KR100369117B1 - Method for manufacturing sugar ester and purifying thereof - Google Patents

Abstract

The present invention relates to a method for preparing a sugar ester and a simple purification method using water as a solvent, by using water instead of a highly toxic organic solvent as a solvent, the solvent does not remain in the product, water / low boiling point organic The present invention relates to a method for producing a sugar ester and a method for purifying the sugar ester, which can shorten the process and improve the yield by cooling and depositing only the sugar ester using a mixed solvent of a solvent.

Description

Method for manufacturing and purifying sugar ester using water as a solvent {Method for manufacturing sugar ester and purifying

The present invention relates to a method for preparing and purifying sugar esters (Sugar Ester), more specifically, toxic organic solvents such as dimethyl formamide (DMF), dimethyl sulfoxide (DMSO) By using water as a solvent but producing sugar ester (SE) under mild conditions such as solvent method, no toxic organic solvent remains in the product and no coloring phenomenon occurs.In addition, water / low boiling organic solvent mixed solvent is used for purification. The present invention relates to a method for producing a sugar ester and a method for purifying the sugar ester which can shorten the process and improve the yield by cooling and depositing only the sugar ester.

Sugar ester (SE) is excellent in emulsification, foamability, washability and solubility, and exhibits a wide range of HLB (hydrophilic-lipophilic balance) so that the surfactant activity is very good.

In addition, sugar esters are not irritating to eyes or skin, have excellent biodegradability, do not cause environmental pollution, and are used in a wide range of applications such as foods, drugs, detergents and cosmetics since they are tasteless, odorless, non-toxic surfactants.

In general, the synthesis process of sugar esters known to date is divided into a solvent method (Solvent method) and a solvent-free method (Solvent-free method).

According to the solvent method shown in European Patent No. 03449849, solid sugar (Sucrose), fatty acid methyl ester, alkali catalyst is used as a solvent to make a liquid phase and the fatty acid methyl ester is transesterified to sugar. A method for synthesizing esters has been proposed. Until recently, toxic organic solvents remained in the final product by using toxic organic solvents such as dimethylformamide, dimethyl sulfoxide, and pyridine as solvents.

As a method for solving this problem, a new purification method is disclosed in Korean Patent Application No. 98-13820, but this method uses a sugar ester prepared by the solvent method and the mixture is dried and then pulverized and powdered. It was composed of complex processes such as filtration, dispersion and washing in neutral salt aqueous solution, and filtration was not complete solution.

In addition, British Patent No. 2256869 discloses a solvent-free method, in which sugar esters are synthesized by using sugar esters as solubilizers in sugar, fatty acid methyl esters, and soaps without using toxic organic solvents such as dimethylformamide. Here's how.

However, this method has a problem that the reaction conditions are very demanding compared to the solvent method and the yield of the produced sugar ester is low as shown in Table 1 below.

Comparison of sugar ester manufacturing conditions Article Law Article Conditions Solvent Law Solvent Law 80 to 150 ° C, 15 to 20 torr 160 to 180 ° C, 0.1 to 3 torr

In addition, also in the purification method, the sugar ester purification method disclosed in the above-mentioned British Patent No. 2256869 and European Patent No. 0349849 is a layer separation method using a large amount of organic solvent to separate the water and the organic solvent layer and then It is a method for purifying the sugar ester solution of the solvent layer, the process is very complicated and requires a number of repeated operations, and because a large amount of solvent is used, the recovery rate is low, the solvent ratio is high, it takes a lot of costs.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for producing a sugar ester in which the reaction conditions are milder than the solvent-free method, and no toxic organic solvent remains in the product and coloration does not occur. .

Another object of the present invention is to provide a method for purifying sugar esters by simple cooling and precipitation.

The above objects of the present invention are used in the manufacture of sugar esters, instead of toxic organic solvents such as dimethylformamide and dimethyl sulfoxide, using water as a solvent, using soap and sugar ester as a compatibilizer, and refining This is achieved by using a mixed solvent of water / low boiling organic solvent in which the sugar ester acts as a reactant while being a compatibilizer. The production and purification method of the above-mentioned sugar ester has the advantage that the process is not complicated and the cost is reduced and the yield of sugar ester is high.

The present invention relates to a method for preparing and purifying a sugar ester, wherein the sugar ester having a high degree of substitution having a monomer content of 20% or less in an aqueous solution containing an alkali catalyst and soap (hereinafter referred to as Sugar ester having a high degree of substitution) Providing a method of preparing a sugar ester having a low degree of substitution (hereinafter referred to as SE-L) having a monomer content of 30% or more by reacting sugar with SE-H). It is.

In addition, the present invention is a high-substituted sugar ester (SE-H) by reacting the low-substituted sugar ester (SE-L) prepared as described above with a fatty acid methyl ester in the presence of an alkali catalyst and soap. It is to provide a method for producing ().

Furthermore, the present invention provides a method for purifying sugar esters by adding a mixed solvent of water / low boiling point organic solvent to the sugar ester mixture prepared as described above, raising the temperature to dissolve it, and then cooling and precipitation it.

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

In the manufacturing process of low-substituted sugar ester (SE-L), a low-substituted sugar ester is obtained by transesterification of sugar and highly substituted sugar ester (SE-H) in an aqueous solution containing an alkali catalyst and soap. (SE-L) is prepared.

First, the sugar, the soap, and the catalyst are dissolved in water at 40 to 60 ° C., and the aqueous solution and the highly substituted sugar ester (SE-H) are adjusted to a mole ratio of sugar / sugar ester of 0.1 to 20. 60-180 ° C., pressure was reacted under reduced pressure (0.1-760 torr) or pressurized condition to blow water vapor in an inert gas, preferably at a temperature of 90-130 ° C. and a pressure of 100-400 torr for 4 to 20 hours. A low ester sugar ester (SE-L) having a monomer content of 30 to 70% is prepared.

At this time, if the reaction temperature is less than 60 ℃ slow water removal rate is high water concentration during the reaction and there is a disadvantage that promotes the side reaction of water and sugar esters resulting in fatty acids are produced, which increases the acid value of the product. If the reaction temperature exceeds 180 ℃ coloration phenomenon occurs due to the carbonization of sugar. When the pressure is less than 0.1 Torr during the reaction, the removal rate of the reactants decreases due to the rapid removal of water from the reaction system, thereby lowering the compatibility of the reactants.

In addition, the low-substituted sugar ester (SE-L) prepared as described above has a molar ratio of fatty acid methyl ester / sugar ester of 0.1 to 10, and the lower-substituted sugar in the presence of fatty acid methyl ester, soap, and catalyst. When the reaction is carried out under the same reaction conditions as in the preparation of the ester (SE-L), a sugar ester having a high degree of substitution (SE-H) is produced.

The soap used in the present invention is characterized in that 1 to 15% by weight is added as fatty acid alkali metal salt or fatty acid alkaline earth metal salt having a fatty acid chain of C ₃ to C ₁₈ . In this case, when the content of soap is less than 1% by weight, the role of the compatibilizer does not sufficiently perform the reaction of the sugar esters and the sugar does not occur, and when the content exceeds 15% by weight, the yield is lowered during purification, resulting in low productivity. There are disadvantages.

The catalyst is sodium hydroxide, sodium carbonate, sodium acetate, potassium hydroxide, potassium carbonate, potassium acetate, zinc acetate And at least one selected from calcium carbonate is added in an amount of 0.1 to 2% of the total weight. If the amount of the added catalyst is less than 0.1% by weight, the conversion rate decreases due to the decrease in reaction rate and the process time is long, and when the content of the catalyst is more than 2% by weight, the salt of the catalyst and fatty acid is generated, which makes it difficult to purify. .

In addition, the fatty acid methyl ester has a fatty acid chain group of C ₁₂ , C ₁₄ , C ₁₆ , C ₁₈ , C ₂₀ and is preferably added so that the molar ratio of fatty acid methyl ester / sugar ester is 0.1 to 10, and is used as a solvent. Water is preferably added in an amount of 10 to 100% by weight based on the sugar used. If the water content is less than 10% by weight, the sugar is not completely dissolved. Fatty acid is generated by the reaction to increase the acid value of the product.

The sugar ester thus prepared may be purified by a simple method according to the present invention.

First, the obtained sugar ester composite is dissolved by adding a mixed solvent of water and a low boiling organic solvent such as methanol, ethanol, acetone, isopropyl alcohol, butanol or hexane and raising the temperature.

At this time, the mixing ratio of water / low boiling organic solvent is 1/5 to 5/1 (weight ratio), preferably 1/3 to 3/1, and the mixed organic solvent is 1 to 10 times to the reaction product, preferably Is added to 1 to 5 times, the temperature is raised to 40 to 60 ℃ completely dissolved and then cooled to -10 to 30 ℃. In this case, when the cooling is performed, crystals are precipitated. The precipitated crystals are filtered to remove the solvent and dried to obtain sugar esters, thereby reducing solvent cost and improving yield of sugar esters.

The following Table 2 shows the dissolution characteristics of the reaction composition during the preparation of the sugar esters. When a mixture of water / low boiling organic solvent is added to the reaction composition to raise the temperature, all the composites are dissolved. It can be seen that the sugar ester can be separated through the process.

Dissolution Characteristics of Reaction Compositions Reaction water Water / Low Boiling Organic Solvent (40 ~ 60 ℃) Water / Low Boiling Organic Solvent (-10 ~ 30 ℃) Unreacted sugar ester fatty acid methyl ester unreacted sugar catalyst ○○○○○ Ｘ ○○○○

Hereinafter, an embodiment of the present invention will be described in detail, but the present invention is not limited thereto.

Example

Example 1

1. In a four-necked reactor equipped with a thermometer, a stirrer, and a pressure reducing device, 100 g of a sugar ester (SE-H) having a monomer content of 6% was added thereto, and the temperature was raised to 60 ° C.

2. A sugar solution in which 100 g of sugar, 2 g of potassium hydroxide (KOH) and 10 g of potassium acetate was dissolved in 40 g of water was added to the reactor and reacted at 110 ° C. at 200 torr for 12 hours.

3. 600 g of a mixed solvent of water / ethanol mixed at 1/3 (weight ratio) was added to the reaction product obtained above, and the resultant was completely dissolved by stirring at 60 ° C. for 3 hours.

4. The solution was left at a low temperature (-10 to 30 ° C.), and the precipitated powder was filtered and dried to obtain 188 g of sugar ester (88.6% yield) of the powder. The composition was mono 28%, di 36%, tree 24 %, Tetra 8%, penta 4%.

Table 3 shows the analysis results of the composite obtained in Example 1.

Item Contents Test Methods External sugar ester content (%) Acid value (mgKOH / g) Water (%) Free suger (%) Chromium (Cr), Lead (Pb) (ppm) Light Yellow Powder98.5% 1.00.90.6 Undetected Analysis by LC Analysis by Karl Fisher Titration Analysis by AA

Example 2

1. In the same device as in Example 1, a solution prepared by completely dissolving 10 g of potassium acetate, 400 g of sugar, and 8 g of potassium hydroxide in 140 g of water was added to 100 g of sugar ester (SE-H) having a monomer content of 6%. The reaction was carried out under the same reaction conditions as 1.

2. 1500 g of a mixed solvent of water / ethanol mixed at 1/3 (weight ratio) was added to the reaction product obtained above, and the mixture was stirred at 60 ° C. for 3 hours to completely dissolve it.

3. The solution was left at a low temperature (-10 to 30 ° C.), and the precipitated powder was filtered and dried to obtain 373 g of sugar ester (yield 72.0%) of the powder. The composition was 64% mono, 28% di, 4 %, Tetra 4%.

Table 4 shows the analysis results of the composite obtained in Example 2 above.

Item Contents Test Methods External sugar ester content (%) Acid value (mgKOH / g) Water (%) Free suger (%) Chromium (Cr), Lead (Pb) (ppm) Light Yellow Powder98.4% 1.01.00.6 Undetected Analysis by LC Analysis by Karl Fisher Titration Analysis by AA

Example 3

1. To 70 g of the product obtained in Example 2, 10 g of potassium acetate, 40 g of methyl stearate, and 1 g of potassium hydroxide were added and reacted under the same reaction conditions as in Example 1.

2. To the reaction product obtained above, 600g of the mixed solvent which mixed water / ethanol in 3/1 (weight ratio) was added, and it stirred for 4 hours at 60 degreeC, and completely dissolved.

3. The solution was left at a low temperature (-10 to 30 ° C.), and the precipitated powder was filtered and dried to obtain 93 g of a sugar ester (yield 76.9%). The composition was mono 1%, di 10%, tree 15 %, Tetra 17%, penta 57%.

Table 5 shows the analysis results of the composite obtained in Example 3.

Item Contents Test Methods External sugar ester content (%) Acid value (mgKOH / g) Water (%) Free suger (%) Chromium (Cr), Lead (Pb) (ppm) Light Yellow Powder98.4% 0.51.10.4Not Detected Analysis by LC Analysis by Karl Fisher Titration Analysis by AA

The present invention is to produce a sugar ester (SE) under mild conditions such as solvent method while using water as a solvent instead of toxic organic solvents such as dimethylformamide and dimethyl sulfoxide, the coloring phenomenon without remaining in the product Since it does not occur, the sugar ester of high quality can be manufactured and used as additives, emulsifiers and dispersing agents for foods, cosmetics and medicines, and the purification is completed by cooling and precipitation using a mixed solvent of water / low boiling point organic solvents. Therefore, the process is greatly shortened and the cost is reduced, and the yield of sugar ester is very high.

Claims (13)

Low-substituted sugar having a monomer content of 30% or more by reacting sugar with a highly substituted sugar ester (SE-H) having a monomer content of 20% or less in an aqueous solution containing an alkali catalyst and soap. Process for producing sugar ester using water as solvent to obtain ester (SE-L) The method of claim 1, wherein the mole ratio of the sugar / sugar ester (SE-H) is 0.1 to 20, wherein the sugar ester using water as a solvent. The method of claim 1, wherein the water used as the solvent is 10 to 100% by weight based on the sugar used. According to claim 1, wherein the alkali catalyst is sodium hydroxide (sodium hydroxide), sodium carbonate (sodium carbonate), sodium acetate (sodium acetate), potassium hydroxide (potassium hydroxide), potassium carbonate, potassium acetate (potassium acetate) ), Zinc acetate, calcium carbonate (calcium carbonate) is one or more selected from 0.1 to 2% by weight, characterized in that the method for producing a sugar ester using water as a solvent. The method of claim 1, wherein the soap (soap) is 1 to 15% by weight of a fatty acid alkali metal salt or fatty acid alkaline earth metal salt having a fatty acid chain of C _{3 ~} C ₁₈ , the sugar ester of using water as a solvent Manufacturing method. The water of the solvent of claim 1, wherein the reaction is carried out at a temperature of 60 to 180 ° C. under reduced pressure (0.1 to 760 torr) or for 4 to 20 hours under pressurized conditions for blowing water vapor with an inert gas. Method for producing a sugar ester. The method for producing a sugar ester using water as a solvent according to claim 6, wherein the reaction temperature is 90 to 130 ° C and the reaction pressure is 100 to 400 torr. A mixed solvent of water and a low boiling point organic solvent is added to the sugar ester prepared by the method of any one of claims 1 to 7, and then dissolved by raising the temperature and then cooled to precipitate and dry the sugar ester. Purification method of sugar ester using water as a solvent. 10. The method according to claim 8, wherein the mixing ratio of the water / low boiling point organic solvent is 1/5 to 5/1 (weight ratio) and added to the reaction product so that it is 1 to 10 times, and the temperature is increased to 40 to 60 ° C to completely dissolve it. It is then cooled to -10 ~ 30 ℃, characterized in that the purification method of the sugar ester using water as a solvent. 10. The sugar ester according to claim 9, wherein the water / low boiling point organic solvent is added at a ratio of 1/3 to 3/1 (weight ratio) to the reaction product by 1 to 5 times. Purification method. The method of claim 8, wherein the organic solvent is at least one selected from methanol, ethanol, acetone, isopropyl alcohol, butanol and hexane. Low-substituted sugar ester (SE-L) having a monomer content of 30% or more is reacted with fatty acid methyl ester in the presence of an alkali catalyst and soap to obtain 20% monomer content. The manufacturing method of the sugar ester using water as a solvent which obtains the sugar ester with high substitution degree (SE-H) which is the following. 13. The solvent according to claim 12, wherein the fatty acid methyl ester has a C ₁₂ , C ₁₄ , C ₁₆ , C ₁₈ , C ₂₀ fatty acid chain group, and the molar ratio of fatty acid methyl ester / sugar ester is 0.1 to 10. Method for producing a sugar ester using water.