KR101907195B1 - Method for purification of polyalkylenecarbonate - Google Patents
Method for purification of polyalkylenecarbonate Download PDFInfo
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- KR101907195B1 KR101907195B1 KR1020150050441A KR20150050441A KR101907195B1 KR 101907195 B1 KR101907195 B1 KR 101907195B1 KR 1020150050441 A KR1020150050441 A KR 1020150050441A KR 20150050441 A KR20150050441 A KR 20150050441A KR 101907195 B1 KR101907195 B1 KR 101907195B1
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G64/00—Macromolecular compounds obtained by reactions forming a carbonic ester link in the main chain of the macromolecule
- C08G64/40—Post-polymerisation treatment
- C08G64/406—Purifying; Drying
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G64/00—Macromolecular compounds obtained by reactions forming a carbonic ester link in the main chain of the macromolecule
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G64/00—Macromolecular compounds obtained by reactions forming a carbonic ester link in the main chain of the macromolecule
- C08G64/02—Aliphatic polycarbonates
- C08G64/0208—Aliphatic polycarbonates saturated
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G64/00—Macromolecular compounds obtained by reactions forming a carbonic ester link in the main chain of the macromolecule
- C08G64/20—General preparatory processes
- C08G64/32—General preparatory processes using carbon dioxide
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Abstract
The present invention relates to a method for purifying a polyalkylene carbonate, and a method for purifying a polyalkylene carbonate according to the present invention is capable of effectively removing an alkylene carbonate without using high temperature and high pressure conditions, It is possible to prepare a polyalkylene carbonate.
Description
The present invention relates to a method for purifying a polyalkylene carbonate.
The global warming phenomenon, where the average temperature of the Earth rises, is caused by excessive use of greenhouse gases by the use of fossil fuels. These greenhouse gases include methane, water vapor, and chlorofluorocarbons, but most of all, industrialization and excessive emissions of carbon dioxide are the main causes.
In order to solve this problem, so-called green chemistry has recently been used to utilize materials that cause environmental problems as industrially useful materials, and in the case of carbon dioxide, researches are being made to manufacture polymers using them as raw materials.
As the polymer which can be produced by using carbon dioxide as a raw material, polyalkylene carbonate can be mentioned. The polyalkylene carbonate can be prepared by reacting carbon dioxide with a cyclic epoxide. The polyalkylene carbonate is a biodegradable polymer having an ester structure in its molecular structure and capable of decomposing in a wet environment. In addition, it is flame retardant and non-toxic in burning, has excellent gas and organic solvent barrier, printing suitability and transparency, and its application fields are various. Especially, it is widely used as a biodegradable packaging material.
However, there are various process difficulties in the production of polyalkylene carbonate, and it is particularly difficult to produce polyalkylene carbonate having high purity. For this reason, in the process of producing a polyalkylene carbonate by the reaction of carbon dioxide with a cyclic epoxide, an alkylene carbonate such as ethylene carbonate or propylene carbonate is produced as a byproduct due to the back biting of the polyalkylene carbonate chain do. Such an alkylene carbonate is desirably removed from the final product because it acts as a plasticizer in the polyalkylene carbonate to deteriorate the processability of the polyalkylene carbonate.
However, since the alkylene carbonate has a stable chemical structure and high breaking point, and it is difficult to use the separation process at high temperature and high pressure owing to the biodegradability of polyalkylene carbonate, separation of alkylene carbonate is difficult.
Conventionally, in order to remove the alkylene carbonate, a method of extracting and removing the final product with a solvent such as alcohol has been used. However, the efficiency of removing by-products is lowered when using alcohol, and polyalkylene carbonate is also partially removed.
In addition, U.S. Patent Application Publication No. US2014 / 0155573 describes a method for purifying a polyalkylene carbonate by adding a polyalkylene carbonate product to water without using an organic solvent and heating it. However, since the above method uses a high temperature, the possibility of decomposition of the polyalkylene carbonate is high, which is undesirable, and the removal efficiency of the alkylene carbonate is not high.
Therefore, the inventors of the present invention have been studying a method for purifying a polyalkylene carbonate which can remove a by-product alkylene carbonate, and as a result, it is possible to effectively remove alkylene carbonate The present inventors have completed the present invention.
The present invention is to provide a method for purifying polyalkylene carbonate which can effectively remove alkylene carbonate without using high-temperature and high-pressure conditions.
In order to solve the above problems, the present invention provides a process for purifying a polyalkylene carbonate comprising the steps of:
1) preparing a feed solution comprising a polyalkylene carbonate;
2) feeding the feed solution and water to a column;
3) contacting the feed solution in the column with water; And
4) recovering the raffinate solution and the extraction solution from the column.
The present invention relates to a method for purifying a polyalkylene carbonate, and more particularly, to a method for removing an alkylene carbonate among byproducts generated in the production of a polyalkylene carbonate.
The polyalkylene carbonate can be prepared by reacting carbon dioxide with a cyclic epoxide (cyclic ether), in which the chain of the polymer is backbased to produce the alkylene carbonate as a byproduct. Since alkylene carbonate acts as a plasticizer in the polymer to deteriorate the processability, it must be removed after the polymerization process.
The polyalkylene carbonate may be a polyethylene carbonate or a polypropylene carbonate, and ethylene carbonate and propylene carbonate may be produced as byproducts, respectively. The two materials are very stable in terms of chemical structure and high in breaking point. Since they have higher breaking points than polyethylene carbonate and polypropylene carbonate, they are difficult to remove by heating or the like. In addition, since polyethylene carbonate and polypropylene carbonate are biodegradable, there is a limitation in using high temperature and high pressure to remove by-products.
Accordingly, the present invention is characterized in that the polyalkylene carbonate polymerization product is contacted with water in a simple and effective manner to remove ethylene carbonate, which is a by-product, under conditions of high temperature and high pressure.
Hereinafter, the present invention will be described in detail.
Polyalkylene carbonate Feed The solution preparation step (step 1)
The feed solution means the polymerization product of polyalkylene carbonate. The feed solution may be prepared by reacting carbon dioxide and a cyclic epoxide in the presence of a catalyst and a chlorine-containing aliphatic hydrocarbon solvent. The carbon dioxide and the cyclic epoxide are polymerized to produce a polymer having units of- (alkylene) -OCO-, wherein the feed solution includes an alkylene carbonate formed by backbiting the chain of the polymer in the polymerization process .
The polyalkylene carbonate may be polyethylene carbonate or polypropylene carbonate. In this case, ethylene oxide and propylene oxide, which are cyclic epoxides, can be used as starting materials, respectively, and ethylene carbonate and propylene carbonate can be produced as byproducts.
As the catalyst that can be used for the polymerization, a zinc dicarboxylate-based catalyst may be used. For example, the zinc dicarboxylate catalyst can be prepared by reacting a zinc precursor and a dicarboxylic acid such as glutaric acid having 3 to 20 carbon atoms, and has a fine crystalline particle shape. Further, as the chlorine-containing aliphatic hydrocarbon solvent, dimethylene chloride or 1,2-dichloroethane can be used.
The viscosity of the feed solution is preferably 200 to 6000 cP at 5 to 45 캜. The viscosity of the feed solution can be adjusted by adjusting the polymerization time or by further removing or adding the solvent used in the polymerization product. When the viscosity is less than 200 cP, the overall process efficiency is lowered due to the low TSC, and the polymer solution disappears in the extraction solution, which is undesirable. When the viscosity exceeds 6000 cP, the efficiency of removing by- Flooding phenomenon occurs and operation is not easy.
Feed Solution and water As a column The supplying step (step 2)
Feeding the feed solution and water to the column to contact the feed solution prepared in
Preferably, the feed solution is fed to the top of the column and water is fed to the bottom of the column. At the upper end of the column, a feed solution supply unit and an extraction solution extraction unit are provided, and a water supply unit and a raffinate extraction unit are provided at the lower end of the column. For the extraction efficiency, it is preferable that the position of the extraction solution extraction portion is higher than the feed solution supply portion and the position of the raffinate extraction portion is lower than the water supply portion. In addition, it is preferable that the feed solution supply part, the extraction solution extraction part, the water supply part and the raffinate extraction part are located in opposite directions with respect to the column.
Since the alkylene carbonate as a by-product in the feed solution has high solubility in water, water is used as an extraction solvent, and the feed solution is contacted with water to transfer the by-product from the feed solution to water to remove the by-product from the feed solution.
In addition, the solvent of the feed solution has a density higher than that of water. For example, the density of dimethylene chloride is about 1.33 g / cm3, which is larger than that of water. Thus, the feed solution is fed to the top of the column to cause the feed solution to move to the bottom in the column, and water is fed to the bottom of the column to move the water to the top in the column, thereby prolonging the contact time.
The weight ratio (S / F) of water (S) and feed solution (F) to the column is preferably 1 to 3.
column of mine Feed Contacting the solution with water (step 3)
Due to the difference in density between the feed solution and the water, each solution moves in the opposite direction in the column, and the feed solution and the water in the column contact each other.
Because the solubility of the alkylene carbonate in water is very high, the alkylene carbonate in the feed solution can migrate to water, and since chlorine-containing aliphatic hydrocarbon solvents such as dimethylene chloride are immiscible with water, The recarbonate can be removed from the feed solution.
At this time, in order for the by-product in the feed solution to move to water, it is preferable that the contact area of the feed solution and water is wide. For this purpose, it is preferable to use a karr column or a khuni column as the column in the present invention.
The column refers to a column having a perforated plate oscillating in the column in the vertical direction and arranged parallel to each other. The perforated plate includes a plurality of perforations having a diameter of about 1.5 mm to 3.0 mm, through which the feed solution and water can move up and down. Also, the number of the perforations may be different from each other, and the opening / closing rate (perforation area / area of the plate) of the perforated plates may be different from each other. Preferably, the perforation plate of the column has a low opening and closing rate toward the bottom of the column.
The perforated plates are connected to an up-and-down vibrating shaft. The perforated plate vibrates vertically due to the vibrations thereof to crumble the feed solution and water to widen the contact area between the feed solution and the water. Thus, after the feed solution is fed to the top of the column, it is moved to the bottom of the column and crushed by the perforation plate, so that the by-products in the feed solution are dissolved and moved in contact with the water.
In addition, the above-mentioned Knee column includes a perforated plate such as the above-mentioned column, but the impeller is provided between the perforated plates instead of vertically vibrating the perforated plate. As the impeller rotates, turbulence is formed and the feed solution is finely crushed to widen the contact area with water.
The rotational speed of the impeller is preferably 150 to 250 rpm. At less than 150 rpm, the effect of breaking down the feed solution is poor, and the removal efficiency of the byproduct is decreased. When the flow rate exceeds 250 rpm, energy consumption is large and flooding phenomenon occurs.
The column process does not require high temperature and high pressure. Since the temperature in the column can be performed at 5 to 45 ° C and can be performed at normal pressure, the process for removing by-products is very simple and the process efficiency is high.
Raffinate The solution and extraction solution recovery step (step 4)
The by-product in the feed solution, particularly the alkylene carbonate, is present in the raffinate solution that is present in the feed solution as the feed solution moves to the bottom of the column and the water moves to the top of the column, Removed.
According to one embodiment of the present invention, it was confirmed that the alkylene carbonate content in the raffinate solution was reduced by 60 to 95% as compared with the alkylene carbonate content in the feed solution.
Since the polylactene carbonate and the solvent used for the polymerization are the main components in the raffinate solution from which the byproduct is removed as described above, the solvent can be removed by drying or the like to produce the highly pure polyalkylene carbonate.
In addition, the extraction solution recovered to the upper end of the column contains alkylene carbonate as a by-product, which is a byproduct moved in the feed solution, and the alkylene carbonate can be recovered by removing water by drying or the like. Since the recovered alkylene carbonate is also industrially applicable in many fields, it can be recovered and used in other fields.
The method for purifying the polyalkylene carbonate according to the present invention can be continuously performed, and thus the polyalkylene carbonate can be purified continuously and stably.
The method for purifying a polyalkylene carbonate according to the present invention can effectively remove an alkylene carbonate without using a high temperature and a high pressure, thereby making it possible to produce a high purity polyalkylene carbonate.
1 is a graph showing the removal efficiency of EC (ethylene carbonate) according to an embodiment of the present invention.
Hereinafter, preferred embodiments of the present invention will be described in order to facilitate understanding of the present invention. However, the following examples are provided only for the purpose of easier understanding of the present invention, and the present invention is not limited thereto.
Example One
Step 1) Preparation of a polyethylene carbonate feed solution
(Fine crystalline particles formed by reacting a zinc precursor and a glutaric acid), methylene chloride, ethylene oxide and carbon dioxide were added to a reactor equipped with a stirrer, and a solution Polymerization proceeded to prepare polyethylene carbonate. At this time, ethylene oxide, carbon dioxide, and methylene chloride were purified before polymerization and kept at a moisture content of less than 10 ppm.
After completion of the solution polymerization under the above conditions, the unreacted ethylene oxide was dissolved in methylene chloride under a reduced pressure, and the carbon dioxide was removed by venting. The polymerized polymer solution was then mixed with dimethyl chloride to give an appropriate viscosity range.
Step 2) Removal of ethylene carbonate using a Carr column
A total of 50 columns were used, each having a perforated plate with different opening and closing rates. The upper and lower six perforated plates in the column had an open / close ratio of 50%, and the open / closed ratio of the perforated plate in the bottom 44nd stage was 25%.
The temperature in the column was maintained at 10 to 15 캜, and the feed solution prepared in the
The contents of the materials shown in Tables 2 and 3 below were measured by taking each sample and converting the peak area ratio of the NMR data into a weight ratio.
(Viscosity 200 cP)
(Viscosity 65 cP)
The EC removal rate according to the volume ratio (S / F) of the water (S) and the feed solution (F) supplied to the column is shown graphically in FIG. As shown in Tables 1 and 2 and FIG. 1, it was confirmed that the removal rate of EC was increased at 2 when the S / F ratio was 1, compared with 1.
Example 2
Step 1) Preparation of a polyethylene carbonate feed solution
(Fine crystalline particles formed by reacting a zinc precursor and glutaric acid), methylene chloride, ethylene oxide, and carbon dioxide were added to a reactor equipped with a stirrer, and a solution Polymerization proceeded to prepare polyethylene carbonate. At this time, ethylene oxide, carbon dioxide, and methylene chloride were purified before polymerization and kept at a moisture content of less than 10 ppm.
After completion of the solution polymerization under the above conditions, the unreacted ethylene oxide was dissolved in methylene chloride under a reduced pressure, and the carbon dioxide was removed by venting. The polymerized polymer solution was then mixed with dimethyl chloride to give an appropriate viscosity range.
Step 2) Removal of ethylene carbonate using a Kuni column
The polyethylene carbonate feed solution prepared in the
The temperature in the column was maintained at 5 to 10 DEG C and was performed under the conditions shown in Table 5 below. The content of the substances in Table 5 below was measured by taking each sample and converting the peak area ratio of the NMR data into a weight ratio.
Example 3
Step 1) Preparation of a polyethylene carbonate feed solution
(Fine crystalline particles formed by reacting a zinc precursor and glutaric acid), methylene chloride, ethylene oxide, and carbon dioxide were added to a reactor equipped with a stirrer, and a solution Polymerization proceeded to prepare polyethylene carbonate. At this time, ethylene oxide, carbon dioxide, and methylene chloride were purified before polymerization and kept at a moisture content of less than 10 ppm.
After completion of the solution polymerization under the above conditions, the unreacted ethylene oxide was dissolved in methylene chloride under a reduced pressure, and the carbon dioxide was removed by venting. The polymerized polymer solution was then mixed with dimethyl chloride to give an appropriate viscosity range.
Step 2) Removal of ethylene carbonate using a Kuni column
The polyethylene carbonate feed solution prepared in the
The temperature in the column was maintained at 35 to 45 DEG C, and was performed under the conditions shown in Table 7 below. In addition, the contents of the substances in Table 3 below were measured by taking each sample and converting the peak area ratio of the NMR data into a weight ratio.
Claims (12)
2) feeding the feed solution to the top of the column and supplying water to the bottom of the column;
3) contacting the feed solution in the column with water; And
4) recovering the raffinate solution and the extraction solution from the column.
A method for purifying a polyalkylene carbonate.
Characterized in that the feed solution is prepared by reacting carbon dioxide and cyclic ether in the presence of a catalyst and a chlorine-containing aliphatic hydrocarbon solvent.
Way.
Wherein the chlorine-containing aliphatic hydrocarbon is dimethylene chloride or 1,2-dichloroethane.
Way.
Wherein the polyalkylene carbonate is a polyethylene carbonate or a polypropylene carbonate.
Way.
Characterized in that the viscosity of the feed solution is from 200 to 6000 cP at 5 to < RTI ID = 0.0 > 45 C. <
Way.
Characterized in that the weight ratio of water to the feed solution (water / feed solution) supplied to the column is between 1 and 3,
Way.
Wherein the column is a column,
Characterized in that the said column has 40 to 50 perforated plates oscillating in the vertical direction and arranged parallel to each other,
Way.
Characterized in that the perforation plate of the column has a low opening and closing rate toward the bottom of the column.
Way.
Wherein the column is a crayon column,
Characterized in that the kuni column comprises 40 to 50 perforated plates arranged parallel to each other and an impeller rotating between 150 and 250 rpm between the perforated plates.
Way.
Wherein step 4 is performed by withdrawing the raffinate solution to the bottom of the column and recovering the extraction solution to the top of the column.
Way.
Characterized in that the content of alkylene carbonate in the raffinate solution is reduced by 60 to 95% by weight relative to the content of alkylene carbonate in the feed solution.
Way.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040171721A1 (en) | 2002-12-16 | 2004-09-02 | Esemplare Pascal E. | Stabilizing polyalkylene carbonate resins |
| KR100516987B1 (en) * | 1997-03-17 | 2005-09-26 | 코닌클리즈케 디에스엠 엔.브이. | Process for purifying caprolactam |
| JP2006104095A (en) | 2004-10-04 | 2006-04-20 | Asahi Kasei Chemicals Corp | Continuous manufacturing method of alkylene carbonate |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100516987B1 (en) * | 1997-03-17 | 2005-09-26 | 코닌클리즈케 디에스엠 엔.브이. | Process for purifying caprolactam |
| US20040171721A1 (en) | 2002-12-16 | 2004-09-02 | Esemplare Pascal E. | Stabilizing polyalkylene carbonate resins |
| JP2006104095A (en) | 2004-10-04 | 2006-04-20 | Asahi Kasei Chemicals Corp | Continuous manufacturing method of alkylene carbonate |
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