KR101794912B1

KR101794912B1 - Method for preparing polyalkylenecarbonate

Info

Publication number: KR101794912B1
Application number: KR1020150051642A
Authority: KR
Inventors: 안용희; 손정민; 이준의; 박승영; 김성경
Original assignee: 주식회사 엘지화학
Priority date: 2015-04-13
Filing date: 2015-04-13
Publication date: 2017-12-01
Also published as: KR20160121871A

Abstract

The present invention relates to a process for producing a polyalkalene carbonate resin. More specifically, by extracting and collecting by-products such as alkylene carbonate produced in the production process of the polyalkylene carbonate resin, it is converted into a diol compound such as ethylene glycol by a ring-opening reaction, There is provided a method for producing a polyalkylene carbonate resin capable of reducing the amount of waste water and greatly improving the wastewater treatment process and suggesting recycling of by-products.

Description

TECHNICAL FIELD The present invention relates to a method for preparing a polyalkylene carbonate resin,

The present invention relates to a process for producing a polyalkylene carbonate resin including a step of effectively treating an alkylene carbonate, which is a by-product generated in a process for producing a polyalkylene carbonate resin.

Polyalkylene carbonate is a non-crystalline transparent resin, unlike an aromatic polycarbonate which is a similar type of engineering plastic, exhibits biodegradability and is thermally decomposable at a low temperature, and has the advantage of being completely decomposed into carbon dioxide and water and having no carbon residue Have.

The polyalkylene carbonate is prepared by polymerization of carbon monoxide and an oxide-based monomer in the presence of a chlorinated solvent, and various impurities are present in the polymerized product after polymerization.

The production process of the polyalkylene carbonate is largely divided into a polymerization process and a post-treatment process. In the post-treatment process, a purification process for removing unreacted residual monomers and impurities other than the polyalkylene carbonate, and a purification process for the purified polyalkylene carbonate Into a pellet.

The types of unreacted residual monomers and impurities to be removed in the post-treatment step are as follows.

Examples of the unreacted residual monomer include carbon dioxide and ethylene oxide when oxide-based ethylene oxide is used. Further, the impurities include catalyst residues, by-products and solvents. The catalyst residue is a Zn-based catalyst, and the byproduct is ethylene carbonate.

Among these, ethylene carbonate has a problem that it occurs continuously during its production due to the backing of the polyethylene carbonate polymer chain. The amount of the ethylene carbonate is generated at a ratio of about 5% in the polymer solution due to the exotherm resulting from the present polymerization process.

Although the ratio of the by-product ethylene carbonate is not high, it acts as a plasticizer in the polymer to deteriorate the processability of the final product, and therefore must be removed after the polymerization. However, the produced ethylene carbonate has high stability, and physical separation from the product is difficult.

Currently, the improvement of the process is inhibiting the production of ethylene carbonate, but the performance is still poor.

In addition, the ethylene carbonate is mainly extracted and removed by water treatment through an RDC column. However, there is a problem that a large amount of waste water is generated to remove ethylene carbonate.

Therefore, there is a need for a new method for more efficiently removing ethylene carbonate from the product while reducing the amount of wastewater generated when ethylene carbonate is removed.

On the other hand, in the past, anionically ring-opening polymerization of ethylene carbonate with potassium methoxide as an initiator and the step of reacting methacryl chloride with a terminal hydroxyl group of the polymer were carried out, and a methacrylate-functionalized poly (ethylene oxide-co -Ethylene carbonate) macromonomer (Journal of Polymer Science Part A: Polymer Chemistry, volume 44, Issue 7, pages 2195-2205).

Also, in connection with the production of polyethylene ether carbonate, a method for carrying out ring-opening polymerization of ethylene carbonate using KOH as an initiator is disclosed. (Macromolecules, 2000, 33 (5), pp 1618-1627).

However, since the above method uses a compound containing an alkali metal as an initiator for ethylene carbonate treatment, there is a problem of low stability and high manufacturing cost.

It is an object of the present invention to provide a method for effectively recycling by-products produced in the process for producing a polyalkylene carbonate resin to reduce the amount of waste water generated and to recycle by-products.

Accordingly, the present invention can improve the wastewater treatment process by reducing the amount of wastewater generated compared to the conventional method by easily converting the byproducts into a diol-based compound such as an alkylene glycol by ring opening reaction under a heterogeneous catalyst, And to provide a method for producing a polyalkylene carbonate resin having excellent physical properties of a final product.

The present invention relates to a process for polymerizing carbon dioxide and an epoxide compound in the presence of a catalyst and a solvent to produce a liquid stream containing an unreacted epoxide compound and a solvent and a gaseous stream containing an unreacted epoxide compound, a polyalkylene carbonate, &Lt; / RTI > And

Removing the by-product from the reaction mixture stream, and distilling and purifying the reaction mixture stream from which the by-product has been removed, the method comprising:

Wherein the purifying step comprises collecting the by-products removed from the reaction mixture stream and converting the product into a diol-based compound by treatment with a by-product stock solution having a concentration of 1 to 5 wt% And a method for producing an alkylene carbonate resin.

The by-product is an alkylene carbonate having 2 to 20 carbon atoms which is substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms; A cycloalkylene carbonate having 4 to 20 carbon atoms which is unsubstituted or substituted with halogen or an alkyl group having 1 to 5 carbon atoms; And styrene carbonate having 8 to 20 carbon atoms substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms. Preferably, the by-product is an alkylene carbonate having 2 to 20 carbon atoms which is substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms.

Also, the diol compound is an alkylene glycol having 2 to 20 carbon atoms which is substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms; A cycloalkylene glycol having 4 to 20 carbon atoms which is substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms; And a styrene alkylene glycol having 8 to 20 carbon atoms substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms.

The by-product can be removed by extraction with water.

The heterogeneous catalyst may be ZnO.

It is preferable that the heterogeneous catalyst is added in a weight ratio of 0.2 to 1 based on the by-product storage solution.

The ring opening reaction may be carried out at a temperature of 100 ° C to 190 ° C for 30 minutes to 1 hour.

In the present invention, the conversion from the by-product to the diol compound may be 54% or more.

The method may further comprise removing the catalyst residue prior to removing the by-product from the reaction mixture stream. The method may further comprise the step of venting unreacted carbon dioxide prior to distilling the reaction mixture stream from which the byproduct has been removed.

The epoxide compound is an alkylene oxide having 2 to 20 carbon atoms which is substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms; A cycloalkylene oxide having 4 to 20 carbon atoms substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms; And styrene oxide having 8 to 20 carbon atoms substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms, and the solvent may include a polyalkylene carbonate using a chlorinated solvent have. The alkylene carbonate may have an alkyl group having 1 to 5 carbon atoms.

The present invention relates to a process for producing a polyalkylene carbonate resin by converting a by-product, such as an alkylene carbonate, produced in a process for producing a polyalkylene carbonate resin into a diol compound such as an alkylene glycol through a ring- Can be reduced. Further, the present invention is excellent in the recycling effect of by-products continuously produced during the process because of the excellent conversion of the alkylene carbonate to the alkylene glycol. Furthermore, the present invention can improve the separation efficiency from the reaction mixture to the polyalkylene carbonate resin, so that the physical properties of the final product can be maintained.

1 is a graph showing the results of measurement of conversion rates of ethylene carbonate-ethylene glycol with respect to time in Comparative Examples 1 and 2.
FIG. 2 is a graph showing the results of measuring the conversion of ethylene carbonate to ethylene glycol over time in Comparative Examples 3 to 4. FIG.
3 is a graph showing the results of measurement of conversion rates of ethylene carbonate to ethylene glycol with respect to time in Comparative Examples 5 to 6. FIG.
4 is a graph showing the results of measurement of conversion rates of ethylene carbonate-ethylene glycol in Examples 1 to 3 of the present invention.

Hereinafter, the present invention will be described in more detail. The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

Also, " comprising "as used herein should be interpreted as specifying the presence of particular features, integers, steps, operations, elements and / or components, It does not exclude the presence or addition of an ingredient.

Hereinafter, a method for producing a polyalkylene carbonate resin according to one preferred embodiment of the present invention will be described in more detail.

According to one embodiment of the present invention, in the polymerization process of carbon dioxide and epoxide compound in the presence of a catalyst and a solvent, a gaseous stream containing an unreacted epoxide compound and a solvent, an unreacted epoxide compound, a polyalkylene carbonate, Preparing a reaction mixture stream comprising a liquid stream containing byproducts; And removing the by-product from the reaction mixture stream, followed by distillation and purification of the reaction mixture stream from which the byproduct has been removed, wherein the step of purifying is a step of purifying the polyalkylene carbonate resin Collecting the byproducts, preparing a byproduct storage solution having a concentration of 1 to 5% by weight, and then conducting a ring-opening reaction under a heterogeneous catalyst to convert the diol compound into a diol compound, and then treating the polyolalkylene carbonate resin.

As described above, unreacted residual monomers and impurities are produced through the production process of the polyalkylene carbonate. The unreacted residual monomers include unreacted epoxide compounds and carbon dioxide. Further, the impurities include catalyst residues, by-products and solvents.

That is, when the polyalkylene carbonate is polymerized by using carbon dioxide and an epoxide compound as monomers in the presence of a catalyst and a solvent in the production of the polyalkylene carbonate, the gas phase stream containing the unreacted epoxide compound and the solvent, the unreacted epoxide compound, A reaction mixture stream comprising a liquid phase stream containing the recarbonate, solvent and byproducts is produced. At this time, the byproduct is a carbonate compound derived from an epoxide compound.

For example, when an alkylene oxide such as ethylene carbonate is used as the epoxide compound, ethylene carbonate is formed as a by-product due to the backbiting of the chain of polyethylene carbonate as shown in Reaction Scheme 1 below.

[Reaction Scheme 1]

If the by-product remains in the resin, it adversely affects the properties of the resin such as lowering the glass transition temperature. Therefore, it is preferable to remove the by-product in the polyalkylene carbonate production process.

The by-products are continuously produced during the production of the polyalkylene carbonate, and they are extracted by water treatment through a rotating disc contactor (RDC column).

However, the conventional process is a simple process of extracting only by-products to treat byproducts, so that the conversion rate of ethylene carbonate-alkylene glycol is slow. In particular, since the conversion rate of ethylene carbonate-alkylene glycol is not high in the past, a large amount of ethylene carbonate which has not been converted into water during water treatment is abandoned as waste water. Therefore, there is a need for a method capable of reducing excessive waste water generation and increasing conversion speed Do.

Therefore, the present invention provides a method for effectively removing the by-product and recycling the by-product in the production process of the polyalkylene carbonate resin.

Specifically, the ethylene carbonate can be removed from the polyalkylene carbonate resin by an extraction method using water. When ethylene carbonate is extracted by adding water as shown in Reaction Scheme 1, ethylene carbonate is converted to an alkylene glycol. Conversion of ethylene carbonate to alkylene glycols can be converted to utility through concentration control.

At this time, the conversion rate can be greatly improved by converting a by-product collected after water treatment into a diol-based compound by a ring-opening reaction under a heterogeneous catalyst, instead of only treating water byproducts such as ethylene carbonate. Therefore, the present invention can significantly reduce the amount of wastewater from which byproducts remain compared to existing ones, and can also propose a new recycling method of by-products.

That is, the recovery of byproducts (preferably, EC) in the present invention can be carried out through RDC columns (water treatment) used in conventional polyalkylene carbonate polymerization processes. By-product is obtained in the form of an aqueous solution through the recovery process. In the case of such a by-product aqueous solution, since the concentration of the by-product is low enough to recover and commercialize the by-product, there is no economical efficiency. Thus, when the by-product is converted into an alkylene glycol (preferably EG) as in the present invention, it can be reused regardless of the concentration.

Then, the polymerization process and the purification process will be described in more detail in the method of the present invention.

Polymerization process

Firstly, in the method of the present invention, it is possible to further include a step of purifying the monomer before the above-mentioned polymerization step of the monomer. Thereafter, the present invention can carry out a process of preparing a reaction mixture stream containing a product, an unreacted monomer, a solvent and a by-product by proceeding polymerization of the monomer, purifying the product, and then pelletizing the product.

In the method for purifying a monomer in the present invention, carbon dioxide, an oxide-based monomer and a solvent used as raw materials are purified before polymerization to keep the water content of the monomer at less than 10 ppm. In addition, the raw material can be passed through a column filled with a molecular sieve. Thus, the step of purifying the monomer comprises passing the monomer through a column packed with molecular sieve to purify the water content of the monomer to less than 10 ppm.

In the present invention, the monomers for use in the reaction include carbon monoxide and oxides. At this time, since the monomer can use a material well known in the art, its conditions and amount of use are not limited to a great extent. For example, as the oxide series monomer, an epoxide compound as described below may be used.

The polymerization step performed following the above step is a step of putting the raw materials into a polymerization reactor and proceeding polymerization under a catalyst to prepare a polyalkylene carbonate.

That is, the present invention relates to a process for the polymerization of carbon dioxide and an epoxide compound in a polymerization reactor in the presence of a catalyst and a solvent, wherein a gaseous stream containing an unreacted epoxide compound and a solvent and an unreacted epoxide compound, a polyalkylene carbonate, Lt; RTI ID = 0.0 > of a < / RTI > The polymerization can be carried out as continuous polymerization by solution polymerization.

The solid content after the solution polymerization is completed may be about 5 to 50 wt%.

The polymerization may be carried out at 50 to 100 ° C and 20 to 40 bar for 2 to 10 hours. The epoxide compound, particularly ethylene oxide, has a self-polymerization temperature of 90? , It may be more preferable to carry out the solution polymerization at a temperature of 60 to 90 DEG C in order to reduce the by-product content due to autopolymerization.

Purification step

On the other hand, after the above-mentioned polymerization process, a reaction mixture stream containing a gaseous stream containing an unreacted epoxide compound and a solvent and a liquid stream containing an unreacted epoxide compound, a polyalkylene carbonate, a solvent and a by- The present invention performs the purification step of the reaction mixture stream.

The purifying step includes removing by-products from the reaction mixture stream and separating the reaction mixture stream from which the by-product has been removed into a distillation column into a gaseous stream and a liquid stream.

In particular, the purifying step may include collecting the by-products removed from the reaction mixture stream, converting the by-product into a by-product storage solution having a concentration of 1 to 5 wt%, and then carrying out a ring- do.

The by-products can be removed by extraction using water, and recovered through water treatment using an RDC column at the time of extraction. The by-product-containing solution recovered through the RDC column can be converted into a diol compound by preparing a stock solution having a predetermined concentration and then adding a heterogeneous catalyst thereto to carry out a ring-opening reaction.

The byproduct storage solution may be an aqueous solution. If the concentration is less than 1% by weight, the economical efficiency may deteriorate. If the concentration is more than 5% by weight, the conversion rate may decrease.

In addition, the use of ZnO as the heterogeneous catalyst is relatively easy to supply and supply, but is more highly converted to a diol-based compound. In addition, when a metal oxide other than the above-mentioned materials is used as a catalyst, the conversion rate to the diol compound may be slow and the cost may be increased. The heterogeneous catalyst for the by-product treatment is used only for the ring-opening reaction to the diol compound and is not used for polymerization.

The heterogeneous catalyst used in the ring-opening reaction is preferably added in a weight ratio of 0.2 to 1 based on the by-product storage solution. At this time, if the amount of the heterogeneous catalyst is too small, there is a problem that the catalyst efficiency is lowered, and if the amount is too large, there is a problem in cost.

At this time, the initial catalyst content standard is based on the amount of the heterogeneous catalyst used in the production process of the polyalkylene carbonate resin. The amount of catalyst used can be increased or decreased based on the conversion of by-products. When more than half of the by-products are converted to other diol-based compounds, they can be reused for their intended use.

Preferably, the epoxide compound used in the polymerization in the present invention may be an alkylene oxide having 2 to 20 carbon atoms which is substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms. Accordingly, the by-product may be an alkylene carbonate having 2 to 20 carbon atoms which is substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms. Most preferably, the by-product may be ethylene carbonate (EC). The diol compound is preferably an alkylene glycol having 2 to 20 carbon atoms which is substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms, and most preferably ethylene glycol (EG).

In the present invention, the conversion of the by-product into the diol compound may be 54% or more.

On the other hand, the method may further comprise removing the catalyst residue before removing by-products from the reaction mixture stream. The method may further comprise the step of venting unreacted carbon dioxide prior to distilling the reaction mixture stream from which the byproduct has been removed.

Since the catalyst accelerates depolymerization as well as polymerization, it is preferable to remove the catalyst after polymerization is completed. Also, in the solution polymerization, the process by which the polymer is decomposed by the catalyst and heat into the backbite and the by-products formed on the polymerization mechanism are removed by a constant method. Accordingly, in the present invention, after the completion of the polymerization, by-products are removed by the above-described method with the catalyst residue by the extraction method, the resin properties can be improved.

In the present invention, the step of removing the catalyst residue and the by-product may be carried out using an extraction column used in a continuous production process. The method of removing the catalyst residue is not limited, and a method well known in the art can be used. As a method of removing the by-products, a water treatment using an RDC column can be used, but the method of recovering and treating the by-products is as described above.

According to this method, the present invention can control the content of byproducts in the total product to less than 1% level.

On the other hand, since the unreacted epoxide compound is an unstable substance that should not come into contact with moisture, it must be recovered immediately after removal of the catalyst residue and by-products, and the amount remaining in the product should be minimized. Accordingly, the present invention can remove the catalyst residues and byproducts from the reaction mixture first, and then perform the unreacted epoxide and solvent recovery process. In addition, the unreacted epoxide contained in the gaseous stream can also be recovered in the column for reuse, thereby reducing manufacturing cost.

In addition, according to the present invention, most of the unreacted epoxide compound is firstly removed through distillation in the liquid phase stream, then recovered together with a solvent such as methylene chloride, and further recovered through a thin film evaporator .

The polymerization process and the purification process of the present invention may be carried out in an apparatus in which a polymerization reactor and a distillation column are connected. The distillation column can also be connected to the RDC column, which is connected to a byproduct recovery device. In the by-product recovery apparatus, a reactor for treating by-products and a device for introducing a heterogeneous catalyst may be connected.

Further, the process for producing the polyalkylene carbonate resin of the present invention can proceed continuously, and various products can be obtained through processing. For example, the resin processed product includes a film, a sheet, a film laminate, a filament, a nonwoven fabric, a molded product and the like.

In the case of using the polyalkylene carbonate of the present invention, various known methods can be mentioned as the product molding method. Examples of the method for obtaining a homogeneous mixture include a method of mixing by a Hensel mixer, a ribbon blender, a blender, or the like. As the melt kneading method, a VAN Antonie Louis Barye mixer, a single-screw or twin-screw compressor, or the like can be used. The shape of the resin composition of the present invention is not particularly limited and may be, for example, a strand, a sheet, a flat plate, a pellet, or the like.

The method of obtaining the molded article by molding the resin of the present invention can be carried out by a known method such as injection molding, compression molding, injection compression molding, gas injection molding, foam injection molding, inflation, T die, A calendar, a blow molding process, a vacuum molding process, and a pressure molding process.

In the present invention, pelletization is used by using extrusion molding. Such a pelletizing process includes a step of putting the reaction mixture into a twin screw extruder to make it into a pellet form. And, as described above, in the pelletizing step, it is preferable to produce a pellet having a size of 1 mm to 5 mm.

Meanwhile, the present invention may further include a step of recovering the polyalkylene carbonate resin after the polyalkylene carbonate resin is formed.

The materials used in the polymerization of the monomer, that is, the materials used in solution polymerization will be described in more detail as follows.

The above-mentioned oxide-based monomer may be an epoxide compound, and examples of the epoxide compound include an alkylene oxide having 2 to 20 carbon atoms, which is substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms; A cycloalkylene oxide having 4 to 20 carbon atoms substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms; And styrene oxide having 8 to 20 carbon atoms substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms. More preferably, the epoxide compound may include an alkylene oxide having 2 to 20 carbon atoms which is substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms.

More preferred examples of the epoxide compound include ethylene oxide, propylene oxide, butene oxide, pentene oxide, hexene oxide, octene oxide, decene oxide, dodecene oxide, tetradecene oxide, hexadecene oxide, Epichlorohydrin, epichlorohydrin, epichlorohydrin, isopropyl glycidyl ether, butyl glycidyl ether, t-butyl glycidyl ether, t-butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, cyclopentene oxide, cyclohexene oxide, cyclooctene oxide, cyclododecene oxide, alpha-pinene oxide, 2,3-epoxy norbornene, limonene oxide, 2,3-epoxypropylbenzene, styrene oxide, phenylpropylene oxide, stilbene oxide, But are not limited to, chlorostilbene oxide, dichlorostilbene oxide, 1,2-epoxy-3-phenoxypropane, benzyloxymethyloxirane, glycidyl-methylphenyl ether, chlorophenyl- Phenyl ether, biphenyl glycidyl ether, glycidyl naphthyl ether, and the like. Preferably, the epoxide compound uses ethylene oxide.

The carbon dioxide may be continuously or discontinuously introduced during the reaction but is preferably continuously introduced. In this case, the polymerization reactor may be a semi-batch type or a closed batch system good. If carbon dioxide is not continuously supplied, production of byproducts such as polyethylene glycol may increase separately from the carbonate copolymerization reaction aimed at in the present invention. The reaction pressure may be 5 to 50 bar, or 10 to 40 bar when carbon dioxide is continuously supplied in the polymerization.

The carbon dioxide may be added in a molar ratio of 1: 1 to 10: 1 based on the epoxide compound. More preferably, the carbon dioxide may be introduced in a molar ratio of 2: 1 to 5: 1 relative to the epoxide compound. If carbon dioxide is introduced at the above ratio, it is preferable to use a semi-batch type system as the polymerization reactor.

The catalyst used in the present invention can be carried out in the presence of a metal complex compound such as zinc, aluminum or cobalt, but a zinc-based catalyst is preferably used. The zinc-based catalyst is not limited in its kind and may include zinc complexes well known in the art.

The catalyst may be added in a molar ratio of 1:50 to 1: 1000, more preferably 1:70 to 1: 600, or 1:80 to 1: 300, based on the epoxide compound . If the ratio is less than 1:50, sufficient catalyst activity is not exhibited in the solution polymerization. If the ratio is more than 1: 1000, by using an excessive amount of catalyst, the by-product may not be produced efficiently, (back-biting), the molecular weight may decrease and the amount of cyclic carbonate produced may increase.

The solvent is preferably used in a weight ratio of 1: 0.1 to 1: 100 based on the epoxide compound, more preferably 1: 1 to 1:10. The solvent may be methylene chloride or ethylene dichloride, more preferably methylene chloride.

Hereinafter, preferred embodiments of the present invention will be described in detail. It should be understood, however, that these examples are for illustrative purposes only and are not to be construed as limiting the scope of the present invention.

[Experimental Conditions]

In the following Examples and Comparative Examples, the conditions for converting the by-products into the diol compound were as follows.

1. The rate of conversion of ethylene glycol and the conversion rate were measured by changing temperature, time, and conditions of the catalyst.

2. Experiments were carried out in an airtight container, and conversion ratios were calculated by calculating the ratio between alkylene carbonate and ethylene glycol through 1 H-NMR analysis.

3. D2O (NMR solvent) was used directly as a solvent to enable analysis after the reaction of ethylene carbonate-ethylene glycol (EC-EG).

[Comparative Examples 1 and 2]

Measurement of conversion of EC-EG at room temperature

In an autoclave polymerization reactor equipped with a stirrer, polyethylene carbonate was prepared by polymerizing ethylene oxide (180 g) and carbon dioxide (40 bar) under a ZnGA catalyst and methylene chloride (900 g). As a result of the polymerization reaction, a reaction mixture stream containing polyethylene carbonate, MC, ethylene carbonate, unreacted ethylene oxide and unreacted carbon dioxide was obtained. At this time, ethylene oxide (EO), carbon dioxide, and solvent (MC) were purified before polymerization and kept to have a water content of less than 10 ppm.

After completion of the solution polymerization under the above-mentioned conditions, the reaction mixture was filtered through a filter by a conventional method to obtain a reaction mixture stream with a minimal catalyst residue content. Unreacted ethylene oxide was dissolved in MC under a low pressure, and carbon dioxide was removed by venting.

Subsequently, by-product ethylene carbonate (EC) was removed using water in an extracting column of the rotating disc contactor type.

Then, MC was removed from the reaction mixture by a conventional evaporation method, and pellets were produced using a twin screw extruder (BA-19, manufactured by BAUTECH).

Thereafter, the pellet was moved to a centrifugal dryer and dried. Then, a final pellet sample (that is, a CAM resin composition including polyethylene carbonate, polylactide and PMMA) was obtained through a pellet recovery device. The recovered pellet specimens were identified by nuclear magnetic resonance spectroscopy and the weight average molecular weight as determined by GPC was 230,000 g / mol.

At this time, the recovered EC was prepared by preparing an EC storage solution having a concentration of 10% by weight and 5% by weight at room temperature, and directly comparing the integrated values of EC and EG by 1H-NMR analysis while stirring them. The results are shown in FIG. 1 and Table 1.

Comparative Example 1 Comparative Example 2 Time (day) 10 wt% 5 wt% 0 0.01 0.01 0.88 0.21 0.34 2 0.35 0.54 3 0.41 0.64 4 0.58 0.89 7 0.71 1.02 8 0.74 1.16 9 0.83 1.28 10 0.95 1.74 11 1.16 1.81 14 1.41 2.31 15 1.58 2.86 16 1.72 2.86 17 1.78 3.02 18 2.62 3.55

As shown in Fig. 1 and Table 1, the conversion rate was measured for a total of 18 days, and since the conversion rate remains linear without abrupt change, the time required for 100% conversion is expected to be approximately 700 days.

EC-EG conversion has been confirmed to proceed at a slower rate, and it is not possible to keep up with the amount of wastewater generated.

[Comparative Examples 3 to 4]

Measurement of conversion of EC-EG at high temperature (60 ° C)

The manufacturing process of the PEC was the same as that of Comparative Example 1, except that the EC processing procedure was changed as follows.

That is, the recovered EC was prepared as an EC storage solution having a concentration of 10% by weight and 5% by weight, and was directly stirred at 60 ° C., and the integrated value of EC and EG was directly compared by 1H-NMR analysis. The conversion rate was checked with the passage of time while sampling and analysis were performed once / day. The results are shown in FIG. 2 and Table 2.

Comparative Example 3 Comparative Example 4 Time (day) 10 wt% 5 wt% 0 0.03 0.06 One 2.83 3.74 4 8.68 10.65 5 10.77 13.93 6 12.80 16.26 7 15.55 19.67 8 18.27 23.87 11 25.57 34.72 12 27.70 37.01 13 30.19 41.05 18 42.39 54.22

As shown in FIG. 2 and Table 2, the conversion rate was measured up to a total of 18 days, and since the conversion rate remained linear without abrupt change, the time required for 100% conversion was estimated to be approximately 40 days.

As a result, the EC-EG conversion rate was increased compared with the room temperature of Comparative Example 1, but the conditions for increasing the conversion rate should be sought because the amount of waste water can not be monitored.

[Comparative Examples 5 to 6]

Measurement of conversion of EC-EG at high temperature (100 ° C, 190 ° C)

That is, the recovered EC was prepared as an EC storage solution having a concentration of 5% by weight, and the conversion was confirmed by directly comparing the integral value of EC and EG through 1 H-NMR analysis while stirring at 190 ° C. Sampling and analysis were performed up to 4 hours, and the conversion rate over time was confirmed.

Comparative Example 5 Comparative Example 6 Time (hr) 190 ℃ 100 ℃ 0.00 0.00 0.00 0.25 79.00 0.50 98.83 4.00 1.00 99.96 7.35 2.00 99.64 9.53 4.00 20.84

As shown in FIG. 3 and Table 3, the conversion rate was measured from 15 minutes to 4 hours, and the conversion rate was significantly increased as compared with Comparative Example 2.

However, the conversion rate increased at 100 캜, but it is somewhat slow for industrial use. In addition, almost all ECs were converted to EG after 30 minutes at 190 占 폚. The conversion rate is fast enough, but is disadvantageous in terms of cost due to the high temperature reaction.

[Examples 1 to 3]

Unevenness Measurement of EC-EG Conversion Rate Using Catalyst

At that time, the recovered EC was prepared and used as an EC storage solution having a concentration of 5% by weight. To each 5 ml of the EC solution, 0.2 g of four kinds of heterogeneous catalysts in the form of powders shown in Table 1 below were added and stirred at 100 ° C for 1 hour .

¹ > H-NMR analysis was performed to directly compare the integral values of EC and EG to confirm the conversion. The results are shown in Fig. 4 and Table 4. When the EG conversion rate greatly increased, a separate reactor was designed and used.

Name Mass (g) Temp (캜) Time (hr) Conversion Rate (%) Control 0 100 One 7.35 Example 1 ZnO 0.1 100 One 33.97 Example 2 ZnO 0.2 100 One 40.81 Example 3 ZnO 0.4 100 One 54.69

4 and Table 4, regardless of the kind of the heterogeneous catalyst, the conversion rate of EC was increased as compared with Comparative Examples 1 to 6.

At this time, there was a difference in the conversion rate depending on the kind of the catalyst, and in the case of ZnO, the conversion rate was relatively high and the supply and demand was easy because it was used as a polymerization catalyst. The rate of introduction is limited assuming that the catalyst is used in the process, and the residence time can be greatly reduced when the catalyst is used at the same temperature.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. something to do. It is therefore intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims

A polymerization process of carbon dioxide and an epoxide compound in the presence of a catalyst and a solvent causes a reaction including a gaseous stream containing an unreacted epoxide compound and a solvent and a liquid stream containing an unreacted epoxide compound, a polyalkylene carbonate, a solvent and a by- Preparing a mixture stream; And
Removing the by-product from the reaction mixture stream, and distilling and purifying the reaction mixture stream from which the by-product has been removed, the method comprising:
The purifying step may include collecting the by-products removed from the reaction mixture stream, converting the product into a by-product storage solution having a concentration of 1 to 5 wt% and then carrying out a ring-opening reaction under a heterogeneous catalyst,
&Lt; / RTI >

The process according to claim 1, wherein the by-product is an alkylene carbonate having 2 to 20 carbon atoms, which is substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms; A cycloalkylene carbonate having 4 to 20 carbon atoms which is unsubstituted or substituted with halogen or an alkyl group having 1 to 5 carbon atoms; And styrene carbonate having 8 to 20 carbon atoms substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms.

3. The process for producing a polyalkylene carbonate resin according to claim 2, wherein the by-product is an alkylene carbonate having 2 to 20 carbon atoms, which is substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms.

[Claim 2] The method according to claim 1, wherein the diol compound is a C2-20 alkylene glycol substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms; A cycloalkylene glycol having 4 to 20 carbon atoms which is substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms; And a styrene alkylene glycol having 8 to 20 carbon atoms which is unsubstituted or substituted with halogen or an alkyl group having 1 to 5 carbon atoms.

The method for producing a polyalkylene carbonate resin according to claim 1, wherein the by-product is removed by an extraction method using water.

The method for producing a polyalkylene carbonate resin according to claim 1, wherein the heterogeneous catalyst is ZnO.

The method for producing a polyalkylene carbonate resin according to claim 1, wherein the heterogeneous catalyst is added in a weight ratio of 0.2 to 1 based on the by-product storage solution.

The method for producing a polyalkylene carbonate resin according to claim 1, wherein the ring-opening reaction is carried out at a temperature of 100 ° C to 190 ° C for 30 minutes to 1 hour.

The process for producing a polyalkylene carbonate resin according to claim 1, wherein the conversion of the by-product to the diol compound is 54% or more.

2. The method of claim 1, further comprising removing the catalyst residue prior to removal of by-products from the reaction mixture stream.

2. The method of claim 1, further comprising venting unreacted carbon dioxide prior to distilling the reaction mixture stream from which the byproduct has been removed.

The epoxy resin composition according to claim 1, wherein the epoxide compound is an alkylene oxide having 2 to 20 carbon atoms, which is substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms; A cycloalkylene oxide having 4 to 20 carbon atoms substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms; And styrene oxide having 8 to 20 carbon atoms substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms,
The solvent may be selected from the group consisting of
A method for producing a polyalkylene carbonate resin.