CN102863567A - Preparation method of polyvinyl alcohol through low-alkali method - Google Patents
Preparation method of polyvinyl alcohol through low-alkali method Download PDFInfo
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- CN102863567A CN102863567A CN2011101890736A CN201110189073A CN102863567A CN 102863567 A CN102863567 A CN 102863567A CN 2011101890736 A CN2011101890736 A CN 2011101890736A CN 201110189073 A CN201110189073 A CN 201110189073A CN 102863567 A CN102863567 A CN 102863567A
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Abstract
The invention provides a preparation method of polyvinyl alcohol through a low-alkali method. The preparation method comprises an aftertreatment step and is characterized in that a washing step is operated in the aftertreatment step. The preparation method of the polyvinyl alcohol through the low-alkali method improves quality of the polyvinyl alcohol, mass percent content of methyl alcohol contained by the polyvinyl alcohol is lower than 1.0%, content of impurities such as acetic acid, methyl acetate and the like is reduced, and influence on the environment of the polyvinyl alcohol manufactured by the method in a using process is reduced. Simultaneously, the preparation method is free of environment pollution, low in production energy consumption and low in cost.
Description
Technical field
The present invention relates to the production technical field of polyvinyl alcohol (PVA), particularly a kind of low alkaline process prepares the method for polyvinyl alcohol.
Background technology
Polyvinyl alcohol (PVA) is to be got through alkali catalyzed alcoholysis by polyvinyl acetate (PVA), and wherein employed alcohol is generally methyl alcohol, obtains polyvinyl alcohol through alcoholysis reaction, and produces the by products such as methyl acetate and sodium-acetate.Polyvinyl alcohol solidifies in pure and mild methyl acetate and obtains solid product, through obtaining product after aftertreatment (pulverizing, squeezing, the drying etc.) step process.Wherein the drying of polyvinyl alcohol is the drying machine inner drying about 100 ℃, in this process, most of methyl alcohol and by-product acetic acid methyl esters can be steamed to be removed, but because the environment solvent strength is high, and partial solvent is wrapped in polyvinyl alcohol inner being difficult for and removes fully, in the polyvinyl alcohol of therefore low alkaline process production generally there is about 2% methanol content.In the use procedure of polyvinyl alcohol product, being wrapped in inner methyl alcohol will overflow, and has influence on the use of downstream user.
What the method for purification of inorganic salt was commonly used in the polyvinyl alcohol is water-soluble alcohol extracting liberation method, its step: with polyvinyl alcohol resin fully dissolving in water, salt constituents wherein also is dissolved in the water first; Because polyvinyl alcohol resin is insoluble in ethanol, behind the ethanol that adds capacity, can separate out immediately; Restir filters, and part salt, methyl alcohol, ritalin are taken away by solution, and drying, pulverizing obtain finished product again to separate out the solid polyethylene alcohol resin.This method can cause that polyvinyl alcohol resin loss is large, ethanol consumption is large, and introduces new impure alcohol, cost and pollute larger.And the product that obtains is block, and density is large, and structure is hard, can produce many grits during pulverizing.
The patent No. is to have introduced water vapor two-step approach purification polyvinyl alcohol resin among the CN1074424C, its step: containing in water vapor and the vapour content atmosphere 20%～80%, carry out the stirring of solid polyethylene alcohol resin, remove organic solvent residual by diluent gass such as water vapor and nitrogen.This method need to consume a large amount of steam and diluent gas, and cost is high, needs simultaneously to carry out the drying treatment of annex to remove moisture.
Introduced the method with aqueous ethanolic solution purify poly (vinyl alcohol) resin in the Chinese patent 200810151479.3, its step: at first polyvinyl alcohol resin is added in the mixed solvent of ethanol water and stir; Add again ethanol or aqueous ethanol, polyvinyl alcohol resin is separated out; Separate at last dry.The method has reduced the product methanol content, but has introduced new ethanol, and the drying treatment that needs simultaneously to add is removed moisture, cost is high.
Summary of the invention
The object of the present invention is to provide a kind of low alkaline process to prepare the method for polyvinyl alcohol, the inventive method can be at the polyvinyl alcohol of the low methanol content of industrial realization low cost production.
The object of the present invention is achieved like this:
A kind of low alkaline process prepares the method for polyvinyl alcohol, comprises post-processing step, it is characterized in that: the described water-washing step that increases in post-processing step.
Above-mentioned post-processing step comprise to the polyvinyl alcohol solid pulverize, squeezing, drying and other steps.
In order to reduce the load of drying treatment, thereby further reduce drying cost, above-mentioned water-washing step is to carry out before the squeezing after the pulverizing in aftertreatment.
In order further to reduce the methanol content of polyvinyl alcohol, the temperature of above-mentioned washing is 5～25 ℃, and washing time is 3～15 minutes; Be preferably 10～20 ℃ of washing temperature, washing time 5～15 minutes.
In order further to reduce environmental pollution, above-mentioned water-washing step separates solid-liquid after also being included in washing, and methyl alcohol, washing water recycle and reuse are reclaimed in liquid phase rectifying after separating, and the solid polycondensation vinyl alcohol resin is carried out drying again after squeezing.
Specifically, a kind of low alkaline process prepares the method for polyvinyl alcohol:
A. polyvinyl acetate (PVA) and methyl alcohol obtain the solid polycondensation vinyl alcohol as reaction raw materials through alkali catalyzed alcoholysis;
B. with solid product through pulverize, after rinse bath is washed and is washed solid-liquid separation, solid phase obtains the polyvinyl alcohol product through pressing and drying again; Wherein washing temperature is 10～20 ℃, and washing time is 5～15 minutes, and the solid-liquid separation after the described washing is that methyl alcohol, simultaneously washing water recycling use are reclaimed in liquid phase rectifying.
Beneficial effect of the present invention
The method that the low alkaline process of the present invention is produced polyvinyl alcohol has improved the quality of final polyvinyl alcohol, wherein the quality percentage composition of contained methyl alcohol is lower than 1.0%, also reduce the content of the impurity such as its contained sodium-acetate, ritalin, reduced the impact of the polyvinyl alcohol environment in use that the inventive method makes; Simultaneously the inventive method environmentally safe, production energy consumption is low, cost is low.
Embodiment
Below by embodiment the present invention is carried out concrete description; be necessary to be pointed out that at this following examples only are used for the present invention is further specified; can not be interpreted as limiting the scope of the invention, the person skilled in art can make some nonessential improvement and adjustment to the present invention according to the invention described above content.
Embodiment 1
A kind of low alkaline process prepares the method for polyvinyl alcohol:
A. polyvinyl acetate (PVA) and methyl alcohol obtain the solid polycondensation vinyl alcohol as reaction raw materials through alkali catalyzed alcoholysis;
B. prepare 15 ℃ water solvent and stirring, polyvinyl alcohol resin after pulverizing is directly added rinse bath, stirred 10 minutes, make the methyl alcohol in the polyvinyl alcohol resin soluble in water, then carry out solid-liquid separation, methyl alcohol, simultaneously washing water recycling use are reclaimed in liquid phase rectifying, and the solid polycondensation vinyl alcohol resin that obtains squeezes, drying, obtain the polyvinyl alcohol resin product after drying is qualified.
Embodiment 2
A kind of low alkaline process prepares the method for polyvinyl alcohol:
A. polyvinyl acetate (PVA) and methyl alcohol obtain the solid polycondensation vinyl alcohol as reaction raw materials through alkali catalyzed alcoholysis;
B. prepare 16 ℃ water solvent and stirring, polyvinyl alcohol resin after pulverizing is directly added rinse bath, stirred 12 minutes, make the methyl alcohol in the polyvinyl alcohol resin soluble in water, then carry out solid-liquid separation, methyl alcohol, simultaneously washing water recycling use are reclaimed in liquid phase rectifying, and the solid polycondensation vinyl alcohol resin that obtains squeezes, drying, obtain the polyvinyl alcohol resin product after drying is qualified.
Embodiment 3
A kind of low alkaline process prepares the method for polyvinyl alcohol:
A. polyvinyl acetate (PVA) and methyl alcohol obtain the solid polycondensation vinyl alcohol as reaction raw materials through alkali catalyzed alcoholysis;
B. prepare 18 ℃ water solvent and stirring, polyvinyl alcohol resin after pulverizing, squeezing is directly added rinse bath, stirred 6 minutes, make the methyl alcohol in the polyvinyl alcohol resin soluble in water, then carry out solid-liquid separation, the solid polycondensation vinyl alcohol resin that obtains carries out drying, obtains the polyvinyl alcohol resin product after drying is qualified, and the content of its methyl alcohol is 0.20%.
Embodiment 4
A kind of low alkaline process prepares the method for polyvinyl alcohol:
A. polyvinyl acetate (PVA) and methyl alcohol obtain the solid polycondensation vinyl alcohol as reaction raw materials through alkali catalyzed alcoholysis;
B. prepare 5 ℃ water solvent and stirring, polyvinyl alcohol resin after pulverizing is directly added rinse bath, stirred 15 minutes, make the methyl alcohol in the polyvinyl alcohol resin soluble in water, then carry out solid-liquid separation, methyl alcohol, simultaneously washing water recycling use are reclaimed in liquid phase rectifying, and the solid polycondensation vinyl alcohol resin that obtains squeezes, drying, obtain the polyvinyl alcohol resin product after drying is qualified, the content of its methyl alcohol is 0.36%.
Embodiment 5
A kind of low alkaline process prepares the method for polyvinyl alcohol:
A. polyvinyl acetate (PVA) and methyl alcohol obtain the solid polycondensation vinyl alcohol as reaction raw materials through alkali catalyzed alcoholysis;
B. prepare 25 ℃ water solvent and stirring, polyvinyl alcohol resin after pulverizing is directly added rinse bath, stirred 3 minutes, make the methyl alcohol in the polyvinyl alcohol resin soluble in water, then carry out solid-liquid separation, methyl alcohol, simultaneously washing water recycling use are reclaimed in liquid phase rectifying, and the solid polycondensation vinyl alcohol resin that obtains squeezes, drying, obtain the polyvinyl alcohol resin product after drying is qualified, the content of its methyl alcohol is 0.4%.
Embodiment 6
A kind of low alkaline process prepares the method for polyvinyl alcohol:
A. polyvinyl acetate (PVA) and methyl alcohol obtain the solid polycondensation vinyl alcohol as reaction raw materials through alkali catalyzed alcoholysis;
B. prepare 13 ℃ water solvent and stirring, polyvinyl alcohol resin after pulverizing is directly added rinse bath, stirred 8 minutes, make the methyl alcohol in the polyvinyl alcohol resin soluble in water, then carry out solid-liquid separation, the solid polycondensation vinyl alcohol resin that obtains squeezes, drying, obtains the polyvinyl alcohol resin product after drying is qualified, and the content of its methyl alcohol is 0.26%.
The comparative example 1
A kind of low alkaline process prepares the method for polyvinyl alcohol: polyvinyl acetate (PVA) and methyl alcohol obtain the solid polycondensation vinyl alcohol as reaction raw materials through alkali catalyzed alcoholysis; After solid product pulverized, squeeze again, carry out drying in 100 ℃ of drying machines and finally make polyvinyl alcohol resin.
The methanol content detected result of the polyvinyl alcohol resin that embodiment 1 makes sees the following form:
| Project | The polyvinyl alcohol resin that comparative example 1 makes | The polyvinyl alcohol resin that embodiment 1 makes |
| Methyl alcohol %(W) | 2.6％ | 0.30％ |
The methanol content detected result of the polyvinyl alcohol resin that embodiment 2 makes sees the following form:
| Project | The polyvinyl alcohol resin that comparative example 1 makes | The polyvinyl alcohol resin that embodiment 1 makes |
| Methyl alcohol %(W) | 2.58％ | 0.25％ |
Claims (9)
1. a low alkaline process prepares the method for polyvinyl alcohol, comprises post-processing step, it is characterized in that: the described water-washing step that also carries out in post-processing step.
2. the method for claim 1 is characterized in that: described aftertreatment be comprise to polyvinyl alcohol pulverize, the pressing and drying step.
3. method as claimed in claim 1 or 2 is characterized in that: described washing is to carry out before the squeezing after the pulverizing in aftertreatment.
4. method as claimed in claim 1 or 2, it is characterized in that: the temperature of described washing is 5～25 ℃, washing time is 3～15 minutes.
5. method as claimed in claim 3, it is characterized in that: the temperature of described washing is 5～25 ℃, washing time is 3～15 minutes.
6. method as claimed in claim 5, it is characterized in that: the temperature of described washing is 10～20 ℃, washing time is 5～15 minutes.
7. method as claimed in claim 1 or 2, it is characterized in that: described water-washing step separates solid-liquid after also being included in washing, methyl alcohol, washing water recycle and reuse are reclaimed in liquid phase rectifying after separating, and the solid polycondensation vinyl alcohol resin is carried out drying again after squeezing.
8. method as claimed in claim 6 is characterized in that: described water-washing step separates solid-liquid after also being included in washing, and methyl alcohol, washing water recycle and reuse are reclaimed in liquid phase rectifying after separating, and the solid polycondensation vinyl alcohol resin is carried out drying again after squeezing.
9. the method for claim 1 is characterized in that:
A. polyvinyl acetate (PVA) and methyl alcohol obtain the solid polycondensation vinyl alcohol as reaction raw materials through alkali catalyzed alcoholysis;
B. with solid product through pulverize, after rinse bath is washed and is washed solid-liquid separation, solid phase obtains the polyvinyl alcohol product through pressing and drying again; Wherein washing temperature is 10～20 ℃, and washing time is 5～15 minutes, and the solid-liquid separation after the described washing is that methyl alcohol, simultaneously washing water recycling use are reclaimed in liquid phase rectifying.
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105906826A (en) * | 2016-04-27 | 2016-08-31 | 安徽皖维高新材料股份有限公司 | Continuous production method of differential polyvinyl alcohol films |
| CN106140717A (en) * | 2016-08-19 | 2016-11-23 | 安徽皖维高新材料股份有限公司 | A kind of polyvinyl alcohol resin rinsing bowl and rapid water cleaning device |
| CN106279479A (en) * | 2015-06-09 | 2017-01-04 | 中国石油化工集团公司 | A kind of method improving product polyvinyl alcohol alcoholysis degree |
| CN106757892A (en) * | 2015-11-19 | 2017-05-31 | 张家港市宏盛贸易有限公司 | Water-soluble fibre rinsing machine |
| CN106757893A (en) * | 2015-11-19 | 2017-05-31 | 张家港市宏盛贸易有限公司 | Water-soluble fibre rinsing machine |
| CN107151283A (en) * | 2017-05-27 | 2017-09-12 | 中国石油化工集团公司 | A kind of preparation method of the special polyvinyl alcohol of optical material |
| CN110028602A (en) * | 2019-04-28 | 2019-07-19 | 安徽皖维高新材料股份有限公司 | A method of reducing impurity content in commercial polyethylene alcohol |
| CN110903415A (en) * | 2019-10-30 | 2020-03-24 | 中国石油化工股份有限公司 | Purification method of PVA (polyvinyl alcohol) raw material for optical film |
| CN117050011A (en) * | 2023-10-11 | 2023-11-14 | 湖南工程学院 | Method for synthesizing 2-methylquinoline by using vinyl acetate as raw material |
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Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106279479A (en) * | 2015-06-09 | 2017-01-04 | 中国石油化工集团公司 | A kind of method improving product polyvinyl alcohol alcoholysis degree |
| CN106757893A (en) * | 2015-11-19 | 2017-05-31 | 张家港市宏盛贸易有限公司 | Water-soluble fibre rinsing machine |
| CN106757892A (en) * | 2015-11-19 | 2017-05-31 | 张家港市宏盛贸易有限公司 | Water-soluble fibre rinsing machine |
| CN105906826A (en) * | 2016-04-27 | 2016-08-31 | 安徽皖维高新材料股份有限公司 | Continuous production method of differential polyvinyl alcohol films |
| CN106140717B (en) * | 2016-08-19 | 2019-01-01 | 安徽皖维高新材料股份有限公司 | A kind of polyvinyl alcohol resin rinsing bowl and quick water washing device |
| CN106140717A (en) * | 2016-08-19 | 2016-11-23 | 安徽皖维高新材料股份有限公司 | A kind of polyvinyl alcohol resin rinsing bowl and rapid water cleaning device |
| CN107151283A (en) * | 2017-05-27 | 2017-09-12 | 中国石油化工集团公司 | A kind of preparation method of the special polyvinyl alcohol of optical material |
| CN110028602A (en) * | 2019-04-28 | 2019-07-19 | 安徽皖维高新材料股份有限公司 | A method of reducing impurity content in commercial polyethylene alcohol |
| CN110028602B (en) * | 2019-04-28 | 2021-09-10 | 安徽皖维高新材料股份有限公司 | Method for reducing impurity content in industrial polyvinyl alcohol |
| CN110903415A (en) * | 2019-10-30 | 2020-03-24 | 中国石油化工股份有限公司 | Purification method of PVA (polyvinyl alcohol) raw material for optical film |
| CN110903415B (en) * | 2019-10-30 | 2023-02-24 | 中国石油化工股份有限公司 | Purification method of PVA (polyvinyl alcohol) raw material for optical film |
| CN117050011A (en) * | 2023-10-11 | 2023-11-14 | 湖南工程学院 | Method for synthesizing 2-methylquinoline by using vinyl acetate as raw material |
| CN117050011B (en) * | 2023-10-11 | 2024-01-23 | 湖南工程学院 | Method for synthesizing 2-methylquinoline by using vinyl acetate as raw material |
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