JP3529920B2 - Production method of high purity alkanolamide - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an alkanolamide, and more particularly to a method for producing a high-purity alkanolamide having a low amide ester content as a by-product from a fatty acid ester and an alkanolamine.

[0002]

2. Description of the Related Art Alkanolamides are widely used in shampoos, kitchen detergents, cosmetics, etc. as a detergent improving agent for liquid detergents, a foaming agent, and a foam stabilizer. Also, various derivatives obtained by further adding alkylene oxide to this alkanolamide, or by further carrying out carboxymethylation, phosphoric acid esterification, and sulfuric acid esterification are low in irritation, and have excellent foaming property and detergency. , As a main base of a surfactant, etc., is compounded in a detergent composition or the like.

As a method for producing this alkanolamide,
A method of reacting a fatty acid ester with an alkanolamine under an alkali catalyst is known. However, in this method, a large amount of amide ester is produced as a by-product, and this amide ester has low solubility in water, which causes turbidity of the liquid product. There is also a problem that impurities are increased when alkylene oxide is further added to the alkanolamide or when it is further derivatized by carboxymethylation, sulfuric acid esterification, phosphoric acid esterification or the like.

As a method for obtaining an alkanolamide having a small amount of by-produced amide ester, an amide ester is produced from a fatty acid and an alkanolamine in a first-step reaction, and then an aminolysis is performed in a second-step reaction to give an amide ester. There is a method of converting into an alkanolamide (Japanese Patent Laid-Open No. 53-44513), but this method has complicated steps and cannot sufficiently reduce the amount of amide ester.

Therefore, an object of the present invention is to provide a method for producing a high-purity alkanolamide in which the amount of by-produced amide ester can be sufficiently and stably reduced and the process is not complicated.

[0006]

Means for Solving the Problems The inventors of the present invention have made earnest studies to solve the above problems, and as a result, surprisingly, the formation of amide ester was found to occur in the catalyst amount, the water content and the acid value (A) of the reaction raw material.
It was found that it is related to V). Therefore,
By controlling the amount of the catalyst to be used within the specific range, it becomes possible to produce a highly pure alkanolamide having a stable amide ester content, and the present invention has been completed. That is, the present invention has the general formula (I)

[0007]

[Chemical 3]

(In the formula, R ¹ represents a linear or branched alkyl or alkenyl group having 7 to 21 carbon atoms, and R ² represents 1 carbon atom.
~ 3 alkyl groups are shown. ) And a general formula (II) H _m N- (R ³ —OH) _n (II) (wherein R ³ represents a linear or branched alkylene group having 1 to 5 carbon atoms). , M and n are 1 or 2 respectively, and m + n =
It is a number of three. ) With an alkanolamine represented by the general formula (III)

[0009]

[Chemical 4]

In the method for producing an alkanolamide represented by the formula (wherein R ¹ , R ³ , m and n have the above-mentioned meanings), an alkali catalyst of an amount satisfying the following formula (1) is used. The present invention provides a method for producing a high-purity alkanolamide, which comprises using

0 <[A− (W + AV)] ≦ 1 (mmol / g) (1) [wherein A is the amount of the alkali catalyst, W is the water content of the reaction raw material, and AV is the acid value of the reaction raw material. In each case, the unit is the amount (mmol) per 1 g of the reaction raw material. The high-purity alkanolamide obtained by the production method of the present invention is excellent as a detergency improver for liquid detergents, a foaming agent, and a foam stabilizer. When it is added or is further derivatized by carboxymethylation, phosphoric acid esterification, sulfuric acid esterification or the like to be used as a surfactant, it is possible to obtain a surfactant having excellent foaming power and detergency.

[0012]

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

The raw material fatty acid ester and alkanolamine used in the production method of the present invention are appropriately selected depending on the kind of the desired alkanolamide. Examples of the fatty acid ester represented by the general formula (I) include caprylic acid, undecanoic acid, lauric acid, myristic acid, pentadecanoic acid, palmitic acid, stearic acid, oleic acid,
Arachidic acid, behenic acid, coconut oil fatty acid, beef tallow fatty acid, and higher fatty acid such as synthetic fatty acid obtained by paraffin oxidation or oxo method, preferably fatty acid having 8 to 14 carbon atoms,
Examples thereof include lower alcohols such as methanol and ethanol, preferably esters with methanol.

Examples of the alkanolamine represented by the above general formula (II) include monoethanolamine, diethanolamine, monopropanolamine, dipropanolamine, monoisopropanolamine, diisopropanolamine and the like, preferably monoethanolamine. It is an amine.

The alkali catalyst used in the present invention is preferably an alkali catalyst which reacts with a fatty acid and does not produce water as a by-product, and more preferably an alkali metal alcoholate. Specific examples thereof include sodium methylate, sodium ethylate, potassium methylate, potassium ethylate and the like, and sodium methylate is particularly preferable.

The general formula (I) used in the present invention
The molar ratio of the fatty acid ester represented by and the alkanolamine represented by the general formula (II) is appropriately selected, but is preferably 1 to 1.3 mol of alkanolamine per 1 mol of fatty acid ester. The amount of alkanolamine
When the amount is 1.3 mol or less, the amount of the remaining alkanolamine decreases, and the physical properties and hue stability are good, which is preferable.

Further, in the present invention, when amidating the above-mentioned fatty acid ester and alkanolamine, it is necessary to use an amount of an alkali catalyst which satisfies the above formula (1), preferably the above formula (1) [A- in 1)
The value of (W + AV)] is more than 0 and 0.5 mmol / g or less, more preferably the value of [A- (W + AV)] is more than 0 and 0.1 mmol / g or less. When the value of [A- (W + AV)] in the above formula (1) is 0 or less, that is, the amount of the alkali catalyst is not more than the molar amount corresponding to the water content and the acid value of the reaction raw material, as described above, the amide ester secondary Undesirable occurrence of raw material In addition, [A− (W
+ AV)] value of more than 1 mmol / g is not preferable because it tends to be colored.

In the present invention, the reaction conditions for reacting the fatty acid ester and the alkanolamine are appropriately selected depending on the kind of raw material, but the reaction temperature is 70 to 150 ° C.,
The reaction pressure is preferably 10 to 400 torr. A moderate reaction rate can be obtained by setting the reaction temperature to 70 ° C or higher.
When the temperature is 50 ° C. or lower, decomposition of amide can be suppressed under high temperature / alkali conditions, which is preferable. Also, if the reaction pressure is set to 10 torr or more, the distillation of alkanolamine can be suppressed,
By setting it to be not more than orr, alcohol by-produced in the reaction system can be appropriately distilled, and an appropriate reaction rate can be obtained, which is preferable.
The reaction time is usually 1 to 6 hours.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples,% is based on weight unless otherwise specified.

Comparative Example 1 214.4 g of methyl laurate was added to a 500 ml four-necked flask.
(1.0 mol) and 61.7 g (1.01 mol) of monoethanolamine were charged. At this time, the amount of water in the system is 0.048 mmol / g and the acid value is
It was 0.0035 mmol / g. Furthermore, 0.029 mmol / g of 28% sodium methylate was charged, and the temperature was raised to 90 ° C under a nitrogen stream,
The pressure was reduced to 50 torr in about 1 hour. In that state, aging was carried out for 2 hours to obtain lauric acid monoethanolamide represented by the following formula (IV).

[0021]

[Chemical 5]

Comparative Example 2 Methyl laurate (214.4 g) was added to a 500 ml four-necked flask.
(1.0 mol) and 61.7 g (1.01 mol) of monoethanolamine were charged. At this time, the amount of water in the system is 0.048 mmol / g and the acid value is
It was 0.0035 mmol / g. Furthermore, 0.043 mmol / g of 28% sodium methylate was charged, and the temperature was raised to 90 ° C. under a nitrogen stream,
The pressure was reduced to 50 torr in about 1 hour. In that state, aging was carried out for 2 hours to obtain lauric acid monoethanolamide represented by the above formula (IV).

Example 1 214.4 g of methyl laurate was added to a 500 ml four-necked flask.
(1.0 mol) and 61.7 g (1.01 mol) of monoethanolamine were charged. At this time, the amount of water in the system is 0.048 mmol / g and the acid value is
It was 0.0035 mmol / g. Furthermore, 28% sodium methylate was charged at 0.065 mmol / g, and the temperature was raised to 90 ° C. under a nitrogen stream,
The pressure was reduced to 50 torr in about 1 hour. In that state, aging was carried out for 2 hours to obtain lauric acid monoethanolamide represented by the above formula (IV).

Example 2 214.4 g of methyl laurate was added to a 500 ml four-necked flask.
(1.0 mol) and 61.7 g (1.01 mol) of monoethanolamine were charged. At this time, the amount of water in the system is 0.048 mmol / g and the acid value is
It was 0.0035 mmol / g. Furthermore, 0.101 mmol / g of 28% sodium methylate was charged, and the temperature was raised to 90 ° C. under a nitrogen stream,
The pressure was reduced to 50 torr in about 1 hour. In that state, aging was carried out for 2 hours to obtain lauric acid monoethanolamide represented by the above formula (IV).

Example 3 Methyl laurate (214.4 g) was added to a 500 ml four-necked flask.
(1.0 mol) and 61.7 g (1.01 mol) of monoethanolamine were charged. At this time, the amount of water in the system is 0.048 mmol / g and the acid value is
It was 0.0035 mmol / g. Furthermore, 0.150 mmol / g of 28% sodium methylate was charged, and the temperature was raised to 90 ° C. under a nitrogen stream,
The pressure was reduced to 50 torr in about 1 hour. In that state, aging was carried out for 2 hours to obtain lauric acid monoethanolamide represented by the above formula (IV).

Example 4 214.4 g of methyl laurate was added to a 500 ml four-necked flask.
(1.0 mol) and 61.7 g (1.01 mol) of monoethanolamine were charged. At this time, the amount of water in the system is 0.048 mmol / g and the acid value is
It was 0.0035 mmol / g. Furthermore, 0.545 mmol / g of 28% sodium methylate was charged, and the temperature was raised to 90 ° C. under a nitrogen stream,
The pressure was reduced to 50 torr in about 1 hour. In that state, aging was carried out for 2 hours to obtain lauric acid monoethanolamide represented by the above formula (IV).

Comparative Example 3 214.4 g of methyl laurate was added to a 500 ml four-necked flask.
(1.0 mol) and 61.7 g (1.01 mol) of monoethanolamine were charged. At this time, the water content in the system was 0.081 mmol / g, and the acid value was
It was 0.0035 mmol / g. Furthermore, 28% sodium methylate was charged at 0.065 mmol / g, and the temperature was raised to 90 ° C. under a nitrogen stream,
The pressure was reduced to 50 torr in about 1 hour. In that state, aging was carried out for 2 hours to obtain lauric acid monoethanolamide represented by the above formula (IV).

Example 5 Methyl laurate (214.4 g) was added to a 500 ml four-necked flask.
(1.0 mol) and 61.7 g (1.01 mol) of monoethanolamine were charged. At this time, the water content in the system was 0.081 mmol / g, and the acid value was
It was 0.0035 mmol / g. Furthermore, 0.101 mmol / g of 28% sodium methylate was charged, and the temperature was raised to 90 ° C. under a nitrogen stream,
The pressure was reduced to 50 torr in about 1 hour. In that state, aging was carried out for 2 hours to obtain lauric acid monoethanolamide represented by the above formula (IV).

Comparative Example 4 Methyl laurate (214.4 g) was added to a 500 ml four-necked flask.
(1.0 mol) and 61.7 g (1.01 mol) of monoethanolamine were charged. At this time, the water content in the system was 0.042 mmol / g, and the acid value was
It was 0.194 mmol / g. Furthermore, 0.043 mmol / g of 28% sodium methylate was charged, and the temperature was raised to 90 ° C. under a nitrogen stream,
The pressure was reduced to 50 torr in about 1 hour. In that state, aging was carried out for 2 hours to obtain lauric acid monoethanolamide represented by the above formula (IV).

Example 6 Methyl laurate 214.4 g in a 500 ml four-necked flask
(1.0 mol) and 61.7 g (1.01 mol) of monoethanolamine were charged. At this time, the water content in the system was 0.042 mmol / g, and the acid value was
It was 0.194 mmol / g. Furthermore, 0.236 mmol / g of 28% sodium methylate was charged, and the temperature was raised to 90 ° C under a nitrogen stream,
The pressure was reduced to 50 torr in about 1 hour. In that state, aging was carried out for 2 hours to obtain lauric acid monoethanolamide represented by the above formula (IV).

In Examples 1 to 6 and Comparative Examples 1 to 4,
Catalyst amount (A), water content (W), acid value (AV), [A-
The value of (W + AV)] and the content of the by-produced lauric acid amide ester represented by the following formula (V) are summarized in Table 1.

[0032]

[Chemical 6]

[0033]

[Table 1]

Note) * 1 Moisture content: Measured by Karl Fischer method * 2 Acid value: Measured according to standard oil and fat analysis test method 2.4.1-83 * 3 Lauric acid amide ester content:% by weight of lauric acid monoethanolamide , Measured by gas chromatography, and in Examples 1-6 and Comparative Examples 1-4, [A-
The relationship between the value of (W + AV)] and the content of lauric acid amide ester in the product is shown in FIG.

[Brief description of drawings]

FIG. 1 is a schematic diagram of Examples 1 to 6 and Comparative Examples 1 to 4.
It is a figure which shows the relationship between the value of [A- (W + AV)], and the lauric acid amide ester content in a product.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-25108 (JP, A) JP-A-7-145122 (JP, A) JP-A-3-502797 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C07C 231/02 C07C 233/18 C07C 233/20

Claims (3)

(57) [Claims] 1. A compound represented by the general formula (I): (In the formula, R ¹ represents a linear or branched alkyl group or alkenyl group having 7 to 21 carbon atoms, and R ² represents an alkyl group having 1 to 3 carbon atoms.), in the general formula _{(II) H m N- (R} 3 -OH) n (II) ( wherein, R ³ represents a linear or branched alkylene group of 1 to 5 carbon atoms, m and n are each 1 or 2, m + n =
It is a number of three. ) With an alkanolamine represented by the general formula (III) (In the formula, R ¹ , R ³ , m and n have the above-mentioned meanings.) In the method for producing an alkanolamide, an amount of an alkali catalyst satisfying the following formula (1) is used. A method for producing a high-purity alkanolamide characterized by: 0 <[A− (W + AV)] ≦ 1 (mmol / g) (1) [wherein A is the amount of the alkali catalyst, W is the water content of the reaction raw material, and AV is the acid value of the reaction raw material. The unit is the amount (mmol) per 1 g of the reaction raw material. ] 2. The method for producing a high-purity alkanolamide according to claim 1, wherein the alkali catalyst is an alkali metal alcoholate. 3. A- (W + A in the above formula (1)
The method for producing a high-purity alkanolamide according to claim 1 or 2, wherein the value of V)] is greater than 0 and 0.5 mmol / g or less.