JP2001002632A - PRODUCTION OF alpha-SULFOFATTY ACID ALKYL ESTER SALT - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an α-sulfofatty acid alkyl ester salt, capable of shortening a reaction time in producing an ce-sulfofatty acid alkyl ester salt from a fatty acid alkyl ester as short as possible and suppressing discoloration. SOLUTION: In this method for producing an α-sulfofatty acid alkyl ester salt including a sulfonation process for bringing a fatty acid alkyl ester into contact with a sulfonating gas, the reaction temperature of the process for bringing the fatty acid alkyl ester into contact with the sulfonating gas is controlled to 110-150 deg.C. Preferably the iodine value of the fatty acid alkyl ester is <=0.3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an α-sulfofatty acid alkyl ester salt, which can reduce the reaction time while suppressing coloring.

[0002]

2. Description of the Related Art Alpha-sulfofatty acid alkyl ester salts are used as surfactants, and are particularly highly evaluated for their performance as detergent materials because of their high detergency, good biodegradability and little impact on the environment. ing. The α-sulfofatty acid alkyl ester salt is obtained by sulfonating a fatty acid alkyl ester with a sulfonating gas to produce an α-sulfofatty acid alkyl ester and neutralizing the same.

[0003]

On the other hand, in the production of α-sulfofatty acid alkyl ester salts, there is a problem that the α-sulfofatty acid alkyl ester is liable to be colored when the fatty acid alkyl ester is sulfonated. For this reason, it has been generally said that the lower the reaction temperature, the more the coloring can be suppressed. However, under the conventional reaction conditions, the reaction rate of the raw materials is low only by bringing the fatty acid alkyl ester into contact with the sulfonated gas, and after that, it is necessary to provide an aging step of maintaining the raw material at a predetermined temperature to further advance the reaction. Was. Therefore, the overall reaction time is long, and improvement in production efficiency has been desired. Therefore, the present invention provides a method for producing an α-sulfofatty acid alkyl ester salt which can minimize the reaction time when producing an α-sulfofatty acid alkyl ester from a fatty acid alkyl ester and can suppress coloring. Make it an issue.

[0004]

As a result of various studies, the present inventors have found that the reaction temperature at the time of bringing the fatty acid alkyl ester into contact with the sulfonated gas is set to a specific range higher than the conventional one, thereby shortening the reaction time. It has been found that the reaction rate can be increased and that an α-sulfofatty acid alkyl ester having the same color tone as the conventional one can be obtained. That is, in order to solve the above-mentioned problem, in the present invention, in a method for producing an α-sulfofatty acid alkyl ester salt comprising a step of bringing a fatty acid alkyl ester into contact with a sulfonating gas to sulfonate, The reaction temperature of the step of contacting the gas is 110 to
A method for producing an α-sulfofatty acid alkyl ester salt characterized by being at 150 ° C. is proposed. The iodine value of the fatty acid alkyl ester is preferably 0.3 or less.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, preferably, the following general formula (I) R ¹ CH ₂ COOR ² (I) (wherein R ¹ is a straight-chain or branched alkyl having 6 to 24 carbon atoms) Or a alkenyl group, and R ² represents a straight-chain or branched alkyl group having 1 to 6 carbon atoms). Fatty acid alkyl esters include animal fats and oils derived from beef tallow, fish oil lanolin, etc .; vegetable fats and oils derived from coconut oil, palm oil, soybean oil, etc .; synthetic fatty acid alkyls derived from the oxo process of α-olefins Ester and the like may be used, and there is no particular limitation.

[0006] Specifically, methyl, ethyl or propyl laurate; methyl, ethyl or propyl myristate; methyl, ethyl or propyl palmitate; methyl, ethyl or propyl stearate; Methyl, ethyl or propyl fish oil fatty acids; methyl, ethyl or propyl coconut oil fatty acids; methyl, ethyl or propyl palm oil fatty acids; methyl, ethyl or propyl palm oil fatty acids, which can be used alone , Or a mixture of two or more. In addition, since a color having a low iodine value is less likely to be colored, a compound having an iodine value of preferably 0.3 or less, more preferably 0.1 or less is used. Use of 0.3 or less is preferable because the effect of improving color tone is extremely large as compared with the case of using 0.3 or more.

It is preferable that the sulfonation is carried out in the presence of a coloring inhibitor. As a coloring inhibitor, an inorganic sulfate having a monovalent metal ion and having an average particle size of 250 μm or less,
Or an organic acid salt is preferred. The inorganic sulfate is not particularly limited as long as it is a powdery anhydrous salt having a monovalent metal ion, and examples thereof include sodium sulfate, potassium sulfate, and lithium sulfate. Average particle size of inorganic sulfate is 250μ
m, preferably 100 μm or less. 250μ
By setting m or less, the contact area with the raw material is increased, and the dispersibility is improved. Inorganic sulfates have a high coloring suppressing effect, are inexpensive in many cases, and are components to be added to detergents, and therefore do not need to be finally removed from the α-sulfofatty acid alkyl ester salt (product). Further, as the organic acid salt, sodium formate, potassium formate, sodium acetate and the like are preferable. The average particle size of the organic acid salt is also 250 μm or less, preferably 100 μm or less, from the viewpoint of improving the contact area with the raw material and the dispersibility. The addition amount of the coloring inhibitor is 0.1 to 3 with respect to the raw material fatty acid alkyl ester.
0% by weight, preferably 0.1 to 20% by weight, more preferably 3 to 20% by weight. If it is less than 0.1% by weight, the effect of addition cannot be obtained.

As the sulfonated gas, SO ₃ gas, fuming sulfuric acid and the like can be exemplified, but SO ₃ gas is preferably used. It is preferable to use SO ₃ gas diluted to a concentration of 1 to 30% by volume with dehumidified air or an inert gas such as nitrogen. SO ₃ is used in an amount of 1.0 to 2.0 times mol, preferably 1.0 to 1.7 times mol, more preferably 1.05 to 1.5 times mol, of the fatty acid alkyl ester as a raw material. If it is less than 1.0 mole, the reaction does not proceed sufficiently, and if it exceeds 2 moles, the reaction becomes excessive and may cause by-products or coloring.

As the reaction system for bringing the fatty acid alkyl ester into contact with the sulfonated gas, a system such as a tank-type reaction, a film reaction, and a tubular gas-liquid multiphase flow reaction is used. As the sulfonation method, any sulfonation method such as a thin film type sulfonation method and a batch type sulfonation method may be used. The reaction time differs depending on the sulfonation method. The reaction time (residence time in the reactor) is 15 to 300 seconds in the thin film type sulfonation method and 10 to 120 seconds in the batch type sulfonation method.
Minutes.

FIG. 1 is a schematic diagram showing an example of a sulfonation apparatus for bringing a fatty acid alkyl ester into contact with a sulfonated gas, in which a tubular gas-liquid multiphase flow reaction is performed by a thin film type sulfonation method. It is. This sulfonation apparatus is particularly suitable for bringing a sulfonation gas into contact with a raw material liquid phase in which particles of a coloring inhibitor such as the above-mentioned inorganic sulfate are dispersed.

A description will be given below together with an operation example of the sulfonation reaction. That is, the raw material fatty acid alkyl ester and coloring inhibitor particles are charged into the stirring tank 1 and heated to a reaction temperature equal to or higher than the melting point of the fatty acid alkyl ester to make the fatty acid alkyl ester liquid, and the coloring agent particles are uniformly mixed by stirring. This is a dispersed raw material liquid phase (solid-liquid mixed phase). The reaction temperature is a temperature at which the fatty acid alkyl ester has fluidity. That is, the melting point of the fatty acid alkyl ester or higher, preferably 110 ° C. or higher. The upper limit of the reaction temperature is substantially 150C, more preferably 120-140C. By setting the reaction temperature to 110 ° C. or higher, the reaction rate of the raw materials increases in a short time, and the aging step can be omitted. 150 ° C
When the amount exceeds the range, coloring tends to be easy.

Next, the solid-liquid mixed phase is withdrawn from the extraction pipe 3 provided at the bottom of the stirring tank 1 by the action of the pump 2, and a part thereof is returned from the circulation pipe 4 and returned from above the stirring tank 1 and circulated. At the same time, the remainder is supplied from the supply pipe 5 to the raw material introduction pipe 8 provided in the introduction section 6. At this time, a sulfonated gas is simultaneously introduced into the introduction section 6 from the sulfonated gas introduction pipe 9.

The introduction section 6 is schematically configured such that a raw material introduction pipe 8 and a sulfonation gas introduction pipe 9 are provided on the side surface of a substantially tubular bottomed main body 7 whose upper part is open. And the body 7
The upper opening (outlet 7b) is connected to the lower end of a reaction tube 12 which is formed in a tubular shape and whose axial direction is vertical, and opens into the reaction tube 12.

The raw material introduction pipe 8 and the sulfonation gas introduction pipe 9 are each bent in a U-shape so that the solid-liquid mixed phase or the sulfonation gas introduced in the horizontal direction can be supplied to the bottom surface in the main body 7. 7a is guided in the vertical direction (downward direction). As described above, the solid-liquid mixed phase and the sulfonated gas supplied into the main body 7 from the raw material introduction pipe 8 and the sulfonated gas introduction pipe 9 collide with the bottom surface 7a, are mixed momentarily, and are inverted and rise. And body 7
Is supplied to the reaction tube 12 from the outlet 7b above the nozzle. The main body 7 is provided with a jacket (not shown) that covers the side surface and the bottom surface 7a. By circulating cold water in the jacket, the sudden heat generated by mixing the fatty acid alkyl ester and the sulfonated gas is cooled. It is supposed to.

In this sulfonation apparatus, the flow velocity of the solid-liquid mixed phase (raw material liquid phase) in the extraction pipe 3, the circulation pipe 4 and the raw material introduction pipe 8 is 0.7 m / sec or more, substantially. Is set to 0.7 to 1.2 m / sec. 0.7
If it is less than m / sec, the composition of the solid-liquid mixed phase may not be stable due to, for example, sedimentation of the coloring inhibitor particles in the tube.

The ratio of the supply volume of the sulfonated gas to the supply volume of the raw material per hour is set to 50 times or more, preferably 200 to 10,000 times. If the ratio is less than 50 times, the solid-liquid mixed phase may not be able to be raised in the reaction tube 12 in the form of an annular liquid film.

The gas velocity in the reaction tube 12 is 10 m /
Or more, preferably 20 to 100 m / sec.
The supply amount of the sulfonated gas is set. If the speed is less than 10 m / sec, the solid-liquid mixed phase may not be able to be raised in the reaction tube 12 in the form of an annular liquid film.

On the other hand, as shown in FIG. 1, a plurality of reaction tubes 12 are arranged in parallel and connected to each other by a connection tube 14. A jacket 13 is provided around the reaction tube 12, and the temperature in the reaction tube 12 can be maintained at a predetermined reaction temperature by flowing hot water, oil, or the like through the jacket 13. The solid-liquid mixed phase supplied to the reaction tube 12 from the inlet 6 as described above is accelerated by the rise of the sulfonated gas supplied at the same time,
By being pressed against the inner wall of the reaction tube 12 by a large amount of sulfonated gas, it rises as an annular liquid film on the inner wall of the reaction tube 12. Then, it is sulfonated by contact with the sulfonated gas. Then, the last reaction tube 1
The solid-liquid mixed layer and the sulfonated gas that have passed through 2 are guided from the recovery section introduction pipe 15 to the recovery section 16. And this collection unit 1
A sulfonate and an exhaust gas are collected from a sulfonate discharge pipe 17 and an exhaust gas discharge pipe 18 provided in 6, respectively.

In the present invention, the temperature at the time of contact between the fatty acid alkyl ester and the sulfonated gas is 110 to 150.
By setting the temperature to ° C., the raw materials can be sufficiently reacted, so that the conventional aging step can be omitted. However, if the reaction rate of the fatty acid alkyl ester has not reached the predetermined reaction rate, Accordingly, a ripening step of keeping the sulfonated product at a predetermined temperature to advance the reaction may be provided. The temperature in the aging step is suitably from 80 to 100 ° C. If the temperature is lower than 80 ° C., the reaction does not proceed
When the temperature exceeds 0 ° C., coloring may be easily performed. The reaction time is a time until a predetermined reaction rate is reached, and is preferably as short as possible. In the present invention, since the reaction before the aging step can be increased as described above, the reaction time of the aging step is shorter than the conventional one, and it is sufficient if the reaction time is 20 minutes or less, preferably 10 minutes or less.

If necessary, after contacting the fatty acid alkyl ester with the sulfonating gas or after the aging step, the SO ₃ bimolecular adduct remaining as a by-product in the sulfonated product is esterified with a lower alcohol. By providing an esterification step to promote the elimination of SO ₃ inserted into the alkoxy group of the bimolecular adduct to obtain an α-sulfofatty acid alkyl ester, the purity can be improved. The lower alcohol used in the esterification step preferably has 1 to 6 carbon atoms, which is the same as the carbon number of the alcohol residue of the fatty acid alkyl ester as the raw material, but is not particularly limited. The lower alcohol is used in an amount of 0.5 to 5.0 times, preferably 0.8 to 2.0 times the mol of the bimolecular adduct in the reaction solution. Reaction temperature is 50 ~
100 ° C, preferably 50 to 90 ° C, reaction time is 5 to 1
20 minutes.

Next, the α-sulfofatty acid alkyl ester (sulfonated product) thus obtained is neutralized with an alkali to form an α-sulfofatty acid alkyl ester salt. The neutralization step is preferably performed when the pH of the neutralized solution of the α-sulfofatty acid alkyl ester and the alkali is in the acidic or weakly alkaline range (pH 4 to 9). In the case of strong alkali, the ester bond may be easily broken. As the alkali, for example, an aqueous solution of an alkali metal, an alkaline earth metal, ammonia, and ethanolamine is used. The concentration of the aqueous alkali solution is 2 to 5
It is about 0% by weight. The neutralization temperature is 30 to 140 ° C., and the neutralization time is 10 to 60 minutes. The concentration of the activator (active ingredient concentration (AI concentration)) in the neutralized liquid (slurry) is 6%.
The content is 0 to 80% by weight, preferably 62 to 75% by weight. The activator concentration is the total concentration of the α-sulfofatty acid alkyl ester salt and the by-product α-sulfofatty acid dialkali salt. Outside this range, the viscosity of the slurry will increase significantly, or in the range where the viscosity of the slurry is low, the activator concentration will decrease significantly. When the viscosity of the slurry is high, handling such as pumping may be difficult, and when the concentration of the activator is low, the production efficiency is disadvantageously reduced.

If necessary, before or after the neutralization step, a treatment for improving the color tone of the α-sulfofatty acid alkyl ester salt to a color close to white can be performed. Examples of the treatment for improving the color tone include a bleaching treatment using a bleaching agent such as hydrogen peroxide, and the treatment is preferably performed after the neutralization step.

After this step, α
From the slurry of sulfo fatty acid alkyl ester salt, α
-A product is obtained by molding the sulfo fatty acid alkyl ester salt into powder, particles and the like.

The embodiments of the present invention are summarized as follows. (1) The reaction temperature when the fatty acid alkyl ester is brought into contact with the sulfonated gas is 110 to 150 ° C., preferably 1 to 150 ° C.
20-140 ° C. (2) The iodine value of the fatty acid alkyl ester is preferably 0.3 or less, more preferably 0.1 or less. (2) In the present invention, the α-sulfofatty acid alkyl ester salt is preferably brought into contact with a fatty acid alkyl ester and a sulfonating gas at a reaction temperature of 110 to 150 ° C., and then esterified with a lower alcohol as necessary to remain. The bimolecular adduct of the by-product is α-sulfofatty acid alkyl ester, which is obtained by neutralization.

[0025]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. (Examples 1 and 2) In a 300 ml glass reactor equipped with a stirrer, as a raw material, a mixed fatty acid methyl ester having a weight ratio of methyl myristate and methyl palmitate of 2: 8 (iodine value: 0.03) And sulfuric anhydride gas (sulfonated gas) diluted to 8% by volume with nitrogen gas was introduced at a constant speed for 60 minutes under the conditions shown in Table 1. Table 1 also shows the measurement results of the conversion and color tone of the raw material of the obtained sulfonated product (α-sulfofatty acid methyl ester). The reaction rate of the raw materials is a value measured by a liquid chromatography method. The color tone is 5% by weight of the sulfonated compound.
The ethanol solution was passed through a 40 mm optical path length, no. It was measured with a Krett photoelectric meter using a 42 blue filter.

(Comparative Examples 1 and 2) Under the conditions shown in Table 1, after contacting the mixed fatty acid methyl ester with the sulfonated gas in the same manner as in Example 1, the reaction rate of the raw material of the obtained sulfonated product was reduced. Because it did not exceed 98%, another 80
While maintaining the temperature at 0 ° C, aging was performed until the reaction rate exceeded 98%. The measurement results of the reaction rate and color tone of the raw material of the obtained sulfonated product are also shown in Table 1.

(Examples 3 to 6) As raw materials, methyl laurate (iodine value: 0.05) was used, and as a coloring inhibitor, anhydrous sodium sulfate having an average particle size of 50 μm was 5% by weight (based on methyl laurate). 1) and brought into contact with sulfuric anhydride gas diluted to 8% by volume with nitrogen gas under the conditions shown in Table 2 in a sulfonation apparatus similar to that shown in FIG. At this time, the residence time of the raw material in the sulfonation apparatus was 60 seconds. In this sulfonation apparatus, the reaction tube and the connection tube are made of stainless steel (SUS31).
6L), each having an inner diameter of 15 mm, a length of 2 m for the reaction tube, and 1 m for the connection tube. And the reaction tube 4
The total length of the book and the three connection pipes was 11 m. The reaction rate and color tone of the obtained sulfonated product were measured in the same manner as in Example 1. The results are shown in Table 2.

(Example 7) As a raw material, a mixed fatty acid methyl ester having a weight ratio of methyl palmitate and methyl stearate of 3: 7 (derived from palm kernel oil, iodine value: 0.
An experiment was performed in the same manner as in Example 3 except that Example No. 05) was used. The experimental conditions and results are shown in Table 2. (Example 8) As a raw material, a mixed fatty acid methyl ester having a weight ratio of methyl palmitate and methyl stearate of 7: 3 (derived from palm stearic acid, iodine value: 0.0
An experiment was performed in the same manner as in Example 3 under the conditions shown in Table 2 except that 6) was used. The experimental conditions and results are shown in Table 2.

(Comparative Examples 3 and 4) The raw materials were brought into contact with the sulfonating gas in the same manner as in Example 3 under the conditions shown in Table 2 except for the reaction temperature. Since the rate did not exceed 98%, an additional 80
While maintaining the temperature at 0 ° C, aging was performed until the reaction rate exceeded 98%. The measurement results of the reaction rate and color tone of the raw material of the obtained sulfonated product are also shown in Table 2.

[0030]

[Table 1]

[0031]

[Table 2]

From the results shown in Tables 1 and 2, in the examples according to the present invention, the reaction rate of the raw material exceeds 98% without providing the aging step, and the aging is performed by contacting with a sulfonated gas at a low temperature. It became clear that the color tone was not inferior to that of the comparative example.

[0033]

As described above, in the present invention, the ripening step can be omitted and the α-color having a color tone comparable to that of the conventional method in which the ripening is carried out at a low temperature.
A sulfo fatty acid alkyl ester salt is obtained. Therefore, the manufacturing time is shortened, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of a sulfonation device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... stirred tank, 2 ... pump, 3 ... extraction pipe, 4 ... circulation pipe, 5 ... supply pipe, 6 ... introduction part, 7 ... main body, 7a ... bottom face,
7b ... outlet, 8 ... raw material introduction pipe, 9 ... sulfonation gas introduction pipe, 12 ... reaction pipe, 13 ... jacket, 14 ... connection pipe,
Reference numeral 15: collection part introduction pipe, 16: collection part, 17: sulfonate discharge pipe, 18: exhaust gas discharge pipe.

Continued on the front page (72) Inventor Masahisa Yoshiya 1-3-7 Honjo, Sumida-ku, Tokyo Inside Lion Corporation (72) Inventor Taku Nishio 1-3-7 Honjo, Sumida-ku, Tokyo Lion stock In-house (72) Inventor Yozo Miyawaki 1-37 Honjo, Sumida-ku, Tokyo F-term in Lion Corporation (reference) 4H003 AB21 FA08 FA14 4H006 AA02 AC61 AC90 BC10 BD10 BD70 BE03 BE10 BE11 BE12 BE13 BE14 BE43

Claims (2)

[Claims] 1. A method for producing an α-sulfofatty acid alkyl ester salt comprising a step of bringing a fatty acid alkyl ester into contact with a sulfonating gas to perform sulfonation, wherein the reaction temperature of the step of bringing the fatty acid alkyl ester into contact with the sulfonating gas is 110. A process for producing an α-sulfofatty acid alkyl ester salt at a temperature of from −150 ° C. 2. The α-acid according to claim 1, wherein the iodine value of the fatty acid alkyl ester is 0.3 or less.
-A method for producing a sulfo fatty acid alkyl ester salt.