JP2000319685A - Production of surfactant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent harm caused by a by-product peroxide in a surfactant production process including a bleaching step under acidic conditions by keeping the concentration of a by-product peroxide in a liquid phase and the oxygen concentration in a gas phase in the bleaching step, each at a specified value or lower. SOLUTION: The concentration of a by-product peroxide in a liquid phase is kept at 1,500 ppm or lower; and the oxygen concentration in a gas phase, at 15 vol.% or lower. The by-product peroxide concentration in a liquid phase can be adjusted by controlling the reaction temperature in the bleaching step, the temperature being preferably 90 deg.C or lower. The oxygen concentration in a gas phase is adjusted by feeding an inert gas before or in the bleaching step. Preferably, the oxygen concentration is also kept even after the bleaching step. Preferably, hydrogen peroxide is used as the bleaching agent. This invention is especially suitable for a bleaching step of an anonic surfactant such as an α-sulfo-fatty acid ester salt or an alkylsulfate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a surfactant including a bleaching step under acidic conditions, and more particularly, to a method for producing a surfactant capable of suppressing accumulation of by-product peroxide in the bleaching step. About.

[0002]

2. Description of the Related Art α-Sulfo fatty acid alkyl ester salts (hereinafter sometimes referred to as α-SF), alkylbenzene sulfonates, alkyl sulfates, α-olefin sulfonates, polyoxyethylene ether sulfates, secondary Anionic surfactants such as alkane sulfonates and higher fatty acid salts; Nonionic surfactants such as polyoxyethylene alkyl ethers, alcohol EO / PO adducts, fatty acid alkanolamides and alkyl polyglycosides; di-long chain alkyl quaternary Cationic surfactants such as ammonium salts and mono-linear alkyl type quaternary ammonium salts; surfactants such as amphoteric surfactants such as alkylmethylaminoacetic acid bedine and fatty acid amide propyl bedine,
The color tone may deteriorate during production or storage. Therefore, in order to improve the color tone of the product, bleaching under acidic conditions using hydrogen peroxide or the like may be performed in the production process. In particular, anionic surfactants such as α-SF and alkyl sulfates that are produced through sulfation or sulfonation may deteriorate in color during the sulfation or sulfonation step, and are often subjected to bleaching. .

[0003]

However, in such a bleaching process, by-product peroxide is generated and easily accumulated, and the by-product peroxide may cause harm during the bleaching process. In addition, by-product peroxides can cause harm not only during the bleaching process but also during subsequent processing and storage.

When the bleaching step is carried out in the presence of a lower alcohol, particularly for the purpose of improving handling such as lowering the viscosity, etc., excess alcohol in which oxygen molecules have been introduced into the alcohol is formed, which is harmful during processing or storage. Could result in Further, lower alcohols are often recovered and recycled in subsequent steps. When the recycling is repeated in this manner, the concentration of by-product peroxide in the lower alcohol gradually increases, and as a result, the concentration of by-product peroxide in the bleaching step increases. In addition, rectification is performed at the time of recovery of lower alcohol, and it is usually heated at this point,
Also in this step, a high peroxide concentration is inconvenient from the viewpoint of safety and the like.

[0005] The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a method for producing a surfactant capable of suppressing harm caused by a by-product peroxide in a bleaching step under acidic conditions. Another object of the present invention is to provide a method for producing a surfactant capable of suppressing harm caused by by-product peroxide in the bleaching step and the subsequent steps. In particular, it is an object of the present invention to provide a method for producing a surfactant capable of solving these problems in a bleaching step in the presence of alcohol.

[0006]

In order to solve the above-mentioned problems, the present invention relates to a method for producing a surfactant including a bleaching step of bleaching under an acidic condition. The present invention proposes a method for producing a surfactant, wherein the concentration is kept at 1500 ppm or less and the oxygen concentration in the gas phase is kept at 15% by volume or less. In this method for producing a surfactant, the reaction temperature in the bleaching step is preferably set to 90 ° C. or lower. Furthermore, a method for producing a surfactant, wherein the oxygen concentration is adjusted by introducing an inert gas.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Examples of the bleaching agent used in the bleaching step under acidic conditions include hydrogen peroxide and hypochlorous acid. Hydrogen peroxide is preferably used because of its high bleaching effect. These bleaches are usually used as an aqueous solution. The amount used is appropriately adjusted depending on the type and color tone of the surfactant, but is usually used in an amount of about 0.5 to 5% by weight based on the weight of the object to be bleached.

[0008] The concentration of by-product peroxide in the liquid phase in the bleaching process under acidic conditions is determined by the safety guideline of the United Nations, 300 m.
j / (71 cal / g) or less and 1500 ppm or less, preferably 10 ppm
It is set to 00 ppm or less. If it exceeds 1500 ppm, it may be inconvenient from the viewpoint of ensuring the safety of the bleaching process and the like, and finally there is a risk of explosion. In addition, it is preferable to maintain this range from the viewpoint of ensuring safety in subsequent steps.

[0009] The concentration of by-product peroxide in the liquid phase is determined by the bleaching step.
By controlling the reaction temperature in the reactor
Can be. The temperature of the bleaching step is preferably below 90 ° C.
More preferably, the temperature is set to 80 ° C. or lower. Over 90 ° C
By-produced peroxide is more likely to be generated, and its concentration increases
This is inconvenient. In addition, in order to perform bleaching,
Has a temperature range of 60 ° C or higher, preferably 70 ° C or higher.
It is. The reaction temperature in the actual production, specifically, bleaching
Type, amount of surfactant, type of surfactant to be manufactured,
Whether or not to add alcohol
Pressure conditions and reaction time depending on the type and amount of
It is appropriately adjusted along with the above. Not particularly limited
However, the pressure in the bleaching process is 0.3-2 kg / cm ^Two,reaction
The time is usually 30 minutes to 2 hours. Also, for example,
In the production of on-surfactants, the bleaching process is alkaline
Before or after neutralization
it can.

When the bleaching step is performed in the presence of a lower alcohol as described above, and the lower alcohol present in the bleaching step contains a by-product peroxide such as a peroxide, and when the lower alcohol is recycled, If necessary, it is preferable to add a reducing agent to the lower alcohol to decompose the by-product peroxide before recycling the recovered lower alcohol recovered after the bleaching step.

The lower alcohol has, for example, a carbon number of 1 to 1.
3, preferably 1-2. Conditions such as the amount of addition are appropriately adjusted depending on the type of surfactant to be produced, production conditions, and the like. Further, even other than lower alcohols, used during the production of the surfactant, including by-product peroxide generated in the bleaching step, is recovered,
It is preferable to perform the same treatment as appropriate for the material to be recycled so as to prevent the accumulation of by-produced peroxide while controlling the temperature in the bleaching step as described above.

The reducing agent is not particularly restricted but includes, for example, organic substances such as formic acid and oxalic acid, sodium sulfite,
An inorganic substance such as sodium hydrogen sulfite is used.
The amount of the reducing agent to be used is adjusted according to the concentration of the by-product peroxide, and is usually used in an amount of about 1 to 1.5 times the amount of the by-product peroxide. When adding the reducing agent, it may be immediately after collection,
Although it may be after rectification, it is preferable to add it before rectification in order to suppress the further generation of by-product peroxide during rectification.
In addition, these treatments are usually carried out every one to three times of recycling, and the frequency is appropriately adjusted depending on the concentration of by-product peroxide and the like.

The oxygen concentration in the gas phase during the bleaching step is 15
It is preferable to keep the content at not more than 10% by volume, preferably at most 10% by volume. This numerical range is in the gas phase in the bleaching process,
For example, it is a value determined from the experimental value of the explosion limit of organic compounds such as flammable lower alcohols and ethers. If the content exceeds 15% by volume, the danger of explosion of by-produced peroxide in the liquid phase increases, in combination with the possibility of combustible compounds in the gas phase, which is inconvenient in terms of ensuring safety. It may be. Particularly in the bleaching step, the temperature may rise locally due to the exothermic reaction at the time of bleaching.
It is important to keep the concentration below volume%. In addition, in the production process of the surfactant production process, not only lower alcohols and ethers but also various flammable organic compounds are present, so that adjustment of the oxygen concentration is important. Specifically, before or during the bleaching step, an inert gas such as nitrogen, helium, or argon is introduced to adjust the oxygen concentration. It is preferable to keep this oxygen concentration even after the bleaching step.

Hereinafter, a specific example to which the present invention is applied is α-
An example of a method for manufacturing SF will be described. FIG. 1 shows α-
FIG. 2 is a flowchart showing an example of an SF manufacturing process.
1 is a schematic configuration diagram of a manufacturing apparatus. First, a fatty acid alkyl ester as a raw material is charged from a raw material supply line 2 into a tank reactor 1. As the fatty acid alkyl ester, for example, one having 6 to 24 carbon atoms derived from a fatty acid and 1 to 6 carbon atoms derived from an alcohol, preferably a saturated fatty acid alkyl ester is used. In this example, a saturated _C14-16 fatty acid methyl ester is used.

In this embodiment, the tank reactor 1 is used, but the reaction system is not particularly limited, and other systems such as a film reaction and a tubular gas-liquid multiphase flow reaction are applied.
The sulfonation method is not particularly limited, and a thin film type sulfonation method, a batch type sulfonation method and the like are applied.

Then, while stirring with the stirrer 1a, the internal temperature of the tank reactor 1 is raised to a predetermined reaction temperature at which the fatty acid alkyl ester has fluidity. The reaction temperature is a temperature not lower than the melting point of the fatty acid alkyl ester, and is in a temperature range from the melting point to 100 ° C higher, preferably from the melting point to 70 ° C higher than the melting point. In this example, the fatty acid alkyl ester has a melting point of 30 ° C. and a reaction temperature of 80 ° C.

A sulfonated gas is introduced into the liquid phase 3 from a gas introduction pipe 4 and brought into contact therewith. At this time, the exhaust gas is discharged from the gas discharge port 5. Examples of the sulfonated gas include SO ₃ gas, fuming sulfuric acid, and the like. Preferably, SO ₃ gas is used, and SO ₃ gas diluted with an inert gas such as air or nitrogen is suitable. The sulfonating gas is used in an amount of 1.0 to 2.0 times, preferably 1.1 to 1.5 times, the mole of the fatty acid alkyl ester. In this embodiment, SO ₃ gas diluted to 8% by volume with nitrogen is
It is used in a molar amount of 1.2 times the amount of the raw material.

The contact time with the sulfonation gas varies depending on the sulfonation method.
0 seconds, about 10 to 20 minutes in the batch type sulfonation method. In this example, the contact time with the sulfonating gas is 15 minutes. In addition, in order to prevent the reaction temperature from excessively rising due to the contact between the raw material and the sulfonated gas and the generation of heat, the feed pump 6a acts to transfer the liquid phase 3 from the circulation line 6 provided at the bottom of the tank reactor 1. Extract a part,
It is cooled by a cooler 6b provided in the middle of the circulation line 6 and returned again from the upper part of the tank type reactor 1 to be circulated.

[0019] Contacting raw materials and sulfonating gas, a reaction occurs to be inserted SO ₃ alkoxy group, SO ₃ one molecule adduct is produced, a sulfone group is introduced into the further position α reacts with SO ₃ generates the SO ₃ bimolecular adduct, final SO ₃ inserted in the alkoxy group is eliminated α- sulfofatty acid alkyl ester is produced. Therefore, in the reaction product brought into contact with the sulfonated gas, a monomolecular adduct, a bimolecular adduct, an unreacted fatty acid alkyl ester,
And other by-products. Therefore, this reaction product is further aged, and S0 from the bimolecular adduct is
Promotes the desorption of ₃ and eventually equilibrates.

In the case of the tank type reactor 1 shown in FIG. 2, the raw material and the sulfonated gas are brought into contact with each other, and then the stirrer 1a
And aged in the tank reactor 1 with stirring. The temperature of the aging step is 70 to 100 ° C. The aging time is usually in the range of 1 to 120 minutes. Further, aging may be omitted depending on the reaction conditions at the time of contact with the sulfonated gas. In this example, the aging conditions are 80 ° C. and 90 minutes.

After the aging step, the reaction product is withdrawn from a withdrawal line 7 provided at the bottom of the tank reactor 1 by a feed pump 7a, a bleach is added from a line 8, and a lower alcohol is added from a line 9. Bleaching under acidic conditions is carried out simultaneously with the esterification described later. The amount of the bleaching agent used is 0.2 to 10% by weight, preferably 0.1% by weight, based on the AI (activator: in this case, the total amount of the α-sulfofatty acid alkyl ester and the SO ₃ bimolecular adduct). 5-5% by weight
It is said. In this example, the bleaching agent is hydrogen peroxide, which is used in a pure content of 0.5% by weight.

Further, a bimolecular adduct is present in the reaction product which has reached equilibrium by aging. Therefore, a lower alcohol is added to make the bimolecular adduct α-sulfofatty acid alkyl ester. This treatment produces a sulfate ester from the lower alcohol, and this treatment is called esterification. The lower alcohol preferably has 1 to 6 carbon atoms, and more preferably has a carbon number equal to that of the alcohol residue of the fatty acid alkyl ester as the raw material. The lower alcohol is consumed by the side reaction with the bleaching agent, and the coexistence of the lower alcohol lowers the viscosity of the reaction mixture and improves the handling as described above. Used in excess. For example, the addition amount of the lower alcohol from the line 9 is 5 to 30% by weight with respect to AI.
In this example, methanol is used, and the amount used is 15% by weight with respect to AI.

Next, the mixture containing the bleach and the lower alcohol is supplied to the mixing line 10 by the action of the feed pump 10a.
And mixed by the mixer 10b. The mixing line 10 branches into a circulation line 11 behind the mixer 10b and the feed pump 10a, and a part of the mixture is supplied as a premix to the front of the mixer 10b.
A circulating bleaching loop is formed (loop system).
That is, the bleaching loop includes the mixing line 10 and the circulation line 1
And 1. Further, a heater 11a is provided in the middle of the mixing line 10 so as to maintain the temperature of the pre-mixture, whose temperature has been reduced by heat radiation, at a predetermined bleaching temperature.

As a result, in the mixing line 10, the reaction product supplied from the extraction line 7, the premix containing the bleach supplied from the circulation line 11, and the bleach newly added from the line 8 are mixed. Since the mixing is performed by the mixer 10b, it is possible to suppress the excessive reaction at the initial stage of the reaction and to suppress the generation of by-products. Mixer 1
The weight of the premix mixed at 0b is at least 5 times the weight of the total weight of unbleached reaction product and bleach.

Next, this mixture is mixed with a bleach-ripened tube 1 in which a heater 12a for maintaining the reaction temperature is inserted in the middle.
The esterified and bleached reaction proceeds in the course of flowing through the bleach ripening tube 12 to obtain an esterified bleached product (bleach bleach acid) (flow tube method). The reaction temperature during the simultaneous bleaching of the esterification is 60 to 90 ° C., and the reaction time is 30 minutes to 2 hours. In this example, the reaction temperature is 80 ° C. and the reaction time is 90 minutes.

As described above, the oxygen concentration in the gas phase can be controlled by appropriately introducing an inert gas into the production system. The position and the number of introduction of the inert gas are not particularly limited as long as they are set so as to be introduced at least once, for example, from the line 7 after the reaction in the tank reactor 1 to the bleaching and aging tube 12. do not do. Preferably, as shown by A to E in the drawing, the extraction line 7
Mixing line 1 before introducing bleach and lower alcohol
In the course of 0, in the circulation line 11, before the lower alcohol mixing tank 13 for supplying the bleached product from the bleaching and aging tube 12 is introduced. The conditions for introducing the inert gas are not particularly limited. In this example, nitrogen is used as the inert gas.

With respect to the oxygen concentration, it is particularly effective to control the oxygen concentration in the bleaching step, but it is preferable to maintain this oxygen concentration in the subsequent steps. For example, a line 15 for extracting a mixture from the lower alcohol mixing tank 13 in the lower alcohol mixing tank 13 indicated by F, G, and H in the figure for the purpose of further suppressing an increase in oxygen concentration due to a side reaction during the neutralization reaction. It is preferable to introduce an inert gas in the middle of the circulation line 18 for performing the neutralization reaction.

Next, since the lower alcohol is consumed in the esterification, the lower alcohol is further added from the line 14 in the lower alcohol mixing tank 13 to prevent a decrease in handling. The addition amount is 5 to 2 with respect to AI.
0% by weight. The addition amount in this example is 10% by weight based on AI.

Further, the bleached product is extracted from the line 15 by the action of the pump 16 a and supplied to the neutralization line 16. A neutralizing agent is supplied from a line 17 between the premixer 16c and the neutralizing mixer 16b. Further, the neutralization line 16 branches to the circulation line 18 behind the premixer 16c, the neutralization mixer 16b, and the feed pump 16a, and a part of the neutralized material is used as a preliminary neutralized material in the middle of the circulation line 18. After being cooled through the cooler 18a, a loop that is supplied to the front of the premixer 16c and circulates is formed (loop neutralization method).

That is, the unneutralized bleached product supplied from the line 15 is sufficiently mixed with the pre-neutralized product supplied from the circulation line 18 by the action of the premixer 16c, and then supplied from the line 17. The mixture is neutralized and neutralized by the neutralizing mixer 16b with the neutralizing agent to obtain an α-SF slurry. As a result, the excess reaction at the beginning of the reaction is suppressed,
The generation of by-products can be suppressed. Circulation line 18
Of the pre-neutralized product supplied from the line 15 is at least 5 times the total weight of the unneutralized bleached product supplied from the line 15 and the neutralizing agent supplied from the line 17.

As the neutralizing agent, for example, an aqueous solution of an alkali metal, an alkaline earth metal, ammonia, ethanolamine or the like is used. In this embodiment, an aqueous solution of sodium hydroxide having a concentration of 48% by weight is used. The neutralization temperature is 50 to 90 ° C., and the neutralization time is 10 to 30 minutes. In this example, the neutralization temperature was 80 ° C and the neutralization time was 20.
Minutes.

Then, the neutralized α-SF slurry is supplied to a concentrator 19 and concentrated to a predetermined concentration. Α- before concentration
When the concentration of the SF slurry is 40 to 45% by weight, usually 6
It is concentrated to about 0 to 70% by weight. The concentration condition is temperature 10
The pressure is set to 0 to 130 ° C and the pressure is set to 1 to 4 kg / cm ² . In this example, the concentration of the α-SF slurry before concentration was 42
% By weight, and the concentration after concentration was 65% by weight. The concentration conditions are a temperature of 110 ° C. and a pressure of 3 kg / cm ² .

Next, the concentrate is withdrawn from the line 20 at the bottom of the tower, supplied to a flash can 21 and flashed.
Since α-SF alone often has an odor, it is preferable to perform this flush to remove the odor. The flash is heated and pressurized as necessary,
The temperature is adjusted to 00 to 150 ° C. and the pressure is adjusted to 1.5 to 11 kg / cm ² , introduced into the flash can 21, and flashed under reduced pressure or normal pressure to deodorize. In this embodiment, 105
C., adjusted to ² kg / cm ² , and flushed under normal pressure. Line 2 at the top of flash can 21
From 3, low-boiling components such as lower alcohols and water removed by flashing are discharged after being cooled by a cooler on the way. Then, α in the flash can 21
-SF is extracted from the line 22 by the action of the pump 22a and is formed into a powder, a particle, or the like to obtain a product α-SF.

On the other hand, lower alcohol and water are extracted from a line 24 at the top of the concentration tower 19, supplied to a rectification column 25 for rectification, and water is discharged from a line 26 at the bottom of the column. Further, the lower alcohol is recovered from the line 27 at the top of the tower, and is recycled into the production system. At this time, as shown by I in the figure, in the rectification tower 25, a rectification is performed by appropriately adding a reducing agent to the lower alcohol before rectification. In this embodiment, sodium sulfite is used as a reducing agent, and each time recycling is performed, 1.5 times by mole of the by-produced peroxide is added.

When the production apparatus is stopped, the bleaching loop consisting of the mixing line 10 and the circulation line 11 and the bleaching agent present in the bleaching and maturation tube 12 cause the oxidation reaction to proceed. After stopping the addition of bleach, to prevent the increase of raw peroxide concentration and oxygen concentration,
The bleaching loop (mixing line 10 + circulation line 11) and the bleach ripening tube 12 are cooled immediately. At this time, if the fluidity of the liquid phase (bleach bleach acid) in the line is lost, it becomes difficult to extract the bleach bleach acid from the production system after cooling. The temperature at which the fluidity of the liquid phase is maintained varies depending on the type of surfactant, the raw material, and the like, but it is usually preferable to set the cooling temperature from the melting point of the liquid phase to a temperature higher by 20 ° C. than the melting point. Therefore, it is preferable to measure and control the temperature of the liquid phase of the bleaching and aging tube 12 from the mixing line 10 when the apparatus is stopped.

It is dangerous if the oxygen concentration in the gas phase increases and exceeds 15% by volume due to the progress of the oxidation reaction. Therefore, the oxygen concentration in the gas phase is measured and managed to diagnose abnormalities. It is preferable. When the oxygen concentration increases, the oxygen concentration in the gas phase is controlled by introducing an inert gas or the like. In this way, finally the liquid phase in a state of fluidity cooled under the appropriate gas phase oxygen concentration,
That is, the bleaching acid is extracted, and the production apparatus is stopped. The bleached bleached acid extracted is neutralized to produce a product.

The control method for stopping the manufacturing apparatus can be applied even when an abnormality such as a power failure occurs. FIG. 3 shows an example of a work flow at the time of the occurrence of a power failure. When a power failure occurs, the backup generator is operated to cool the bleaching loop and to cool the bleaching and aging tube by an engine pump or the like. At this time, the temperature of the liquid phase is controlled while measuring the temperature of the liquid phase so that the lower limit value of the temperature of the liquid phase falls within the temperature range from the melting point to 20 ° C. higher than the melting point as described above. In addition, the oxygen concentration in the gas phase is measured so as not to exceed 15% by volume, and an inert gas is introduced as necessary. Then, for example, when the power failure recovers within six hours, it returns to a normal state, and when it does not recover, the backup generator is operated to extract the bleach-based bleaching acid and neutralize it. As long as the bleaching loop and the bleach ripening tube can be cooled simultaneously at the time of the power failure, the method of distributing the emergency power supply used for cooling is not particularly limited, and a device that can be driven at the time of the power failure can be appropriately allocated. Further, the time until the bleach-based bleaching acid is extracted is not particularly limited, and can be appropriately adjusted according to the characteristics of the product, the production conditions in the factory, and the like.

[0038]

EXAMPLES Experiments were actually conducted in accordance with the above-described examples. A series of production cycles was repeated 10 times, and the lower alcohol was recycled 10 times. At this time, the bleached product immediately after the bleaching step was extracted for each production cycle, and the concentration of permethanol in the liquid phase was analyzed and determined by liquid chromatography. The oxygen concentration in the gas phase was measured by a galvanic cell type oxygen meter in the production system. As a result, in each of the production cycles, the permethanol concentration in the liquid phase in the bleaching step was 1500 ppm or less, and the oxygen concentration in the gas phase was 15% by volume or less, and safe operation was possible.

The embodiments of the present invention are summarized as follows. (1) The present invention is suitably applied particularly to anionic surfactants such as α-SF and alkyl sulfates produced through sulfation or sulfonation. (2) As the bleaching agent used in the bleaching step, hydrogen peroxide, hypochlorous acid and the like are used, and hydrogen peroxide is preferably used. (3) The by-product peroxide concentration in the liquid phase is 1500 ppm or less, preferably 1000 ppm or less. (4) The temperature of the bleaching step is preferably 90 ° C. or lower, more preferably 80 ° C. or lower. Further, in order to perform bleaching, the temperature range is substantially 60 ° C. or higher, preferably 70 ° C. or higher. (5) The oxygen concentration in the gas phase during the bleaching step is 15% by volume or less,
It is preferable to keep it at 10% by volume or less. (6) Those used in the bleaching step of lower alcohols and the like contain by-product peroxides, and when recycling this, before the recycling, a reducing agent may be added as necessary to produce the by-product peroxide. It is preferable to decompose the oxide.

[0040]

As described above, according to the present invention, in a method for producing a surfactant including a bleaching step of bleaching under acidic conditions, the concentration of by-product peroxide in the liquid phase in the bleaching step is 1500 ppm or less. 15% by volume oxygen concentration
By keeping below, it is possible to suppress the harm caused by the by-product peroxide.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a first example of an α-SF manufacturing process.

FIG. 2 is a schematic configuration diagram of a manufacturing apparatus used in the process shown in FIG.

FIG. 3 is a work flow when a power failure occurs in the manufacturing process shown in FIGS. 1 and 2;

[Explanation of symbols]

10: mixing line, 11: circulation line, 12: bleach aging tube.

Claims (3)

[Claims] In a method for producing a surfactant comprising a bleaching step of bleaching under acidic conditions, the concentration of by-produced peroxide in the liquid phase in the bleaching step is kept at 1500 ppm or less, and the concentration of oxygen in the gas phase is kept at 15% by volume or less. A method for producing a surfactant. 2. The method for producing a surfactant according to claim 1, wherein the reaction temperature in the bleaching step is 90 ° C. or lower. 3. The method for producing a surfactant according to claim 1, wherein the oxygen concentration is adjusted by introducing an inert gas.