CN102757342A - Method for purifying by-product methyl acetate generated during production of PVA (polyvinyl acetate) - Google Patents
Method for purifying by-product methyl acetate generated during production of PVA (polyvinyl acetate) Download PDFInfo
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- CN102757342A CN102757342A CN201210253745XA CN201210253745A CN102757342A CN 102757342 A CN102757342 A CN 102757342A CN 201210253745X A CN201210253745X A CN 201210253745XA CN 201210253745 A CN201210253745 A CN 201210253745A CN 102757342 A CN102757342 A CN 102757342A
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- ritalin
- extractive distillation
- methyl acetate
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- azeotropic mixture
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Abstract
The invention discloses a method for purifying by-product methyl acetate generated during production of PVA (polyvinyl acetate). The method comprises the three unit processes: extractive distillation, purification and drying. The extractive distillation process is that an azeotropic mixture of by-product crude methyl acetate, methanol and water is added from the middle lower part of an extractive distillation column, an extracting agent is added from the upper part of the extractive distillation column, the temperature at the top of the extractive distillation column is controlled to 55 to 65 DEG C; and the azeotropic mixture of methyl acetate and methanol as well as the extracting agent is discharged from the top of the extractive distillation column; and the purification process is that the azeotropic mixture of methyl acetate and methanol as well as the extracting agent, which is discharged from the top of the extractive distillation column, is sent to a purification column for purification, and pure methyl acetate is obtained in a column bottom, and dried to obtain finished methyl acetate. The extracting agent is acetic acid or acetic acid aqueous solution, does not bring new substances to a system, and can be recycled; and methyl acetate with the purity of more than 99.5% and the yield of more than 90% can be obtained under the condition of smaller additive amount of azeotropic mixture of by-product crude methyl acetate, methanol and water as well as the extracting agent.
Description
One, technical field
The present invention relates to a kind of purification technique of by product, the purification process of by-product methyl acetate during specifically a kind of Z 150PH (PVA) is produced.
Two, background technology
Ritalin is a kind of colourless inflammable liquid, has aromatic odour, can with most of immiscible organic solvents, be widely used as industrial solvent.It can be used in the paint, also is used for the manufacturing of leatheroid and spices and is used as greasy extraction agent.High-purity methyl acetate is broad-spectrum important organic raw material, can be used for acetic acid synthesized, aceticanhydride, methyl acrylate, vinyl acetate between to for plastic and ethanamide etc.Ritalin carbonylation system aceticanhydride be make at present in the aceticanhydride technology most economical; This technology is compared with traditional ketenes method, acetoxylation method; Significant meliority is arranged cutting down the consumption of energy and reduce aspects such as environmental pollution; It has broken away from the dependence to petroleum, is the important breakthrough of C1 chemistry large industrialized technological development.
In Z 150PH (PVA) production process, produce a large amount of ritalin by products, according to measuring and calculating, 1 ton of PVA of every production can produce 1.5 ~ 1.8 tons of ritalins.Most of PVA producer is in order to recycle sub product; Ritalin is decomposed through resin; Obtain the mixture of dilute acetic acid and methyl alcohol and ritalin, obtain ritalin, in this Production Flow Chart in rectifying separation; Its shortcoming: 1. relate to the cl ions, sulfonate ion of acetic acid, ritalin and trace etc. in the system, very serious to equipment corrosion.2. acetic acid-water belongs to difficult separation mixture, and it is big that dilute acetic acid is put forward dense energy consumption, in the PVA production cost, occupies very high ratio.Seek ritalin purification process and device to reduce production costs for this reason.
The CN102295557A patent has described salt extraction and the compression rectification mode that combines is made with extra care the Z 150PH by-product methyl acetate.Its technology is that raw material ritalin, carbinol mixture are got into extraction tower, and extraction agent is a salt, utilizes the effect Dichlorodiphenyl Acetate methyl esters-methyl alcohol of salt to separate.This technology is not enough has brought new material (extraction agent)-salt into in the system, affects for back system purifying.Therefore salt has consumption in the production process in addition, and not only energy consumption is big but also material consumption is also bigger.
Three, summary of the invention
The present invention aims to provide the purification process of by-product methyl acetate in a kind of PVA production, and technical problem to be solved is in the process of purifying, not introduce new material, cuts down the consumption of energy, and improves product purity.
The purification process of by-product methyl acetate during PVA of the present invention produces comprises extracting rectifying, purifying and dry each unit process:
Said extracting rectifying is that the azeotropic mixture of the thick ritalin of by product, the first alcohol and water middle and lower part from extractive distillation column is added; Extraction agent adds from the top of extractive distillation column; Thick ritalin, the azeotropic mixture of first alcohol and water and the volume ratio of extraction agent are 60-80:1-3, and the top temperature control of extractive distillation column is at 55-65 ℃, and tower is pressed and is 60-101KPa; Theoretical plate number is the 35-45 piece, and reflux ratio is 2-4:1; The tower still is collected the first alcohol and water in the extracting rectifying process, and the azeotropic mixture and the extraction agent of ritalin and methyl alcohol are discharged from cat head; Constitute thick ritalin 78% by mass percentage, methyl alcohol 20%, water 2%; Said extraction agent is the acetum of mass concentration 70-100%;
Said purifying is that the ritalin of extracting rectifying column overhead discharge and the azeotropic mixture and the extraction agent of methyl alcohol are sent into purification column, and the temperature control of purifying cat head is at 60-110 ℃, and tower is pressed and is 600-850KPa, and theoretical plate number is the 35-40 piece, and reflux ratio is 3-5:1; Through purifying, the tower still obtains pure ritalin, and the azeotropic mixture circulation that cat head obtains ritalin, methyl alcohol and extraction agent gets into the extractive distillation column circular treatment, gets product after the pure ritalin drying with the collection of tower still.
Extraction agent turns back to extractive distillation column through the extraction recovery and recycles.
Compare with other Technologies, the present invention has following advantage:
1, the inventive method technology is simple, and the ritalin product purity reaches more than 99.5% after the purifying drying.
2, the extraction agent that uses of the present invention is the aqueous solution of acetic acid or acetic acid; Can not increase novel substance to system; Can recycle, and under the situation of addition less (thick ritalin, the azeotropic mixture of first alcohol and water and the volume ratio of extraction agent are 60-80:1-3), can obtain purity more than 99.5%, the ritalin of yield more than 90%.
3, the inventive method is specially adapted to the thick ritalin of purifying, and technical process is simple, and is energy-conservation.
Four, embodiment
The purification process of by-product methyl acetate during PVA produces in the embodiment of the invention comprises extracting rectifying, purifying and dry each unit process:
1, extracting rectifying
The azeotropic mixture of the thick ritalin of by product, first alcohol and water is added from the middle and lower part of extractive distillation column (under 20 blocks of column plates with 60-80m
3/ h charging), extraction agent is with 1-3m
3/ h adds from the top of extractive distillation column, and the top temperature control of extractive distillation column is at 55-65 ℃, atmospheric operation, and theoretical plate number is 40, reflux ratio is 2-4:1, tower still discharging 30-45m
3/ h; The tower still is collected the first alcohol and water in the extracting rectifying process, and the azeotropic mixture and the extraction agent of ritalin and methyl alcohol are discharged from cat head; Constitute thick ritalin 78% by mass percentage, methyl alcohol 20%, water 2%; Said extraction agent is the acetum of mass concentration 70-100%.
2, purifying
The ritalin of extracting rectifying column overhead discharge and the azeotropic mixture and the extraction agent of methyl alcohol are sent into purification column, and the temperature control of purifying cat head is at 60-110 ℃, and tower is pressed and is 750KPa, and theoretical plate number is 35, and reflux ratio is 3-5:1, tower still discharging 30-45m
3/ h; Through purifying, the tower still obtains pure ritalin, and the azeotropic mixture circulation that cat head obtains ritalin, methyl alcohol and extraction agent gets into the extractive distillation column circular treatment.
3, drying
Purifying Tata stilling fluid is sent into the drying tower drying, and to obtain purity be 99.5% high-purity methyl acetate finished product, and yield can reach more than 90%.
Claims (3)
1. the purification process of by-product methyl acetate during a PVA produces comprises extracting rectifying, purifying and dry each unit process, it is characterized in that:
Said extracting rectifying is that the azeotropic mixture of the thick ritalin of by product, the first alcohol and water middle and lower part from extractive distillation column is added; Extraction agent adds from the top of extractive distillation column; Thick ritalin, the azeotropic mixture of first alcohol and water and the volume ratio of extraction agent are 60-80:1-3; The top temperature control of extractive distillation column is at 55-65 ℃, and the azeotropic mixture and the extraction agent of ritalin and methyl alcohol are discharged from cat head; Constitute thick ritalin 78% by mass percentage, methyl alcohol 20%, water 2%; Said extraction agent is the acetum of mass concentration 70-100%;
Said purifying is that the ritalin of extracting rectifying column overhead discharge and the azeotropic mixture and the extraction agent of methyl alcohol are sent into purification column, and the temperature control of purifying cat head is at 60-110 ℃, and tower is pressed and is 600-850KPa; Through purifying, the tower still obtains pure ritalin, gets product after the pure ritalin drying with the collection of tower still.
2. purification process according to claim 1 is characterized in that:
The extracting rectifying Tata is pressed and is 60-101KPa, and theoretical plate number is the 35-45 piece, and reflux ratio is 2-4:1.
3. purification process according to claim 1 is characterized in that:
The purifying Tata is pressed and is 600-850KPa, and theoretical plate number is the 35-40 piece, and reflux ratio is 3-5:1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201210253745XA CN102757342A (en) | 2012-07-19 | 2012-07-19 | Method for purifying by-product methyl acetate generated during production of PVA (polyvinyl acetate) |
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| CN201210253745XA CN102757342A (en) | 2012-07-19 | 2012-07-19 | Method for purifying by-product methyl acetate generated during production of PVA (polyvinyl acetate) |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102924275A (en) * | 2012-11-27 | 2013-02-13 | 福州大学 | Refining method for alcoholysis waste liquid in PVA (polyvinyl alcohol) production and test device for same |
| CN104529764A (en) * | 2014-11-29 | 2015-04-22 | 惠州中创化工有限责任公司 | Method for extracting sec-butyl acetate by-product heavy hydrocarbon |
| CN106397203A (en) * | 2016-08-19 | 2017-02-15 | 安徽皖维高新材料股份有限公司 | Method for stable control of pressurized rectification tower top pressure in methyl acetate refining pressure-swing distillation |
| CN109467499A (en) * | 2018-08-03 | 2019-03-15 | 天津大学 | The anticorrosion process and device of methyl acetate hydrolysis and acetic acid refining during polyvinyl alcohol disposing mother liquor |
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| US4435595A (en) * | 1982-04-26 | 1984-03-06 | Eastman Kodak Company | Reactive distillation process for the production of methyl acetate |
| CN101306994A (en) * | 2008-06-18 | 2008-11-19 | 河北工业大学 | Technological process for producing high-purity methyl acetate and device |
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2012
- 2012-07-19 CN CN201210253745XA patent/CN102757342A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4435595A (en) * | 1982-04-26 | 1984-03-06 | Eastman Kodak Company | Reactive distillation process for the production of methyl acetate |
| CN101306994A (en) * | 2008-06-18 | 2008-11-19 | 河北工业大学 | Technological process for producing high-purity methyl acetate and device |
Non-Patent Citations (1)
| Title |
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| 李俊岭等: "副产品中萃取精馏制备高纯度醋酸甲酯探索", 《化工生产与技术》 * |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102924275A (en) * | 2012-11-27 | 2013-02-13 | 福州大学 | Refining method for alcoholysis waste liquid in PVA (polyvinyl alcohol) production and test device for same |
| CN104529764A (en) * | 2014-11-29 | 2015-04-22 | 惠州中创化工有限责任公司 | Method for extracting sec-butyl acetate by-product heavy hydrocarbon |
| CN104529764B (en) * | 2014-11-29 | 2016-08-24 | 惠州宇新化工有限责任公司 | A kind of method extracting sec-butyl acetate by-product heavy hydrocarbon |
| CN106397203A (en) * | 2016-08-19 | 2017-02-15 | 安徽皖维高新材料股份有限公司 | Method for stable control of pressurized rectification tower top pressure in methyl acetate refining pressure-swing distillation |
| CN106397203B (en) * | 2016-08-19 | 2019-05-07 | 安徽皖维高新材料股份有限公司 | A kind of method that stability contorting methyl acetate refines compression rectification top of tower pressure in variable-pressure rectification technique |
| CN109467499A (en) * | 2018-08-03 | 2019-03-15 | 天津大学 | The anticorrosion process and device of methyl acetate hydrolysis and acetic acid refining during polyvinyl alcohol disposing mother liquor |
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Application publication date: 20121031 |