rectifying tower to react with dimethylamine to generate DMAC, and generating a large amount of residual liquid containing DMAC, acetic acid, tetramethylurea and high-boiling-point impurities at the bottom of the rectifying tower after DMF is recovered by rectification, and is characterized by comprising the following steps of:
a. adding the residual liquid into a reaction kettle, adding sodium hydroxide according to the amount of acetic acid in the residual liquid with equal molar ratio for neutralization reaction, determining the content of the acetic acid through central control analysis, wherein the neutralization has the function of reacting the acetic acid in a system into sodium acetate to fix the acetic acid;
b. after the temperature of the reaction liquid in the neutralization reaction is not increased any more, steam is started under the condition of-0.098 MPa to distill the reaction liquid at the temperature of 60-110 ℃, distilled products are condensed to 30-50 ℃ by circulating water to obtain a mixed solution which does not contain acid DMAC, water and tetramethylurea, and after the solvent in the reaction liquid in the reaction kettle is distilled to be dry, dry powdery sodium acetate is formed in the reaction kettle;
c. continuously pumping the mixed solution without the acid DMAC, the water and the tetramethylurea to a dehydrating tower for dehydration, controlling the pressure of the dehydrating tower at-0.098 MPa and the temperature at 60-100 ℃, sending distilled wastewater to a sewage treatment station, and obtaining a mixture of the anhydrous DMAC and the tetramethylurea at the bottom of the tower;
d. feeding a mixture of anhydrous DMAC and tetramethylurea into a rectifying tower for rectification, controlling the pressure of the rectifying tower at-0.098 MPa and the temperature at 80-100 ℃, condensing the rectified gas phase to 30-50 ℃ at the tower top through circulating water, and obtaining a high-purity DMAC finished product liquid; the tetramethylurea solution with the content of 60 percent is obtained at the bottom of the rectifying tower.
The further technical scheme is that 5-10% of the total amount of the high-purity DMAC liquid obtained in the step d) is extracted and flows back to enter a rectifying tower to exchange heat with the rectified gas phase to form circulating distillation.
The further technical scheme is that the residual liquid comprises the following components: 60% DMAC, 20% acetic acid, 20% tetramethylurea and part of high-boiling impurities.
The further technical proposal is that the PH of the neutralization reaction is 7-8.
The further technical scheme is that the bottoms of the dehydration tower and the rectifying tower are respectively connected with a liquid phase inlet of a reboiler at the bottom of the tower, and a gas phase outlet of the reboiler is respectively connected with the middle parts of the dehydration tower and the rectifying tower.
The further technical scheme is that the mass percent of high-purity DMAC (dimethylacetamide) extracted from the top of the rectifying tower is more than or equal to 99.5%, the water content is less than 500ppm, and the high-purity DMAC can be directly sold as a product.
The further technical scheme is that tetramethylurea solution with the content as high as 60% is obtained at the bottom of the rectifying tower in the step d), and light component DMAC is removed firstly through rectification, and then high-purity tetramethylurea is rectified.
Compared with the prior art, the method has the advantages that the method for treating the rectified residual liquid is found, valuable DMAC in the residual liquid is recovered by further treating the residual liquid, the amount of the residual liquid at the bottom of the tower is reduced, the difficulty in recovering the residual liquid is reduced, the solvent recovery efficiency is improved, pollution caused by treatment of the residual liquid with economic value as hazardous waste is avoided, the energy consumption is saved, and the production cost is greatly reduced. The process is worthy of popularization and application.
Drawings
FIG. 1 is a process flow diagram of the process of the present invention;
FIG. 2 is a schematic view of the dehydration column of FIG. 1;
FIG. 3 is a schematic diagram of the rectifying column structure shown in FIG. 1.
Detailed Description
In order to explain technical contents, structural features, achieved objects and effects of the technical solutions in detail, the following detailed description is given with reference to specific embodiments.
Example 1
As shown in figure 1, 1500L of raffinate obtained after DMAC rectification in the sucralose production process containing DMAC, acetic acid, tetramethylurea and part of high-boiling-point impurities is added into a reaction kettle, 500L of sodium hydroxide with the same molar quantity as the acetic acid is added, the reaction is naturally carried out while stirring, the temperature is raised to about 78 ℃, after the reaction is completed, negative pressure is opened, steam is introduced into a jacket for reduced pressure distillation (-0.098 MPa, 60-100 ℃) so that a mixed solution which is obtained after a distillate is condensed to 30-50 ℃ by circulating water and does not contain DMAC, water and tetramethylurea enters an acid-free raffinate intermediate tank, and high-purity sodium acetate with the content of 99.5% is obtained in the reaction kettle by evaporation.
Referring to fig. 2, continuously pumping the mixed solution containing no acid DMAC, water and tetramethylurea into a dehydrating tower for dehydrating and rectifying (0.098 MPa, 60-100 ℃ in the dehydrating tower), heating the mixed solution by using a reboiler connected with the dehydrating tower, controlling the temperature of the reboiler at 116 ℃ and 0.093MPa, returning the gas phase evaporated by the reboiler to the bottom of the dehydrating tower to exchange heat with the mixed solution and then discharging the gas phase from the top of the dehydrating tower, condensing the gas phase discharged from the top of the dehydrating tower into liquid, extracting part of the liquid to flow back into the dehydrating tower, controlling the temperature of the top of the dehydrating tower at 39 ℃ and 0.095MPa, and extracting the rest condensed liquid as wastewater to be subjected to sewage treatment.
Referring to fig. 3, a mixture of anhydrous DMAC and tetramethylurea obtained at the bottom of the dehydration tower directly enters a rectification tower, the mixture is heated by a reboiler connected with the rectification tower, the temperature of the reboiler is controlled to be 118 ℃ and 0.093MPa, a gas phase evaporated by the reboiler returns to the bottom of the rectification tower to exchange heat with the mixture and then is discharged from the top of the rectification tower, the gas phase discharged from the top of the rectification tower is condensed into liquid, part of the liquid is extracted and flows back into the rectification tower, the temperature of the top of the rectification tower is controlled to be 98 ℃ and 0.095MPa, the extracted part is finished DMAC, the purity of the finished product is not less than 99.5 percent, the moisture is not more than 500ppm, and.
The tetramethylurea material with the content of 60 percent is obtained at the bottom of the rectifying tower. Rectifying the obtained tetramethylurea material, removing a light component DMAC (dimethylacetamide) firstly, and rectifying to obtain tetramethylurea.
Example 2
Adding 1500L of DMAC (dimethylacetamide) rectification residual liquid in the sucralose production process containing DMAC, acetic acid, tetramethylurea and part of high-boiling-point impurities into a reaction kettle, adding 500L of sodium hydroxide with the same molar weight as the acetic acid, reacting while stirring to naturally heat to about 78 ℃, after the reaction is completed, opening negative pressure, introducing steam into a jacket for reduced pressure distillation, introducing distillate into an acid-free residual liquid intermediate tank, and evaporating to dryness in the reaction kettle to obtain high-purity sodium acetate. And continuously pumping the acid-free DMAC into a dehydrating tower, dehydrating and rectifying, heating by using a reboiler, controlling the temperature to be 114 ℃ and 0.093MPa, extracting the part of the top of the tower at reflux, controlling the temperature to be 36 ℃ and 0.095MPa at the top of the tower, and treating the part of the extracted part by wastewater to remove sewage. Directly feeding the tower bottom into a rectifying tower, heating by a reboiler, controlling the temperature to be 120 ℃ and-0.093 MPa, extracting reflux parts from the tower top, controlling the temperature at the tower top to be 96 ℃ and-0.095 MPa, selling DMAC (dimethyl acetamide) finished products as extracted parts, and continuously recovering tetramethylurea and DMAC from tetramethylurea-containing materials at the tower bottom. The purity of the obtained DMAC finished product is more than or equal to 99.5 percent, and the water content is less than or equal to 500ppm, and the DMAC finished product can be directly sold as a finished product.
It should be noted that, although the above embodiments have been described herein, the invention is not limited thereto. Therefore, based on the innovative concepts of the present invention, the technical solutions of the present invention can be directly or indirectly applied to other related technical fields by making changes and modifications to the embodiments described herein, or by using equivalent structures or equivalent processes performed in the content of the present specification and the attached drawings, which are included in the scope of the present invention.
Claims (7)
1. A recovery method of DMAC residual liquid in sucralose production comprises the steps of sending acid-containing DMF recovered in sucralose production to a rectifying tower to react with dimethylamine to generate DMAC, and generating a large amount of residual liquid containing DMAC, acetic acid, tetramethylurea and high-boiling-point impurities at the bottom of the rectifying tower after DMF is recovered by rectification, and is characterized by comprising the following steps of:
a. adding the residual liquid into a reaction kettle, and adding sodium hydroxide according to the amount of acetic acid in the residual liquid with equal molar ratio for neutralization reaction;
b. after the temperature of the reaction liquid in the neutralization reaction is not increased any more, steam is started under the condition of-0.098 MPa to distill the reaction liquid at the temperature of 60-110 ℃, distilled products are condensed to 30-50 ℃ by circulating water to obtain a mixed solution which does not contain acid DMAC, water and tetramethylurea, and after the solvent in the reaction liquid in the reaction kettle is distilled to be dry, dry powdery sodium acetate is formed in the reaction kettle;
c. continuously pumping the mixed solution without the acid DMAC, the water and the tetramethylurea to a dehydrating tower for dehydration, controlling the pressure of the dehydrating tower at-0.098 MPa and the temperature at 60-100 ℃, sending distilled wastewater to a sewage treatment station, and obtaining a mixture of the anhydrous DMAC and the tetramethylurea at the bottom of the tower;
d. feeding a mixture of anhydrous DMAC and tetramethylurea into a rectifying tower for rectification, controlling the pressure of the rectifying tower at-0.098 MPa and the temperature at 80-100 ℃, condensing the rectified gas phase to 30-50 ℃ at the tower top through circulating water, and obtaining high-purity DMAC finished product liquid; the tetramethylurea solution with the content of 60 percent is obtained at the bottom of the rectifying tower.
2. The method for recycling the DMAC raffinate in the sucralose production according to claim 1, wherein 5-10% of the total amount of the DMAC liquid with high purity obtained in step d) is extracted and refluxed into the rectifying tower to exchange heat with the rectified gas phase to form the circular distillation.
3. The method for recovering DMAC raffinate from sucralose production according to claim 1 or 2, wherein the raffinate comprises: 60% DMAC, 20% acetic acid, 20% tetramethylurea and part of high-boiling impurities.
4. The method for recovering DMAC raffinate from sucralose production according to claim 1, 2 or 3, wherein said neutralization reaction pH is from 7 to 8.
5. The method for recovering the DMAC residual liquid in the sucralose production according to claim 1, wherein the DMAC residual liquid at the top of the rectifying tower has the high purity of more than or equal to 99.5 percent by mass and the water content of less than 500ppm, and can be directly sold as a product.
6. The method for recovering the residual liquid of DMAC in the production of sucralose according to claim 1, wherein the tetramethylurea solution with the content of 60 percent is obtained at the bottom of the rectifying tower in the step d), and the light component DMAC is removed firstly through rectification, and then the high-purity tetramethylurea is rectified.
7. The method for recovering the DMAC residual liquid in the sucralose production according to claim 1, wherein the tops of the dehydrating tower and the rectifying tower are sequentially connected with a condenser, a reflux tank and a vacuum pump through pipelines, and the vacuum pump is connected to the tops of the dehydrating tower and the rectifying tower through a pipeline; the bottoms of the dehydration tower and the rectifying tower are respectively connected with the liquid phase inlet of a reboiler at the bottom of the tower, and the gas phase outlet of the reboiler is respectively connected with the middle parts of the dehydration tower and the rectifying tower.
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| CN202010439442.1A CN111592469A (en) | 2020-05-22 | 2020-05-22 | Method for recovering DMAC (dimethylacetamide) residual liquid in sucralose production |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112047832A (en) * | 2020-09-18 | 2020-12-08 | 北京化工大学 | N, N-dimethylacetamide wastewater recovery process |
| CN112574052A (en) * | 2020-11-30 | 2021-03-30 | 安徽金禾实业股份有限公司 | Distillation treatment method of DMAC reaction solution |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120157676A1 (en) * | 2009-03-30 | 2012-06-21 | Tate & Lyle Technology Ltd. | Process for removing dimethylamine |
| CN105418447A (en) * | 2015-12-17 | 2016-03-23 | 烟台国邦化工机械科技有限公司 | DMAC (dimethylacetamide) rectification device and technique |
| CN106831471A (en) * | 2017-01-20 | 2017-06-13 | 福州大学 | A kind of method for removing a small amount of acid or glacial acetic acid and refining DMF |
| WO2017190299A1 (en) * | 2016-05-05 | 2017-11-09 | 章旭元 | Seven-tower five-effect rectification system for dmac or dmf waste liquid and method for recovering same |
| CN109503409A (en) * | 2018-12-10 | 2019-03-22 | 安徽金禾实业股份有限公司 | Sucralose is esterified reaction acid DMF processing method and processing device |
| CN110423192A (en) * | 2019-08-14 | 2019-11-08 | 郑州中科新兴产业技术研究院 | A kind of recovery method of spandex DMAC/ acetic acid organic liquid waste |
| CN110759832A (en) * | 2019-11-16 | 2020-02-07 | 安徽金禾实业股份有限公司 | DMAC (dimethylacetamide) residual liquid recycling device and method |
-
2020
- 2020-05-22 CN CN202010439442.1A patent/CN111592469A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120157676A1 (en) * | 2009-03-30 | 2012-06-21 | Tate & Lyle Technology Ltd. | Process for removing dimethylamine |
| CN105418447A (en) * | 2015-12-17 | 2016-03-23 | 烟台国邦化工机械科技有限公司 | DMAC (dimethylacetamide) rectification device and technique |
| WO2017190299A1 (en) * | 2016-05-05 | 2017-11-09 | 章旭元 | Seven-tower five-effect rectification system for dmac or dmf waste liquid and method for recovering same |
| CN106831471A (en) * | 2017-01-20 | 2017-06-13 | 福州大学 | A kind of method for removing a small amount of acid or glacial acetic acid and refining DMF |
| CN109503409A (en) * | 2018-12-10 | 2019-03-22 | 安徽金禾实业股份有限公司 | Sucralose is esterified reaction acid DMF processing method and processing device |
| CN110423192A (en) * | 2019-08-14 | 2019-11-08 | 郑州中科新兴产业技术研究院 | A kind of recovery method of spandex DMAC/ acetic acid organic liquid waste |
| CN110759832A (en) * | 2019-11-16 | 2020-02-07 | 安徽金禾实业股份有限公司 | DMAC (dimethylacetamide) residual liquid recycling device and method |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112047832A (en) * | 2020-09-18 | 2020-12-08 | 北京化工大学 | N, N-dimethylacetamide wastewater recovery process |
| CN112574052A (en) * | 2020-11-30 | 2021-03-30 | 安徽金禾实业股份有限公司 | Distillation treatment method of DMAC reaction solution |
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Application publication date: 20200828 |