JP2972396B2 - Method for producing fatty acid diethanolamide having low diethanolamine content - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fatty acid diethanolamide having a low content of diethanolamine and little coloring with time.

[0002]

2. Description of the Related Art Fatty acid diethanolamide is a surfactant which has been known for a long time. By blending it with other surfactants, the surfactant has excellent foaming power, penetrating power,
Gives detergency, thickening power, and has very low toxicity and good biodegradability, so it has long been used by those skilled in the art as an essential ingredient in cosmetics such as shampoos, kitchen detergents, and toiletries. .

[0003]

However, fatty acid diethanolamide contains about 2 to 8% of diethanolamine used as an impurity in its production as an impurity. For this reason, the appearance of the product changes with time, and coloring often occurs.

[0004] Methods for removing ethanolamines include distillation and separation and purification using a column. However, at present, there is no satisfactory method for removing diethanolamine because these methods are difficult to separate and remove sufficiently from the physical properties of fatty acid diethanolamide and increase the cost.

Also, Japanese Patent Application Laid-Open No. 2-300153 proposes reacting an acid anhydride or an acid chloride with unreacted diethanolamine to form a stable derivative. Acetic acid is said to be superior. However, when the acid anhydride or acid chloride of a lower fatty acid is reacted, the product emits a bad smell, and when deodorized by heating under reduced pressure, coloring is caused. When the constituent fatty acid composition of the fatty acid chloride is on the lower fatty acid side of the constituent fatty acid composition of the fatty acid diethanolamide, the thickening property, which is the main performance of the fatty acid diethanolamide, is deteriorated. become worse.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to reduce diethanolamine, which is an impurity of conventional fatty acid diethanolamide, and as a result, the composition ratio of fatty acid diethanolamide to unreacted diethanolamine is reduced to that of unreacted diethanolamine. It has been found that by reacting a fatty acid chloride similar to that described above, the diethanolamine content can be reduced without impairing the main performance of fatty acid diethanolamide, and the present invention has been completed.
That is, the present invention relates to a compound represented by the general formula (I) containing diethanolamine as an impurity:

Embedded image (I) wherein R ₁ CO represents a saturated or unsaturated fatty acid residue having 8 to 22 carbon atoms, and a fatty acid diethanolamide represented by the general formula (II) R ₂ COCl (II) ₂ CO has the same carbon number distribution as R ₁ CO or 40%
Or more. The present invention relates to a method for producing a fatty acid diethanolamide having a low diethanolamine content, which comprises adding a fatty acid chloride represented by the formula (1) to acylate diethanolamine.

The fatty acid diethanolamide used in the present invention contains unreacted diethanolamine, and the constituent fatty acid is a saturated or unsaturated fatty acid having 8 to 22 carbon atoms. Representative examples of fatty acids include coconut oil fatty acids, palm kernel oil fatty acids, lauric acid, myristyl acid, tallow fatty acid, hardened tallow fatty acid, oleic acid, oleic acid,
Fatty acids such as castor oil fatty acids and hydrogenated castor oil fatty acids.

[0008] The fatty acid chloride represented by the general formula (II) used for the purpose of acylation has a constituent fatty acid composition which is the same as that of the fatty acid diethanolamide or 40% or more. Is desirable. When the constituent fatty acid composition of the fatty acid chloride is lower than the constituent fatty acid composition of the fatty acid diethanolamide, the thickening property, which is the main performance of the fatty acid diethanolamide, is worse, and when it is the higher fatty acid side, the low-temperature stability is poor. Become.

The molar ratio of the fatty acid chloride to diethanolamine is preferably 0.15 to 0.5 times mol of diethanolamine measured by hydrochloric acid titration. When the molar ratio is 0.15 or less, the residual ratio of diethanolamine is high, and when the molar ratio is 0.5 or more, fatty acids remain, which is not preferable.

The surfactants of the present invention can be blended with other surfactants commonly used in the surfactant industry. Examples of such surfactants include fatty acid soap, higher alcohol sulfate, polyoxyethylene higher alcohol sulfate, higher alcohol phosphate, polyoxyethylene higher alcohol phosphate, and polyoxyethylene higher fatty acid phosphate. Acid ester salts, sulfonated higher fatty acid salts, higher alcohol sulfosuccinate salts, acylmethyl taurates,
Anionic surfactants such as N-long chain acyl-glutamate, N-long chain acyl-sarcosine salt, N-long chain acyl-N-alkyl-β alanine salt, acyl isethionate, α-olefin sulfonate, Nonionic surfactants such as fatty acid monoethanolamide and polyoxyethylene fatty acid monoethanolamide, amphoteric surfactants such as alkyl imidazolinium betaine and fatty acid amide propyl betaine type, and cations such as quaternary ammonium salt type cationic surfactant There are surfactants and the like.

If necessary, a solubilizing agent such as glycols, an emollient such as ester oil, a humectant such as hyaluronic acid, chitin and chitosan, a cell activator such as aloe extract and placenta extract, allantoin, An anti-inflammatory agent such as glycyrrhizic acid, an anti-dandruff agent such as zinc pyrithione and pyrocton olamine, a bactericide, a fragrance, a pigment and the like can also be added.

[0012]

The present invention will be described in more detail with reference to the following examples.

Example 1 Palm oil fatty acid methyl ester (C ₈ 8.2%, C ₁₀ 6.8)
_{%, C 12 49.5%, C} 14 17.7%, C 16 8.4%, C 18 2.6
%, C ₁₈ F ₁ 5.8%, C ₁₈ F ₂ 1.0%) 2.2 kg, diethanolamine 1.1 kg, sodium methylate 28
Take 18 g of a 10% methanol solution and raise the temperature to 80 ° C.
The pressure is gradually reduced, and the pressure is reduced to 10 mmHg over about 3 hours to remove methanol. After removing about 300 g of methanol, the mixture was aged for about 1 hour under the same conditions to obtain 3 kg of coconut oil fatty acid diethanolamide. The coconut oil fatty acid diethanolamide was titrated with 0.1 N hydrochloric acid using BPB (bromophenol blue) as an indicator. As a result, the content of diethanolamine was 5.8%.
Then, to 1 kg of this coconut oil diethanolamide was added 51 g of coconut oil fatty acid chloride (molar ratio of diethanolamine to 0.4 times mole), followed by stirring for 1 hour. When the diethanolamine content of this product was measured by the same method,
1.1%.

Example 2 328 g of diethanolamine, 2.5 parts of sodium hydroxide
g, 668 g of coconut oil is charged, and 80 ° C., 30 mmH
g under reduced pressure for 1 hour to obtain 1 kg of coconut oil fatty acid diethanolamide. Using BPB (bromophenol blue) as an indicator, the reaction product was titrated with 0.1N hydrochloric acid. As a result, the content of diethanolamine was 5.3%. To 100 g of the reaction product was added 5.5 g of lauric chloride (molar ratio of diethanolamine to 0.5 times mol), and the mixture was stirred for 1 hour. The diethanolamine content of this product was measured by the same method and found to be 0.3%.

Comparative Example 1 (Example in which acylation treatment is not performed with fatty acid chloride) The reaction product of Example 1 before addition of coconut oil fatty acid chloride.

Comparative Example 2 (Example in which acetic anhydride was used as an acylating agent) 4.5 g of acetic anhydride (0.8 times by mole relative to diethanolamine) was added to 100 g of the reaction product of Example 1 before the addition of coconut fatty acid chloride. After stirring for 1 hour, the mixture was heated at 80 ° C. for 1 hour under a reduced pressure of 20 mmHg for deodorization. During this operation, the color became light brown. The diethanolamine content of this product was measured by the same method and found to be 1.4%.

Comparative Example 3 (Example in which the constituent fatty acid composition of the fatty acid chloride is higher than the constituent fatty acid composition of the fatty acid diethanolamide) Stearic acid chloride was added to 100 g of the reaction product before addition of the coconut fatty acid chloride in Example 1. 7 g (molar ratio of diethanolamine to 0.4 times mol) was added, and the mixture was stirred for 1 hour. The diethanolamine content of this product was measured by the same method and found to be 1.2%.

Comparative Example 4 (Example in which the fatty acid composition of fatty acid chloride is lower than that of fatty acid diethanolamide) 100 g of the reaction product of Example 1 before addition of coconut oil fatty acid chloride was added to caprylic acid chloride. Then, 0.6 g (0.4 times by mol of diethanolamine) was added and stirred for 1 hour. The diethanolamine content of this product was measured by the same method and found to be 1.0%.

The properties of each of the coconut oil fatty acid diethanolamides thus obtained were measured by the following methods.

1. Odor The odor two days after production was determined by olfaction.

2. Coloring with time After storage at 50 ° C. for 2 months, it was visually judged as follows. ○ ・ ・ ・ No coloring △ ・ ・ ・ Slightly coloring × ・ ・ ・ Coloring

3. Thickening A liquid detergent composition having the following formulation was prepared, and the viscosity at 25 ° C. was measured using a B-type rotational viscometer. Liquid detergent composition Sodium lauryl ether sulfate 12% Coconut oil fatty acid diethanolamide 8% Citric acid Amount to make pH 7 Water Residue

4. Low-temperature stability The liquid detergent composition prepared for the measurement of the above-mentioned viscosity increase was stored at -5 ° C for one week, and judged as follows. ○ ・ ・ ・ Transparent and uniform △ ・ ・ ・ Slightly cloudy × ・ ・ ・ Cloudy or separated

Measurement Results and Brief Description In the tables, the unit of viscosity indicated by thickening is cp (centipoise). The coconut oil fatty acid diethanolamide obtained in Example 2 was inferior in viscosity to the coconut oil fatty acid diethanolamide obtained in Comparative Example 1, but this was due to the reaction between coconut oil and diethanolamine. Glycerin, and has a lower amide content than the coconut oil diethanolamide obtained in Comparative Example 1.

[Table 1]

The fatty acid diethanolamide type surfactant obtained according to the present invention has an extremely low diethanolamine content, so that coloring with time hardly occurs.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C07C 231/24 C07C 231/02 C07C 233/18 C07C 233/20

Claims (2)

(57) [Claims] 1. A compound of the general formula (I) containing diethanolamine as an impurity. (I) wherein R ₁ CO represents a saturated or unsaturated fatty acid residue having 8 to 22 carbon atoms, and a fatty acid diethanolamide represented by the general formula (II) R ₂ COCl (II) R ₂ CO has the same carbon number distribution as R ₁ CO or 40%
Or more. A method for producing a fatty acid diethanolamide having a low content of diethanolamine, wherein the fatty acid chloride represented by the formula (1) is added for acylation. 2. The reaction molar ratio of fatty acid chloride to diethanolamine is 0.15 to 0.5 times mol of diethanolamine measured by hydrochloric acid titration.
The manufacturing method as described.