JPH0987379A - Production of polyoxyalkylene fatty acid amide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a process for producing a high-purity polyoxyalkylene fatty acid amide with little amt. of a by-product by adjusting the water content of an alkanolamide obtd. by the fatty acid process to a specified value or lower before using the alkanolamide. SOLUTION: A polyoxyalkylene fatty acid amide is produced by the addition reaction of a 2-4C alkylene oxide to a fatty acid alkanolamide represented by formula II (wherein (q) is 0-1; and q+m is 2) and obtd. by reacting a fatty acid represented by formula I (wherein R is a 7-21C linear or branched alkyl or alkenyl group) with an alkanolamine represented by the formula: Hp N-[R'- OH]m (wherein R' is a 1-5C linear or branched alkylene group; and (p) and (m) are each 1-2 provided p+m is 3), subject to the condition that the water content of the fatty acid alkanolamide represented by formula II is adjusted to 0.5wt.% or lower before the addition reaction. The adjustment of water content is performed by thermal dehydration under reduced pressure, purification by recrystallization, azeotropic dehydration, etc.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a high-purity polyoxyalkylene fatty acid amide with less by-products.

[0002]

2. Description of the Related Art As a method for producing a polyoxyalkylene fatty acid amide, there is a method of adding an alkylene oxide to a fatty acid alkanolamide. As a method for producing the fatty acid alkanolamide as a raw material used at this time, there are a methyl ester method by aminolysis of a fatty acid methyl ester and an alkanolamine, and a fatty acid method in which a fatty acid and an alkanolamine are dehydrated.

In the alkylene oxide addition reaction using a fatty acid alkanolamide obtained by the methyl ester method as a raw material, the desired product can be obtained in high purity by selecting appropriate reaction conditions. However, it involves a step of esterifying a fatty acid, which is disadvantageous in terms of price. On the other hand, in the case of the alkylene oxide addition reaction using the fatty acid alkanolamide obtained by the fatty acid method as the raw material, the amount of by-products increases compared to the case where the fatty acid alkanolamide by the methyl ester method is used as the raw material, and the alkylene oxide average The number of added moles is lower than the theoretical value. Therefore, it is necessary to react a large amount of alkylene oxide in order to obtain the target number of moles of alkylene oxide added, and the amount of by-products increases correspondingly and the purity decreases. Therefore, when the produced polyoxyalkylene fatty acid amide or its derivative (for example, carboxymethylated product, sulfuric acid esterified product, phosphoric acid esterified product, etc.) is used as a surfactant, there is a problem that performance or appearance is affected.

Therefore, an object of the present invention is to provide a method for efficiently producing a polyoxyalkylene fatty acid amide with a small amount of by-products.

[0005]

Means for Solving the Problems The inventors of the present invention have made diligent studies in such a situation. As a result, when the water content in the fatty acid alkanolamide obtained by the fatty acid method is 0.5% by weight, the purity of the target product and the alkylene oxide addition The inventors have found that the number of moles has a great influence, and have completed the present invention. That is, the present invention provides a compound represented by the general formula (I):

[0006]

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(Wherein R represents a straight-chain or branched alkyl or alkenyl group having 7 to 21 carbon atoms) and a general formula (II) H _p N- [R'-OH ] _m (II) (In the formula, R ′ represents a linear or branched alkylene group having 1 to 5 carbon atoms, p and m are 1 or 2, respectively, and p + m = 3.
Is the number of. ), Which is obtained by reacting with an alkanolamine represented by the general formula (III)

[0008]

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(Wherein R, R ′ and m have the above-mentioned meanings, q is 0 or 1, provided that q + m = 2), and the fatty acid alkanolamide has 2 to 2 carbon atoms. In producing a polyoxyalkylene fatty acid amide by adding the alkylene oxide of 4, the compound of the general formula (II
The water content in the fatty acid alkanolamide represented by I)
The present invention provides a method for producing a polyoxyalkylene fatty acid amide, which is adjusted to 0.5% by weight or less.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below.

In the fatty acid represented by the general formula (I) used in the present invention, R represents a linear or branched alkyl group or alkenyl group having 7 to 21 carbon atoms, preferably 9 to 17 carbon atoms. It is a straight-chain alkyl group. Specific examples of the fatty acid represented by the general formula (I) include caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, coconut oil fatty acid, tallow fatty acid, palm oil fatty acid, palm kernel oil fatty acid. Etc.

The alkanolamine represented by the general formula (II) used in the present invention is a compound having an amino group having active hydrogen and a hydroxyalkyl group, specifically, monoethanolamine, diethanolamine and monoisopropanolamine. , Diisopropanolamine and the like, and monoethanolamine and diethanolamine are preferable.

The fatty acid alkanolamide represented by the general formula (III) used in the present invention is a dehydration reaction between the fatty acid represented by the general formula (I) and the alkanolamine represented by the general formula (II). Any of those having a purity of 90% or more, and preferably 95% or more with a low content of aminoester or amide ester is preferable. A known method may be used for the dehydration reaction of the fatty acid represented by the general formula (I) and the alkanolamine represented by the general formula (II). For example, it may be obtained by reacting at a temperature of 140 to 180 ° C. it can.

In the present invention, the water content in the fatty acid alkanolamide represented by the general formula (III) obtained by the above reaction is adjusted to 0.5% by weight or less, preferably 0.3% by weight or less, and the alkylene is adjusted. React with oxides. When the amount of water in the fatty acid alkanolamide represented by the general formula (III) exceeds 0.5% by weight, the amount of by-products rapidly increases. The reason for this is not clear, but when the water content is 0.5% by weight or less, the reaction between the water and the alkylene oxide is preferential, and polyalkylene glycol is mainly produced.
It is considered that when the content exceeds 5% by weight, hydrolysis of the amide group as shown in the following reaction formula is promoted to form a fatty acid and an alkanolamine. Therefore, 1 equivalent of water produces 1 equivalent of fatty acid and 3 equivalents of alkanolamine, a total of 4 equivalents, alkylene oxide is consumed in large amounts, by-products increase, and the purity of the target product may decrease. Conceivable.

[0015]

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(In the formula, R, R ', m, p and q have the above-mentioned meanings.) In the present invention, the water content in the fatty acid alkanolamide represented by the general formula (III) is 0.5% by weight or less. The method for adjusting the above is not particularly limited, but can be adjusted by methods such as dehydration under reduced pressure by heating, purification by recrystallization, and azeotropic dehydration. In the present invention, the water content in the fatty acid alkanolamide represented by the general formula (III) may be measured by the Karl Fischer method.

In the present invention, the water content is adjusted as described above.
A polyoxyalkylene fatty acid amide is obtained by reacting a fatty acid alkanolamide represented by the general formula (III) adjusted to 0.5% by weight or less with an alkylene oxide. Examples of the alkylene oxide used in the present invention include ethylene oxide, propylene oxide and butylene oxide, preferably ethylene oxide and propylene oxide, and more preferably ethylene oxide. In the alkylene oxide addition reaction, it is preferable to use a metal hydroxide such as sodium hydroxide or potassium hydroxide; a sodium methylate; a basic catalyst such as an amine in an amount of 0.01 to 5 mol% with respect to the fatty acid alkanolamide.

The addition reaction temperature of the alkylene oxide in the present invention is not a problem as long as it is equal to or higher than the melting point of the fatty acid alkanolamide represented by the general formula (III), but as low as possible is preferable in order to suppress by-products due to thermal decomposition. Specifically, it is preferably 120 ° C. or lower, more than the melting point of the fatty acid alkanolamide, and more preferably 80 to 110 ° C. The number of addition moles of alkylene oxide is not particularly limited, but the average number of addition moles of alkylene oxide is preferably 1 to 20 moles, more preferably 1 to 5 moles. If necessary, the produced polyoxyalkylene fatty acid amide may be purified by vacuum distillation with a low boiling point, steam distillation with a low boiling point, or the like.

[0019]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. still,
The purity and the average number of moles of alkylene oxide added were determined by gas chromatography using trimethylsilylation of the reaction product.

Examples 1 to 4 and Comparative Examples 1 to 2 Lauric acid and monoethanolamine were reacted at 160 ° C. to obtain lauric acid monoethanolamide, which was purified by recrystallization (ethanol) to obtain a water content. 0.03% by weight of lauric acid monoethanolamide was obtained (purity> 99
%). A known amount of water was added thereto to obtain the water content shown in Table 1, 0.1 mol% of NaOH was added as a catalyst, and 3 mol of ethylene oxide was reacted at 100 ° C. under a pressure of 0.5 to 4 kg / cm ² . The purity of the obtained polyoxyethylene lauric acid monoethanolamide and the average number of moles of ethylene oxide added are shown in Table 1.

[0021]

[Table 1]

Examples 5 to 8 and Comparative Examples 3 to 4 Instead of lauric acid monoethanolamide of Example 1, lauric acid diethanolamide having a water content of 0.04% by weight obtained by reacting lauric acid with diethanolamine was used. , Except that the water content was adjusted as shown in Table 2,
The same operation as in Example 1 was performed. Table 2 shows the purity of the obtained polyoxyethylene lauric acid diethanolamide and the average number of moles of ethylene oxide added.

[0023]

[Table 2]

Reference Example 70% to 75% of 375 g of polyoxyethylene lauric acid monoethanolamide obtained in Examples 1 to 4 and Comparative Examples 1 and 2 was used.
After heating to ℃, sodium monochloroacetate (hereinafter SMCA
116 g and solid sodium hydroxide 44 g were added at the ratio shown in Table 3.

[0025]

[Table 3]

After the above addition was completed, the mixture was further stirred for 1 hour. Then, the temperature was adjusted to 85 ° C., 20 g of water was added, and the mixture was stirred for 1 hour to obtain 555 g of sodium polyoxyethylenelauric acid amide acetate. The reaction rate at this time was measured by the alkali-epton method. The results are shown in Table 4.

[0027]

[Table 4]

Claims (5)

[Claims] 1. A compound of the general formula (I) (In the formula, R represents a linear or branched alkyl or alkenyl group having 7 to 21 carbon atoms.) And a general formula (II) H _p N- [R′-OH] _m ( II) (In the formula, R ′ represents a linear or branched alkylene group having 1 to 5 carbon atoms, p and m are 1 or 2, respectively, and p + m = 3.
Is the number of. ), Which is obtained by reacting with an alkanolamine represented by the general formula (III): (In the formula, R, R ′ and m have the above-mentioned meanings, q is 0 or 1, provided that q + m = 2.), The fatty acid alkanolamide is represented by C 2-4 alkylene. When producing a polyoxyalkylene fatty acid amide by adding an oxide, the water content in the fatty acid alkanolamide represented by the general formula (III) is adjusted to 0.5% by weight or less, and the polyoxyalkylene fatty acid amide is characterized. Manufacturing method. 2. The production method according to claim 1, wherein the alkanolamine represented by the general formula (II) is monoethanolamine or diethanolamine. 3. The method according to claim 1, wherein the alkylene oxide is ethylene oxide. 4. The alkylene oxide addition reaction temperature is 1
The production method according to any one of claims 1 to 3, wherein the temperature is 20 ° C or lower and the melting point of the fatty acid alkanolamide represented by the general formula (III) or higher. 5. The production method according to claim 1, wherein the average number of moles of added alkylene oxide is 1 to 20 moles.