JP2003104936A - Method for producing fatty acid hydroxycarboxylic acid ester salt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrial method by which a fatty acid hydroxycarboxylic acid ester salt can be produced in a high purity at a low cost. SOLUTION: This method for producing the fatty acid hydroxycarboxylic acid ester salt comprises bringing a hydroxycarboxylic acid into contact with an alkali catalyst and then reacting the product with a long chain fatty acid lower alcohol ester.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a fatty acid hydroxycarboxylic acid ester salt. More specifically, the present invention relates to a method for industrially and easily producing a fatty acid hydroxycarboxylic acid ester salt.

[0002]

BACKGROUND OF THE INVENTION Fatty acid hydroxycarboxylic acid ester salts are anionic surfactants, and in particular, fatty acid lactic acid esters are used as emulsifiers in foods and cosmetics (JP-A-1-6237, JP-A-hei-6237). 2-25412). The fatty acid lactic acid ester salt exhibits excellent surface-active ability in the pH range of the neutral range in the aqueous solution form. Further, it has a characteristic that it has a relatively low Kraft point and is excellent in storage stability at a temperature of room temperature or higher (JP-A-8-1).
No. 76068).

As its production method, a method of directly esterifying a long-chain carboxylic acid and a hydroxycarboxylic acid in the presence of an alkali catalyst (US Pat. No. 2,733,252) and an acid chloride of a long-chain carboxylic acid Method of reacting with hydroxycarboxylic acid or a salt thereof (JP-A-9-20
8448) and a method of transesterifying a long-chain carboxylic acid lower alcohol ester and a hydroxycarboxylic acid salt in an organic solvent in the presence of a nonionic or anionic surfactant (JP-A-7-324402).

In the conventional direct esterification method, in addition to the target fatty acid hydroxycarboxylic acid ester, a considerable amount of the hydroxycarboxylic acid or salt thereof used as the raw material remains. In addition, hydroxycarboxylic acid is very easy to polymerize under this reaction condition, and the product includes polymerized hydroxycarboxylic acid and fatty acid ester derived from polymerized hydroxycarboxylic acid. Therefore, the purity of the target hydroxycarboxylic acid ester salt becomes low. In the acid chloride method, the reaction rate of the target fatty acid hydroxycarboxylic acid ester is improved to some extent, and the target product is further purified and highly purified by extraction. However, in the acid chloride method, industrialization is not preferable in terms of cost because of the problem of equipment corrosion.

[0005]

Further, a transesterification method in an organic solvent has been reported. In this method, the solubility of the alkali catalyst in the system is low, and in the solvent reaction, the alkali catalyst is a raw material fatty acid. Since the alcohol ester is consumed for saponification, the amount of the net catalyst acting as a catalyst decreases, resulting in a problem that the reaction rate becomes slow. In view of these problems of the prior art, the present invention has an object to provide an industrial method capable of producing a fatty acid hydroxycarboxylic acid ester salt with high purity and at low cost.

[0006]

As a result of intensive studies to solve the above problems, the present inventors have conducted a transesterification reaction between a hydroxycarboxylic acid salt and a long-chain fatty acid lower alcohol ester in the presence of an alkali catalyst. By
It was found that the fatty acid hydroxycarboxylic acid ester salt can be obtained with good productivity by preventing the polymerization of the raw material hydroxycarboxylic acid salt, and that the amount of soap by-produced in the solvent method can be suppressed. The present invention has been provided.

That is, the present invention provides a method for producing a fatty acid hydroxycarboxylic acid ester salt by reacting a hydroxycarboxylic acid salt with a long-chain fatty acid lower alcohol ester, wherein the hydroxycarboxylic acid salt is an alkali metal or alkaline earth metal salt. A mixture obtained from at least one compound selected from carbonates, bicarbonates or hydroxides, and a hydroxycarboxylic acid, wherein the equivalent ratio m of the alkali metal and the alkaline earth metal to the carboxyl group of the hydroxycarboxylate is m. Is 1 <m ≦ 1.5, and a method for producing a fatty acid hydroxycarboxylic acid ester salt is provided.

In the production method of the present invention, the hydroxycarboxylic acid salt and the long-chain fatty acid lower alcohol ester can be transesterified in an organic solvent or without a solvent. Further, the hydroxycarboxylic acid salt can be transesterified with the long-chain fatty acid lower alcohol ester in a state of being desolvent-dried into a granule or a powder. further,
The hydroxycarboxylic acid salt can also be transesterified with the long chain fatty acid lower alcohol ester in solution. In the production method of the present invention, it is preferable that the hydroxycarboxylic acid salt and the long-chain fatty acid lower alcohol ester are transesterified in the presence of a nonionic or anionic surfactant. The amount of the nonionic or anionic surfactant used is preferably 0.05 mol times or more based on the hydroxycarboxylic acid salt. The reaction between the long-chain fatty acid lower alcohol ester and the hydroxycarboxylic acid salt is preferably carried out at 60 to 200 ° C. under atmospheric pressure or reduced pressure under an inert gas stream.

Further, in the production method of the present invention, it is preferable to use the long-chain fatty acid lower alcohol ester in an amount of 0.1 to 5 mole times with respect to the hydroxycarboxylic acid salt. Also,
It is preferable to react the long-chain fatty acid lower alcohol ester with the hydroxycarboxylic acid salt to remove the residual fatty acid lower alcohol ester or hydroxycarboxylic acid salt from the reaction mixture. The hydroxycarboxylic acid salt used in the production method of the present invention is preferably a lactate salt, a tartrate salt, a malate salt, or a citrate salt, and the long-chain fatty acid lower alcohol ester is a saturated or unsaturated C8 to C22 ester. It is preferably a lower alcohol ester of carboxylic acid.

The present invention also provides a fatty acid hydroxycarboxylic acid ester salt produced by the above production method, which is characterized by containing no polymer.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for producing the fatty acid hydroxycarboxylic acid ester salt of the present invention will be described in detail. In addition, in this specification, "-" is used in the meaning including the numerical value described before and after that as a lower limit and an upper limit.

The hydroxycarboxylic acid salt used in the present invention is a mixture obtained from at least one compound selected from alkali metal and alkaline earth metal carbonates, bicarbonates or hydroxide compounds, and a hydroxycarboxylic acid. is there. Equivalent ratio of alkali metal and alkaline earth metal to carboxyl group of hydroxycarboxylate m
Is 1 <m ≦ 1.5. The lower limit is preferably 1.05 ≦ m, more preferably 1.1 ≦ m. The upper limit is preferably m ≦ 1.3, and m ≦
More preferably, it is 1.25. When m ≦ 1, the conversion of hydroxycarboxylate becomes insufficient, and 1.5 <
In m, the amount of soap by-produced by the reaction with the long-chain fatty acid lower alcohol ester increases.

Examples of the hydroxycarboxylic acid include lactic acid, tartaric acid, malic acid and citric acid. All of them can be obtained by the fermentation method or the synthetic method, and those having high purity are desirable.

In the production method of the present invention, at least one compound selected from carbonates, bicarbonates or hydroxides of alkali metals and alkaline earth metals and hydroxycarboxylic acid are provided in the above equivalent ratio. May be directly mixed with the above, or may be adjusted to have the above-mentioned equivalent ratio after forming the hydroxycarboxylic acid salt in advance. Usually, when mixing, it is dissolved in a suitable solvent, but water is preferable as the solvent. Usually, at the time of mixing, any of reduced pressure, normal pressure and increased pressure may be used, and the temperature may be in the range of normal temperature to 200 ° C., but may be appropriately selected depending on the solvent used.

The hydroxycarboxylic acid salt thus obtained is reacted with the long-chain fatty acid lower alcohol ester in either a solution, a concentrated solution in which a part of the solvent is removed, or a solid in which the solvent is removed and dried. Can be used for When the solvent is removed to obtain a dried solid, granules or powders are preferable because they are easy to handle.

In the present invention, a lower alcohol ester of a saturated or unsaturated fatty acid having 8 to 22 carbon atoms is used as the long chain fatty acid lower alcohol ester. The fatty acid species may have a branch. Fatty acids corresponding to this include caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, elaidic acid, behenic acid, erucic acid and the like. Further, as the lower alcohol, 1 having 1 to 4 carbon atoms is used.
Grade alcohol is preferred. Corresponding lower alcohols include methanol, ethanol, propanol,
Butanol and the like can be mentioned. These long-chain fatty acid lower alcohol esters can also be used as a mixture having the corresponding carbon number. Long chain fatty acid lower alcohol ester is 0.1 to 5 relative to hydroxycarboxylic acid salt.
Use the mole times.

In the production method of the present invention, a hydroxycarboxylic acid salt is reacted with a long-chain fatty acid lower alcohol ester in an organic solvent or without a solvent. As the organic solvent, tertiary amines, amides, or dialkyl sulfoxides are desirable.

In the case of a solvent-free reaction, it is possible to add it dropwise to a long-chain fatty acid lower alcohol ester in a state of being dissolved in a suitable solvent such as an aqueous solution. It is desirable that the solvent in the dropped solution be instantly vaporized and removed from the system. By keeping the water content in the reaction system low in the dehydrated and dried state,
It is possible to reduce the amount of soap produced as a by-product. However, depending on the physical properties of the hydroxycarboxylic acid salt, the state of being dissolved in an appropriate solvent has the advantage of easier preparation.

The reaction of the long-chain fatty acid lower alcohol ester with the hydroxycarboxylic acid salt may be carried out in the presence of a nonionic or anionic surfactant. Nonionic surfactants corresponding to this include sucrose fatty acid ester, glycerin fatty acid ester and organic acid ester derivatives thereof,
Examples thereof include polyglycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, and other polyhydric alcohol ester types. Examples of the anionic surfactant include fatty acid soap. During the transesterification reaction, a fatty acid soap derived from a long-chain fatty acid lower alcohol ester is by-produced and plays a role of a surfactant. However, by adding the above-mentioned surfactant in the reaction system in advance,
It is possible to increase the initial rate of the transesterification reaction. It is more preferable to use the target fatty acid hydroxycarboxylic acid ester salt as the surfactant, since other surfactants do not remain as impurities in the product.

The reaction temperature depends on the presence or absence of a solvent. In the absence of solvent, in order to homogenize the hydroxycarboxylic acid salt and the long-chain fatty acid lower alcohol ester, 120 to 200 ° C
Is desirable. When the reaction is carried out in an organic solvent, the organic solvent plays a role of homogenizing the system, so that the reaction can be carried out at a relatively low temperature, preferably 60 to 1
It is 20 ° C.

The pressure during the reaction is usually 100 Torr or less, preferably 60 Torr or less. It is desirable to carry out while distilling off the by-product methanol. In particular,
In the case of the reaction in an organic solvent, it is desirable to connect a condenser to the upper part of the reactor, separate the solvent and by-produced methanol, and reflux only the solvent to the reactor.

In the production method of the present invention, the hydroxycarboxylic acid salt is previously brought into contact with an alkali catalyst to give an active hydroxycarboxylic acid salt, which is reacted with a long-chain fatty acid lower alcohol ester. As compared with the case where the acid salt and the alkali catalyst are separately added to the long-chain fatty acid lower alcohol ester, the fatty acid hydroxycarboxylic acid ester salt can be obtained with higher productivity, and in the solvent method, the by-produced soap is produced. It is possible to reduce the amount.

In the production method of the present invention, a polymerization product derived from hydroxycarboxylic acid is not by-produced. Depending on the application, from the obtained reaction mixture, the residual hydroxycarboxylic acid salt or the long-chain fatty acid lower alcohol ester, if it is an organic solvent reaction, by removing the solvent together,
The target fatty acid hydroxycarboxylic acid ester salt can be obtained in high purity.

After the reaction, the residual fatty acid alcohol ester is removed from the reaction mixture if necessary. The method for removing the fatty acid alcohol ester may be either distillation or extraction. Desirably, it is distillation, and more preferably, it is distilled off using a thin film evaporator.

After the reaction, the residual hydroxycarboxylic acid salt is removed from the reaction mixture if necessary. Extraction is the preferred method of removal. By refining the above reaction mixture, the target fatty acid hydroxycarboxylic acid ester salt can be obtained with a high purity of 80% or more. The term "fatty acid hydroxycarboxylic acid ester salt" as used herein means a monoester carboxylic acid salt of one molecule of hydroxycarboxylic acid and one molecule of fatty acid. It does not include a compound having a moiety in which two or more molecules of hydroxycarboxylic acid are polymerized.

As described above, according to the production method of the present invention, a highly pure fatty acid hydroxycarboxylic acid ester salt can be efficiently obtained at low cost. The fatty acid hydroxycarboxylic acid ester salt provided by the production method of the present invention is widely used as an anionic surfactant. In particular, fatty acid lactic acid esters are used as emulsifiers in foods and cosmetics.

[0027]

EXAMPLES The features of the present invention will be described more specifically below with reference to examples and comparative examples. Materials shown in the following examples,
The usage amount, ratio, processing content, processing procedure, etc. can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be limitedly interpreted by the following specific examples.

Example 1 Sodium lactate (purity 60
%) 38.5 g, KOH 2.8 g was added, and 180 ° C.
It was dehydrated at 5 Torr. The obtained sodium lactate was pulverized and dried under a nitrogen atmosphere. 176.9 g of lauric acid methyl ester was charged into a reaction vessel, and pulverized and dried sodium lactate was added at 150 ° C. 150 ° C, 60 Tor
The reaction was carried out at r for 6 hours. Sodium lactate conversion rate 69%
Thus, a reaction mixture containing 21% by weight of sodium lactate laurate was obtained. Using a thin film evaporator from the reaction mixture,
The residual fatty acid methyl ester was distilled off. The amount of liquid supplied to the thin film evaporator is 120 (kg / h), the operating temperature is 150 ° C,
The pressure was 0.01 (kPa (abs)). Sodium lauric acid lactate 75%, Lauric acid soap 12
% And sodium lactate 13% were obtained. For quantitative analysis, the obtained reaction mixture was treated directly or by trimethylsilylation, and the composition was analyzed by gas chromatography. Silicone OV-17 as analytical column
-Thermon 3000 was used.

Comparative Example 1 176.9 g of lauric acid methyl ester was charged into a reaction vessel, and at 150 ° C., 23.11 g of sodium lactate and 2.8 g of KOH were added. 150
The reaction was carried out at 60 ° C. and 60 Torr for 6 hours. A reaction mixture containing 17% by weight of sodium laurate was obtained at a conversion of sodium lactate of 54%. Residual fatty acid methyl ester was distilled off from the reaction mixture using a thin film evaporator. The amount of liquid supplied to the thin film evaporator was 120 (kg / h), the operating temperature was 150 ° C., and the pressure was 0.01 (kPa (abs)). Sodium laurate lactate 65%, laurate soap 14% and sodium lactate 21% were obtained. The reaction mixture was analyzed in the same manner as in Example 1.

Example 2 Sodium lactate (purity 60
%) 38.5 g to which 2.8 g of KOH was added to obtain an aqueous solution of sodium lactate. 176.9 g of lauric acid methyl ester was charged into a reaction vessel, and an aqueous sodium lactate solution was added dropwise at 150 ° C. and 60 Torr over 4 hours. 150
The reaction was carried out at 60 ° C. and 60 Torr for 6 hours. A reaction mixture containing 20% by weight of sodium lactate laurate with a conversion of sodium lactate of 64% was obtained. Residual fatty acid methyl ester was distilled off from the reaction mixture using a thin film evaporator. The amount of liquid supplied to the thin film evaporator was 120 (kg / h), the operating temperature was 150 ° C., and the pressure was 0.01 (kPa (abs)). 71% sodium lauric acid lactate, 14% lauric acid soap, and 15% sodium lactate were obtained. The reaction mixture was analyzed in the same manner as in Example 1.

Example 3 38.5 g of sodium lactate (purity 60%) was placed in a reaction vessel, 2.8 g of KOH was added, and dehydration was performed at 180 ° C. and 5 Torr. The mixture was allowed to cool to 150 ° C., 176.9 g of lauric acid methyl ester was charged, and the mixture was reacted at 150 ° C. and 60 Torr for 8.5 hours.
A reaction mixture liquid having a sodium lactate conversion rate of 86% and containing 27% by weight of sodium laurate lactate was obtained. Residual fatty acid methyl ester was distilled off from the reaction mixture using a thin film evaporator. The amount of liquid supplied to the thin film evaporator is 120 (kg
/ H), operating temperature 150 ° C., pressure 0.01 (kPa (a
bs)). Sodium laurate lactate 8
6%, lauric acid soap 9% and sodium lactate 5% were obtained. The reaction mixture was analyzed in the same manner as in Example 1.

Example 4 38.5 g of sodium lactate (purity 60%) was placed in a reaction vessel, 2.8 g of KOH was added, and dehydration was performed at 180 ° C. and 5 Torr. After cooling to 150 ° C., 176.9 g of lauric acid methyl ester and 5.1 g of potassium laurate were charged, and 150 ° C., 60 To
The reaction was carried out at rr for 6.5 hours. Sodium lactate conversion 8
A reaction mixture containing 27% by weight of sodium laurate lactate at 9% was obtained. Residual fatty acid methyl ester was distilled off from the reaction mixture using a thin film evaporator. Liquid supply to thin film evaporator is 120 (kg / h), operating temperature is 150
C. and pressure 0.01 (kPa (abs)). Sodium laurate lactate 85%, Lauric acid soap 1
1% and sodium lactate 4% were obtained. The reaction mixture was analyzed in the same manner as in Example 1.

Example 5 Sodium lactate (purity 60
%) 19.27 g with KOH 1.4 g, 180
It was dehydrated at 5 ° C. and 5 Torr. The obtained sodium lactate was pulverized and dried under a nitrogen atmosphere. 100 g of dimethyl sulfoxide (DMSO) and 88.44 g of methyl lauric acid were charged in a reaction vessel, and pulverized and dried sodium lactate was added at 90 ° C. 4 at 90 ° C and 20 Torr
Reacted for hours. A reaction mixture liquid containing 15% by weight of sodium lactate laurate at a conversion of sodium lactate of 99% was obtained. DMSO was extracted and removed from the reaction mixture, and the residual fatty acid methyl ester was distilled off using a thin film evaporator. The amount of liquid supplied to the thin film evaporator is 120 (kg / h),
Operating temperature 150 ° C, pressure 0.01 (kPa (abs))
And Sodium laurate lactate 92% and lauric acid soap 8% were obtained. The reaction mixture was analyzed in the same manner as in Example 1.

Comparative Example 2 DMSO100 was placed in a reaction vessel.
g, 88.44 g of lauric acid methyl ester,
Sodium lactate 11.56g, KOH 1.4g at 90 ℃
Was added. The reaction was carried out at 90 ° C. and 20 Torr for 4 hours. A reaction mixture containing sodium lactate laurate at 8% by weight was obtained at a sodium lactate conversion of 54%. DMSO was extracted and removed from the reaction mixture, and the residual fatty acid methyl ester was distilled off using a thin film evaporator. Liquid supply to thin film evaporator is 120 (kg / h), operating temperature is 150
C. and pressure 0.01 (kPa (abs)). Sodium lauric acid lactate 64%, Lauric acid soap 1
5% and sodium lactate 21% were obtained. The reaction mixture was analyzed in the same manner as in Example 1.

The reaction conditions and analysis results of Examples 1 to 5 and Comparative Examples 1 and 2 are summarized in Table 1.

[0036]

[Table 1]

[0037]

Industrial Applicability By using the production method of the present invention, a fatty acid hydroxycarboxylic acid ester salt can be produced with high purity and at a low cost. Since the fatty acid hydroxycarboxylic acid ester salt can be easily produced with a purity of 80% or more, the production method of the present invention is suitable for industrialization. The fatty acid hydroxycarboxylic acid ester salt produced is excellent as a surfactant, and the production method of the present invention has extremely high industrial utility.

Continued front page    F-term (reference) 4H006 AA02 AC48 BA72 BB10 BB70                       BC10 BC11 BC34 BD10 BS10                       BT12                 4H039 CD10 CD40 CE10

Claims (14)

[Claims] 1. A method for producing a fatty acid hydroxycarboxylic acid ester salt by reacting a hydroxycarboxylic acid salt with a long-chain fatty acid lower alcohol ester, wherein the hydroxycarboxylic acid salt is a carbonate of an alkali metal or an alkaline earth metal, A mixture obtained from at least one compound selected from bicarbonate or hydroxide and hydroxycarboxylic acid, wherein the equivalent ratio m of the alkali metal and alkaline earth metal to the carboxyl group of the hydroxycarboxylic acid is 1 < m ≦
A method for producing a fatty acid hydroxycarboxylic acid ester salt, which is 1.5. 2. The production method according to claim 1, wherein the hydroxycarboxylic acid salt and the long-chain fatty acid lower alcohol ester are transesterified in an organic solvent. 3. The production method according to claim 1, wherein the hydroxycarboxylic acid salt and the long-chain fatty acid lower alcohol ester are transesterified in the absence of a solvent. 4. A hydroxycarboxylic acid salt is dessolvated and dried to form granules or powder, which is transesterified with a long-chain fatty acid lower alcohol ester.
The manufacturing method according to claim 1. 5. The production method according to claim 1, wherein the hydroxycarboxylic acid salt is transesterified with the long-chain fatty acid lower alcohol ester in a solution state. 6. The production according to claim 1, wherein the hydroxycarboxylic acid salt and the long-chain fatty acid lower alcohol ester are transesterified in the presence of a nonionic or anionic surfactant. Method. 7. The production method according to claim 6, wherein the amount of the nonionic or anionic surfactant used is 0.05 mol times or more with respect to the hydroxycarboxylic acid salt. 8. The method according to claim 1, wherein the long-chain fatty acid lower alcohol ester and the hydroxycarboxylic acid salt are reacted at 60 to 200 ° C. 9. The production method according to claim 1, wherein the long-chain fatty acid methyl ester and the hydroxycarboxylic acid salt are reacted under an inert gas stream under normal pressure or reduced pressure. 10. The production method according to claim 1, wherein the long-chain fatty acid lower alcohol ester is used in an amount of 0.1 to 5 mol per mol of the hydroxycarboxylic acid salt. 11. The residual fatty acid lower alcohol ester or hydroxycarboxylic acid salt is removed from the reaction mixture by reacting a long chain fatty acid lower alcohol ester with a hydroxycarboxylic acid salt.
10. The manufacturing method according to any one of 10. 12. The hydroxycarboxylic acid salt is a lactate salt,
It is tartrate, malate or citrate, The manufacturing method in any one of Claims 1-11 characterized by the above-mentioned. 13. The lower chain ester of a long-chain fatty acid lower alcohol ester is a lower alcohol ester of a saturated or unsaturated carboxylic acid having 8 to 22 carbon atoms.
2. The manufacturing method according to any one of 2. 14. A fatty acid hydroxycarboxylic acid ester salt produced by the production method according to claim 1, which does not contain a polymer.