JPH06228052A - Production of high-purity polyglycerol ester of fatty acid - Google Patents

Abstract

PURPOSE:To obtain a high-purity polyglycerol ester of a fatty acid having excellent physical properties by readily and efficiently removing the unreacted polyglycerol from an esterification reactional product containing the unreacted polyglycerol according to the liquid-liquid extraction. CONSTITUTION:A polyglycerol is made to react with a fatty acid or an ester thereof to provide an esterification reactional product containing the unreacted polyglycerol. The resultant esterification reactional product is then subjected to the liquid-liquid extraction with a mixed solvent of methyl ethyl ketone with water at (10:90) to (90:10) weight ratio as an extracting solvent at 50-100 deg.C, preferably 60-90 deg.C temperature under conditions so as to provide the esterification reactional product in an amount of 25-100 pts.wt., preferably 45-75 pts.wt. based on 100 pts.wt. total amount of the methyl ethyl ketone and water. The resultant extract solution is separated into layers at >=50 deg.C to remove the unreacted polyglycerol into the aqueous phase. The methyl ethyl ketone is distilled away from the oily phase to afford the high-purity polyglycerol ester of the fatty acid. The reactional molar ratio of the fatty acid (ester) to the polyglycerol is preferably regulated to <=2 to carry out the reaction.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a polyglycerin fatty acid ester. The polyglycerin fatty acid ester obtained by the present invention is useful as a surfactant in the fields of food emulsifiers, detergents, film antifogging agents, cosmetics, pharmaceuticals and the like.

[0002]

2. Description of the Related Art Polyglycerin fatty acid ester is a surfactant approved as a food additive, and in recent years, its application field has expanded and its usage has increased. Polyglycerin fatty acid ester is obtained by reacting polyglycerin with a fatty acid or a fatty acid ester. The polyglycerin fatty acid ester is characterized in that an ester having a wide range of HLB can be obtained by variously selecting the polymerization degree of polyglycerin which is a hydrophilic group and the chain length of a fatty acid which is a hydrophobic group.

Since both polyglycerin fatty acid ester and polyglycerin have extremely high boiling points, they cannot be efficiently separated by a technique such as molecular distillation. Therefore, ordinary polyglycerin fatty acid ester contains unreacted polyglycerin. Are sold in the form of commercial products. This tendency is remarkable in a high HLB polyglycerol fatty acid ester having a small degree of esterification of polyglycerin. High HLB here
Means an HLB value of 10 or more. For example, in the case of a polyglycerin fatty acid ester having an HLB value of about 10, 20 to 40% of unreacted polyglycerin is contained.

Since unreacted polyglycerin itself does not have an emulsifying function, a product containing a large amount of unreacted polyglycerin has a reduced emulsifying ability per unit weight. A product containing a large amount of unreacted polyglycerin is a highly solid semi-solid product, and in actual use, operability such as weighing, mixing and dissolving is extremely poor. This tendency is remarkable in the polyglycerol fatty acid ester having a high HLB.

Furthermore, when such a product is used in a highly hydrophobic environment, polyglycerin easily separates, and therefore the amount used is limited. When an antifogging agent such as a stretch film is used, unreacted polyglycerin is
There are also problems such as adversely affecting the physical properties of the resin. As a method for removing unreacted polyglycerin from the esterification reaction product, for example, at least one selected from water-soluble organic solvents and water, and at least one selected from water-insoluble organic solvents A method of separating unreacted polyglycerin by liquid separation in combination with is proposed (JP-A-63-23837).

Examples of non-water-soluble organic solvents include hydrocarbons such as benzene, toluene, xylene, hexane and heptane, and many organic solvents such as diethyl ether, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate and chloroform. However, it is only benzene, toluene and xylene that the effect has been specifically confirmed. However, it is not preferable in terms of safety to use these aromatic hydrocarbons for the production of polyglycerin fatty acid ester for food emulsifiers.

On the other hand, the water-soluble solvent which is used in combination with the non-water-soluble organic solvent is also specifically used, such as methanol or water-containing ethanol, water-containing t-butanol, etc. The example used is not shown. According to the knowledge of the present inventors, when only water is used for a water-insoluble organic solvent such as benzene, toluene, xylene, etc., emulsion phase formation, three-phase separation, etc. are observed and there is a problem in liquid separation. Therefore, it cannot be used as an industrial separation means. This tendency is particularly remarkable when a polyglycerol fatty acid ester reaction solution having a high HLB is treated, and a microemulsion is also formed depending on the operating conditions.

As another method for removing unreacted polyglycerin, there is a method for removing unreacted polyglycerin by contacting and adsorbing a solution of an esterification reaction product with an alkylsilylated silica gel (JP-A-3-81252). Proposed. However, this method has a drawback that the operation cost is high and the operation is complicated.

[0009]

However, the conventional methods have several problems such as safety, operability, separation efficiency of unreacted polyglycerin, and operation cost, which are industrially applied. In view of these circumstances, the present invention is excellent in performing purification easily and efficiently in a step of removing unreacted polyglycerin by liquid-liquid extraction from an esterification reaction product containing unreacted polyglycerin, and performing purification at low cost. The purpose of the present invention is to provide a polyglycerin fatty acid ester having excellent physical properties.

[0010]

Means for Solving the Problems In the study of liquid-liquid extraction conditions for producing a polyglycerin fatty acid ester having a small amount of unreacted polyglycerin and excellent properties, the present inventors have used methyl ethyl ketone as an extraction solvent. Surprisingly, with water and water, liquid separation was performed without adding a salting-out agent only within the range of specific extraction operating conditions in which a high-concentration esterification reaction product was treated at a high extraction temperature with respect to the total amount of the solvent. We have found what is possible and have achieved that goal.

That is, according to the present invention, an esterification reaction product containing unreacted polyglycerin obtained by reacting polyglycerin with a fatty acid or a fatty acid ester is prepared from the following (a) and (b): A method for producing a high-purity polyglycerin fatty acid ester, which comprises contacting and mixing under the conditions, separating at 50 ° C. or higher to remove unreacted polyglycerin in an aqueous phase, and distilling off methyl ethyl ketone from the oil phase. Is provided. (A) Methyl ethyl ketone: water 10:90 to 90: 1
0 (weight ratio) (b) The amount of the esterification reaction product is 25 to 100 parts by weight with respect to the total amount of methyl ethyl ketone and water.

The present invention will be described in detail below. The method for producing polyglycerin in the present invention is not particularly limited, but it is usually obtained by adding a small amount of an acid or an alkali to glycerin as a catalyst and heating at a high temperature of 180 ° C. or higher under normal pressure or reduced pressure. If necessary, treatment such as neutralization and desalting is carried out after the reaction. The degree of polymerization of polyglycerin is not particularly limited as long as it is 2 or more, but an average degree of polymerization of 2 to 10 is particularly preferable. There are (n + 2) hydroxyl groups in one molecule of polyglycerol having an average degree of polymerization of n.

As the fatty acid raw material to be reacted with this polyglycerin, free fatty acid or its lower alkyl ester is used. The type of fatty acid is not particularly limited, and linear or branched, saturated or unsaturated fatty acid having 6 to 22 carbon atoms is preferably used. Further, a hydroxyl group-substituted fatty acid can also be used.
Examples of such fatty acid raw materials include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid,
Examples thereof include erucic acid, elaidic acid, ricinoleic acid, and methyl, ethyl, glycerin esters of these fatty acids, and fats and oils. The fatty acids may be used alone or in combination of two or more depending on the purpose.

The reaction molar ratio of fatty acid or fatty acid alkyl ester to polyglycerin in the present invention is not particularly limited, but is preferably selected from 2 or less. When the molar ratio exceeds 2, it is difficult to obtain the polyglycerol fatty acid ester with high HLB which is the object of the present invention. Also, if the number exceeds 2, the amount of unreacted polyglycerin to be removed decreases.
The need for separation is also reduced.

The esterification reaction of polyglycerin and fatty acid or transesterification reaction of fatty acid ester is
Usually, it is carried out at a high temperature of 130 ° C. or higher in the presence of an alkali catalyst to give a polyglycerol fatty acid ester having an average substitution rate of about 8 to 35%. As the system, either a reduced pressure system or a normal pressure system can be used. If necessary, neutralize after the reaction,
Process such as desalting. It is also possible to enzymatically esterify using a lipase or the like.

In the present invention, methyl ethyl ketone and water are used as the solvent for extracting the esterification reaction product in liquid form. Liquid ratio (weight ratio) of methyl ethyl ketone and water is 1
It is selected from the range of 0:90 to 90:10. It is preferably carried out in the range of 20:80 to 80:20. In the range other than this, methyl ethyl ketone or water will be insufficient, and upon extraction, the distribution to each phase will reach saturation and separation will be insufficient.

The amount of the esterification reaction product with respect to the total amount of methyl ethyl ketone and water is 25 to 100% by weight (20 to 50% by weight based on total), preferably 45 to 7%.
It is 5% by weight. On the lower concentration side (less than 25%), an emulsified phase is formed and it is difficult to perform liquid separation. On the high-concentration side (more than 100%), upon extraction, the distribution to each phase reaches saturation, resulting in insufficient separation.

As a method for mixing the esterification reaction product and the extraction solvent, the esterification reaction product is dispersed and dissolved in water and then mixed with methyl ethyl ketone, or conversely, after the esterification reaction product is dissolved in methyl ethyl ketone,
There are a method of mixing with water, a method of dissolving the esterification reaction product in a mixed solvent of methyl ethyl ketone and water, and the like, and any mixing method can achieve the object of the present invention.

Further, the extraction operation is carried out by using a device such as a mixer / settler combination, a multi-stage (perforated plate type, rotating disc type, etc.) countercurrent extractor. Extraction temperature is usually 50-1
It is carried out at 00 ° C, preferably 60 to 90 ° C. When the extraction temperature is 50 ° C. or lower, three-phase separation or an emulsified phase is formed and the liquid separation is insufficient. Further, when the temperature is 100 ° C. or higher, the azeotropic point of the extraction solvent is obviously exceeded, so that an extraction device having a pressure resistant structure is required, which leads to an increase in equipment costs and the like, which is not preferable.

That is, in any of the extraction conditions such as the liquid ratio of methyl ethyl ketone / water, the treatment amount of the esterification reaction product with respect to the extraction solvent, and the extraction operation temperature, the treatment is carried out outside the operation range satisfying all the above operation conditions. Doing so is not preferable because it causes inconveniences such as emulsion phase formation, three-phase separation, or microemulsion formation. The polyglycerin fatty acid ester treated as described above becomes a product through a solvent distillation step.

[0021]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. Example 1 57 g (0.2 mol) of stearic acid and 1.6 g of sodium carbonate were added to 758 g (1 mol) of polyglycerin having an average degree of polymerization of 10 and heated at 200 ° C. for 4 hours under a nitrogen stream. About 810 g of a pale yellow, highly adherent paste-like semi-solid was obtained.

To 100 g of this esterification reaction product (67% to the solvent), 75 g of methyl ethyl ketone was added,
After heating to 60 ° C. to dissolve it, 75 g of deionized water at 60 ° C. was added and thoroughly stirred and mixed. After 10 minutes of standing at the same temperature, the aqueous phase was separated and the oil phase was dried under reduced pressure to obtain about 15 g of pale yellow solid polyglycerol fatty acid ester. When the esterification reaction product and the polyglycerin fatty acid ester were subjected to gel filtration chromatography analysis under the following conditions, about 85 wt% of unreacted polyglycerin in the reaction solution was removed to 5 wt% after the extraction treatment. .

[0023]

[Table 1] (Gel filtration chromatography analysis conditions) Column: Tosoh G2000HXL x 2 Eluent: Tetrahydrofuran Flow rate: 0.5 ml / min Temperature: 40 ° C Detector: Differential refractometer

The average substitution rate of the polyglycerin fatty acid ester obtained by chemical analysis such as hydroxyl value and saponification value based on the standard oil and fat analysis test method (Japan Oil Chemistry Association) is 17
%, And the HLB value calculated from Griffin's formula is 1
It was 2.7. Griffin's formula HLB = 20 × M _H / M (M: molecular weight, M _H = hydrophilic partial molecular weight)

Example 2 57 g (0.2 mol) of oleic acid and 1.6 g of sodium carbonate were added to 758 g (1 mol) of polyglycerin having an average degree of polymerization of 10 and heated at 200 ° C. for 4 hours under a nitrogen stream. As a result, about 810 g of an orange liquid polyglycerin fatty acid ester was obtained.

75 g of methyl ethyl ketone was added to 100 g of this esterification reaction product (67% to the solvent),
After heating to 60 ° C. to dissolve it, 75 g of deionized water at 60 ° C. was added and thoroughly stirred and mixed. After 10 minutes of standing, the aqueous phase was separated and removed, the methyl ethyl ketone was distilled off from the oil phase, and the mixture was dried under reduced pressure to give a pale yellow solid polyglycerol fatty acid ester (about 17).
g was obtained.

When subjected to the same analysis as in Example 1, unreacted glycerin in the esterification reaction product was about 83% by weight, but about 5% by weight in the product polyglycerin fatty acid ester. The average substitution rate of the ester is 1
It was 4% and the HLB value was 13.6.

Example 3 To 462 g (1 mol) of polyglycerin having an average degree of polymerization of 6 were added 200 g (1 mol) of lauric acid and 1.3 g of sodium carbonate, and heated under a nitrogen stream at 200 ° C. for 4 hours. As a result, about 640 g of a pale yellow, highly adherent, paste-like semi-solid was obtained.

75 g of methyl ethyl ketone was added to 100 g of this esterification reaction product (67% to the solvent),
After heating to 60 ° C. to dissolve it, 75 g of deionized water at 60 ° C. was added and thoroughly stirred and mixed. After 10 minutes of standing at the same temperature, the aqueous phase was separated and the oil phase was evaporated to dryness under reduced pressure to obtain about 70 g of a pale yellow solid polyglycerol fatty acid ester. When the obtained polyglycerin fatty acid ester was subjected to the same analysis as in Example 1, about 30 wt% of unreacted polyglycerin in the reaction solution was removed to about 1 wt% or less. The average substitution rate of the polyglycerol fatty acid ester obtained by chemical analysis such as hydroxyl value and saponification value was 2 as in Example 1.
It was 1%, and the HLB value calculated from Griffin's formula was 11.4.

Comparative Example 1 120 g of benzene was added to 30 g of the esterification reaction product obtained in Example 1 (20% with respect to the solvent), and after thorough mixing,
When 30 g of demineralized water was added and mixed sufficiently with stirring and allowed to stand at room temperature, an emulsified phase was formed and liquid separation was impossible. The same was true when hexane or chloroform was used instead of benzene.

Comparative Example 2 To 30 g of the esterification reaction product obtained in Example 2 (20% with respect to the solvent) was added 120 g of toluene, and the mixture was heated to 40 ° C. and dissolved, and then 30 g of demineralized water at 40 ° C. When the mixture was added and mixed with sufficient stirring, an emulsified phase was formed and liquid separation was impossible.
The same was true when hexane or chloroform was used instead of toluene.

Comparative Example 3 To 8 g of the esterification reaction product obtained in Example 1 (5% to solvent), 75 g of methyl ethyl ketone was added, and 60
After heating to dissolve at 0 ° C. and dissolving, 75 g of deionized water at 60 ° C. was added and sufficiently stirred and mixed, whereby an emulsified phase was formed and liquid separation was impossible. Comparative Example 4 75 g of methyl ethyl ketone was added to 100 g of the esterification reaction product obtained in Example 1 (67% with respect to the solvent), heated at 40 ° C. and dissolved, and then demineralized water 75 at 40 ° C.
When g was added and mixed thoroughly with stirring, an emulsified phase was formed,
Separation was impossible. When this was heated to 60 ° C., it easily separated.

[0033]

According to the present invention, unreacted polyglycerin can be efficiently removed from polyglycerin fatty acid ester containing unreacted polyglycerin. The resulting polyglycerin fatty acid ester has excellent properties such as various inconveniences in use caused by the inclusion of unreacted polyglycerin, and high effective concentration as a surfactant.

With regard to the polyglycerol fatty acid ester having a high HLB having a saturated fatty acid having 14 or more carbon atoms, the present invention makes it possible to provide a product much easier to handle than the conventional product. Further, the method of the present invention does not require a large amount of equipment, the operation and maintenance costs are not only relatively small, but the separated unreacted polyglycerin is desalted because a salting-out agent is not added during liquid-liquid extraction. After purification, the product can be subjected to the esterification reaction again without requiring a great cost.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kosuke Ozaka Sanryo Kasei Co., Ltd. Research Institute, 1000, Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa

Claims (2)

[Claims] 1. An esterification reaction product containing unreacted polyglycerin obtained by reacting polyglycerin with a fatty acid or a fatty acid ester is brought into contact with methyl ethyl ketone and water under the following conditions (a) and (b). A method for producing a high-purity polyglycerin fatty acid ester, which comprises mixing and then separating the mixture at 50 ° C. or higher to remove unreacted polyglycerin in an aqueous phase and distilling off methyl ethyl ketone from the oil phase. (A) Methyl ethyl ketone: water 10:90 to 90: 1
0 (weight ratio) (b) The amount of the esterification reaction product is 25 to 100 parts by weight with respect to the total amount of methyl ethyl ketone and water. 2. The process according to claim 1, wherein the reaction molar ratio of fatty acid or fatty acid ester to polyglycerin is 2 or less.