JP2007176894A - Production method for anionic surfactant composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an efficient production method for an anionic surfactant composition containing an alkyl ether sulfate salt of high concentration and a light color. <P>SOLUTION: In the production method for a composition containing as the main component an anionic surfactant comprising an alkyl ether sulfate salt represented by following general formula (1) by means of sulfating a higher alcohol or its alkylene oxide adduct followed by neutralization, the first neutralization is conducted keeping the pH at 2 to 5 and the second neutralization is conducted until a pH of 10 or higher is attained. The above formula is: RO(AO)<SB>n</SB>SO<SB>3</SB>M (1), wherein R indicates an alkyl group or an alkenyl group; A indicates an alkylene group; M indicates a hydrogen atom or an alkali metal; and n indicates a number of 0 to 100 on average. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing an anionic surfactant composition, and more particularly, to an efficient method for producing an anionic surfactant composition comprising a high concentration light-colored alkyl ether sulfate ester as a main component.

Anionic surfactants composed of sulfate esters of higher alcohols or their alkylene oxide adducts are less irritating to the skin and are widely used as main active agents for liquid detergents such as dishwashing detergents, shampoos and clothing detergents. ing. However, at present, this alkyl ether sulfate ester salt has a light yellow color, and it is desired to lighten or decolorize the product to improve its commercial value.
As a method for lightening an anionic surfactant, bleaching with hypochlorite or hydrogen peroxide is generally used. Hypochlorite has a high bleaching effect, but skin sensitization has been pointed out, and bleaching with hypochlorite is not adopted due to voluntary regulations of the industrial association. Further, since hydrogen peroxide has a low bleaching effect, a large amount of use is required for lightening. For this reason, hydrogen peroxide may remain in the product, and if the amount of residual hydrogen peroxide is large, there is a risk that the dye in the product such as shampoo may be faded.

On the other hand, for example, Patent Documents 1 and 2 are known as methods for producing a light-colored alkyl ether sulfate ester salt. Patent Document 1 discloses a method in which hydrogen peroxide and succinic anhydride or benzoic anhydride are allowed to act on an alkyl ether sulfate ester aqueous solution or slurry. However, in this method, since the remaining amount of hydrogen peroxide is large, it is necessary to perform post-treatment such as thermal decomposition treatment or sulfite treatment.
In Patent Document 2, one or more reducing agents selected from sulfurous acid, bisulfurous acid and their salts are added and bleached during or after neutralization of the alkyl ether sulfate ester salt, and then bleached with an oxidizing agent. A method of processing is disclosed. Although this method is a useful lightening method, it is not satisfactory and further improvement has been desired.

Japanese Patent Publication No. 60-51520 Japanese Patent No. 3429653

  This invention makes it a subject to provide the efficient manufacturing method of the anionic surfactant composition which has a high concentration light-colored alkyl ether sulfate ester salt as a main component.

The present inventors paid attention to the neutralization step of the alkyl ether sulfate ester salt and found that a light-colored alkyl ether sulfate ester salt can be efficiently produced by performing specific two-step neutralization.
That is, in the present invention, a higher alcohol or an alkylene oxide adduct thereof is sulfated and then neutralized, and a surfactant composed of an alkyl ether sulfate represented by the following general formula (1) is a main component. A method for producing an anionic surfactant composition, wherein the first stage neutralization treatment is carried out while maintaining the pH at 2 to 5, and the second stage neutralization treatment is carried out until the pH reaches 10 or more. Method.
_{RO (AO) n SO 3 M} (1)
(In the formula, R represents a linear or branched alkyl group or alkenyl group having 9 to 24 carbon atoms, and A represents a linear or branched alkylene group having 2 to 4 carbon atoms. M represents a hydrogen atom or an alkali metal, and n represents an average value of 0 to 100.)

  According to the production method of the present invention, it is possible to efficiently produce an anionic surfactant composition mainly composed of a high-concentration, light-colored alkyl ether sulfate ester salt. In addition, the amount of oxidant remaining in the resulting anionic surfactant composition can be greatly reduced.

The alkyl ether sulfate salt in the present invention is represented by the following general formula (1).
_{RO (AO) n SO 3 M} (1)
(In the formula, R represents a linear or branched alkyl group or alkenyl group having 9 to 24 carbon atoms, and A represents a linear or branched alkylene group having 2 to 4 carbon atoms. M represents a hydrogen atom or an alkali metal, and n represents an average value of 0 to 100.)
In the formula (1), R is preferably a linear or branched alkyl group or alkenyl group having 12 to 20 carbon atoms. When R has 9 to 24 carbon atoms, the alkyl ether sulfate ester salt has a good balance of surface activity and solubility in water. Examples of the alkyl group and alkenyl group include various decyl groups, various dodecyl groups, various tetradecyl groups, various hexadecyl groups, various octadecyl groups, various icosyl groups, various docosyl groups, various octadecenyl groups, and the like.
Examples of the alkylene group having 2 to 4 carbon atoms represented by A include an ethylene group, a propylene group, a 1-methyltrimethylene group, a trimethylene group, and a tetramethylene group. Among these, an ethylene group and a propylene group are particularly preferable.
Examples of the alkali metal of M include sodium, potassium, lithium and the like. Among these, sodium and potassium are preferable, and sodium is particularly preferable.
n is preferably 0 to 100, more preferably 1 to 5.

The alkyl ether sulfate ester salt can be obtained by subjecting a higher alcohol or an alkylene oxide adduct thereof to sulfation, followed by a two-step neutralization treatment described later.
Here, specific examples of higher alcohols include natural alcohols derived from green perfume oil, coconut oil, palm oil, beef tallow and the like, and synthetic higher alcohols obtained by the oxo method, Ziegler method and paraffin direct oxidation method, etc. Can be mentioned. Examples of the alkylene oxide adduct include an ethylene oxide and / or propylene oxide adduct of the higher alcohol. Among these, an ethylene oxide adduct having an average addition mole number of 1 to 5 is particularly preferable.

Examples of the sulfating agent used for sulfating a higher alcohol or an alkylene oxide adduct thereof include sulfur trioxide gas and chlorosulfonic acid. From the viewpoint of reducing the amount of chloride in the resulting anionic surfactant composition, it is preferable to use sulfur trioxide gas.
There is no restriction | limiting in particular in the method of sulfation, It can carry out by a conventional method. For example, using a thin film type continuous reaction apparatus, diluted with an inert gas such as air or nitrogen, preferably with a sulfur trioxide gas having a concentration of 1 to 30% by volume, more preferably 1 to 20% by volume, higher alcohol or The alkylene oxide adduct can be sulfated. When the concentration of sulfur trioxide is in the range of 1 to 30% by volume, the gas volume is not too large and excessive reaction can be suppressed.
The amount of sulfur trioxide used is usually in the range of stoichiometric amount × (0.95 to 1.05), preferably in the range of stoichiometric amount × (0.97 to 1.01). If the amount of sulfur trioxide used is within the above range, the amount of unreacted substances can be reduced, and the production of colored components and odorous components (for example, lower aldehydes, lower ketones, cyclic ethers, etc.) as by-products can be suppressed. be able to.

The reaction apparatus is not particularly limited, and for example, a tank reaction apparatus, a thin film reaction apparatus, or the like can be used. As the thin film reactor, for example, a falling thin film reactor, a rising thin film reactor, a tubular gas-liquid mixed phase flow reactor, or the like can be used. The reaction time when using a thin film reactor is about 10 to 300 seconds.
The sulfation temperature is preferably 15 to 70 ° C, more preferably 15 to 50 ° C. If it is 15 degreeC or more, the local excess reaction by fluid fall can be suppressed, and if it is 70 degrees C or less, decomposition | disassembly of a product can be suppressed.

The alkyl ether sulfate obtained as described above is neutralized so as to be an aqueous solution having an alkyl ether sulfate salt concentration of 10 to 70% by mass.
In the present invention, the neutralization treatment is performed in two stages, and the first stage neutralization treatment is performed at pH 2 to 5, and then the second stage neutralization treatment is performed at pH 10 or more.
The neutralization treatment in the first stage can be performed at a pH of 2 to 5, preferably 2 to 4, by continuously mixing the alkyl ether sulfate and the neutralizing agent. If pH is the range of 2-5, the initial hue of the alkyl ether sulfate ester salt can be made into a light color.

The neutralization treatment time of the first stage can obtain the effect of lightening even in a short time, but in the case of further lightening, the effect of lightening can be further obtained by keeping the pH acidic for a certain time, Therefore, various methods can be applied depending on the neutralization method.
For example, when two independent neutralizers using a continuous circulation neutralization system are installed, it is also effective to adjust the pH to 2 to 5 in the first half neutralizer and to pH 10 or more in the subsequent second neutralizer. Is. In this case, the residence time in the neutralizer corresponds to the retention time under acidic conditions.
Furthermore, when performing light coloration, it can achieve by providing a holding tank etc. between two neutralizers, and hold | maintaining at pH 2-5 for arbitrary time. The holding time at pH 2-5 is preferably within 30 hours, more preferably within 25 hours. Within this time range, it is preferable that the quality other than the hue is impaired due to hydrolysis of the alkyl ether sulfate or the like.
In the case of a batch type neutralizer, the pH in the tank can be adjusted to 2 to 5 by adjusting the flow rates of the alkyl ether sulfate and the neutralizing agent. Also in this case, the target anionic surfactant composition can be obtained by controlling the time for maintaining at pH 2 to 5 in the same manner as described above.

Examples of the neutralizing agent used include an aqueous solution of a basic alkali metal compound.
Examples of the basic alkali metal compound include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, lithium carbonate and the like. Among these, sodium hydroxide and potassium hydroxide are particularly preferable.
The concentration of the neutralizing agent is not particularly limited, and it is preferable to obtain sufficient fluidity in accordance with the viscosity behavior in the aqueous solution or slurry of the anionic surfactant composition after neutralization. The neutralizing agent is usually used at a concentration of 10 to 50% by mass.

An organic solvent can be blended with the neutralizing agent. Examples of the organic solvent include ethanol, isopropyl alcohol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerin, isoprene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, pentyl glyceryl ether, octyl glyceryl ether, and the like. In these, a C1-C6 alcohol is preferable and ethanol and propylene glycol are especially preferable. The compounding amount of the organic solvent is preferably 5 to 25% by mass, more preferably 8 to 25% by mass, and particularly preferably 10 to 20% by mass in the anionic surfactant composition.
The neutralization temperature in the first stage is preferably 20 to 60 ° C, more preferably 20 to 50 ° C. As the neutralization system, for example, either a batch system or a continuous system can be adopted. A continuous circulation neutralization system equipped with an external cooling device using a line mixer or the like is preferable from the viewpoints of reaction efficiency and constant temperature maintenance. After the neutralization treatment, the pH can be further finely adjusted by batch operation or continuous operation as necessary.

In the present invention, it is preferable to add an oxidizing agent during the neutralization treatment in the first stage. The oxidizing agent is stable at pH 2 to 5 in the neutralization treatment in the first stage, exhibits only a little oxidative bleaching function, and is substantially oxidative bleaching function for the first time under the condition of pH 10 or more in the neutralization treatment in the second stage. Demonstrate. By adding the oxidizing agent in this first stage, the amount of the oxidizing agent used can be reduced and a high oxidative bleaching effect can be obtained. Further, this method is preferable because it is not necessary to newly install an oxidizer addition facility, and the facility cost is reduced. Furthermore, after adding an oxidizing agent and stirring and mixing, even if it is left in, for example, a product storage tank, it is preferable because the oxidative bleaching process proceeds.
The oxidizing agent that can be used is not particularly limited, but hydrogen peroxide is preferable. The addition amount of the oxidizing agent is preferably 0.001 to 1% by mass, more preferably 0.002 to 0% in terms of a pure component per surfactant or an effective amount of an aqueous solution or slurry of the surfactant composition. 0.5% by mass, particularly preferably 0.004 to 0.2% by mass. If the addition amount of the oxidant is within the above range, the oxidative bleaching effect is sufficient, and there is no possibility that problems such as a large amount of the oxidant remaining in the product and fading the dye in the product occur.

The neutralization treatment in the second stage is preferably performed within 30 hours, more preferably within 25 hours after the neutralization treatment in the first stage. If it is within this time, the hue of the anionic surfactant composition which has the alkyl ether sulfate ester salt as a main component will be maintained well, and the quality other than the hue will not be impaired.
The pH of the neutralization treatment in the second stage is 10 or more, preferably 10 to 13, more preferably 10.5 to 12.5. If the pH is 10 or more, the hue of the alkyl ether sulfate ester salt can be kept light, and when an oxidizing agent is added in the first stage, the oxidizing bleaching function of the oxidizing agent is the second stage. The hue is substantially improved and the hue can be greatly improved. In the neutralization treatment in the second stage, it is not necessary to perform heat treatment. Usually, it can carry out at 10-60 degreeC, Preferably it is 20-50 degreeC.
The reaction mixture mainly composed of the alkyl ether sulfate obtained as described above can remove bubbles under reduced pressure as necessary.

An anionic surfactant composition mainly composed of a surfactant comprising an alkyl ether sulfate represented by the general formula (1) obtained by the production method of the present invention has a pH of 10 or more, preferably Has an amount of residual hydrogen peroxide of 50 mg / kg or less, preferably 40 to 70% by mass, more preferably 50 to 65% by mass of the alkyl ether sulfate ester salt, and the above organic solvent, particularly having 1 carbon atom. Preferably, it contains 5 to 25 mass%, more preferably 10 to 20 mass%.
For this reason, the obtained anionic surfactant composition can be suitably used as a component of the liquid detergent composition. In this case, auxiliary agents such as pigments, fragrances, solubilizers, and builders can be appropriately added to the liquid detergent composition as necessary. Furthermore, other anionic surfactants, cationic surfactants, amphoteric surfactants, amide type nonionic surfactants and the like can be added for the purpose of adjusting detergency and foaming.
Such a liquid detergent composition is used, for example, in shampoos, body shampoos, kitchen detergents, liquid soaps and the like.

In the following Examples and Comparative Examples, “%” is “% by mass” unless otherwise specified.
Example 1
Examples 1-4 and Comparative Examples 1-2
(1) Manufacture of higher alcohol ethoxylate sulfate sodium salt Ethoxylate (average ethylene oxide addition) of higher alcohols mainly composed of 12 and 13 carbon atoms (trade name; NEODOL23, manufactured by Shell) using a thin film sulfation reactor. Mole number 2.0) is sulfated with sulfur trioxide gas diluted with dry air, neutralized with sodium hydroxide solution containing ethanol, and higher alcohol ethoxylate sulfate sodium salt (hereinafter “sodium sulfate ester”). An aqueous solution (surfactant composition) having a concentration of 54% of “salt” and 14% of ethanol was prepared.
(2) Decolorization treatment 35% hydrogen peroxide is added to the aqueous sulfuric acid sodium salt solution obtained in (1) so as to be 0.005 to 0.02% by mass, and the pH shown in Table 1 is obtained. After adjusting with a sodium hydroxide aqueous solution and holding for 24 hours (first stage neutralization treatment), the pH is adjusted with a sodium hydroxide aqueous solution (second stage neutralization treatment) so that the pH shown in Table 1 is obtained. An agent composition was obtained.

Using the surfactant composition obtained above, the hue and the amount of remaining hydrogen peroxide were measured by the following method. The results are shown in Table 1.
(I) Hue The surfactant composition was diluted with water so that the effective content was 10%, and adjusted to pH 7.0 with phosphoric acid and sodium hydroxide aqueous solution. Subsequently, the absorbance at a wavelength of 420 nm was measured with a spectrophotometer using pure water as a control in a 1 cm cell, and the resultant was multiplied by 1000 to obtain a hue.
(Ii) Amount of hydrogen peroxide 5 g of the surfactant composition (sample) is precisely weighed in an Erlenmeyer flask equipped with a stopper, and 100 mL of water is added and dissolved. To the obtained sample solution, 10 mL of dilute sulfuric acid and 10 mL of 10% potassium iodide solution are added, stoppered, mixed well with shaking, and left in a dark place for 30 minutes. Titrate with a 0.1 mol / L sodium thiosulfate standard solution, add a starch indicator just before the end point, and use the point where the blue color disappears as the end point. At the same time, a blank test was performed, and the titer was corrected by the following formula to determine the amount of hydrogen peroxide.

  In the formula, A is the titration amount (mL) of the 0.1 mol / L sodium thiosulfate standard solution required for the titration of the sample, and B is the titration of the 0.1 mol / L sodium thiosulfate standard solution required for the titration of the blank test. The amount (mL), f is the titer of 0.1 mol / L sodium thiosulfate standard solution, and S is the sample amount (g).

  From Table 1, if the added amount of hydrogen peroxide is in the range of 0.001 to 1% by mass per surfactant, the more the added amount of hydrogen peroxide, the better the hue improvement effect of the final product. I understand.

Examples 5-10
0.02% by mass of 35% hydrogen peroxide was added to the higher alcohol ethoxylate sulfate sodium salt aqueous solution prepared in the same manner as in Example 4, and the pH was adjusted with the aqueous sodium hydroxide solution to the pH shown in Table 2. After maintaining for a predetermined time (first-stage neutralization treatment), a surfactant composition was obtained by adjusting with a sodium hydroxide aqueous solution (second-stage neutralization treatment) so that the pH in Table 2 was obtained.
Using the obtained surfactant composition, the hue and the amount of remaining hydrogen peroxide were measured in the same manner as in Example 4. The results are shown in Table 2.

  From Table 2, if the neutralization treatment at the first stage is carried out while maintaining the pH at 2 to 5 and the neutralization treatment at the second stage is carried out until the pH becomes 10 or more, the surface activity is good and the amount of residual oxidizing agent is small. It turns out that an agent composition can be obtained easily.

Claims (7)

A method for producing a composition comprising, as a main component, a surfactant composed of an alkyl ether sulfate salt represented by the following general formula (1), after sulfating a higher alcohol or an alkylene oxide adduct thereof. A method for producing an anionic surfactant composition, wherein the neutralization treatment at the first stage is carried out while maintaining the pH at 2 to 5, and the neutralization treatment at the second stage is carried out until the pH becomes 10 or more.
_{RO (AO) n SO 3 M} (1)
(In the formula, R represents a linear or branched alkyl group or alkenyl group having 9 to 24 carbon atoms, and A represents a linear or branched alkylene group having 2 to 4 carbon atoms. M represents a hydrogen atom or an alkali metal, and n represents an average value of 0 to 100.)   The method for producing an anionic surfactant composition according to claim 1, wherein the second stage neutralization treatment is performed within 30 hours after the first stage neutralization treatment.   The manufacturing method of the anionic surfactant composition of Claim 1 or 2 which adds an oxidizing agent at the time of the neutralization process of a 1st step.   The method for producing an anionic surfactant composition according to claim 3, wherein the oxidizing agent is hydrogen peroxide.   The manufacturing method of the anionic surfactant composition of Claim 3 or 4 which adds an oxidizing agent 0.001-1 mass% per said surfactant.   The manufacturing method of the anionic surfactant composition whose residual hydrogen peroxide amount is 50 mg / kg or less by the method in any one of Claims 1-5.   Content of the alkyl ether sulfate ester salt represented by the said Formula (1) by the method in any one of Claims 1-5 is 40-70 mass%, and the content of C1-C6 alcohol is 5 The manufacturing method of the anionic surfactant composition which is -25 mass%.