JPH10175940A - Light-colored alkyl ester salt of alpha-sulfo fatty acid and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject compound (α-SF) with only a small amount of byproducts, having a light color near white by performing a sulfonation and an aging reactions of an alkyl ester of a saturated fatty acid in the presence of a specific nitrogen-containing compound or aromatic hydroxy compound. SOLUTION: The objective compound is produced by a sulfonation step for bringing an alkyl ester of a saturated fatty acid of the formula R1 CH2 COOR2 (R1 is a 6-24C alkyl; R2 is a 1-6C alkyl) into contact with a sulfonation gas, and an aging step for eliminating SO3 from two-molecular adduct with the SO3 , in the presence of at least one kind of a nitrogen-containing compound such as a metal amide, a carbonamide, an amidesulfate, a carbamate, an aspartate and a glutamate, or an aromatic hydroxyl compound such as hydroquinone, butylhydroxyanisole, dibutylhydroxytoluene and a gallic acid ester at least in the aging step.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an .alpha.-sulfofatty acid alkyl ester salt and a method for producing the same, and more particularly to a method for producing a light-colored .alpha.-sulfofatty acid alkyl ester salt having a color close to white and a method for producing the same. It relates to a light-colored α-sulfofatty acid alkyl ester salt.

[0002]

2. Description of the Related Art Alkyl α-sulfofatty acid ester salts
Is one of its uses as a surfactant.
High purification power, good biodegradability, and low environmental impact
Performance as a cleaning material
I have. The α-sulfofatty acid alkyl ester salt is a fat
Fatty acid alkyl ester is SO _Three Sulfonating with
It is then obtained by neutralization with an alkali.

[0003] The mechanism of sulfonation of fatty acid alkyl esters is described in Smith and Stirton: JAOCS vol. 4
4, p. 405 (1967), Schmid, Baumann, Stein,
Dolhaine: Proceeding of the World Surfactants Con
gress Munchen, vol. 2, P. 105: Gel-nhausen,
Kurle (1984) and H. Yoshimura: Oil Chemistry (JJOC)
S), 41, 10 (1992),
It is known that the reaction proceeds according to the following reaction formula.

[0004]

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In this sulfonation reaction, when SO ₃ is reacted with a fatty acid alkyl ester, it is efficient if SO ₃ is directly coordinated to the α-position of the fatty acid ester to form an α-sulfo fatty acid alkyl ester. First, a reaction to be inserted into an alkoxy group occurs, and a single molecule SO ₃ adduct is formed. Then, in the next step, it reacts with SO ₃ to introduce a sulfone group at the α-position, thereby producing an SO ₃ biadduct (hereinafter abbreviated as “biadduct”).
At this stage, if the introduction of SO ₃ is stopped and the state of heating is maintained, SO ₃ inserted into the alkoxy group is eliminated to produce an α-sulfofatty acid alkyl ester. This step is called an "aging step".

[0006] The α-sulfofatty acid alkyl ester obtained through the aging step can be neutralized with an alkali in the next neutralization step to obtain the desired α-sulfofatty acid alkyl ester salt. . Less than,
This α-sulfofatty acid alkyl ester salt is referred to as “α-S
F ”.

[0007]

However, the α-sulfofatty acid alkyl ester produced by the conventional production method is markedly colored, and therefore the α-SF obtained after alkali neutralization is also colored. When used as a material for a cleaning agent, a product cannot be produced in a state where α-SF is colored. Therefore, conventionally, bleaching treatment under severe conditions using hydrogen peroxide or the like is performed before or after this neutralization step. Had been done.

However, in these neutralization and bleaching steps, some ester bonds are cleaved, so that α-
There is a problem that by-products of sulfo fatty acids or α-sulfo fatty acid dialkali salts cannot be avoided. Since these by-products have low detergency as a detergent active ingredient and poor water solubility, it is difficult to efficiently obtain α-SF suitable as a detergent when these substances are produced in a large amount as a by-product. Therefore, if the bleaching step not directly involved in the production of α-SF can be omitted or simplified, the production of these undesirable by-products can be suppressed, and the production equipment can be reduced and the environment can be improved. Become.

It has been found that one of the causes of the coloring of the α-sulfofatty acid alkyl ester is due to the presence of excess sulfonated gas in the sulfonation step. However, the reaction to the bimolecular adduct does not proceed smoothly unless the sulfonated gas is present in excess.

It has also been confirmed that this coloring proceeds particularly during the aging step. However, this aging step cannot be simplified. That is, if aging is not performed sufficiently, a large amount of unreacted fatty acid alkyl ester remains, and a bimolecular adduct remains in the next alkali neutralization step, for example, when neutralized with sodium hydroxide or the like, shown below. Such a reaction occurs, and a large amount of α-sulfofatty acid disodium having poor detergency and water solubility is generated.

[0011]

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As described above, when the neutralization is performed in a state where the SO ₃ elimination reaction in the aging step is insufficient and the bimolecular adduct is present in a large amount in the sulfonation reaction product, α-sulfo fatty acid disodium is produced. As a result, the physical properties of the surfactant, such as the detergency and the penetrating power, are reduced. Therefore,
The production of α-sulfofatty acid alkyl esters which are light-colored near white and contain as little by-products as possible is an important issue when producing light-colored and high-performance α-SF.

The method for obtaining the light-colored α-SF includes inorganic sulfates (JP-A-51-43716), long-chain fatty acid amides (WO 9003967), pyridine (DE 4030852), and thiodiglycol.
A method has been proposed in which a sulfonation reaction is performed in the presence of a rudiester (DE Publication No. 4224735).
However, when a long-chain fatty acid amide is used, a sufficient effect cannot be obtained unless the amount of addition is large, and when pyridine is used, there is a problem in terms of odor. And the effect of improving the color tone was not always satisfactory. The present invention has been made in order to solve the above-mentioned problems, and has a light color α-
An object of the present invention is to provide a SF and a method for manufacturing the same.

[0014]

Means for Solving the Problems The inventors of the present invention have found that when a certain type of nitrogen-containing compound or aromatic hydroxy compound is used in the sulfonation / ripening reaction of a saturated fatty acid alkyl ester, by-products are reduced. The inventors have found that α-SF with improved color tone can be obtained, and as a result of intensive studies, have reached the present invention.

Therefore, the method for producing α-SF of the present invention
Is represented by the following general formula (I) R₁CH_TwoCOOR_Two ... (I) (where R₁ Represents an alkyl group having 6 to 24 carbon atoms;
_Two Represents an alkyl group having 1 to 6 carbon atoms)
Contact the fatty acid alkyl ester with the sulfonated gas
Sulphonation step and the sulphonation step
SO_Three From bimolecular adduct to SO _Three To remove α-s
Aging step for producing rufofatty acid alkyl ester
The method for producing α-SF containing at least
In the forming step, at least one kind selected from the following group A is included.
A nitrogen compound, or at least one selected from the following group B:
Characterized by the presence of one aromatic hydroxy compound
It is assumed that.

In the above, the compounds of Group A and Group B are as follows. Group A: metal amide, carboxylic acid amide, amide sulfate,
Carbamate, aspartate, glutamate,
Aminosalicylate, aminobenzenesulfonate, thiourea, hydrazine, hydroxylamine, phenothiazine, N, N'-diphenyl-p-phenylenediamine, N, N'-disec-butyl-p-phenylenediamine, and 4, 4'-tetramethyl-diaminodiphenylmethane. Group B: hydroquinone, butylhydroxyanisole,
Dibutylhydroxytoluene, and gallic acid esters.

The present invention also provides α-SF produced by the above-mentioned production method.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The method for producing α-SF of the present invention generally comprises a sulfonation step, an aging step, and a neutralization step. In this sulfonation step and / or the aging step, at least one type of nitrogen-containing compound selected from the following group A is used. Compound or at least one aromatic hydroxy compound selected from the following group B.

Group A: metal amide, carboxylic acid amide, amide sulfate, carbamate, aspartate, glutamate, aminosalicylate, aminobenzenesulfonate, thiourea, hydrazine, hydroxylamine, phenothiazine, N, N'-diphenyl-p-phenylenediamine, N, N'-disec-butyl-p-phenylenediamine, 4,4'-tetramethyl-diaminodiphenylmethane. In the above, the metal of the metal amide is preferably a monovalent metal such as an alkali metal, and the counter ion of various salts is preferably an alkali metal or ammonium. The carboxylic acid of the carboxamide is formic acid, acetic acid, propionic acid, or butyric acid. The substitution position of the amino group in the aminosalicylate and aminobenzenesulfonate is arbitrary.

Group B: hydroquinone, butylhydroxyanisole, dibutylhydroxytoluene, gallic acid ester. In the above-mentioned butylhydroxyanisole and dibutylhydroxytoluene, the substitution positions of the butyl group and the hydroxy group are arbitrary, and the alcohol residue in the gallic acid ester is preferably C ₁ -C ₄ .

The sulfonation step is a step of contacting the saturated fatty acid alkyl ester represented by the general formula (I) with a sulfonated gas to form a bimolecular adduct. In this step, SO ₃ is eliminated from the body to produce an α-sulfofatty acid alkyl ester. Generally, since the sulfonation step and the aging step are performed successively in the same reaction vessel, prior to any of these steps, preferably the compound of any of the above-mentioned group A or group B is added prior to the sulfonation step. . As a result, the color tone of the α-sulfofatty acid alkyl ester obtained after the aging step is improved, and consequently, after the neutralization step, a light-colored α-SF close to white of the present invention can be obtained.

In the production method of the present invention, the saturated fatty acid alkyl ester used as a starting material has a fatty acid residue having 6 to 24 carbon atoms in the general formula (I);
The alcohol residue has 1 to 6 carbon atoms, and the total carbon number of both alcohols is 9 to 26. The alkyl esters of saturated fatty acids include animal fats and oils derived from beef tallow, fish oil, etc., vegetable fats and oils derived from coconut oil, palm oil, soybean oil, etc., and synthetic fatty acids derived from the oxo process of α-olefins. It may be any of alkyl esters and the like, and is not particularly limited.

Preferred examples of the saturated fatty acid alkyl ester include, for example, methyl or ethyl laurate, methyl or ethyl palmitate, methyl or ethyl stearate, methyl or ethyl hardened tallow fatty acid, methyl or ethyl hardened fish oil fatty acid, Methyl or ethyl coconut fatty acid, methyl or ethyl pam oil fatty acid, methyl or ethyl pam kernel oil fatty acid and the like can be mentioned. These saturated fatty acid alkyl esters may be used alone or as a mixture. However, the iodine value is preferably 0.5 or less, more preferably 0.1 or less, because the lower the iodine value, the more difficult it is to color during the production process. It is said.

It is preferable that a compound selected from the group A or the group B (hereinafter referred to as "coloring inhibitor") is added to and mixed with the saturated fatty acid alkyl ester before sulfonation from the viewpoint of workability. However, even after addition and mixing after the sulfonation step and before the aging step,
The progress of coloring during the aging step can be suppressed.

The addition amount of the coloring inhibitor is in the range of 0.1% by weight to 30% by weight based on the fatty acid alkyl ester.
Preferably, it is in the range of 1% by weight to 10% by weight. When the amount is less than 0.1% by weight, the effect of improving color tone is hardly recognized, and when it exceeds 30% by weight, the α
-The amount of the non-surfactant component derived from the coloring inhibitor in the SF product may increase, and the performance as a surfactant may decrease.

The sulfonation step in the present invention can be carried out using any conventionally known sulfonation technology such as a gas-liquid multiphase flow reaction of a thin film type or a tubular type, or a batch type or continuous type reaction of a reaction tank. Good. Batch-type sulfonation is preferred if the color tone of the resulting α-sulfofatty acid alkyl ester is emphasized, and thin-film or tubular sulfonation is preferred if productivity and cost are emphasized.

As the sulfonating gas, SO ₃ gas, fuming sulfuric acid or the like can be used. Preferably, SO ₃ gas is used. In particular, SO ₃ gas diluted with an inert gas such as air or nitrogen to a concentration of 3% by volume to 30% by volume is suitably used.

The amount of SO ₃ to be introduced is in the range of 1.0 to 1.5 moles, more preferably 1.05 to 1.3 moles of the raw material saturated fatty acid ester. Is preferred. If it is less than 1.0 mole, the sulfonation reaction does not proceed sufficiently, and if it exceeds 1.5 moles, the sulfonation reaction becomes severe and coloring due to local heat generation becomes remarkable, and a light-colored target product is obtained. It becomes frustrating.

The reaction temperature in the sulfonation step may be at least the freezing point of the saturated fatty acid alkyl ester,
More preferably, the temperature is set in a range from the freezing point temperature to 70 ° C. higher than the freezing point. The reaction time of the sulfonation step varies depending on the sulfonation method, for example, 5 seconds to 60 seconds in the thin film type sulfonation method and 10 seconds in the batch type sulfonation method.
Minutes to about 120 minutes.

The aging step for removing SO ₃ from the bimolecular adduct is preferably performed at a reaction temperature in the range of 70 ° C. to 120 ° C. and a reaction time of 1 minute, depending on the conversion of the saturated fatty acid alkyl ester. It is performed within a range of ~ 120 minutes. If the reaction temperature is lower than 70 ° C. or the reaction time is shorter than 1 minute, the elimination reaction does not proceed sufficiently. If the reaction temperature is higher than 120 ° C. or the reaction time is longer than 120 minutes, the coloring of the product increases. This is not preferred because of the tendency to be made.

After the completion of the aging step, if necessary, a small amount of a lower alcohol may be added to the reaction system to carry out esterification, thereby suppressing the formation of α-sulfofatty acid disalt.

To use the α-sulfofatty acid alkyl ester formed after the aging step as a surfactant,
A neutralization step with an alkali is required. In the neutralization step, the reaction between the α-sulfofatty acid alkyl ester and the alkali is preferably performed in an acidic or weakly alkaline environment. When this reaction is performed under strong alkalinity,
The possibility that the ester bond is cleaved is increased and an α-sulfofatty acid disalt is formed, which is not preferable.

Examples of the alkali which can be used for the neutralization reaction include, for example, alkali metal hydroxide, alkaline earth metal hydroxide, ammonia, ethanolamine and the like. Before or after this neutralization step, a bleaching treatment can be performed if necessary.

The embodiments of the present invention described above are summarized below. (1) In a preferred method for producing α-SF of the present invention, a mixture of a saturated fatty acid alkyl ester and the coloring inhibitor in the range of 0.1% by weight to 30% by weight based on the saturated fatty acid alkyl ester is used. A sulfonation step in which the saturated fatty acid alkyl ester is brought into contact with SO ₃ gas at a reaction temperature in a range of 70 ° C. higher than the freezing point, and a bimolecular adduct formed in the sulfonation step
A ripening step of eliminating O ₃ .

(2) As the sulfonating gas used in the sulfonation step, SO ₃ gas is preferable, and in particular, SO ₃ gas diluted with an inert gas such as air or nitrogen to a concentration of 3 to 30% by volume is used. Is preferred. (3) The reaction temperature in the aging step is preferably in the range of 70 ° C to 120 ° C, and the reaction time is preferably in the range of 1 minute to 120 minutes. (4) The iodine value of the raw material saturated fatty acid alkyl ester is preferably 0.5 or less, more preferably 0.1 or less.

(5) After the aging step, α-SF suitable as a surfactant can be obtained by neutralization with an alkali in an acidic or weakly alkaline environment. (6) The α-SF of the present invention is produced through at least an aging step carried out in the presence of the coloring inhibitor, and preferably from 0.1% by weight to the saturated fatty acid alkyl ester. The mixture with the coloring inhibitor in the range of 30% by weight is mixed with SO at a reaction temperature within a range of 70 ° C. higher than the freezing point of the saturated fatty acid alkyl ester from the freezing point.
It is produced through at least a sulfonation step of contacting with _three gases and a ripening step of desorbing SO ₃ from the bimolecular adduct formed in the sulfonation step.

[0037]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the technical scope of the present invention. (Examples 1 to 16) Methyl myristate (raw material) having an iodine value of 0.13 was added to the following A as a coloring inhibitor.
The nitrogen-containing compounds of the group were mixed and placed in a 300 ml glass reactor equipped with jacket cooling and a stirrer, and the temperature was raised to 80 °
, A 1.2-fold molar amount of sulfuric anhydride gas (relative to the methyl myristate) diluted to 7% by volume with N ₂ gas was introduced over a period of 60 minutes. The mixture was aged by continuing stirring for 30 minutes.
No. 6 α-sulfomyl myristate (α-sulfofatty acid alkyl ester) was produced.

The coloring inhibitors used in the examples are as follows. Example 1 Ammonium Amido Sulfate Example 2 Ammonium Amido Sulfate Example 3 Sodium Amide Example 4 Formic Amide Example 5 Ammonium Carbamate Example 6 Sodium Aspartate Example 7 Sodium Glutamate Example 8 Aminosalicylic Acid Sodium Example 9: Sodium aminobenzenesulfonate Example 10: Thiourea Example 11: Hydrazine Example 12: Hydroxylamine Example 13: Phenothiazine Example 14: N, N'-diphenyl-p-phenylenediamine Example 15 : N, N'-di-secondary-butyl-p-phenylenediamine Example 16: 4,4'-tetramethyl-diaminodiphenylmethane The amount of each of the above-mentioned coloring inhibitors is as% by weight based on methyl myristate (raw material). It is shown in Table 1.

Comparative Example 1 Methyl α-sulfomyristate of Comparative Example 1 was produced in the same manner as in the above Example except that no coloring inhibitor was added.

For Examples 1 to 16 and Comparative Example 1, the conversion of the raw material methyl myristate was determined, and the color tone of the resulting methyl α-sulfomyristate was measured as follows. After the aging step under the above conditions, a 5% by weight ethanol solution of methyl α-sulfomyristate was treated with a 40 mm optical path length, No. It was measured with a Kret photoelectric meter using a 42 Blue filter. The smaller the value, the lighter the color. Table 1 shows the above results.

[0041]

[Table 1]

As is clear from Table 1, the methyl α-sulfomyristate of Examples 1 to 16 in which the nitrogen-containing compound of Group A was used as a coloring inhibitor did not use any coloring inhibitor. The color tone is improved as compared with that of Example 1.

Each of the obtained α-methylsulfomyristate of Examples 1 to 16 and Comparative Example 1 was neutralized according to a conventional method, and none of the colors changed. Therefore, α-SF obtained from Examples 1 to 16 was obtained without using the above-mentioned coloring inhibitor.
It is clear that the color tone is superior to SF.

(Examples 17 to 21) An iodine value of 0.1.
13 methyl myristate (raw material) was mixed with a group B aromatic hydroxy compound shown below as a coloring inhibitor,
Placed in a jacket cooling and equipped with a stirrer 300ml glass reactor, while maintaining the temperature at 80 ° C., 7 with N ₂ gas
A 1.2-fold molar amount of sulfuric anhydride gas (relative to the methyl myristate) diluted to volume% was introduced over 60 minutes, and after the total amount was introduced, the mixture was aged by continuing stirring for 30 minutes while maintaining at 85 ° C. The methyl α-sulfomyristate (α-sulfofatty acid alkyl ester) of Examples 17 to 21 was produced.

The coloring inhibitors used in each of the examples are as follows. Example 17: Hydroquinone Example 18: Hydroquinone Example 19: Butylhydroxyanisole Example 20: Dibutylhydroxytoluene Example 21: Propyl gallate The amount of each of the above color inhibitors is based on the weight of methyl myristate (raw material). % Are shown in Table 2.

With respect to the above-mentioned Examples 17 to 21,
The reaction rate of the raw material methyl myristate was determined, and the color tone of the obtained methyl α-sulfomyristate was measured in the same manner as in Examples 1 to 16. Table 2 shows the above results.

[0047]

[Table 2]

As is clear from Table 2, Examples 17 to 17 in which the aromatic hydroxy compounds of Group B were used as the coloring inhibitors were used.
Each of the methyl α-sulfomyristates of Example 21 has an improved color tone as compared with that of Comparative Example 1 (see Table 1) in which no coloring inhibitor is used.

When the methyl α-sulfomyristate of Examples 17 to 21 obtained here was neutralized according to a conventional method, no color change was observed. Therefore, it is clear that the α-SF obtained from Examples 17 to 21 is superior in the color tone to the α-SF produced without using the coloring inhibitor.

Example 22 Using a continuous thin-film type sulfonation apparatus made of stainless steel, methyl laurate / methyl myristate / methyl palmitate (mixing weight ratio: 3/6/1) having an iodine value of 0.08 was used. SO ₃ gas diluted to 5% by volume with dry air was added to the mixed solution (raw material) at a temperature of 80 ° C.
For sulfonation. The product of this sulfonation step was sampled in a 300 ml glass container, and ammonium amide sulfate was used as a coloring inhibitor in an amount of 5% by weight based on the raw material equivalent of the sampled product.
The mixture was added and aged at 85 ° C. for 60 minutes to produce an α-sulfofatty acid alkyl ester. Reaction rate is 9
8.3% and the color tone was 1040.

From the results of Example 22, it was found that sulfonation was carried out in a continuous thin film type sulfonation apparatus, a mixed fatty acid ester was used as a raw material, and a coloring inhibitor was added at the beginning of the aging step after the sulfonation step was completed. It can be seen that a light-colored α-SF having a good color tone can be obtained with a good yield.

[0052]

The method of the present invention for producing α-SF includes a step of sulfonating and aging a saturated fatty acid alkyl ester in the presence of a specific nitrogen-containing compound or an aromatic hydroxy compound. The obtained α-SF of the present invention has a light color close to white in color tone,
The subsequent bleaching step can be omitted or simplified. Further, the α-SF of the present invention reduces the content of undesired by-products as compared with the light-colored α-SF produced through the conventional extreme bleaching step, and increases the efficacy as a detergent.

Claims (2)

[Claims] 1. The following general formula (I): R ₁ CH ₂ COOR ₂ ... (I) wherein R ₁ represents an alkyl group having 6 to 24 carbon atoms;
₂ and sulfonation step of contacting a saturated fatty acid alkyl esters and sulfonated gas represented by an alkyl group having 1 to 6 carbon atoms), an SO ₃ from SO ₃ bimolecular adduct produced in the sulfonation step A ripening step of forming an α-sulfofatty acid alkyl ester by elimination, wherein at least the ripening step includes the following Group A: Group A: metal amide, carboxylic acid amide, Amide sulfate,
Carbamate, aspartate, glutamate,
Aminosalicylate, aminobenzenesulfonate, thiourea, hydrazine, hydroxylamine, phenothiazine, N, N'-diphenyl-p-phenylenediamine, N, N'-disec-butyl-p-phenylenediamine, and 4, At least one nitrogen-containing compound selected from 4′-tetramethyl-diaminodiphenylmethane,
Or the following group B: group B: hydroquinone, butylhydroxyanisole,
A method for producing a pale-color α-sulfofatty acid alkyl ester salt, comprising at least one aromatic hydroxy compound selected from dibutylhydroxytoluene and gallic acid ester. 2. A light-color α-sulfofatty acid alkyl ester salt produced by the production method according to claim 1.