JPH09255773A - Production of polyoxyalkylene fatty acid alkanolamide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a highly pure polyoxyalkylene fatty acid alkanolamide from an inexpensive fatty acid. SOLUTION: A polyoxyalkylene fatty acid alkanolamide represented by the formula (wherein n is an integer of 1 or greater; X, Y<1> and Y<2> are each H or CH3 ; RCO is a residue of a 6-22C linear or branched saturated or unsaturated fatty acid; and W is H or an oxyalkylene) is produced by reacting 1mol of a fatty acid with 1.0-2.0mol% of an alkanolamine at 80-180 deg.C, adding a dehydrator or a metal alcoholate acting also as a dehydrator to the reaction system to lower the content of the water remaining in the system to 0.0% or below, thereby accomplishing the amidation reaction to produce a fatty acid alkanolamide and allowing the product to enter into an addition reaction with an alkylene oxide under elevated pressure.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a highly pure polyoxyalkylene fatty acid alkanolamide.

[0002]

2. Description of the Related Art Polyoxyalkylene fatty acid alkanolamides have good foaming power and excellent solubility.
It is widely used as the main agent and auxiliary agent for detergents.

Conventionally, a method for producing a polyoxyalkylene fatty acid alkanolamide has been a method in which a fatty acid methyl ester and an alkanolamine are reacted under an alkali catalyst to obtain a fatty acid alkanolamide, and further an alkylene oxide is added.

As a method for obtaining a fatty acid alkanolamide, a method of directly reacting a fatty acid with an alkanolamine has been known for a long time.

However, in the method of using fatty acid methyl ester as a raw material, unreacted ester and alcohol by-produced in the reaction remain during the production of fatty acid alkanolamide, resulting in odor and solubility after addition of alkylene oxide. There are drawbacks that have an adverse effect. Further, the price of fatty acid methyl ester is higher than that of the corresponding fatty acid, which is economically disadvantageous.

In addition, in the method of directly reacting a fatty acid with an alkanolamine, it is difficult to remove water generated by the reaction and remains in the system, which adversely affects the subsequent addition of alkylene oxide and a large amount of by-products such as polyethylene glycol. There is a drawback that

[0007]

The object of the present invention is to improve the drawbacks of the conventional method for producing polyoxyalkylene fatty acid alkanolamides, and to produce highly pure polyoxyalkylene fatty acid alkanolamides from economically inexpensive fatty acids as raw materials. A manufacturing method is provided.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that after directly reacting a fatty acid with an alkanolamine, water in the system is further removed by using a dehydrating agent. It was found that a highly pure and high-quality polyoxyalkylene fatty acid alkanolamide can be produced from an inexpensive fatty acid as a raw material by adding alkylene oxide after completely removing the present invention, and completed the present invention.

That is, the present invention provides a compound represented by the general formula (1):

[0010]

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In the formula, RCO represents a straight chain or branched chain saturated or unsaturated fatty acid residue having 6 to 22 carbon atoms, and 1 mol of the fatty acid represented by the general formula (2)

[0012]

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(Wherein X represents H or CH ₃ , and Z represents H
Or CH ₂ CH ₂ OH) is reacted with 1.0 to 2.0 mol of an alkanolamine at a temperature of 80 to 180 ° C., and then a dehydrating agent or a metal alcoholate also serving as a dehydrating agent is added to the reaction mixture to leave the system. The amidation reaction is completed so that the water content is 0.1% or less, and then the general formula (3)

[0014]

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A fatty acid alkanolamide represented by the formula (wherein RCO, X and Z are as defined above) is prepared, and then a compound of the general formula (4)

[0016]

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An alkylene oxide represented by the formula (wherein Y represents H or CH ₃ ) is added under pressure to give a general formula (5).

[0018]

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(In the formula, n represents an integer of 1 or more, Y ¹ and Y ² represent H or CH ₃ , RCO and X are as defined above, and W is H or the general formula (6)).

[0020]

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(In the formula, m represents an integer of 0 or more, Y ¹ and Y ² are the same as defined above), and relates to a process for producing a polyoxyalkylene fatty acid alkanolamide.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a polyoxyalkylene fatty acid alkanolamide of the present invention will be described in detail below.

In the fatty acid represented by the general formula (1) used as a raw material in the present invention, RCO has 6 carbon atoms.
The linear or branched saturated or unsaturated fatty acid residue of -22 is not particularly limited, and even a single composition,
A mixture of two or more kinds may be used. Examples of the fatty acid represented by the general formula (1) include lauric acid, myristic acid, stearic acid, oleic acid, coconut fatty acid, palm fatty acid, and beef tallow fatty acid.

As the alkanolamine represented by the general formula (2), any of monoethanolamine, isopropanolamine and diethanolamine can be selected.

In the reaction between the fatty acid of the general formula (1) and the alkanolamine of the general formula (2), the reaction mole number of the alkanolamine is 1.0 to 2.0 mol, preferably 1.
It is 0 to 1.2 mol. If the alkanolamine is less than 1.0 mol, the alkanolamine will be insufficient and unreacted fatty acid will remain in the system, which is not preferable.
When it exceeds the molar amount, it takes a long time to distill the unreacted alkanolamine, the heat history of the system increases, and a side reaction occurs during distilling the alkanolamine, which is not preferable.

The reaction temperature at this time is 80 to 180 ° C, preferably 140 to 160 ° C. When the reaction temperature is less than 80 ° C, the reaction does not proceed, and when it exceeds 180 ° C, it is higher than the boiling point of the alkanolamine, so that the alkanolamine is distilled out and a side reaction occurs due to the lack of alkanolamine in the system. Therefore, neither is preferable.

However, in this reaction, as shown in the following reaction formula, water is also by-produced in addition to the target fatty acid alkanolamide.

[0028]

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When alkylene oxide is added in the next step with water remaining in the system, alkylene oxide reacts with water to produce polyethylene glycol, polypropylene glycol, etc., as shown in the following reaction formula,
The purity of the target polyoxyalkylene fatty acid alkanolamide is reduced.

[0030]

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Therefore, in order to increase the purity of the polyoxyalkylene fatty acid alkanolamide, it is necessary to reduce the residual water content in the system to 0.1% or less. Therefore, a commonly used dehydrating agent such as a molecular sieve can be used for the purpose of removing water, but it is most preferable to use a metal alcoholate having both a catalytic action for the alkylene oxide addition reaction in the next step and a dehydrating effect. It is possible to increase the purity of the polyoxyalkylene fatty acid alkanolamide and is economical.

As the metal alcoholate used also as a dehydrating agent and as a catalyst, alkali metal compounds are particularly preferable, and sodium methylate, sodium ethylate, potassium methylate, potassium ethylate, aluminum isopropylate and the like can be mentioned.

The fatty acid alkanolamide obtained by the above method has a very high purity and almost no water is present in the system. A polyoxyalkylene fatty acid alkanolamide of high purity and high quality can be produced by adding the alkylene oxide of the general formula (4) to this under pressure. Further, by using a fatty acid which is a cheaper raw material than fatty acid methyl ester, it is economically superior. As the alkylene oxide represented by the general formula (4), either ethylene oxide or propylene oxide can be selected.

The addition reaction of the alkylene oxide is carried out, for example, under the pressure of 0.2-10.0 kg / cm ² by 80-1.
It may be carried out at 30 ° C.

[0035]

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

Example 1 73 g (1.2 mol) of monoethanolamine was added to 200 g (1.0 mol) of lauric acid and reacted at 160 ° C. for 4 hours while removing water produced. After removing excess monoethanolamine under reduced pressure, 1 g of sodium methylate was added and the pressure was reduced again, and lauric acid monoethanolamide 24 was added.
3 g was obtained (residual water content 0.02%). To this, 132 g of ethylene oxide was added, and 120 g was added in the autoclave.
The reaction was carried out at 1 ° C for 1 hour to obtain 375 g of polyoxyethylene (3) lauric acid monoethanolamide.

Example 2 81 g (1.1 mol) of isopropanolamine was added to 200 g (1.0 mol) of lauric acid, and the reaction was carried out at 150 ° C. for 5 hours while removing the produced water. After removing excess isopropanolamine under reduced pressure, sodium methylate 1
g was added and the pressure was reduced again, and 257 g of lauric acid monoisopropanolamide was obtained (residual water content 0.02%). To this, 88 g of ethylene oxide was added and reacted in an autoclave at 120 ° C. for 2 hours to obtain 345 g of polyoxyethylene (2) lauric acid isopropanolamide.

Example 3 70 g (1.15 mol) of monoethanolamine was added to 228 g (1.0 mol) of myristic acid, and the reaction was carried out at 160 ° C. for 4 hours while removing the produced water. After removing excess monoethanolamine under reduced pressure, sodium methylate 1
After addition of g and re-pressurization, 289 g of myristic acid monoethanolamide was obtained (residual water content 0.02%). 114 g of propylene oxide was added thereto, and the mixture was reacted in an autoclave at 150 ° C. for 2 hours to obtain 403 g of polyoxypropylene (2) myristic acid monoethanolamide.

Example 4 121 g (1.15 mol) of diethanolamine was added to 210 g (1.0 mol) of coconut oil fatty acid and reacted at 155 ° C. for 6 hours while removing water produced. After removing excess diethanolamine under reduced pressure, sodium methylate 1 g
Was added and the pressure was reduced again, and coconut fatty acid diethanolamide 28 was added.
7 g was obtained (residual water content 0.03%). 220g of ethylene oxide was added to this, and 120g was added in the autoclave.
The reaction was carried out at 2 ° C. for 2 hours to obtain 507 g of polyoxyethylene (5) coconut fatty acid diethanolamide.

Comparative Example 1 61 g (1.0 mol) of monoethanolamine and 0.5 g of sodium methylate were added to 214 g (1.0 mol) of methyl laurate, and the produced methanol was removed at 90 ° C. for 2 hours. The reaction was carried out to obtain 243 g of lauric acid monoethanolamide. 88 g of ethylene oxide was added thereto, and the mixture was reacted in an autoclave at 120 ° C. for 1 hour to obtain 331 g of polyoxyethylene (2) lauric acid monoethanolamide.

Comparative Example 2 61 g (1.0 mol) of monoethanolamine and 0.5 g of sodium methylate were added to 224 g (1.0 mol) of coconut fatty acid methyl ester, and the resulting methanol was removed at 2 ° C at 90 ° C. After reacting for a time, 253 g of coconut fatty acid monoethanolamide was obtained. 86 g of propylene oxide was added to this, and the mixture was heated to 150 in an autoclave.
Reaction at ℃ for 1 hour, polyoxypropylene (1.5)
339 g of coconut fatty acid monoethanolamide was obtained.

Comparative Example 3 To 214 g (1.0 mol) of methyl laurate, 75 g (1.0 mol) of isopropanolamine and 0.5 g of sodium methylate were added, and the reaction was carried out at 90 ° C. for 2 hours while removing methanol produced. Then, 332 g of lauric acid monoethanolamide was obtained. To this, 88 g of ethylene oxide was added, and reacted in an autoclave at 120 ° C. for 2 hours to obtain 331 g of polyoxyethylene (2) lauric acid isopropanolamide.

Comparative Example 4 200 g (1.0 mol) of lauric acid and 73 g (1.2 mol) of monoethanolamine were added, and the reaction was carried out at 160 ° C. for 4 hours while removing water produced, and 243 g of lauric acid monoethanolamide. Got To this, 132 g of ethylene oxide was added and reacted in an autoclave at 120 ° C. for 1 hour to obtain 375 g of polyoxyethylene (3) lauric acid monoethanolamide.

The polyoxyalkylene fatty acid alkanolamides obtained in Examples 1 to 4 and Comparative Examples 1 to 4 were analyzed for content of alcohol and ester by gas chromatography (GLC). In addition, thin layer chromatography (T
The presence / absence of polyethylene glycol, polypropylene glycol and other impurities was examined by LC). Also 10%
An aqueous solution was prepared and smelled at 70 ° C. Table 1 shows the results.

[0045]

[Table 1]

The polyoxyalkylene fatty acid alkanolamides produced in Examples 1 to 4 were of high quality with no odor and other impurities.

On the other hand, the polyoxyalkylene fatty acid alkanolamides produced in Comparative Examples 1 to 3 had an ester odor and impurities such as methanol were confirmed, and the polyoxyalkylene fatty acid alkanolamides produced in Comparative Example 4 were polyethylene glycol. Impurities such as are confirmed.

As is clear from the results shown in Table 1, the polyoxyalkylene fatty acid alkanolamide produced by the method of the present invention is a highly pure polyoxyalkylene fatty acid alkanolamide containing no impurities such as alcohol and polyethylene glycol. Recognize.

[0049]

Industrial Applicability By using the production method of the present invention, a polyoxyalkylene fatty acid alkanolamide can be economically obtained with high purity from an inexpensive fatty acid.

Claims (1)

[Claims] 1. A compound of the general formula (1) (Wherein RCO represents a straight chain or branched chain saturated or unsaturated fatty acid residue having 6 to 22 carbon atoms) with respect to 1 mol of the fatty acid represented by the general formula (2): (In the formula, X represents H or CH ₃ , and Z is H or CH ₂ C.
Alkanolamine 1.0 represented by H ₂ OH)
˜2.0 mol is reacted at a temperature of 80 to 180 ° C., and then a dehydrating agent or a metal alcoholate also serving as a dehydrating agent is added to carry out the amidation reaction so that the residual water content in the system is 0.1% or less. When completed, the general formula (3): A fatty acid alkanolamide represented by the formula (wherein RCO, X and Z are the same as defined above) is prepared, and then a compound of the general formula (4) An alkylene oxide represented by the formula (wherein Y represents H or CH ₃ ) is added under pressure to the general formula (5): (In the formula, n represents an integer of 1 or more, Y ¹ and Y ² represent H or CH ₃ , RCO and X are the same as defined above,
W is H or general formula (6) (In the formula, m represents an integer of 0 or more, Y ¹ and Y ² are the same as defined above), and a method for producing the polyoxyalkylene fatty acid alkanolamide.