KR102178516B1 - Catalyst for esterification and manufacturing method thereby - Google Patents

Abstract

The esterification catalyst according to the present invention includes a polystyrene sulfonate-chitosan copolymer, thereby improving the initial esterification reaction rate to obtain an ester compound in a high yield in a short time, and improving mechanical strength to provide excellent long-term stability. There is.

Description

Esterification reaction catalyst and its manufacturing method {CATALYST FOR ESTERIFICATION AND MANUFACTURING METHOD THEREBY}

The present invention relates to an esterification reaction catalyst that improves the initial esterification reaction rate and has excellent mechanical strength and can be used for a long time, and a method for producing the same.

Esterification reaction refers to a reaction in which an acid and an alcohol are reacted to form an ester compound. The esterification reaction is a reversible reaction in which the synthesis and separation of an ester compound are simultaneously performed. Due to the nature of the reversible reaction, in order to synthesize an ester compound with a high yield in a short time, an esterification reaction catalyst having an excellent initial reaction rate with a reactant is required.

Typically, the esterification catalyst is an Amberlyst-based resin. However, since the Amberlyst-based resin is not excellent in the initial reaction rate with the reactant, there is a problem that the yield of the ester-based compound is lowered.

In addition, the Amberlyst-based resin has a problem of deteriorating long-term stability due to weak mechanical strength.

An object of the present invention is to provide a novel esterification catalyst in order to solve the above problems.

Another object of the present invention is to provide a method for preparing the novel esterification catalyst.

However, the technical problem to be achieved by the present invention is not limited to the above-mentioned problems, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

According to an embodiment of the present invention, the esterification catalyst according to the present invention includes a polystyrene sulfonate-chitosan copolymer.

In addition, according to another embodiment of the present invention, the method for preparing an esterification reaction catalyst according to the present invention includes the steps of (a) preparing a chitosan solution, (b) treating the chitosan solution with alkali to prepare chitosan beads, (c) mixing the chitosan beads and a crosslinking agent to prepare crosslinked chitosan beads, and (d) mixing the crosslinked chitosan beads and polystyrene sulfonate to prepare a polystyrenesulfonate-chitosan copolymer.

The esterification reaction catalyst according to the present invention includes a polystyrene sulfonate-chitosan copolymer, thereby having an effect of obtaining an ester-based compound in a high yield in a short time. In addition, the esterification catalyst according to the present invention includes a polystyrene sulfonate-chitosan copolymer, thereby improving mechanical strength and thus has excellent long-term stability.

The method for preparing an esterification reaction catalyst according to the present invention is to prepare a polystyrene sulfonate-chitosan copolymer by mixing crosslinked chitosan beads and polystyrene sulfonate, thereby using an eco-friendly and inexpensive material to produce an ester-based compound in a short time. At the same time, the mechanical strength is improved, so that an esterification catalyst having excellent long-term stability can be prepared.

1 is a graph showing the conversion rate of ethyl lactate using the esterification catalysts of Example 1 and Comparative Examples 1 and 2 of the present invention.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, only to make the disclosure of the present invention thorough by listening to the present embodiments, and to obtain ordinary knowledge in the art It is provided to completely inform the scope of the invention to those who have it, and the invention is only defined by the scope of the claims.

< Esterification Reaction catalyst>

The esterification catalyst according to the present invention includes a polystyrenesulfonate-chitosan copolymer.

Polystyrene sulfonate is a compound in which the hydrogen group of polystyrene is substituted with a sulfone group. Specifically, the chemical structure of the polystyrene sulfonate is shown in Chemical Structural Formula 1 below.

[Chemical Structural Formula 1]

Sulfone group (SO ₃ ^-) of the polystyrene sulfonate is an anionic type, sulfonic groups of polystyrene sulfonate in the anionic form (SO ₃ ^-) is combined with an amino group (NH ₂₎ of chitosan that will be described later polystyrene sulfonate-chitosan Copolymers can be formed.

Chitosan (chitosan) is a natural polymer material, N-acetyl glucosamine (n-acetyl glucosamine) is a compound combined. Specifically, the chemical structure of the chitosan is shown in Chemical Formula 2 below.

[Chemical Formula 2]

Amino groups of the chitosan (NH ₂₎ is a sulfone group (SO ₃ ^-) of the polystyrene sulfonate - it is possible to form the chitosan-copolymer of polystyrene sulfonate in combination with.

The polystyrene sulfonate-chitosan copolymer may be a graft copolymer in which a chitosan polymer is branched to a polystyrene sulfonate polymer main chain. The polystyrene sulfonate-chitosan copolymer exhibits a form of a graft copolymer, so that the chitosan may be located inside the polystyrene sulfonate-chitosan copolymer structure. In addition, the polystyrene sulfonate may be located outside the structure of the polystyrene sulfonate-chitosan copolymer. The chitosan is located inside the polystyrene sulfonate-chitosan copolymer structure, thereby improving the mechanical strength of the esterification reaction catalyst containing the polystyrene sulfonate-chitosan copolymer. The polystyrene sulfonate is located outside the structure of the polystyrene sulfonate-chitosan copolymer, thereby improving the initial reaction rate with the reactant of the esterification reaction catalyst containing the polystyrene sulfonate-chitosan copolymer.

The esterification catalyst according to the present invention may be a polystyrene sulfonate-chitosan copolymer supported on a zirconia compound.

The zirconia compound refers to a compound containing zirconium (Zr), which is a transition metal. The type of the zirconia compound containing zirconium (Zr) used in the present invention is not particularly limited, but a zirconyl chloride (ZrOCl ₂ ) compound may be used as an example.

The zirconia compound may be used as a carrier for the polystyrene sulfonate-chitosan copolymer. The zirconia compound is used as a support for the polystyrene sulfonate-chitosan copolymer, so that the esterification reaction catalyst in which the zirconia compound is supported on the polystyrene sulfonate-chitosan copolymer has an effect of further improving the initial reaction rate with the reactant. .

As described above, the esterification reaction catalyst including the polystyrene sulfonate-chitosan copolymer improves the initial reaction rate with the reactant, thereby obtaining an ester-based compound with high yield in a short time. In addition, the esterification reaction catalyst containing the polystyrene sulfonate-chitosan copolymer has an excellent long-term stability due to improved mechanical strength. In addition, the esterification reaction catalyst in which the zirconia compound is supported on the polystyrene sulfonate-chitosan copolymer further improves the initial reaction rate with the reactant, thereby obtaining an ester-based compound with a higher yield in a short time.

< Esterification Method of manufacturing reaction catalyst>

The method for producing an esterification reaction catalyst according to the present invention includes (a) preparing a chitosan solution, (b) treating the chitosan solution with alkali to prepare chitosan beads, (c) mixing the chitosan beads and a crosslinking agent. And (d) mixing the crosslinked chitosan beads and polystyrene sulfonate to prepare a polystyrene sulfonate-chitosan copolymer.

First, the manufacturing method according to the present invention includes the step of (a) preparing a chitosan solution.

The chitosan solution may be prepared by mixing chitosan flakes with an acid solution. The acid solution used for preparing the chitosan solution is not particularly limited, and acetic acid may be used as an example. In addition, chitosan flakes used in the preparation of the chitosan solution are not particularly limited, and as an example, chitosan flakes having a weight average molecular weight of 190,000 to 375,000 may be used.

Specifically, the chitosan solution is a step of preparing a mixture by dissolving chitosan flakes in acetic acid at a temperature of about 20 to 30°C, passing the mixture through a filter to remove undissolved chitosan flake particles, and then obtaining a chitosan solution. Can be manufactured by

Next, the manufacturing method according to the present invention includes the step of (b) treating the chitosan solution with an alkali to prepare chitosan beads.

The chitosan beads may be prepared as chitosan beads after alkali treatment of the chitosan solution with an alkali solution. The pH of the chitosan solution that has been alkali-treated with the alkali solution may exhibit weak basicity as 8 to 9. The alkali solution used in the manufacture of chitosan beads is not particularly limited, and an aqueous sodium hydroxide (NaOH) solution may be used as an example.

Specifically, the chitosan beads are prepared by mixing a chitosan solution and sodium hydroxide at a temperature of about 20 to 30°C, stirring the chitosan solution and the sodium hydroxide for about 12 to 18 hours to obtain chitosan beads. I can.

Next, the manufacturing method according to the present invention includes (c) preparing crosslinked chitosan beads by mixing the chitosan beads and a crosslinking agent.

The method of preparing the crosslinked chitosan beads may include mixing the chitosan beads and a crosslinking agent, and washing the chitosan beads mixed with the crosslinking agent with water. The crosslinking agent used to prepare the crosslinked chitosan beads is not particularly limited, and epichlorohydrin (C ₃ H ₅ OCl) may be used as an example.

Specifically, the method of preparing the crosslinked chitosan beads is the step of mixing the chitosan beads and the epichlorohydrin at a rotation speed of 100 to 300 rpm in a temperature range of 40 to 60°C, until the epichlorohydrin is about pH 7. It can be prepared by washing the chitosan beads mixed with hydrin with water to obtain crosslinked chitosan beads.

Next, the manufacturing method according to the present invention includes the step of (d) preparing a polystyrene sulfonate-chitosan copolymer by mixing the crosslinked chitosan beads and polystyrene sulfonate.

The method for preparing the polystyrenesulfonate-chitosan copolymer may include preparing a mixture by mixing the crosslinked chitosan beads and the polystyrenesulfonate, and adding an acid to the mixture. In addition, the method of adding an acid to the mixture may be performed by adding the acid to the mixture at one time or by evenly distributing the acid to the mixture and adding the acid per unit time.

Specifically, the method of preparing the polystyrene sulfonate-chitosan copolymer comprises mixing the crosslinked chitosan beads and the polystyrene sulfonate for 12 to 18 hours at a rotation speed of 100 to 300 rpm in a temperature range of 20 to 60°C. Can be manufactured. Thereafter, after adding hydrochloric acid (HCl) to the mixture at a time, the mixture and the hydrochloric acid may be stirred at a rotation speed of 100 to 300 rpm in a temperature range of 10 to 50°C. After the mixture and the hydrochloric acid are stirred for 15 to 25 hours, a polystyrene sulfonate-chitosan copolymer can be prepared.

In addition, the method of preparing the polystyrene sulfonate-chitosan copolymer is to prepare a mixture by mixing the crosslinked chitosan beads and the polystyrene sulfonate for 12 to 18 hours at a rotation speed of 100 to 300 rpm in a temperature range of 20 to 60 °C. can do. Thereafter, hydrochloric acid evenly distributed to the mixture may be added every about 1 hour. After the evenly distributed hydrochloric acid is added to the mixture, the mixture and the hydrochloric acid may be stirred at a rotation speed of 100 to 300 rpm in a temperature range of 10 to 50°C. After the mixture and the hydrochloric acid are stirred for 15 to 25 hours, a polystyrene sulfonate-chitosan copolymer can be prepared.

The method of adding an acid to the mixture can be performed by two processes as described above. Among the two processes, the total amount of acid added to the mixture may be the same. Among the above two processes, the esterification reaction catalyst prepared by adding an acid to the mixture at once has an excellent long-term stability due to further improved mechanical strength. The esterification reaction catalyst prepared by the method of equally distributing an acid to the mixture and adding it per unit time among the above two processes further improves the initial reaction rate with the reactant, thereby obtaining an ester-based compound in a higher yield in a short time. There is an effect.

In addition, the manufacturing method according to the present invention may further include the step of (e) supporting the zirconia compound on a polystyrenesulfonate-chitosan copolymer after the step (d).

The step of supporting the zirconia compound on the polystyrenesulfonate-chitosan copolymer comprises preparing a mixture by mixing the polystyrenesulfonate-chitosan copolymer and a solution containing a zirconia compound, and drying the mixture to prepare the zirconia compound into polystyrene. It may include the step of supporting the sulfonate-chitosan copolymer.

Specifically, the step of supporting the zirconia compound on the polystyrene sulfonate-chitosan copolymer is by mixing the polystyrene sulfonate-chitosan copolymer and the zirconyl chloride (ZrOCl ₂ ) compound for 30 minutes to 2 hours at a temperature of about 25°C. Preparing a mixture, drying the mixture at a temperature range of 60 ~ 100 ℃ for 8 ~ 12 hours may include the step of supporting the zirconia compound on the polystyrene sulfonate-chitosan copolymer.

The esterification reaction catalyst in which the zirconia compound is supported on the polystyrenesulfonate-chitosan copolymer further improves the initial reaction rate with the reactant, thereby obtaining an ester-based compound with a higher yield in a short time.

Hereinafter, preferred embodiments are presented to aid in understanding the present invention. However, the following examples are provided for easier understanding of the present invention, and the contents of the present invention are not limited by the following examples.

< Example >

<Example 1>

1) Preparation of chitosan solution: After adding 20 g of chitosan powder to 980 g of 1% acetic acid aqueous solution at room temperature, the mixture is stirred until the chitosan powder is completely dissolved. It is then filtered to remove solid impurities and a clear solution is obtained.

2) Preparation of chitosan beads: While stirring 1.5 L of 2M NaOH aqueous solution, 700 g of the chitosan solution obtained in the step 1) was added at room temperature at a rate of 10 mL/h, and the resulting solution containing chitosan beads was further stirred for 15 hours. do. Chitosan beads are washed several times with ultrapure water so that the pH is 8-9.

3) Crosslinking of chitosan beads: The chitosan beads prepared in the above step 2) were added to 1L of a 0.38M NaOH aqueous solution, and then the mixture to which 30g of epihydrochlorin was added is stirred at 50°C for 12-18 hours. The crosslinked chitosan beads are washed with ultrapure water to a pH of about 7.

4) Grafting polystyrene sulfonate onto chitosan beads: Add 70 g of 25% poly(sodium 4-styrenesulfonate) aqueous solution to 250 mL of ultrapure water containing crosslinked chitosan beads prepared in the above 3) process, and 12 at 40°C. After stirring for ~18 hours, 12.5 mL of 37% hydrochloric acid was added, followed by stirring at room temperature for 20 hours. The obtained solid was washed three times with 1L of 0.1M HCl ethanol/ultrapure water (1:1 weight ratio) solution and three times with 1L of ethanol.

5) Zr support: 500 g of the beads prepared in the above 4) process in 500 ml of ethanol were mixed with 500 ml of ethanol, and 100 to 500 g of zirconyl chloride (30 wt%) in hydrochloric acid were added to this solution, The mixture was stirred at room temperature for 1 hour, washed three times with 1 L of 0.1M HCl ethanol/ultrapure water (1:1 weight ratio) solution and three times with 1L of ethanol. The washed solid is dried to obtain a catalyst (Zr-PSS-CS).

6) Thermal decompression treatment: Put the catalyst prepared in the step 5) in a vacuum oven and subjected to a reduced pressure treatment at 140 to 300°C for 2 hours to obtain a catalyst having excellent mechanical strength.

<Comparative Example 1>

Amerlyst-15 (manufacturer: Rohm & Haas) was used as an esterification catalyst.

<Comparative Example 2>

Amerlyst-39 (manufactured by Rohm & Haas) was used as an esterification catalyst.

<Experimental Example>

A mixture of 0.4 g of the catalyst of Example 1 and Comparative Examples 1,2 and 40 mL of ethanol was heated to 80°C while stirring. After the addition of 20 mL of lactic acid, 1 mL of the mixture was collected in aliquots for each time while stirring, and GC (Gas Chromatography) analysis was performed, as shown in Table 1 and FIG. 1 below.

As shown in Table 1 and FIG. 1, when the esterification reaction catalyst of Example 1 is used compared to the case of using the esterification reaction catalyst of Comparative Examples 1,2, the initial esterification reaction rate is improved and a high yield in a short time It can be seen that ethyl lactate can be obtained.

Example 1 Comparative Example 1 Comparative Example 2 Zr-PSS-CS catalyst used Using Amerlyst-15 catalyst Amerlyst-39 catalyst used TOS(h) Conversion rate (%) TOS(h) Conversion rate (%) TOS(h) Conversion rate (%) 0.37 24.43 0.45 11.17 0.47 17.14 0.90 40.10 0.97 20.82 0.95 30.69 1.75 50.45 1.65 29.94 1.63 41.67 2.90 55.65 3.02 41.76 3.00 51.53 3.98 56.66 4.57 48.82 4.55 57.09 5.28 60.64 5.72 51.54 5.70 58.54 6.62 61.92 7.38 52.38 7.37 60.63 8.12 63.13 - - - -

* TOS: time on stream (time)

Although the present invention has been described above, the present invention is not limited by the embodiments disclosed in the present specification, and it is apparent that various modifications may be made by a person skilled in the art within the scope of the technical idea of the present invention. In addition, even if not explicitly described and described the effect of the configuration of the present invention while describing the embodiments of the present invention, it is natural that the predictable effect by the configuration should also be recognized.

Claims (12)

delete delete delete (a) preparing a chitosan solution;
(b) treating the chitosan solution with an alkali to prepare chitosan beads;
(c) preparing crosslinked chitosan beads by mixing the chitosan beads and a crosslinking agent; And
(d) preparing a polystyrene sulfonate-chitosan copolymer by mixing the crosslinked chitosan beads and polystyrene sulfonate; Including,
The step (d),
(d-1) preparing a mixture by mixing the crosslinked chitosan beads and the polystyrene sulfonate; And
(d-2) adding an acid to the mixture; containing
Method for producing an esterification reaction catalyst.
The method of claim 4,
After step (d),
(e) supporting a zirconia compound on the polystyrene sulfonate-chitosan copolymer; It characterized in that it further comprises
Method for producing an esterification reaction catalyst.
The method of claim 4,
The chitosan solution of step (a) is
Characterized in that prepared by mixing chitosan flakes in an acid solution
Method for producing an esterification reaction catalyst.
The method of claim 4,
The pH of the alkali-treated chitosan solution in step (b) is 8-9.
Method for producing an esterification reaction catalyst.
The method of claim 4,
The crosslinking agent in step (c) is characterized in that epichlorohydrin (epichlorohydrin)
Method for producing an esterification reaction catalyst.
The method of claim 4,
The step (c),
(c-1) mixing the chitosan beads and the crosslinking agent; And
(c-2) washing the chitosan beads mixed with the crosslinking agent with water; including
Method for producing an esterification reaction catalyst.
delete The method of claim 4,
The method of adding an acid to the mixture in step (d-2)
Characterized in that the method of adding the acid to the mixture at once
Method for producing an esterification reaction catalyst.
The method of claim 4,
The method of adding an acid to the mixture in step (d-2)
It is characterized in that the method of adding the acid per unit time by evenly distributing the acid to the mixture
Method for producing an esterification reaction catalyst.

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