JPH09157234A - Production of fatty acid alkanolamide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a fatty acid alkanolamide having excellent purity and color on an industrial scale in high efficiency and shortened reaction time. SOLUTION: A fatty acid alkanolamide is produced by reacting a fatty acid with an alkanolamine by adding the alkanolamine to the fatty acid in two steps. In the 1st step, the fatty acid is reacted with 0.6-0.95 times mol of the alkanolamine at 130-200 deg.C for 1-8 hours to an extent to leave a certain amount of unreacted fatty acid without completely forming the objective fatty acid amide. The alkanolamine is added to the system in the 2nd step in an amount of 1.0-1.3 times mol (including the amount added in the 1st step) of the fatty acid and made to react at 130-200 deg.C in the absence of catalyst.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a fatty acid alkanolamide. Fatty acid alkanolamides are often used as detergency improving agents for liquid detergents, foaming agents, foam stabilizers, and the like. Nonionic surfactants obtained by addition polymerization of fatty acid alkanolamides with ethylene oxide or propylene oxide have excellent compatibility with other surfactants and inorganic builders, and have improved detergency, dispersibility and viscosity. It has high biodegradability and low toxicity, and is used for liquid detergents and cosmetic raw materials.

[0002]

2. Description of the Related Art Conventionally, high-purity fatty acid alkanolamides have been obtained by condensing alcohol esters of fatty acids such as fatty acid methyl esters and alkanolamines in the presence of a basic catalyst. With this method, a high-purity fatty acid alkanolamide can be produced, but since the ester used as a raw material requires a step of condensing a fatty acid with a lower alcohol to form an ester, a step for producing the fatty acid alkanolamide is required. However, there is a problem in that it is uneconomical because of a long period of time, and alcohol is by-produced during the production of fatty acid alkanolamide. Therefore, a method of using fatty acid itself and alkanolamine as raw materials for producing a high-purity fatty acid alkanolamide has been earnestly desired.

As a method for producing a fatty acid alkanolamide by reacting a fatty acid with an alkanolamine, there is a method in which a large excess of alkanolamine and a fatty acid are reacted without a solvent. (Oil Chemistry, Vol. 24, No. 12, 869-8
73, 1975) Since this method uses a large excess of alkanolamine, the purity after production is low, and a step of removing the large excess of alkanolamine by distillation or the like is necessary to obtain a highly pure fatty acid alkanolamide. In addition, there is a problem in that alkanolamine is present in a large excess, so that coloring easily occurs.

As a method for avoiding the use of a large excess of alkanolamine, there is JP-A-48-8722. In the method shown in this patent, 0.5 to 0.6 mol of alkanolamine is added to a fatty acid in the presence of a basic catalyst, and the fatty acid amide ester is at least almost completely formed with each other. React and then the second of the reaction
In the step, 0.5 mol of alkanolamine is further added to complete the reaction of the fatty acid amide ester to the fatty acid amide.

According to this method, although the excess amount of alkanolamine can be reduced, the purity of the fatty acid amide ester before re-adding the alkanolamine affects the final purity of the fatty acid amide, so that the fatty acid in the first step It is necessary to minimize the remaining rate. However, as a result of the studies by the present inventors, the reaction time required for producing the fatty acid amide ester to reach the purpose is as long as 24 hours or more, and it cannot be said that the method has been completed as an industrial production method.
Further, when the fatty acid amide ester is decomposed by the alkanolamine in the next step, it is necessary to add a basic catalyst such as sodium methoxide or sodium hydroxide for promoting the reaction. However, these basic catalysts cause coloration of the fatty acid alkanolamide, which causes deterioration of the hue of the fatty acid alkanolamide.

As a method similar to this, Japanese Patent Publication No. 56-49
There is 903. In this method, 1.0 to 1.3 times mol of alkanolamine with respect to fatty acid is added in two steps, and in addition, in the second step, a basic catalyst uniformly dissolved in alkanolamine is added. It has a feature.

[0007]

However, even in this method, although the second step is completed at a reaction temperature of less than 100 ° C. in 4 hours, the reaction of the first step has a large amount of unreacted fatty acid. Up to about 3% of the amount added before the reaction, preferably 1.5
It is necessary to continue until it becomes less than%. As a result of examination by the present inventors, the first-step reaction requires 15 hours or more, and the fatty acid amide obtained as a result has a purity of about 93%, and it is assumed that a fatty acid alcohol ester is used as a raw material. It is lower than the comparison. As described above, it is hard to say that the conventional method has been established as a method for efficiently producing a highly pure fatty acid alkanolamide on an industrial scale by using a fatty acid and an alkanolamine as raw materials. An object of the present invention is to provide an efficient production method on an industrial scale in a method for producing a highly pure fatty acid alkanolamide using a fatty acid and an alkanolamine as raw materials.

[0008]

Means for Solving the Problems As a result of intensive studies on the above problems, the present inventors have found that in a method of adding an alkanolamine to a fatty acid in two steps, a fatty acid amide ester is completely added in the first step. It was found that by carrying out the addition of alkanolamine in the second stage without formation, fatty acid alkanolamide can be obtained more efficiently and in higher yield than the conventional method, and the present invention was completed. Came to let. Further, according to the method of the present invention, since it is not necessary to completely form the fatty acid amide ester, a basic catalyst for decomposing the fatty acid amide ester is not required, and the reaction of the second step can be easily performed only by adding the alkanolamine. At the same time, I also found that I could complete.

That is, the method for producing a fatty acid alkanolamide of the present invention is a method for producing a fatty acid alkanolamide by reacting a fatty acid with an alkanolamine, wherein in the first step, the fatty acid and 0.6 to
0.95 times mole of alkanolamine at a temperature of 130 to 2
The reaction is carried out at 00 ° C for 1 to 8 hours, and then, as a second step, alkanolamine is added in an amount of 1.0 to 1.3 times the molar amount of the fatty acid together with the amount added in the first step, and no catalyst is added. At a temperature of 130 to 200 ° C. for 1 to 8 hours.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The fatty acid used in the present invention is a linear or branched aliphatic carboxylic acid having 8 to 22 carbon atoms, which is obtained from natural fats and oils, such as caprylic acid, lauric acid, stearic acid, oleic acid and coconut oil. Fatty acids, beef tallow fatty acids, synthetic fatty acids and the like can be mentioned. Moreover, as the alkanolamine in the present invention, monoethanolamine, monoisopropanolamine, or the like is preferably used.

The total amount of alkanolamine used in the reaction is 1.0 to 1.3 times the mole of the fatty acid. 1.
When the amount is less than 0 times the molar amount, it is not preferable because the conversion rate of the fatty acid used as a raw material decreases and the by-products increase. Also, 1.
If the amount used exceeds 3 times the molar amount, the purity of the product is lowered due to the remaining alkanolamine, which is not preferable.

In the method of the present invention, the alkanolamine is 2
Add in portions. This is because when the acid is excessive in the first-step reaction, the acid itself acts as a catalyst to promote amidation and esterification. The addition amount of the alkanolamine in the first stage is 0.5 to 0.9 with respect to the fatty acid.
It is preferably 5 times the mole. If it is less than 0.5 times by mole, the conversion of the raw material fatty acid is suppressed, which is not preferable. Further, when it is used in excess of 0.95 times by mole, the excess ratio of the acid is lowered and the reaction rate is decreased, which is not preferable.

The temperature for reacting the alkanolamine and the fatty acid is 130 to 200 ° C, preferably 130 to 1
The temperature is 80 ° C, more preferably 140 to 170 ° C. If the temperature is lower than 130 ° C., the reaction proceeds slowly and the object of the present invention cannot be achieved. Further, even if the reaction is carried out at a temperature exceeding 200 ° C., there is no particularly effective difference, and rather the product is remarkably colored due to the alteration of the alkanolamine, which is not preferable.

The reaction time of the first step varies depending on the amount of alkanolamine added, but is in the range of 1 to 8 hours. Even if the second stage reaction is started in less than 1 hour, the effect of addition in two portions cannot be obtained. Also, no effective difference is observed even if the reaction is performed for more than 8 hours. The first-step reaction thus performed is completed, and the second-step reaction is performed. In this case, the alkanolamine to be added is the deficiency of the amount added in the first step relative to the total amount to be added. In this second-step reaction, the reaction rate is lowered and the hue is deteriorated, so no basic catalyst is added. The reaction time in the second step varies depending on the amount of alkanolamine added, but is 1 to 8
Time range. If it is less than 1 hour, the reaction is not completed, which is not preferable. Also, no effective difference is observed even if the reaction is performed for more than 8 hours.

In the method of the present invention, when the fatty acid alkanolamide is produced from the fatty acid and the alkanolamine, the reaction can be further advantageously performed by performing the reaction under reduced pressure. The reduced pressure condition is not particularly limited as long as it is sufficient for dehydration, and the suitable temperature varies depending on the reaction temperature.
The range is 00 torr. The dehydration can be performed under reduced pressure at all times during the reaction, but the reaction can be sufficiently promoted even if the dehydration is intermittently performed under reduced pressure. For example, the reaction rate is high at the beginning of the reaction because of the large amount of fatty acids, and it is not necessary to carry out the reaction under reduced pressure.

In order to suppress the coloring of the fatty acid alkanolamide produced, the reaction is preferably carried out under a nitrogen stream. The fatty acid alkanolamide thus produced has a high purity and does not require any particular purification, and can be used as it is as a raw material for a reaction with ethylene oxide or propylene oxide in the next step.

[0017]

The present invention will be described in detail below with reference to Examples.
The present invention is not limited to these examples. In the following examples,% is based on weight. The concentration of each component was analyzed by gas chromatography. Regarding the hue, each reaction solution was dissolved and compared with APHA.

Example 1 In a 100 ml four-necked flask, 40.0 g of lauric acid was added.
(0.2 mol) and monoethanolamine 7.9 g (0.
(13 mol) was added, and the mixture was reacted at 150 ° C. for 6 hours under a nitrogen stream at atmospheric pressure. To this was added 4.9 g of monoethanolamine (0.
(08 mol) was added, and the mixture was further reacted for 5 hours. Table 1 shows the analysis results after the reaction.

Example 2 40.0 g of lauric acid (0.
2 mol) and 9.8 g of isopropanolamine (0.13
Mol) was added, and the mixture was reacted at 150 ° C. for 6 hours under a normal pressure nitrogen stream. To this, 6.0 g of isopropanolamine (0.0
(8 mol) was added and the reaction was further continued for 5 hours. Table 1 shows the analysis results after the reaction.

Example 3 40.0 g of lauric acid was added to 56.9 g of stearic acid (0.
The same procedure as in Example 1 was repeated except that the amount was changed to 2 mol). Table 1 shows the analysis results after the reaction.

Example 4 9.8 g (0.16 g) of the first stage monoethanolamine
Mol) and 3.1 g (0.05 mol) of monoethanolamine in the second step were added, and the same procedure as in Example 1 was performed. Table 1 shows the analysis results after the reaction.

Example 5 The reaction time of the first step was 8 hours, and the reaction time of the second step was 8 hours.
The procedure was the same as in Example 1 except that the time was set. Table 1 shows the analysis results after the reaction.

Example 6 9.8 g (0.16 g) of the first stage monoethanolamine
Mol) and 6.1 g (0.10 mol) of monoethanolamine in the second step were added, and the same procedure as in Example 1 was performed. Table 1 shows the analysis results after the reaction.

Example 7 40.0 g of lauric acid (0.
2 mol) and 7.9 g (0.13 mol) of monoethanolamine were added, and the mixture was allowed to react for 2 hours while distilling off water at 150 ° C. under a normal pressure nitrogen stream. Reduced pressure (5
After the reaction was performed at 60 torr), 4.9 g (0.08 mol) of monoethanolamine was added thereto, and the reaction was further performed under reduced pressure for 5 hours. Table 1 shows the analysis results after the reaction.

Example 8 40.0 g of lauric acid (0.
2 mol) and 9.8 g of monoisopropanolamine (0.
(13 mol) was added, and the mixture was allowed to react for 2 hours while distilling off water at 150 ° C. under a normal pressure nitrogen stream. After performing the reaction at the same temperature for 1 hour under reduced pressure (560 torr), 6.0 g (0.08 mol) of monoisopropanolamine was added thereto, and further reacted for 5 hours under reduced pressure. Table 1 shows the analysis results after the reaction.

Example 9 40.0 g of lauric acid was added to 56.9 g of stearic acid (0.
The reaction was performed in the same manner as in Example 7 except that the amount was changed to 2 mol). Table 1 shows the analysis results after the reaction.

Example 10 9.8 g (0.16 g) of the first stage monoethanolamine
Mol) and 3.1 g (0.05 mol) of monoethanolamine in the second stage were added, and the same procedure as in Example 7 was performed. Table 1 shows the analysis results after the reaction.

Comparative Example 1 The procedure of Example 1 was repeated, except that monoethanolamine was added all at once and reacted for 11 hours. Table 1 shows the analysis results at the end of the reaction.

Comparative Example 2 The procedure of Example 1 was repeated except that the reaction time of the first step was 0.5 hours and the reaction time of the second step was 8 hours. Table 1 shows the analysis results after the reaction.

Comparative Example 3 40.0 g of lauric acid (0.
2 mol) and 1.5 ml of 11.7% methanolic sodium methylate were added, and 6.1 g (0.1 mol) of monoethanolamine was added in a molten state at about 60 to 70 ° C.
The reaction was carried out at 150 ° C. for 24 hours under a normal pressure nitrogen stream. To this, 6.1 g (0.1 mol) of monoethanolamine was added,
The reaction was continued for 5 hours. Table 1 shows the analysis results after the reaction.

Comparative Example 4 40.0 g of lauric acid (0.
2 mol) and 7.3 g (0.12 mol) of monoethanolamine were added, and the reaction was carried out under a normal pressure nitrogen stream at 150 ° C. until 0.2 mol of water was distilled. The time required for the reaction is 2
It was 0 hours. To this, monoethanolamine 5.5
What melt | dissolved 0.16g of sodium hydroxide in g (0.09mol) was added, and it heated at 90 degreeC for 4 hours. Table 1 shows the analysis results after the reaction.

Comparative Example 5 40.0 g of lauric acid (0.
2 mol) and 7.3 g (0.12 mol) of monoethanolamine were added, and the reaction was carried out at 170 ° C. under normal pressure nitrogen stream until 0.2 mol of water was distilled. The time required for the reaction is 1
5 hours. To this, monoethanolamine 5.5
What melt | dissolved 0.22g of potassium hydroxide in g (0.09mol) was added, and it heated at 90 degreeC for 4 hours. Table 1 shows the analysis results after the reaction.

[0033]

[Table 1]

[0034]

INDUSTRIAL APPLICABILITY According to the method for producing a fatty acid alkanolamide of the present invention, a fatty acid alkanolamide can be produced by using a fatty acid instead of an alcohol ester of a fatty acid which has been conventionally used for producing a fatty acid alkanolamide. Also, according to this method, a highly pure fatty acid alkanolamide can be industrially produced efficiently without using a third additive such as a basic compound.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kyoyoshi Watanabe 1-6 Takasago, Takaishi-shi, Osaka Mitsui Toatsu Chemical Co., Ltd.

Claims (4)

[Claims] 1. A method for producing a fatty acid alkanolamide by reacting a fatty acid with an alkanolamine, the method comprising:
The amount of the fatty acid and 0.6 to 0.95 times the molar amount of the alkanolamine reacted with the fatty acid at a temperature of 130 to 200 ° C. for 1 to 8 hours, and then the alkanolamine added to the first step as the second step. A method for producing a fatty acid alkanolamide, characterized in that the fatty acid alkanolamide is added in an amount of 1.0 to 1.3 times the molar amount of the fatty acid and allowed to react at a temperature of 130 to 200 ° C. for 1 to 8 hours without a catalyst. 2. The method for producing a fatty acid alkanolamide according to claim 1, wherein the alkanolamine is monoethanolamine and monoisopropanolamine. 3. The fatty acid having 8 to 22 carbon atoms.
A method for producing the fatty acid alkanolamide described. 4. The method for producing a fatty acid alkanolamide according to claim 1, wherein the reaction is carried out under reduced pressure.