KR20160100114A - Method for preparing polyalkylenecarbonate - Google Patents

Abstract

The present invention relates to a manufacturing method of a polyalkylene carbonate resin. More particularly, the manufacturing method of a polyalkylene carbonate resin uses a distributor installed to a distillation apparatus to purify a polyalkylene carbonate-containing reaction mixture generated during a manufacturing process of a polyalkylene carbonate resin, and reduces a concentration of an unreacted monomer to be less than 1 wt% while separating polyalkylene polycarbonate from the reaction mixture. Thus, the manufacturing method of the polyalkylene carbonate resin reuses and easily handles a separated solvent while producing a product having excellent physical properties.

Description

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

The present invention improves the distillation method of the mixture of the unreacted monomers and the solvent contained in the reaction mixture in the production process of the polyalkylene carbonate resin to reduce the concentration of the unreacted monomer to less than 1 wt% To 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 production of the polyalkylene carbonate is carried out by monomeric polymerization of carbon dioxide and oxide in the presence of a chlorinated solvent, and various impurities are present in the polymerization result after polymerization.

The production process of the polyalkylene carbonate is 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 process for pelletization are included do.

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 ethylene oxide is used as an oxide series, and the impurities include catalyst residues, by-products and solvents. The catalyst residues are Zn-based catalysts and byproducts are ethylene carbonate.

However, in the past, when ethylene oxide and a solvent were mixed, distillation data were insufficient. In addition, conventional methods have not been able to separate ethylene oxide and solvent at less than 1 wt.% (Ethylene oxide concentration) due to the misuse of the filler material in the distillation column and the distributor member. Therefore, the conventional method has a problem that the concentration of the unreacted ethylene oxide in the solvent is high even when the reaction mixture is distilled, making it difficult to reuse and handle the solvent.

It is an object of the present invention to provide a process for preparing a polyalkylene carbonate resin, which comprises purifying a reaction mixture containing a polyalkylene carbonate, an unreacted monomer, a solvent and a by- By weight to less than 100% by weight, to thereby provide a method for enhancing the reusability and handling of the solvent.

Accordingly, the present invention designs the nozzle type distributor in the distillation column so that the dispersion can be well dispersed in the distillation column, thereby lowering the concentration of the unreacted oxide type monomer, thereby easily separating the solvent and improving the ease of reuse and handling of the solvent And a method for producing a polyalkylene carbonate resin which can increase the physical properties of the product.

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 to produce a gas phase containing an unreacted epoxide compound and a solvent and an unreacted epoxide compound, a polyalkylene carbonate, Preparing a reaction mixture stream comprising a liquid phase stream; And

And purifying the reaction mixture stream, the method comprising:

Wherein the purifying step comprises separating the gaseous stream and the liquid stream by introducing the reaction mixture stream into a distillation column having a nozzle type distributor inside the column,

A method for producing a polyalkylene carbonate resin is provided.

The nozzle-type distributor may include a reflux distributor for separating the gaseous stream and a feed distributor for separating the liquid stream.

The distillation column includes a two-stage section in which the top of the column and the bottom of the column are separated at a ratio of 3: 7 based on the total column height.

A reflux distributor for separating the gaseous stream is provided in the upper part of the column, and a feed distributor for separating the liquid stream is installed in the lower end of the column.

And the fillets of the wire mesh type are respectively filled in the two-stage section.

The nozzle-type distributor includes a distributor tube and a plurality of nozzles provided at the lower end of the distributor tube, and the average diameter of the nozzles may be 1 mm to 3 mm.

The distillation column may have a diameter of 45 mm to 55 mm and a height of 1,150 mm to 1,250 mm.

A top drum for collecting the gaseous stream may be connected to the upper end of the distillation column and a lower drum for collecting the liquid stream may be connected to a lower portion of the distillation column. The concentration of the epoxide compound in the liquid stream collected in the lower drum may be less than 1% by weight.

The method may further comprise venting unreacted carbon dioxide prior to feeding the reaction mixture stream to the distillation column.

The method may further comprise the step of removing the catalyst residue and byproducts by an extraction method prior to feeding the reaction mixture stream to the distillation column.

The catalyst may be a zinc-based catalyst. The by-product may include an alkylene carbonate having 1 to 5 carbon atoms.

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.

In the present invention, a nozzle type distributor is installed in a distillation column to improve separation efficiency of a mixture of an unreacted monomer and a solvent in a process of purifying a reaction mixture stream produced in a process for producing a polyalkylene carbonate resin. It is possible to increase the separation efficiency of the reaction monomer / solvent by about 20 times. In addition, the production method of the present invention can reduce the concentration of the unreacted monomers contained in the reaction mixture to less than 1 wt%, thereby improving the ease of handling and handling of the solvent and improving the separation efficiency and maintaining the physical properties of the final product There is an effect that can be.

FIG. 1 is a view illustrating a process for producing a polyalkylene carbonate of Example 1 according to an embodiment of the present invention.
FIG. 2 is a schematic view of a distillation apparatus having a nozzle-type distributor in a column according to an embodiment of the present invention.
3 is a view showing a process for producing polyalkylene carbonate of Comparative Example 1 of the prior art.

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, there is provided 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, comprising the steps of reacting a gaseous stream containing an unreacted epoxide compound and a solvent with an unreacted epoxide compound, Preparing a reaction mixture stream comprising a liquid stream containing an alkylene carbonate, a solvent and a by-product; And purifying the reaction mixture stream, wherein the purifying step comprises the steps of feeding the reaction mixture stream into a distillation column having a nozzle type distributor in the inside of the column, And separating the gaseous stream and the liquid stream.

The present invention relates to a process for producing a polyalkylene carbonate resin in which a concentration of an unreacted epoxide compound is reduced in a purification process for removing unreacted epoxide compounds, And more particularly, to a method for improving separation efficiency.

That is, by using a distillation column equipped with a nozzle type distributor in the purification process, the concentration of the unreacted epoxide compound can be largely lowered to improve the separation efficiency of the solvent. For example, the present invention can provide a process for separating ethylene oxide / solvent mixture of less than 1 wt% (ethylene oxide concentration) after polymerization using ethylene oxide and chloride series solvents.

The method of the present invention may further include a step of removing by-products and catalyst residues such as ethylene carbonate and a step of removing carbon dioxide before the solvent removing step.

Therefore, the present invention can improve the physical properties of the resulting polyalkylene carbonate resin by using a purification process that continuously removes elements that adversely affect the physical properties of the product after polymerization. Further, the present invention can produce a resin continuously from the introduction of a monomer, and after the polymerization, the monomer can be recovered and reused to reduce the manufacturing cost.

In addition, the present invention has a new apparatus for solving the problems of conventional distillation columns, and confirmed the effect of the distributor through gas chromatography analysis.

Each step of the method for producing the polyalkylene carbonate resin of the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a view illustrating a process for producing a polyalkylene carbonate of Example 1 according to an embodiment of the present invention.

As shown in FIG. 1, the present invention utilizes a device comprising a feed drum, a distillation column equipped with a nozzle type distributor, and an upper drum and a lower drum connected to the distillation column to produce a polyalkylene carbonate . At this time, an oil circulator may be connected to the distillation column. The upper part of the distillation column may also include a vacuum pump and a condenser. A vacuum pump and plate type condenser may be connected between the lower part of the distillation column and the lower part of the drum.

At this time, although not shown in the figure, polymerization of monomers and carbon dioxide can proceed in the polymerization reactor, and then the reaction mixture stream obtained from the polymerization reactor can be introduced into the supply drum. The reaction mixture stream may then be distilled in a distillation column equipped with a nozzle-type distributor and subjected to purification to separate the gaseous stream and the liquid stream into upper and lower drums. 1, a nozzle type distributor inside the distillation column is not shown.

Accordingly, the process of the present invention is a process for the production of a process for the preparation of an epoxidized product, which comprises polymerizing carbon dioxide and an epoxide compound in the presence of a catalyst and a solvent to form a gaseous stream containing unreacted epoxide compounds and a solvent and an unreacted epoxide compound, a polyalkylene carbonate, A polymerization reactor for producing a reaction mixture comprising a liquid stream, a feed drum connected to the polymerization reactor for feeding the reaction mixture stream to the distillation column, a feed drum connected to the feed drum for purifying the reaction mixture, An upper drum connected to the upper end of the distillation column for collecting a gaseous stream containing an unreacted epoxide compound and a solvent in the reaction mixture, and a non-reactive epoxide in the reaction mixture, Side compounds, polyalkylene carbonates, solvents and by-products For collecting a liquid stream, it is possible to use the device the lower drum is provided that is installed connected to the lower distillation column.

In the meantime, the polymerization process and the purification process will be described in more detail in the process 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 separating the gaseous stream and the liquid stream by injecting the reaction mixture stream into a distillation column having a nozzle type distributor inside the column.

The present invention provides a method of disposing a nozzle type distributor inside a distillation column to separate the gaseous stream and the liquid stream contained in the reaction mixture stream to reduce the concentration of the unreacted epoxide compound contained in the liquid stream to less than 1 wt% to provide. Also, the solvent can be effectively separated and removed through such a method, and the removed solvent can be recovered and reused.

That is, 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. Therefore, in the present invention, catalyst residues and byproducts are first removed from the reaction mixture by a process described below, followed by an unreacted epoxide and a 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.

Specifically, the present invention employs the apparatus of FIG. 1 to introduce a reaction mixture into a distillation column, and then performs a purification process of separating the gas-phase stream and the liquid-phase stream through the distillation column.

At this time, it is preferable that the nozzle type distributor provided in the column includes a reflux distributor for separating the gaseous stream and a feed distributor for separating the liquid stream.

The reflux distributor may dispense the gaseous stream of the reaction mixture stream introduced into the column through the nozzle to increase the recovery rate of unreacted epoxide compounds.

The feed distributor can also dispense the liquid stream in the reaction mixture stream through a nozzle to reduce the concentration of the unreacted epoxide compound to less than 1 wt% as described above to easily separate the solvent from the mixture with the solvent.

In the meantime, the present invention can increase the separation efficiency by dividing and dividing the filling section in the column at a predetermined ratio. In addition, the present invention can increase the separation efficiency by using a filler of a wire mesh type. Therefore, the distillation column of the present invention is preferably a packed column. This method of the present invention can increase the separation efficiency of the mixture by about 20 times as compared with the existing column operation.

Preferably, the distillation column comprises a two-stage compartment in which the top of the column and the bottom of the column are separated at a ratio of 3: 7 based on the total column height.

In the present invention, the upper and lower portions of the distillation column are formed at a ratio of 3: 7 for the following two reasons.

First, when the column height is limited, the longer the feeding period, the greater the classification of the liquid phase and the liquid phase of the initially introduced solution. However, the present invention uses a filler-type column capable of distillation even if the height is limited, instead of a column in which a plurality of trays are placed on the column to raise the column, so that only the section to be supplied can not be made long. Therefore, in the present invention, the filler material type column is used in order to make the height even if the height is limited, and the ratio is specified as 3: 7.

Also, in order for the refluxed solution to be distilled, it is necessary to have a space in which the filling material can sufficiently enter the section coming back to the top. In view of this, in the present invention, distillation can be maximized in all sections by optimizing the distillation column at a specific ratio of 3: 7. At this time, when the ratio is 2: 8 or 1: 9 in the distillation column, the solution containing the epoxide compound / solvent (for example, EO / MC) in the gaseous phase is not sufficiently transferred to the filler zone The distillation efficiency may be lowered.

In addition, when the distillation column is divided into two stages, a reflux distributor for separating the gaseous stream is installed in the upper part of the column, and a feed distributor for separating the liquid stream is installed in the lower end of the column . The upper end of the distillation column is connected to the upper end of the distillation column for collecting the vapor stream, and the lower end of the distillation column is connected to the lower end of the lower column for collecting the liquid stream. According to the present invention, the concentration of the epoxide compound in the liquid stream collected in the lower drum may be less than 1% by weight.

And the filler of a wire mesh type may be filled in the two-stage section.

In the present invention, the height of the nozzle-type distributor and the distillation column provided in the distillation column can be appropriately adjusted as required, but the following conditions are preferably satisfied.

For example, the nozzle-type distributor may include a distributor tube and a plurality of nozzles disposed at the lower end thereof, and the average diameter of the nozzles may be 1 mm to 3 mm.

The distillation column may have a diameter of 45 mm to 55 mm and a height of 1,150 mm to 1,250 mm.

FIG. 2 is a schematic view of a distillation apparatus having a nozzle-type distributor in a column according to an embodiment of the present invention. As shown in FIG. 2, a reflux distributor and a feed distributor are installed in the distillation column of the present invention.

After the reaction mixture is introduced into the distillation column, the gaseous stream is transferred to a reflux distributor and the liquid stream is transferred to the feed distributor and then separated through the respective nozzles to be connected to the bottom of the distillation column and the upper drum connected to the top of the distillation column And transferred to the lower drum. Thereafter, the unreacted epoxide compound is recovered from the upper drum through the additional purification process, and the polyalkylene carbonate and the solvent, which are the products, can be recovered from the lower drum.

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 .

Alternatively, the method may further comprise venting unreacted carbon dioxide prior to feeding the reaction mixture stream to the distillation column.

The method may further comprise the step of removing the catalyst residue and byproducts by an extraction method prior to feeding the reaction mixture stream to the distillation column.

That is, since the catalyst not only promotes polymerization but also depolymerization, it is preferable to remove the catalyst after polymerization is completed. Also, in solution polymerization, by-products can be generated in the polymerization mechanism and in the process in which the polymer is decomposed into a backbite by the catalyst and heat. 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. Such by-products may include an alkylene carbonate having 1 to 5 carbon atoms, for example, ethylene carbonate.

Therefore, in the present invention, after the completion of the polymerization, the catalyst residue and the by-products are removed by an extraction method, whereby the resin properties can be improved.

Preferably, the step of removing the catalyst residue and the byproduct can be carried out by utilizing an extraction column used in a continuous production process, and the method is not limited, and a method well known in the art can be used.

In this method, the present invention can effectively control the content of by-products in the total product to less than 1% level.

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.

[Examples 1 to 3]

The polyethylene-carbonate resin was continuously produced using the apparatus of Fig.

A solution of diethyl-zinc catalyst, solvent, ethylene oxide (EO) and carbon dioxide was added to the autoclave reactor equipped with a stirrer to proceed the polymerization, and solution polymerization was carried out under the conditions shown in Table 1 to prepare polyethylene Carbonate. At this time, ethylene oxide (EO), carbon dioxide, and solvent were purified before polymerization and kept at a water content of less than 10 ppm.

Example 1 Example 2 Example 3 Cat.amt (g) 0.4 0.4 0.4 EO (g) 5.58 8.03 8.54 Solvent (MC) (g) 8.53 8.53 8.57 EO / cat. 62 89 95 CO ₂ (bar) 20 25 30 Temperature (° C) 70 70 70 time (h) 3 3 3 yield (g) 9.72 12.44 9.11 yield (g / g-cat) 24 31 23 activation (g / g-cat.hr) 8.1 10.37 7.59 EO conversion rate (%) 87 78 53 TOF (mol / mol-cat.hr) 17.98 23.01 16.85

After completion of the solution polymerization in each of the above-mentioned conditions, in a reaction mixture stream containing a gaseous stream containing unreacted EO, MC and a liquid phase stream containing unreacted EO, polyalkylene carbonate, MC and by-products, Residues and byproducts were removed by extraction. Residual carbon dioxide was removed by venting.

The remaining reaction mixture stream was introduced into the feed drum of Figure 1 and the EO / MC mixture was separated using the distillation column of Figure 2. The distillation conditions of the column are as follows.

1) Packing matrial: Wire mesh type

Specific surface: 1000 M2 / m3

Pressure drop: 1 ~ 1.5 mbar / m

HETP: 0.06 to 0.055 HETP / m

2) Packed column: diameter = 50.8 mm, height = column top height 330 mm, column bottom height 880 mm

3) Reflux ratio: 2.33 (g / min)

4) In order to facilitate dispersion in the column, the nozzle type distributor installation of FIG. 2

5) Segregation of Fill Material (2nd Stage): Filling the fill material at the top of the column with a height of 330 mm and a column bottom height of 880 mm

At this time, the EO compositions of Examples 1 to 3, which were fed into the feed drum, were changed to Tables 2 to 4 and the compositions of EO of the bottom drum and distillation were measured with time.

Thereafter, the polyethylene carbonate was recovered by a conventional method and pelletized and dried. Finally, a final pellet specimen 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. In the final product, the content of the polyethylene carbonate was 99 wt%, the catalyst content was less than 500 ppm, and the content of by-products was 1 wt% or less.

Example 1 Feed composition (% by weight) Top composition (% by weight) Bottom composition (% by weight) F0 5.8 T1 / B1 12.1 0.4

Note: FO means the first EO concentration, T1: T means TOP, 1 means order from the number of times of distillation, B1: means Bottom, and 1 means order from the number of times of distillation.

Example 2 Feed composition (% by weight) Top composition (% by weight) Bottom composition (% by weight) F0 9.7 T1 / B1 17.1 One

Note: FO means the first EO concentration, T1: T means TOP, 1 means order from the number of times of distillation, B1 means Bottom, 1 means order from the number of times of distillation.

Example 3 Feed composition (% by weight) Top composition (% by weight) Bottom composition (% by weight) F0 6.1 T1 / B1 11.6 2.08 T2 / B2 16.8 2.08 T3 / B3 18.0 1.42 T4 / B4 15.9 0.69 T5 / B5 14.3 0.37 T6 / B6 12.1 0.19 T7 / B7 15.9 0.22 T8 / B8 16.4 0.14

T1 to T8: T means TOP, 1 to 8 means the number of repeats of the distillation, B1 to B8: B means bottom, Means the number of cycles of distillation

It can be seen from Tables 2 to 4 that the EO concentration in the lower drum is very small, ranging from 0.14 to 2.08% by weight. In addition, it can be seen that the distillation is carried out more than four times in the case of Example 3, and the EO concentration is greatly reduced.

In this case, when the bottom EO composition is 2.08% by weight, it is an initial value generated when the operation conditions are adjusted according to the feed composition ratio, and refers to the EO concentration in the wastewater recovered when the operation conditions are stabilized. This can result in a very low bottom composition depending on time or operating conditions, and the critical value in Example 3 means T4 / B4 to T8 / B8.

[Comparative Examples 1 and 2]

Using the apparatus of Fig. 1, a polyalkylene carbonate was prepared. The distillation conditions of the column are as follows. The compositions of EO supplied are shown in Tables 5 and 6.

1) Packing matrial: SUS ball type (diameter: 6mm)

2) Packed column: diameter = 60 mm, height = 700 mm

3) Reflux ratio: 1.33 (g / min)

4) Using SUS ball type as distributor

5) Filler section is not separated (1st stage)

6) The solution in the feed drum becomes vapor and passes under the column (introducing the stirring system to activate the vapor)

7) Supply EO concentration: 5.57% by weight, TOP EO concentration: 9.51-8.14% by weight, Bottom EO concentration:

Feed composition (% by weight) Top composition (% by weight) Bottom composition (% by weight) F0 5 T1 / B1 - 3 T2 / B2 5.2 1.5 T3 / B3 6.1 1.3 T4 / B4 6.1 3 T5 / B5 6.5 2.2 T6 / B6 6.2 1.5

Feed composition (% by weight) Top composition (% by weight) Bottom composition (% by weight) F0 5.57 T1 / B1 9.51 4.5 T2 / B2 9.04 3.19 T3 / B3 8.48 2.77 T4 / B4 8.2 2.51 T5 / B5 8.14 2.29

As shown in Tables 5 and 6, it can be seen that the EO concentration in the bottom drum is higher than 1.5 wt% in the conventional method.

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 (14)

A polymerization process of carbon dioxide and an epoxide compound in a polymerization reactor in the presence of a catalyst and a solvent enables a gas phase stream containing an unreacted epoxide compound and a solvent to react with a liquid stream containing an unreacted epoxide compound, a polyalkylene carbonate, ≪ / RTI > And
And purifying the reaction mixture stream, the method comprising:
Wherein the purifying step comprises separating the gaseous stream and the liquid stream by introducing the reaction mixture stream into a distillation column having a nozzle type distributor inside the column,
A method for producing a polyalkylene carbonate resin.
The method according to claim 1,
Wherein the nozzle-type distributor comprises a reflux distributor for separating the gaseous stream and a feed distributor for separating the liquid stream.
The process according to claim 1, wherein the distillation column
Wherein the column top and bottom columns are separated at a ratio of 3: 7 based on the total column height.
The method of claim 3,
Wherein a reflux distributor for separating the gaseous stream is provided in the upper part of the column and a feed distributor for separating the liquid stream is installed in the lower end of the column.
The method of claim 3,
And a filler of a wire mesh type is packed in each of the two-stage section sections.
The method according to claim 1,
Wherein the nozzle-type distributor comprises a distributor tube and a plurality of nozzles provided at a lower end thereof, wherein the average diameter of the nozzles is 1 mm to 3 mm.
The method according to claim 1,
Wherein the distillation column has a diameter of 45 mm to 55 mm and a height of 1,150 mm to 1,250 mm.
The method according to claim 1,
Wherein a top drum for collecting the gaseous stream is connected to the top of the distillation column and a bottom drum for collecting the liquid stream is connected to the bottom of the distillation column.
9. The method of claim 8, wherein the concentration of the epoxide compound in the liquid stream collected in the lower drum is less than 1 wt.%.
2. The method of claim 1, further comprising venting unreacted carbon dioxide prior to feeding the reaction mixture stream to the distillation column.
2. The method of claim 1, further comprising removing the catalyst residue and by-product by an extraction method prior to feeding the reaction mixture stream to the distillation column.
The method for producing a polyalkylene carbonate resin according to claim 1, wherein the catalyst is a zinc-based catalyst.
The method for producing a polyalkylene carbonate resin according to claim 1, wherein the by-product comprises an alkylene carbonate having 1 to 5 carbon atoms.
The method according to claim 1,
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 which is substituted or unsubstituted with halogen or an alkyl group having 1 to 5 carbon atoms,
Wherein the solvent is a chlorinated solvent.

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