KR20230130346A - Purification method for 2,3-butanediol - Google Patents

Abstract

The present invention relates to a method for purifying 2,3-butanediol.
The method for purifying 2,3-butanediol of the present invention involves adding a hydroxide containing an alkali metal to crude 2,3-butanediol containing impurities produced by fermentation and polymerizing it through saponification and condensation under alkaline conditions. Impurities are removed, a metal catalyst is added to the solution from which the impurities have been removed, and a hydrogenation reaction is performed to reduce impurities such as aldehydes or ketones, which are causes of unpleasant odors, and then distilled to achieve high purity through an efficient and simple process in terms of economic efficiency. At the same time, it is possible to solve the discoloration and off-odor problems at the same time and provide 2,3-butanediol of a quality suitable for use as a cosmetic raw material.

Description

Purification method of 2,3-butanediol {PURIFICATION METHOD FOR 2,3-BUTANEDIOL}

The present invention relates to a method for purifying 2,3-butanediol, and more specifically, to saponification under alkaline conditions by adding a hydroxide containing an alkali metal to crude 2,3-butanediol containing impurities produced by fermentation. And condensation reaction is performed to remove impurities, a catalyst is added to the solution from which the impurities have been removed, hydrogenation is performed to reduce impurities such as aldehydes and ketones, which cause unpleasant odors, and then distilled to provide an efficient and simple process in terms of economic efficiency. It relates to a method for purifying 2,3-butanediol that has high purity and simultaneously solves the problems of discoloration and off-flavor.

Butanediol includes four isomers: 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 2,3-butanediol, and three types of butanediol other than 2,3-butanediol. While it can be produced by artificially refining and processing, 2,3-butanediol (Butane-2,3-diol) is difficult to synthesize directly and is classified as a natural substance that is easily accessible in nature. For example, 2,3-butanediol exists in nature in soil, water, grains, plants, fermented foods, and even in the intestines of our bodies, and is also found in wine made from fermented grapes and in Korea's representative fermented food, soybean paste.

Therefore, among the four isomers of butanediol, 1,4-butanediol and 1,3-butanediol are the most used because they are chemically inexpensive and easy to produce. In particular, 1,4-butanediol is used as a solvent or as an elastic agent. It is also used as a raw material for the manufacture of fibers and polyurethane, so it is currently of industrial importance. In particular, 1,3-butanediol can often be seen under the name 'butylene glycol' in cosmetic ingredient lists. It is used as a moisturizer because of its moisture-attracting properties, and as a solvent to help control viscosity and dissolve substances. Because it performs a ritual role, it is used as a raw material for cosmetics.

On the other hand, 2,3-butanediol, which replaces 1,3-butanediol (butylene glycol), a chemical product currently used as a cosmetic moisturizer, and is synthesized through a bio-based fermentation process, has excellent skin stability and feeling of use. It is attracting attention as a non-toxic and non-irritating eco-friendly cosmetic raw material. In addition to cosmetic raw materials, 2,3-butanediol can be used in everyday lotions, creams, ointments and medicines, and can also be applied to various everyday healthcare products consisting of emulsifiers and humectants. there is.

Accordingly, because 2,3-butanediol can be applied to a wide range of uses, interest in methods for easily producing 2,3-butanediol raw material industrially or separating and purifying it is increasing.

As a prior art therefor, Patent Document 1 is a method for separating and purifying 1,3-butanediol and 2,3-butanediol from a microbial culture medium producing 1,3-butanediol and 2,3-butanediol, specifically 1, By evaporating the microbial culture that produces 3-butanediol and 2,3-butanediol, passing it sequentially through a condenser to simultaneously dehydrate and decontaminate, and separating and purifying 1,3-butanediol and 2,3- A method for separating and purifying butanediol is presented.

In particular, 2,3-butanediol, a polyhydric alcohol produced through microbial metabolism, can easily undergo a radical reaction when a hydroxyl group is located on an adjacent carbon. Such radical reactions can occur due to light, active oxygen, and water, and can occur at high temperatures. It can be accelerated under the following conditions.

The radical reaction of 2,3-Butanediol produces acetoin, acetaldehyde, butanone, etc. through electron transfer and oxidation and reduction reactions with active oxygen and moisture. It can generate various volatile substances. The generation of these volatile substances causes the unpleasant odor of polyhydric alcohol. As a method of eliminating the unpleasant odor of polyhydric alcohol and improving the odor of polyhydric alcohol, conventional techniques can be applied to adsorb existing impurities or remove them through air circulation, etc.

As another method for eliminating the unpleasant odor of polyhydric alcohol and improving the odor of polyhydric alcohol, Patent Document 2 provides a method for effectively controlling the production of substances that cause unpleasant odor in the process of rectifying 2,3-butanediol obtained through fermentation. A method for purifying 2,3-butanediol suitable for use as a raw material for cosmetics is disclosed by removing dissolved oxygen, removing moisture, and distilling.

More specifically, A) adding crude 2,3-butanediol to the reactor; B) With stirring, 0.5 to 10 weight of at least one moisture remover selected from the group consisting of CaCl ₂ , MgSO ₄ , Na ₂ SO ₄ , CaSO ₄ , K ₂ CO ₃ , CaO and BaO based on 2,3-butanediol. Adding at a rate of %; C) removing dissolved oxygen through inert gas purging; and D) recovering purified 2,3-butanediol through reduced pressure distillation.

However, although the above purification process can remove other impurities, there are bound to be limitations in removing impurities generated during the purification process, and in the case of polyhydric alcohols, which are mostly liquid substances, a reduced pressure distillation method is used to purify to a pure substance level. However, because it involves high temperatures, the probability of impurities forming during the process increases in the case of polyhydric alcohols, and as a result, even if reduced pressure distillation method is used, unpleasant odors may not be removed.

Therefore, in order to be applied to cosmetics, medicine, etc., colorless and odorless 2,3-butanediol is required. However, due to trace impurities not removed during the separation and purification process, the 2,3-butanediol stock solution has a yellowish-white color and a foul odor. can be paid.

Patent Document 3 discloses a method for decolorizing and deodorizing polyhydric alcohol and a decolorizing and deodorizing system. More specifically, a mixed solution containing the first polyhydric alcohol obtained through a separation process is prepared, and the mixed solution is distilled to preliminary remove foreign and off-flavor substances to produce a pretreatment solution. A method for decolorizing and decolorizing polyhydric alcohols that increases the removal rate of exotic and off-flavor substances through a combination of distillation treatment and adsorption treatment is reported.

Accordingly, the present inventors have made continuous efforts to implement an efficient purification method of 2,3-butanediol containing impurities produced by fermentation, and as a result, crude 2,3-butanediol containing impurities produced by fermentation has been purified. Impurities are converted to substances with higher molecular weight and removed through saponification and condensation reaction through strong alkali treatment, and the off-flavor substances remaining in small quantities are reduced through hydrogenation reaction and then processed through fractional distillation to achieve high purity and eliminate discoloration and off-flavor problems. The present invention was completed by simultaneously solving the problem and providing 2,3-butanediol of a quality suitable for use as a cosmetic raw material.

Republic of Korea Patent Publication No. 2016-0008756 (published on January 25, 2016) Republic of Korea Patent No. 1575717 (announced on December 8, 2015) Republic of Korea Patent Publication No. 2019-0014431 (published on February 12, 2019)

The purpose of the present invention is to provide a method for purifying 2,3-butanediol of a quality suitable for use as a cosmetic raw material from crude 2,3-butanediol containing impurities resulting from fermentation.

Another object of the present invention is to provide a method for purifying 2,3-butanediol that has high purity and simultaneously solves the problems of discoloration and off-flavor through an efficient and simple process in terms of economic efficiency.

In order to achieve the above object, the present invention involves adding a hydroxide containing an alkali metal to crude 2,3-butanediol containing impurities produced by fermentation, stirring while maintaining alkaline conditions, and adding a metal catalyst. Thus, a method for purifying 2,3-butanediol is provided by performing a reduction process by hydrogenation reaction and then distillation.

Specifically, the present invention is a saponification and condensation reaction under alkaline conditions in which crude 2,3-butanediol containing impurities produced by fermentation is added with a hydroxide containing an alkali metal, thereby converting the impurities into a substance with a higher molecular weight. A method for purifying 2,3-butanediol is provided, which includes converting and removing the impurities, subjecting a small amount of off-flavor-causing substances remaining through a hydrogenation reaction to a reduction process, and performing a fractional distillation process.

In the alkaline condition, after adding the hydroxide containing the alkali metal, the hydroxide containing the alkali metal may be additionally added so that the pH of the solution is maintained at a strong alkaline condition of 10 or more until the reaction is completed.

It is preferable that the hydroxide containing the alkali metal is added in a ratio of 0.1 to 10% by weight based on crude 2,3-butanediol.

The reduction process by the hydrogenation reaction uses a metal catalyst selected from the group consisting of a nickel-based catalyst, a catalyst activated by nickel, and a metal support.

The nickel-activated catalyst is a catalyst in which nickel has been activated with any one selected from the group consisting of zinc, aluminum, boron, silicon, organic acid, chromium, phosphorus, sodium, sulfur, and cobalt.

In addition, the metal carrier is one in which a rare earth metal is supported on activated carbon, and the rare earth metal is any one selected from the group consisting of nickel, cobalt, rhodium, palladium, and platinum.

The metal catalyst used in the reduction process by the hydrogenation reaction is preferably added at a ratio of 0.1 to 1% by weight based on crude 2,3-butanediol. At this time, for the hydrogenation reaction, a metal catalyst is added and hydrogen gas is added to maintain the pressure at 5 kgf/cm2 until the reaction is completed.

In the method for purifying 2,3-butanediol of the present invention, fractional distillation is performed under a vacuum of 5 to 10 torr at an internal temperature of 85 to 105°C of the reactor after removing impurities.

According to the purification method of 2,3-butanediol of the present invention, 2,3-butanediol is provided with high purity and simultaneously solves the problems of discoloration and off-odor, so that it can be used as a cosmetic raw material.

The purification method of the present invention is an efficient and simple process in terms of economic efficiency, and can provide 2,3-butanediol of a quality suitable for use as a cosmetic raw material.

Figure 1 shows the spectroscopic test results of crude 2,3-butanediol containing impurities used in the purification method of 2,3-butanediol of the present invention;
Figure 2 is a spectroscopic test result of 2,3-butanediol purified according to the purification method of the present invention;
Figure 3 is a photo result of the visually confirmed shape of 2,3-butanediol obtained according to the purification method of the present invention before (crude) and after (purification).

Hereinafter, the present invention will be described in detail.

The present invention provides a method for purifying crude 2,3-butanediol containing impurities produced by fermentation.

Figure 1 shows the spectroscopic test results of crude 2,3-butanediol containing impurities used in the purification method of 2,3-butanediol of the present invention, showing various impurities obtained during fermentation, such as carboxylic acid, aldehyde, Organic components such as ketone proteins can be confirmed.

The present invention relates to a method for purifying 2,3-butanediol, which decolorizes and deodorizes crude 2,3-butanediol containing impurities of various organic components produced by the above fermentation to a level suitable for cosmetic use. .

Accordingly, in the present invention, a hydroxide containing an alkali metal is added to crude 2,3-butanediol containing impurities produced by fermentation, stirred while maintaining alkaline conditions, and a metal catalyst is added to cause a hydrogenation reaction. A method for purifying 2,3-butanediol is provided, which involves distillation after a reduction process.

More preferably, the method for purifying 2,3-butanediol of the present invention is saponification and By condensation reaction, impurities become more polymerized. The first process to remove impurities,

After the above process, a second process of removing off-flavor-causing substances through a reduction process by hydrogenation reaction by adding a metal catalyst, and

After the above process, the third process is performed by fractional distillation of the solution from which impurities have been removed.

When explaining the purification method of 2,3-butanediol of the present invention by process, the first process is to purify crude 2,3-butanediol containing impurities into meso 2,3, which is three isomers produced as by-products during the fermentation process. -Butanediol, S,S-2,3-butanediol, and R,R-2,3-butanediol are commonly referred to as 2,3-butanediol, and are referred to as crude 2,3-butanediol.

As confirmed in Figure 1, crude 2,3-butanediol containing impurities in the first process is acetoin, acetaldehyde, butanone, organic acid, inorganic acid, and ketone ester as by-products generated during the fermentation process. This means that it contains various impurities such as polyvalent organic substances including aldehydes and proteins.

Therefore, it is a synthetic product with a 2,3-butanediol content of 50% by weight or more or an impurity of 1 to less than 50% by weight, or it is adopted and purified from a commercial product. The present invention purifies highly pure, colorless and odorless 2,3-butanediol from a mixture containing 50% by weight or more of crude 2,3-butanediol.

In the production method of the present invention, the first step is to react under alkaline conditions by adding a hydroxide containing an alkali metal to the crude 2,3-butanediol, and the alkaline conditions are from the introduction of a hydroxide containing an alkali metal. Until the completion of the reaction, the pH of the solution is maintained in a strongly alkaline condition of 10 or more, and more preferably, the pH of the solution is maintained at 10 to 13.5. In order to maintain the above conditions during the process, hydroxide containing an alkali metal can be additionally added. .

Additionally, in order to maintain the strong alkaline conditions during the process, it is preferable to use NaOH or KOH as the hydroxide containing an alkali metal.

The reaction in which strong alkali is added in the first process is carried out at a temperature not exceeding 90°C, and if the pH drops during the process, additionally added and reacted under alkaline conditions for 2 to 5 hours.

In the first step, the hydroxyl group of NaOH or KOH base is subjected to a saponification and condensation reaction with the carboxylic acid salt of the impurity in crude 2,3-butanediol by treatment with a strong alkali, thereby converting it into a material with a higher molecular weight. Remove. At this time, in the first process, it is preferable that the hydroxide containing alkali metal is added at a ratio of 0.1 to 10% by weight based on crude 2,3-butanediol. If the amount is less than 0.1% by weight, purification efficiency is reduced, and 10% by weight is added. If the percentage is exceeded, it is undesirable because an excessive amount is added beyond the stoichiometry required for the reaction.

In the purification method of the present invention, in the second process, after the above process, a metal catalyst is added to reduce and deodorize the off-odor-causing substances through a reduction process through a hydrogenation reaction.

In the second process, 10% of purified water and 0.1 to 1% by weight of a metal catalyst were added to crude 2,3-butanediol.

The metal catalyst may be any one selected from the group consisting of nickel-based catalysts, catalysts activated by nickel, and metal supports. Specifically, inexpensive nickel-based catalysts are most preferable.

The nickel-activated catalyst includes a catalyst made by activating nickel with any one selected from the group consisting of zinc, aluminum, boron, silicon, organic acid, chromium, phosphorus, sodium, sulfur, and cobalt.

Additionally, the metal support may also include a catalyst in which any one rare earth metal selected from the group consisting of nickel, cobalt, rhodium, palladium, and platinum is supported on activated carbon.

The hydrogenation reaction is adjusted to a pressure of 5kg/cm2 by adding hydrogen gas, and when the pressure in the reactor drops, additional hydrogen gas is added to maintain a pressure of 5kgf/cm2 to maintain a constant pressure, and no hydrogen gas is needed. The reaction ends at . The reduction reaction ends when hydrogen is added under a metal catalyst, that is, when no more hydrogen is absorbed.

After completion of the reaction, nitrogen gas is introduced into the reactor to replace the interior of the reactor with nitrogen.

In the purification method of the present invention, the internal temperature of the reactor performing the third process is between 85 and 105°C and fractional distillation is performed under a vacuum of 5 to 10 torr to remove substances such as moisture and odorous substances that initially appear. By removing it and receiving the main product, the desired purified 2,3-butanediol can be obtained.

Figure 2 is a spectroscopic test result of 2,3-butanediol purified according to the purification method of the present invention, showing impurities removed from crude 2,3-butanediol containing the impurities of Figure 1 according to the purification process. ,3-butanediol can be confirmed.

Figure 3 is a photo result of the visually confirmed shape of 2,3-butanediol obtained according to the purification method of the present invention before (crude) and after (purification), crude 2,3 in Figure 1 -Butanediol represents a yellowish solution, and 2,3-butanediol in a transparent (colorless) solution was confirmed with the naked eye after the purification process in Figure 2.

In addition, as a result of the sensory evaluation of the off-odor of the purified 2,3-butanediol solution, it was evaluated without unpleasant odor, thereby solving the problem of conventional discoloration and off-odor at the same time, and from the purification method of the present invention, it is colorless and odorless and has a high purity of 99.7% or more. The desired purified 2,3-butanediol can be obtained.

Hereinafter, the present invention will be described in more detail through examples.

These examples are intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to these examples.

<Example 1>

100 g of crude 2,3-butanediol containing 94% of 2,3-butanediol was placed in an autoclave equipped with a 1L stirrer, 3 g of NaOH and 10 g of purified water were added, the temperature was raised to 90°C, and the mixture was stirred for 2 hours. Afterwards, 0.1 g of activated carbon loaded with 1% Raney nickel was added, and the hydrogen cylinder was connected to an autoclave to completely replace the inside with hydrogen, and the internal pressure of the autoclave was maintained at 5 kg/cm2 for 10 hours. After completion of the reaction, the interior was replaced with nitrogen, and the contents in the autoclave were vacuum distilled to collect 10% of the primary stream and the remaining main stream to obtain colorless and odorless 2,3-butanediol with a purity of 99.5% or higher.

<Example 2>

100 g of crude 2,3-butanediol containing 90% by weight of 2,3-butanediol was placed in an autoclave equipped with a 1L stirrer, 3 g of NaOH and 10 g of purified water were added, the temperature was raised to 90°C, and the mixture was stirred for 2 hours. Afterwards, 0.1 g of activated carbon loaded with 1% palladium was added, and the hydrogen bomb was connected to the autoclave to completely replace the inside with hydrogen, and the internal pressure of the autoclave was maintained at 5 kg/cm2 for 10 hours. After completion of the reaction, the interior was replaced with nitrogen, and the contents in the autoclave were vacuum distilled to collect 10% of the primary stream and the remaining main stream to obtain colorless and odorless 2,3-butanediol with a purity of 99.5% or higher.

<Example 3>

100 g of crude 2,3-butanediol containing 94% by weight of 2,3-butanediol was placed in an autoclave equipped with a 1L stirrer, 3 g of NaOH and 10 g of purified water were added, the temperature was raised to 90°C, and the mixture was stirred for 2 hours. Afterwards, 0.2 g of activated carbon loaded with 0.5% rhodium was added, and the hydrogen bomb was connected to an autoclave to completely replace the inside with hydrogen and maintain the internal pressure of the autoclave at 5 kg/cm2 for 10 hours. After completion of the reaction, the interior was replaced with nitrogen, and the contents in the autoclave were vacuum distilled to collect 10% of the primary stream and the remaining main stream to obtain colorless and odorless 2,3-butanediol with a purity of 99.5% or higher.

<Example 4>

100 g of crude 2,3-butanediol containing 94% by weight of 2,3-butanediol was placed in an autoclave equipped with a 1L stirrer, 3 g of NaOH and 10 g of purified water were added, the temperature was raised to 90°C, and the mixture was stirred for 2 hours. After adding 0.1 g of Raney cobalt catalyst, the hydrogen cylinder was connected to the autoclave to completely replace the inside with hydrogen, and the internal pressure of the autoclave was maintained at 5 kg/cm2 for 10 hours. After the reaction was completed, the inside was replaced with nitrogen, and the contents in the autoclave were vacuum distilled to collect 10% of the primary stream and the remaining main stream to obtain colorless and odorless 2,3-butanediol with a purity of 99.5% or higher.

<Experimental Example 1>

1. Spectroscopic results

Using GC-Mass spectroscopy for crude 2,3-butanediol used in Example 1, Figure 1 shows the fraction of crude 2,3-butanediol containing impurities produced by fermentation before purification. This is an optical result, and Figure 2 shows the spectroscopic results of 2,3-butanediol after fractional distillation in the purification method of the present invention.

As a result, purification of 2,3-butanediol was confirmed by confirming that the impurity peak disappeared according to the 2,3-butanediol purification method of the present invention.

2. Sensory evaluation

The transparency of the solution at each stage of the purification method of 2,3-butanediol of the present invention performed in Example 1 was visually evaluated.

As a result, as shown in Figure 3, a yellowish solution of crude 2,3-butanediol was confirmed, and after purification of 2,3-butanediol obtained according to the purification method of the present invention, it was a transparent (colorless) solution to the naked eye. 2,3-butanediol was confirmed.

In addition, a sensory evaluation of off-flavor was performed on 2,3-butanediol purified from crude 2,3-butanediol using 10 trained researchers.

Specifically, 5 ml of 2,3-butanediol purified in Examples 1 to 4 was added to 95 ml of water maintained at 80°C, stirred, and evaluated by smell. At this time, odorless water was given a score of 10, and the score was calculated according to the degree of off-odor. As a control, a commercial product, 2,3-butanediol from Company G, was evaluated in the same manner.

As a result, the 2,3-butanediol obtained according to the method for purifying 2,3-butanediol of the present invention was transparent and colorless and odorless without any off-flavor, which is especially important as a cosmetic raw material.

In addition, the method for purifying 2,3-butanediol of the present invention is economical and can secure high purity at the level of 99.5%.

In the above, the present invention has been described in detail only with respect to the described embodiments, but it is clear to those skilled in the art that various changes and modifications are possible within the technical scope of the present invention, and it is natural that such changes and modifications fall within the scope of the appended patent claims.

Claims (10)

In crude 2,3-butanediol containing impurities produced by fermentation,
A method for purifying 2,3-butanediol in which a hydroxide containing an alkali metal is added, stirred while maintaining alkaline conditions, a metal catalyst is added, a reduction process is performed by hydrogenation, and then distillation is performed. The method of separating purified 2,3-butanediol according to claim 1, wherein hydroxide containing an alkali metal is additionally added so that the pH of the solution is maintained at a strong alkaline condition of 10 to 13.5 until the reaction is completed. . The method for separating purified 2,3-butanediol according to claim 1, wherein the hydroxide containing the alkali metal is added in a ratio of 0.1 to 10% by weight based on crude 2,3-butanediol. The method for separating purified 2,3-butanediol according to claim 1, wherein the metal catalyst is one selected from the group consisting of a nickel-based catalyst, a catalyst activated by nickel, and a metal support. The method of claim 4, wherein the nickel-activated catalyst is a nickel-activated catalyst selected from the group consisting of zinc, aluminum, boron, silicon, organic acid, chromium, phosphorus, sodium, sulfur, and cobalt. A method of separating purified 2,3-butanediol. The method for separating purified 2,3-butanediol according to claim 4, wherein the metal carrier is a rare earth metal supported on activated carbon. The method of separating purified 2,3-butanediol according to claim 6, wherein the rare earth metal is any one selected from the group consisting of nickel, cobalt, rhodium, palladium, and platinum. The method for separating purified 2,3-butanediol according to claim 1, wherein the metal catalyst is added at a ratio of 0.1 to 1% by weight based on crude 2,3-butanediol. The method of separating purified 2,3-butanediol according to claim 1, wherein the reduction process is performed by adding a metal catalyst and introducing hydrogen gas so that the pressure is maintained at 5 kgf/cm2 until the reaction is completed. The separation of purified 2,3-butanediol according to claim 1, wherein after the distillation in the third process removes impurities, fractional distillation is performed under 5 to 10 torr vacuum at an internal temperature of 85 to 105 ° C. of the reactor. method.