KR20180010819A - Method for preparation of organic zinc-carbon black composite catalyst - Google Patents

Abstract

The present invention relates to a method for producing an organic zinc-carbon black composite catalyst capable of being used as a catalyst in the production of polyalkylene carbonate. The organic zinc-carbon black composite produced by the production method is capable of preventing formation of aggregates in a medium while the catalyst has nanometer-scaled particle size, by forming organic zinc on carbon black. In addition, the organic zinc-carbon black composite easily removes catalysts remaining in a produced polyalkylene carbonate resin.

Description

TECHNICAL FIELD The present invention relates to an organic zinc-carbon black composite catalyst,

The present invention relates to a process for preparing an organic zinc-carbon black composite catalyst which can be used as a catalyst for the production of polyalkylene carbonate.

Since the Industrial Revolution, mankind has built a modern society by consuming a large amount of fossil fuels, while increasing the atmospheric carbon dioxide concentration and further promoting this increase by environmental destruction such as deforestation. Since global warming is caused by the increase of greenhouse gases such as carbon dioxide in the atmosphere and freon or methane, it is very important to reduce the atmospheric concentration of carbon dioxide which contributes to global warming. Are being carried out on a global scale.

Among them, the copolymerization reaction of carbon dioxide and epoxide found by Inoue et al. Is expected as a reaction to solve the problem of global warming, and it is actively studied not only in terms of fixation of chemical carbon dioxide but also in the use of carbon dioxide as carbon resources . Particularly, in recent years, the polyalkylene carbonate resin obtained by the polymerization of carbon dioxide and epoxide is widely regarded as a kind of biodegradable resin.

Various catalysts for the production of such polyalkylene carbonate resins have been studied and proposed, and zinc dicarboxylate-based catalysts such as zinc glutarate catalysts having zinc and dicarboxylic acid bonded thereto are known as typical catalysts.

Such a zinc dicarboxylate catalyst, typically zinc glutarate catalyst (ZnGA), is formed by reacting a zinc precursor with a dicarboxylic acid such as glutaric acid and has a fine crystalline particle shape. However, it has been difficult to control the zinc dicarboxylate type catalyst in the form of crystalline particles so as to have a uniform and fine particle size in its production process. Conventional zinc dicarboxylate catalysts have a particle size on the nanometer scale, but as agglomerates of the catalyst particles in the medium are formed, agglomerates having a larger particle diameter and a smaller surface area are formed. Thus, the production of a polyalkylene carbonate resin There is a problem that the catalytic activity decreases. Accordingly, there is a demand for a method capable of inhibiting formation of agglomerates in the medium while having a nanometer-scale particle size of the zinc dicarboxylate-based catalyst.

Further, after the polyalkylene carbonate resin is produced, a part of the zinc dicarboxylate catalyst is left in the polyalkylene carbonate resin, and it is necessary to remove the polyalkylene carbonate to maintain the purity and color of the polyalkylene carbonate. However, existing zinc dicarboxylate catalysts having a nanometer-scale particle size have a disadvantage in that they are difficult to remove when they remain in the polyalkylene carbonate resin.

Thus, in the present invention, when a zinc dicarboxylate-based catalyst is formed on a support of a carbon black as described later, the zinc dicarboxylate-based catalyst has a nanometer-scale particle size and agglomerates are formed in the medium And that it is easy to remove the residual catalyst in the produced polyalkylene carbonate resin, thereby completing the present invention.

The present invention provides a process for preparing a catalyst for producing a polyalkylene carbonate resin, which is excellent in catalytic activity and can easily remove the residual catalyst in the produced polyalkylene carbonate resin. will be.

The present invention also provides a catalyst prepared by the above production method and a process for producing a polyalkylene carbonate resin using the same.

In order to solve the above problems, the present invention provides a method for producing an organic zinc-carbon black composite, comprising the steps of:

1) mixing a zinc precursor and carbon black;

2) sintering the mixture to produce a zinc oxide-carbon black composite; And

3) reacting the zinc oxide-carbon black composite with C _4-10 dicarboxylic acid.

As a catalyst for the production of polyalkylene carbonate resins, zinc dicarboxylate-based catalysts such as zinc glutarate catalysts combined with zinc and dicarboxylic acid are known. Conventional zinc dicarboxylate catalysts have a particle size on the nanometer scale, but the catalytic activity is lowered due to agglomeration of the catalyst particles during the reaction, and it is difficult to remove the catalyst remaining in the produced polyalkylene carbonate resin .

Therefore, in the present invention, by using an organic zinc catalyst having a nanometer-scale particle size on carbon black using carbon black as a support, it is possible to prevent coagulation between catalysts as described above, It is possible to produce a catalyst which is easy to remove the catalyst.

Further, in order to form an organic zinc catalyst on carbon black, the present invention is characterized in that zinc oxide is first formed on carbon black, and then the catalyst is reacted with C _4-10 dicarboxylic acid.

Hereinafter, the present invention will be described in detail.

Step 1

Step 1 of the present invention is a step of preparing a step for forming ZnO on the carbon black of Step 2, which is a step of mixing a zinc precursor and carbon black.

The zinc precursor may be Zn (NO ₃ ) ₂ , Zn (acac) ₂ , Zn (OH) ₂ , Zn (OAc) ₂ , ZnSO ₄ , and Zn (ClO ₃ ) ₂ can be used.

Also, it is preferable to mix 9 mg to 20 mg of carbon black to 1 mmol of the zinc precursor. If it is out of the above range, the amorphous material formed from the zinc precursor may not grow on the surface of the carbon black.

The mixing temperature of step 1 is preferably 140 to 160 ° C. The solvent to be used in the mixing of step 1 is preferably triethylene glycol, ethylene glycol or diethylene glycol. The mixing time of step 1 is preferably 2 hours to 4 hours.

Further, after the mixing of the step 1, centrifugation, washing and / or drying may be performed if necessary.

Step 2

Step 2 according to the present invention is a step of sintering the mixture prepared in step 1 to prepare a zinc oxide-carbon black composite.

Through the above step 1, a zinc precursor is present on the carbon black, and the zinc precursor can be sintered to form zinc oxide on the carbon black. As a result, zinc oxide is formed on the carbon black, and in step 3 described later, zinc oxide reacts with C _4-10 dicarboxylic acid to form organic zinc on the carbon black.

Preferably, the sintering temperature in step 2 is 300 ° C to 400 ° C, more preferably 325 ° C to 375 ° C. Also preferably, the sintering time in step 2 is 4 hours to 8 hours, more preferably 5 hours to 7 hours.

Through the step 2, zinc oxide having a diameter of 1 nm to 100 nm can be grown on the carbon black.

Step 3

Step 3 according to the present invention is a step of reacting the zinc oxide-carbon black composite prepared in Step 2 with C _4-10 dicarboxylic acid to prepare an organic zinc-carbon black composite.

Preferably, the C _4-10 dicarboxylic acid is a compound represented by the following formula (1).

[Chemical Formula 1]

HOOC-R-COOH

In the above formula (1), R is C _2-8 alkylene.

More preferably, R is straight chain C _2-8 alkylene. Examples of the C _4-10 dicarboxylic acid include glutaric acid, adipic acid, pimelic acid, or succinic acid.

In the zinc oxide-carbon black composite produced in the step 2, since zinc oxide is formed on the carbon black, zinc oxide may react with C _4-10 dicarboxylic acid to form organic zinc on the carbon black. Through this, by preparing an organic zinc catalyst having a particle size of nanometer scale on carbon black, it is possible to suppress the aggregation between catalysts in the polymerization of polyalkylene carbonate and to exhibit high catalytic activity.

In addition, since the catalyst remaining in the produced polyalkylene carbonate resin is formed on the carbon black, the polyalkylene carbonate resin is dissolved but dissolved in a solvent which does not dissolve the carbon black, for example, triethylene glycol There is an advantage in that the catalyst can be separated.

The C _4-10 dicarboxylic acid is preferably reacted with 1 mole or more of moles of zinc oxide per mole of zinc oxide so that the zinc oxide reacts with all the C _4-10 dicarboxylic acids. For example, It is preferable to react the moles. When the amount exceeds 10 mols, the reaction does not substantially improve.

Preferably, the reaction temperature in step 3 is 50 ° C to 60 ° C. Also preferably, the reaction time in step 3 is 15 to 30 hours.

Further, after the step 3, centrifugation, washing and / or drying may be performed if necessary.

Through the step 3, organic zinc having a diameter of 50 nm to 500 nm can be grown on the carbon black.

Organic zinc - carbon black complex

The present invention also provides an organic zinc-carbon black composite produced by the above-described production method.

As described above, the organic zinc-carbon black composite produced according to the present invention is characterized in that organic zinc particles serving as a catalyst are formed on the carbon black. Accordingly, there is an effect that aggregation of the catalysts is inhibited during the production of the polyalkylene carbonate with the organic zinc-carbon black composite, and thus the catalytic activity is remarkably excellent.

Further, since the organic zinc is formed on the carbon black, there is a feature that the catalyst remaining in the polyalkylene carbonate can be removed by the method of removing the carbon black.

Polyalkylene Of carbonate  Produce

The present invention also provides a process for producing a polyalkylene carbonate using the above-described organic zinc-carbon black composite as a catalyst.

Except for using the organic zinc-carbon black composite according to the present invention as a catalyst, conventionally known methods for producing polyalkylene carbonate can be applied without limitation. For example, there is provided a process for producing a polyalkylene carbonate resin comprising the step of solution polymerization of a monomer containing an epoxide and carbon dioxide in the presence of an organic zinc-carbon black composite according to the present invention.

In such a solution polymerization, the solvent includes, for example, methylene chloride, ethylene dichloride, trichloroethane, tetrachloroethane, chloroform, acetonitrile, propionitrile, dimethylformamide, N- Methyl acetate, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, acetone, cyclohexanone, trichlorethylene, methyl acetate, vinyl acetate, ethyl acetate, At least one selected from the group consisting of propyl acetate, butyl lactone, caprolactone, nitropropane, benzene, styrene, xylene and methyl propasol can be used. In either case, by using methylene chloride or ethylene dichloride as a solvent, the progress of the polymerization reaction can be more effectively performed.

The organic zinc-carbon black composite according to the present invention may be added in a molar ratio of about 1:50 to 1: 1000 as compared to the epoxide. More preferably, the organozinc catalyst can be introduced at a molar ratio of from about 1:70 to 1: 600, or from about 1:80 to 1: 300, relative to the epoxide. If the ratio is too small, it is difficult to exhibit sufficient catalytic activity in solution polymerization. On the other hand, if the amount is excessively large, by using an excessive amount of catalyst, by-products may not be produced, or by back- This can happen.

On the other hand, as the epoxide, 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. Typically, as the epoxide, an alkylene oxide having 2 to 20 carbon atoms, which is substituted or unsubstituted with a halogen or an alkyl group having 1 to 5 carbon atoms, may be used. Most typically, ethylene oxide is used as the epoxide.

In addition, the above-mentioned solution polymerization can be carried out at about 50 to 100 DEG C and about 15 to 50 bar for about 1 to 60 hours. Further, it is more appropriate that the solution polymerization is carried out at about 70 to 90 DEG C and about 20 to 40 bar for about 3 to 40 hours.

Meanwhile, the remaining polymerization processes and conditions except for the above-mentioned matters may depend on conventional polymerization conditions for the production of the polyalkylene carbonate resin, and a further explanation thereof will be omitted.

As described above, the organic zinc-carbon black composite produced by the production method according to the present invention is characterized in that organic zinc is formed on the carbon black, so that the catalyst has a nanometer-scale particle size and agglomerates are formed in the medium And it is also easy to remove the residual catalyst in the produced polyalkylene carbonate resin.

FIG. 1 shows the results of TEM analysis of ZnO-Vulcan prepared in one embodiment of the present invention.
2 shows the XRD analysis results of ZnO-Vulcan prepared in one embodiment of the present invention.
FIG. 3 shows the results of TEM analysis of ZnGA-Vulcan prepared in one embodiment of the present invention.
FIG. 4 shows the XRD analysis results of ZnGA-Vulcan prepared in one embodiment of the present invention.
5 shows the results of a TEM analysis of the ZnGA produced in Comparative Example 1 of the present invention.
6 shows XRD analysis results of ZnGA produced in Comparative Example 1 of the present invention.
7 shows the results of TEM analysis of ZnGA + Vulcan prepared in Comparative Example 2 of the present invention.
8 shows the XRD analysis results of ZnGA + Vulcan prepared in Comparative Example 2 of the present invention.
9 shows the results of measurement of the solvent dispersibility of the catalysts prepared in Examples and Comparative Examples of the present invention. 9 (a), 9 (b) and 9 (c) show the measurement results of permeability after 1 hour, 4 hours and 7 hours, respectively.
FIG. 10 shows the results of separating ZnGA-Vulcan prepared according to an embodiment of the present invention into polyethylene carbonate.

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 : Preparation of catalyst

(Step 1)

3.570 g (12 mmol) of zinc precursor (Zn (NO ₃ ) ₂ ) and 172 mg of carbon black (Vulcan X-72) were added to 160 mL of triethylene glycol and stirred at room temperature. The reaction was then continued for 3 hours. After cooling to room temperature, the mother liquor was removed by centrifugation and centrifuged with toluene and ethanol to wash. Vacuum-dried at 70 ° C and then calcined at 350 ° C for 6 hours to form zinc oxide on carbon black, which was named 'ZnO-Vulcan'.

The ZnO-Vulcan thus prepared was analyzed by TEM (FIG. 1), and it was confirmed that ZnO was grown to a size of 20 to 30 nm on the Vulcan X-72. In addition, it was confirmed by XRD analysis (FIG. 2) that crystalline ZnO was formed on Vulcan X-72.

Also, the content of Zn in ZnO-Vulcan was measured as 69.9 wt% by ICP analysis. Assuming that all of the zinc precursors used form ZnO, the content of Zn in the ZnO-Vulcan is 68.3 wt%, indicating that Zn of the zinc precursor added to the reaction almost participated in the reaction. The prepared ZnO-Vulcan was composed of 85 wt% of ZnO and 15 wt% of carbon black (Vulcan X-72).

(Step 2)

0.24 g of the ZnO-Vulcan prepared in the above Step 1 was added to 9 mL of toluene, and the temperature was raised to 55 ° C, followed by the addition of 0.466 g of glutaric acid. After stirring for 24 hours, it was cooled to room temperature and centrifuged to remove the mother liquor. After centrifugation with acetone and washing three times, vacuum drying was conducted at 70 ° C to form zinc glutarate on carbon black, which was named 'ZnGA-Vulcan'.

The ZnGA-Vulcan thus prepared was analyzed by TEM (FIG. 3), and ZnGA was grown on the Vulcan X-72 to a size of 80 to 450 nm. Also, through XRD analysis (FIG. 4), it was confirmed that ZnO reacted with glutaric acid without residual ZnO to form ZnGA.

Also, the content of Zn in ZnGA-Vulcan was measured as 31.1 wt% by ICP analysis. Assuming that ZnO forms all of ZnO, the content of Zn in ZnGA-Vulcan is 30.9 wt%, and ZnO is almost completely involved in the reaction.

Comparative Example  1: Preparation of catalyst

As a comparative example, unlike the above examples, ZnGA free of carbon black was prepared. Specifically, 0.24 g of ZnO (Sigma Aldrich) was added to 9 mL of toluene, and the temperature was raised to 55 DEG C, followed by the addition of 0.466 g of glutaric acid. After stirring for 24 hours, it was cooled to room temperature and centrifuged to remove the mother liquor. Centrifuged with acetone, washed three times, and vacuum dried at 70 ° C to prepare zinc glutarate (ZnGA).

As a result of the analysis of the ZnGA by the TEM (FIG. 5), it was confirmed that the ZnGA was grown to a size of 200 to 1200 nm. Also, through XRD analysis (FIG. 6), it was confirmed that ZnO was formed by reacting ZnO with glutaric acid without residual ZnO.

Comparative Example  2: Preparation of catalyst

As a comparative example, a catalyst was prepared by mixing ZnO, Vulcan X-72 and glutaric acid in the same amount as used in the above examples. Specifically, 0.204 g of ZnO (Sigma Aldrich) and 0.036 g of carbon black (Vulcan X-72) were placed in 9 mL of toluene, and the temperature was raised to 55 캜. Then, 0.466 g of glutaric acid was added. After stirring for 24 hours, it was cooled to room temperature and centrifuged to remove the mother liquor. After centrifugation with acetone and washing three times, the catalyst was vacuum dried at 70 ° C., and the catalyst was named 'ZnGA + Vulcan'.

The ZnGA + Vulcan thus prepared was analyzed by TEM (FIG. 7), and it was confirmed that the ZnGa + Vulcan was grown to a size of 200 to 1200 nm. Also, through XRD analysis (FIG. 8), it was confirmed that ZnO was formed by reacting ZnO with glutaric acid without residual ZnO.

Experimental Example  1: Determination of solvent dispersibility of catalyst

In order to confirm that the catalyst according to the present invention was inhibited from agglomerating during the reaction, the dispersibility of the catalyst prepared in the above Examples and Comparative Examples was confirmed using Turbiscan equipment (Formulaction).

Specifically, 150 mg of each catalyst prepared in the above Examples and Comparative Examples was placed in a cylindrical cell (diameter 25.4 mm, height 55 mm) containing 20 mL of a methylene chloride solvent. After being shaken by hand, they were placed in a Turbiscan apparatus in a dispersed state, and after 1 hour, 4 hours and 7 hours, the transmittance of 880 nm light was measured. The results are shown in FIG.

As shown in FIG. 9, the permeability of the Example was lower than that of Comparative Example, and thus the solvent dispersion was excellent, which means that the catalyst of the Example was inhibited from intergranular aggregation.

Experimental Example  2: Polyethylene Of carbonate  Produce

0.2 g of the catalyst prepared in the above Example or Comparative Example was added to 8.5 g of methylene chloride, the internal air was reduced by a vacuum pump, and then 8.5 g of ethylene oxide was added. Carbon dioxide was then pressurized to 30 bar. After the reaction was carried out at 70 DEG C for 3 hours with stirring, unreacted carbon dioxide, ethylene oxide and methylene chloride were removed, and the mixture was dried at room temperature for 15 hours or longer to prepare polyethylene carbonate.

The prepared polyethylene carbonate was quantitatively determined, and then the catalytic activity was calculated by dividing the amount of the added catalyst. The results are shown in Table 1 below.

catalyst Catalytic activity (g / g · cat [ZnGA]) Example 38.8 Comparative Example 1 18.9 Comparative Example 2 21.9

As shown in Table 1, the catalytic activity of the catalyst according to the present invention was significantly higher than that of Comparative Examples 1 and 2.

Experimental Example  3: Separation of catalyst

In Experimental Example 1, 0.5 g of polyethylene carbonate prepared from ZnGA-Vulcan was added to 5 g of methylene chloride, and the mixture was stirred for 4 to 5 hours. Then, the mixture was centrifuged at 5,000 rpm for 5 minutes using a centrifuge. As a result, it was confirmed that the ZnGA-Vulcan catalyst and the polyethylene carbonate resin dissolved in methylene chloride were separated as shown in FIG.

Claims (12)

1) mixing a zinc precursor and carbon black;
2) sintering the mixture to produce a zinc oxide-carbon black composite; And
3) reacting the zinc oxide-carbon black composite with C _4-10 dicarboxylic acid.
A method for producing an organic zinc-carbon black composite.
The method according to claim 1,
In step 1, 9 mg to 20 mg of carbon black is mixed with 1 mmol of the zinc precursor,
Gt;
The method according to claim 1,
The zinc precursor is _{Zn (NO 3) 2, Zn} (acac) 2, Zn (OH) 2, Zn (OAc) 2, ZnSO 4, and Zn (ClO ₃₎ is any one selected from the group consisting of _2,
Gt;
The method according to claim 1,
Wherein the mixing temperature in step 1 is 140 to 160 DEG C,
Gt;
The method according to claim 1,
Wherein the solvent of step 1 is triethylene glycol, ethylene glycol, or diethylene glycol,
Gt;
The method according to claim 1,
Wherein the sintering temperature in step 2 is 300 to 400 DEG C,
Gt;
The method according to claim 1,
Wherein the sintering time of step 2 is 4 hours to 8 hours,
Gt;
The method according to claim 1,
Wherein the C _4-10 dicarboxylic acid is a compound represented by the following formula (1)
Manufacturing method:
[Chemical Formula 1]
HOOC-R-COOH
In Formula 1,
R is C _2-8 alkylene.
The method according to claim 1,
_Wherein the C _4-10 dicarboxylic acid is glutaric acid, adipic acid, pimelic acid, or succinic acid,
Gt;
The method according to claim 1,
Wherein the reaction temperature of Step 3 is 50 to 60 DEG C,
Gt;
The method according to claim 1,
Wherein the reaction time of step 3 is 15 hours to 30 hours,
Gt;
12. A catalyst composition for the production of polyethylene carbonate, comprising an organic zinc-carbon black composite prepared by the process of any one of claims 1-11.

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