Preparation method of organic zinc catalyst and poly(alkylene carbonate) resin

Abstract

The present invention relates to a preparation method of an organic zinc catalyst capable of preparing an organic zinc catalyst having a finer and more uniform particle size and more improved activity during a polymerization process for preparing a poly(alkylene carbonate) resin, and a preparation method of a poly(alkylene carbonate) resin using the organic zinc catalyst. The preparation method of an organic zinc catalyst includes reacting a zinc precursor and a dicarboxylic acid in the presence of a dispersant to form a zinc dicarboxylate-based catalyst, wherein a reaction step is performed under a condition at which the number of moles of the dicarboxylic acid present in a reaction system is larger than that of the zinc precursor throughout the entire reaction step.

Claims

1. A preparation method of an organic zinc catalyst, the preparation method comprising: providing a zinc precursor surface-treated with a dispersant; and reacting the surface-treated zinc precursor with a dicarboxylic acid having 3 to 20 carbon atoms to form a zinc dicarboxylate-based catalyst, wherein the reaction step is performed under a condition at which the number of moles of the dicarboxylic acid present in a reaction system is larger than that of the zinc precursor throughout the entire reaction step, wherein the dispersant is an anionic surfactant.

2. The preparation method of claim 1, wherein the dispersant is an alkyl phenol ethoxylated phosphate ester represented by the following Chemical Formula 1: ##STR00002## wherein, in Chemical Formula 1, R.sup.1 to R.sup.3 are each independently hydrogen or a straight or branched chain alkyl group having 8 to 12 carbon atoms, at least one of R.sup.1 to R.sup.3 being a straight or branched chain alkyl group having 8 to 12 carbon atoms; M.sup.1 and M.sup.2 are each independently hydrogen, ammonium, or a monovalent metal ion; and n is an integer of 3 to 100.

3. The preparation method of claim 1, wherein the zinc precursor surface treated by the dispersant is formed by mixing the zinc precursor with the dispersant in a solvent.

4. The preparation method of claim 3, wherein the dispersant is mixed at a content of 0.01 to 10 wt % with respect to the zinc precursor.

5. The preparation method of claim 1, wherein the dicarboxylic acid is used in a ratio of 1.05 to 1.5 moles based on 1 mole of the zinc precursor.

6. The preparation method of claim 1, wherein the zinc precursor includes a zinc compound selected from the group consisting of zinc oxide, zinc sulfate (ZnSO.sub.4), zinc chlorate (Zn(ClO.sub.3).sub.2), zinc nitrate (Zn(NO.sub.3).sub.2), zinc acetate (Zn(OAc).sub.2), and zinc hydroxide.

7. The preparation method of claim 1, wherein the dicarboxylic acid having 3 to 20 carbon atoms includes an aliphatic dicarboxylic acid selected from the group consisting of malonic acid, glutaric acid, succinic acid, and adipic acid, or an aromatic dicarboxylic acid selected from the group consisting of terephthalic acid, isophthalic acid, homophthalic acid, and phenyl glutaric acid.

8. The preparation method of claim 1, wherein the reaction step is performed in a liquid medium, while adding a solution or dispersion containing the zinc precursor in portions 2 times or more to a solution or dispersion containing the dicarboxylic acid.

9. The preparation method of claim 8, wherein the reaction step is performed while adding a solution or dispersion containing the zinc precursor at an amount obtained by dividing the entire use amount of the zinc precursor into 2 to 10 to the solution or dispersion containing the dicarboxylic acid at the same time interval.

10. The preparation method of claim 8, wherein the reaction step is performed while dripping the solution or dispersion containing the zinc precursor in a droplet form into the solution or dispersion containing the dicarboxylic acid.

11. The preparation method of claim 8, wherein the liquid medium includes one or more kinds of solvents selected from the group consisting of toluene, hexane, dimethylformamide, ethanol, and water.

12. The preparation method of claim 1, wherein the organic zinc catalyst is in a form of particles having an average particle size of 0.5 m or less.

13. The preparation method of claim 1, wherein the organic zinc catalyst having a surface area of 1.8 m.sup.2/g or more is prepared.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(1) Hereinafter, preferred examples of the present invention will be provided for understanding of the present invention. It is to be understood that the examples are only for illustrative purposes and are not intended to limit the scope of the present invention.

EXAMPLE 1: Preparation of Organic Zinc Catalyst in Presence of Dispersant (Molar Ratio of ZnO and Glutaric Acid=1:1.2)

(2) In a 250 mL round bottom flask, 7.93 g (0.06 mol) of glutaric acid and 0.1 mL of acetic acid were added to and dispersed in 100 mL of toluene under reflux, followed by heating at 55 C. for 30 minutes.

(3) Separately, 4.1 g (0.05 mol) of ZnO was added to and stirred with 50 mL of toluene to which 0.02 g of nonylphenol ethoxylated phosphate ester was added, thereby preparing a Zn dispersion.

(4) The ZnO dispersion was divided into 4 portions based on volume, and a reaction was performed by primarily adding a portion of the ZnO dispersion to a glutaric acid solution. After 1 hour, the reaction was performed by adding another portion of the ZnO dispersion, and after 1 hour therefrom, the reaction was performed by adding another portion of the ZnO dispersion. After another hour, the reaction was performed by adding the remaining portion of the ZnO dispersion. The mixed solution was heated at 110 C. for 2 hours. After a white solid was produced, the produced white solid was filtered, washed with acetone/ethanol, and dried at 130 C. in a vacuum oven.

(5) An organic zinc catalyst of Example 1 was prepared by the method as described above. As a result of scanning electron microscope (SEM) analysis, it was confirmed that the organic zinc catalyst of Example 1 had an average particle size of about 0.2 m and a particle size standard deviation of 0.04 m.

EXAMPLE 2: Preparation of Organic Zinc Catalyst in Presence of Dispersant (Molar Ratio of ZnO and Glutaric Acid=1:1.5)

(6) In a 250 mL round bottom flask, 9.91 g (0.075 mol) of glutaric acid and 0.1 mL of acetic acid were added to and dispersed in 100 mL of toluene under reflux, followed by heating at 55 C. for 30 minutes.

(7) Separately, 4.1 g (0.05 mol) of ZnO was added to and stirred with 50 mL of toluene to which 0.02 g of nonylphenol ethoxylated phosphate ester was added, thereby preparing a Zn dispersion.

(8) The ZnO dispersion was divided into 4 portions based on volume, and a reaction was performed by adding a portion of the ZnO dispersion to a glutaric acid solution. After 1 hour, the reaction was performed by adding another portion of the ZnO dispersion, and after 1 hour therefrom, the reaction was performed by adding another portion of the ZnO dispersion. After an additional hour, the reaction was performed by adding the remaining portion of the ZnO dispersion. The mixed solution was heated at 110 C. for 2 hours. After a white solid was produced, the produced white solid was filtered, washed with acetone/ethanol, and dried at 130 C. in a vacuum oven.

(9) An organic zinc catalyst of Example 2 was prepared by the method as described above. As a result of scanning electron microscope (SEM) analysis, it was confirmed that the organic zinc catalyst of Example 2 had an average particle size of about 0.25 m and a particle size standard deviation of 0.03 m.

EXAMPLE 3: Preparation of Organic Zinc Catalyst in Presence of Dispersant (Molar Ratio of ZnO and Glutaric Acid=1:1)

(10) In a 250 mL round bottom flask, 6.61 g (0.05 mol) of glutaric acid and 0.1 mL of acetic acid were added to and dispersed in 100 mL of toluene under reflux, followed by heating at 55 C. for 30 minutes.

(11) Separately, 4.1 g (0.05 mol) of ZnO was added to and stirred with 50 mL of toluene to which 0.02 g of nonylphenol ethoxylated phosphate ester was added, thereby preparing a Zn dispersion.

(12) The ZnO dispersion was divided into 4 portions based on volume, and a reaction was performed by adding a portion of the ZnO dispersion to a glutaric acid solution. After 1 hour, the reaction was performed by adding another portion of the ZnO dispersion, and after 1 hour therefrom, the reaction was performed by adding another portion of the ZnO dispersion. After an additional hour, the reaction was performed by adding the remaining portion of the ZnO dispersion. The mixed solution was heated at 110 C. for 2 hours. After a white solid was produced, the produced white solid was filtered, washed with acetone/ethanol, and dried at 130 C. in a vacuum oven.

(13) An organic zinc catalyst of Example 3 was prepared by the method as described above. As a result of scanning electron microscope (SEM) analysis, it was confirmed that the organic zinc catalyst of Example 3 had an average particle size of about 0.6 m and a particle size standard deviation of 0.18 m.

EXAMPLE 4: Preparation of Organic Zinc Catalyst in Presence of Dispersant Molar Ratio of Zinc Nitrate [Zn(NO3)2] and Glutaric Acid=1:1.2

(14) An organic zinc catalyst of Example 4 was prepared by the same method as in Example 1, except for using 11.36 g (0.06 mol) of Zn(NO.sub.3).sub.2 instead of ZnO as a zinc precursor.

(15) The organic zinc catalyst of Example 4 was confirmed by SEM analysis, and as a result, it was confirmed that that the organic zinc catalyst of Example 4 had an average particle size of about 0.8 m and a particle size standard deviation of about 0.20 m.

COMPARATIVE EXAMPLE 1: Preparation of Organic Zinc Catalyst (Molar Ratio of ZnO and Glutaric Acid=1:1)

(16) In a 250 mL round bottom flask, 6.61 g (0.05 mol) of glutaric acid, 4.1 g (0.05 mol) of ZnO, and 0.1 mL of acetic acid were added to and dispersed in 150 mL of toluene under reflux. Then, the mixed solution was heated at 55 C. for 3 hours and at 110 C. for 4 hours. After a white solid was produced, the produced white solid was filtered, washed with acetone/ethanol, and dried at 130 C. in a vacuum oven.

(17) An organic zinc catalyst of Comparative Example 1 was prepared by the method as described above. As a result of scanning electron microscope (SEM) analysis, it was confirmed that the organic zinc catalyst of Comparative Example 1 had a particle size of about 1 to 2 m and a particle size standard deviation of 0.4 m or more.

COMPARATIVE EXAMPLE 2: Preparation of Organic Zinc Catalyst (Molar Ratio of ZnO and Glutaric Acid=1:1.2)

(18) In a 250 mL round bottom flask, 7.93 g (0.06 mol) of glutaric acid and 0.1 mL of acetic acid were added to and dispersed in 100 mL of toluene under reflux, followed by heating at 55 C. for 30 minutes.

(19) Separately, 4.1 g (0.05 mol) of ZnO was added to and stirred with 50 mL of toluene, thereby preparing a ZnO dispersion.

(20) The glutaric acid dispersion was divided into 4 portions based on volume, and a reaction was performed by adding a portion of glutaric acid dispersion to the ZnO solution. After 1 hour, the reaction was performed by adding another portion of the glutaric acid dispersion, and after 1 hour therefrom, the reaction was performed by adding another portion of the glutaric acid dispersion. After an additional hour, the reaction was performed by adding the remaining portion of the glutaric acid dispersion. The mixed solution was heated at 110 C. for 2 hours. After a white solid was produced, the produced white solid was filtered, washed with acetone/ethanol, and dried at 130 C. in a vacuum oven.

(21) An organic zinc catalyst of Comparative Example 2 was prepared by the method as described above. The organic zinc catalyst of Comparative Example 2 was confirmed by SEM analysis, and as a result, it was confirmed that that the organic zinc catalyst of Example 2 had an average particle size of about 1.7 m and a particle size standard deviation of about 0.43 m or more.

Polymerization Example

(22) Polyethylene carbonate was polymerized and prepared by the following method using the catalysts of the examples and comparative examples.

(23) First, in a glove box, 0.4 g of the catalyst and 8.25 g of dichloromethane (methylene chloride) were put into a high pressure reactor, and 8.9 g of ethylene oxide was added thereto. Thereafter, the reactor was pressurized to 30 bar using carbon dioxide. A polymerization reaction was performed at 70 C. for 3 hours. After the reaction was terminated, unreacted carbon dioxide and ethylene oxide were removed together with dichloromethane, which was a solvent. In order to confirm an amount of the prepared polyethylene carbonate, the remaining solid was completely dried and then weighed. Activities and yields of the catalysts depending on results of the polymerization as described above are shown in the following Table 1.

(24) TABLE-US-00001 TABLE 1 Molar ratio of Yield Activity of catalyst ZnO:Glutaric acid (g) (g-polymer/g-catalyst) Example 1 1:1.2 20.9 67.0 Example 2 1:1.5 16.5 64.2 Example 3 1:1 20.1 50.3 Example 4.sup.(a) 1:1.2 14.3 35.8 Comparative 1:1 11.9 29.8 Example 1.sup.(b) Comparative 1:1.2 10.2 25.5 Example 2.sup.(c) .sup.(a)Zn(NO.sub.3).sub.2 was used instead of ZnO .sup.(b)ZnO and glutaric acid were injected at once .sup.(c)Glutaric acid was injected in portions to the ZnO dispersion

(25) Referring to Table 1, it was confirmed that the catalysts of the examples had excellent activities as compared to the catalysts of the comparative examples, and preparation of polyethylene carbonate with high yields was enabled.