JPH07247258A - Production of polyoxyethylene ether sulfate - Google Patents

Abstract

PURPOSE:To obtain a polyoxyethylene ether sulfate useful as a surfactant usable as liquid detergent, shampoo, pharmaceuticals, cosmetics, etc., by sulfating a polyoxyethylene ether in the presence of a compound having amide group and converting the product into a salt. CONSTITUTION:A polyoxyethylene ether sulfate can be produced by sulfating a compound of formula RO-(CH2CH2O)nH (R is a hydrocarbon residue; (n) is 1-20) with a sulfating agent (e.g. sulfur trioxide) in the presence of a compound having amide group and expressed by formula (R<1> to R<3> each is a 1-20C alkyl which may form a ring) (e.g. 1,3-dimethyl-2-imidazolidinone) at 20-60 deg.C using a thin film sulfating apparatus and converting the product into a salt by treating with a basic substance. Since the product has extremely low 1,4-dioxane content, it can be used without purification.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing polyoxyethylene ether sulfate. The polyoxyethylene ether sulfate obtained by the method of the present invention has 1,
It has a low content of 4-dioxane and is useful as a surfactant used in liquid detergents, shampoos, medicines, cosmetics and the like.

[0002]

BACKGROUND OF THE INVENTION Various methods are known as methods for producing polyoxyethylene ether sulfate. For example, there is a method in which an alkanol or an alkylphenol is reacted with ethylene oxide, the resulting addition product is sulphated with chlorosulfonic acid or sulfur trioxide, and finally treated with an alkali compound to give a salt. At this time, 1,4-dioxane is always contained in the product as a by-product. The amount is generally 100 to 500 ppm in the product when using chlorosulfonic acid,
When using sulfur trioxide, 300-2000p in the product
It is called pm.

1,4-Dioxane can be a health hazard, and manufacturers and users are trying to reduce it to eliminate that possibility. For example, JP-A-57-116062 and US Pat. No. 4,
No. 285,881 adopts a method of subjecting the product to azeotropic distillation, and in German Patent Application Publication No. 3,126,175, the aqueous solution of polyoxyethylene ether sulfate after treatment with an alkali compound is concentrated and reduced in pressure. The 1,4-dioxane is removed by adopting the method of heat treatment below.

However, these methods have a problem in terms of manufacturing cost such that the processing apparatus is complicated and processing time and a large amount of energy are required. Furthermore, although the amount of 1,4-dioxane contained in the finally obtained polyoxyethylene ether sulfate can be reduced,
The amount of 1,4-dioxane by-produced does not change, and it cannot be said that this is a fundamental solution.

Further, there are two types of methods for producing polyoxyethylene ether sulfate, that is, a batch method and a thin film method. We have previously performed 15 to 15 by performing sulfation under a specific condition in the thin film method. Succeeded in reducing the content of 1,4-dioxane to about 60 ppm (Japanese Patent Laid-Open No. Sho 6-66).
No. 4-19055). However, further reduction is desired.

[0006] Therefore, as a result of study to find a method for effectively reducing or suppressing the by-product of 1,4-dioxane as a by-product, and making the purification after the production of the target substance substantially unnecessary, the present study was conducted. The invention was completed.

[0007]

Thus, according to the present invention, the general formula (I) RO- (CH ₂ CH ₂ O) _n H (I) (wherein R is a hydrocarbon residue and n is an average addition) 1 in moles
A polyoxyethylene ether represented by the formula (2) to 20) is treated with a sulfating agent in the presence of a compound having an amide group using a thin-film sulfating device to be sulfated, and then converted into a salt. A method for producing a characteristic polyoxyethylene ether sulfate is provided.

As the polyoxyethylene ether of the general formula (I) which is a raw material for the method of the present invention, known substances can be used. The hydrocarbon residue in the definition of R in the general formula (I) is preferably a linear or branched alkyl group having an average carbon number of 8 to 20 or a phenyl group substituted with this alkyl group. Examples of the linear or branched alkyl group having an average carbon number of 8 to 20 include the following. First, as the straight-chain alkyl group, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl or icosyl can be mentioned. On the other hand, as the branched alkyl group, ethylhexyl, dimethylhexyl, trimethylhexyl, methylheptyl, dimethylheptyl, trimethylheptyl,
Tetramethylheptyl, ethylheptyl, methyloctyl, methylnonyl, methyldecyl, methylundecyl,
Examples thereof include methyldodecyl, methyltridecyl, methyltetradecyl, methylpentadecyl, methylhexadecyl, methylheptadecyl, methyloctadecyl and methylnonadecyl.

Further, the above-mentioned phenyl group substituted with an alkyl group can also be used as a hydrocarbon residue, and the substitution position of the alkyl group is not particularly limited and may be either the ortho position or the para position. The above alkyl group has an average carbon number of 8
Within the range of 20 to 20, a plurality of kinds may be combined, and an average carbon number of 9 to 13 is particularly preferable.

Compounds having an average added mole number n of --CH ₂ CH ₂ O-- groups of 1 to 20, especially 2 to 6, are used. The compound having an amide group used in the method of the present invention has an action of forming a complex with a sulfating agent to moderate the sulfating condition and neutralizing a sulfate ester produced by sulfation to give 1,4-dioxane. It is considered to exhibit the action of capturing and suppressing the free acid which is the cause of the by-product of.

The compound having an amide group for exhibiting such an action is represented by the general formula (II)

[0012]

[Chemical 2]

(In the formula, R ¹ , R ² and R ³ are the same or different, and are an alkyl group having 1 to 20 carbon atoms which may be substituted with a hydrogen atom or a hydroxyl group, or R ¹ and R ² or R 3.
³ or R ² and R ³ may together form a ring). 1 carbon atom in the definition of general formula (II)
~ 20 alkyl groups include methyl, ethyl, propyl,
Linear alkyl groups such as butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl or icosyl, isopropyl, isobutyl, se
c-Butyl, tert-butyl, neopentyl, tert-pentyl, isopentyl, dimethylbutyl, isohexyl, methylhexyl, ethylhexyl, dimethylhexyl, trimethylhexyl, methylheptyl, dimethylheptyl, trimethylheptyl, tetramethylheptyl, ethylheptyl, methyloctyl And a branched alkyl group such as methylnonyl, methyldecyl, methylundecyl, methyldodecyl, methyltridecyl, methyltetradecyl, methylpentadecyl, methylhexadecyl, methylheptadecyl, methyloctadecyl or methylnonadecyl.

The above alkyl group may be substituted with one or more hydroxyl groups, of which hydroxyalkyl groups such as hydroxymethyl, hydroxyethyl and hydroxypropyl are preferred. Further, in the formula, R ¹ and R ² or R ³ , or R ² and R ³ may be taken together to form a ring.

Specific examples of the compound of the general formula (II) include N, N-dimethylformamide, N, N-dimethylacetamide, N-methylformamide, and 8 to 2 carbon atoms.
Aliphatic amide compounds such as N, N-dimethylalkaneamide having 0 alkyl group and N, N-diethanolalkaneamide having alkyl group having 8 to 20 carbon atoms, N-
R ¹ and R ² such as methylpyrrolidone and caprolactam
Or R ³ together forms a ring or
Examples thereof include alicyclic amide compounds in which R ² and R ³ are combined to form a ring, such as pyrrolidinecarboxaldehyde and 1-acetylpiperidine. Furthermore, the general formula (I
1,3-Dimethyl-2-imidazolidinone and the like which are not included in I) can also be used as the amide group-containing compound of the present invention.

Among these, the particularly preferable amide group-containing compound has a function as a surfactant itself or a polyoxyethylene ether which is a surfactant, considering that it remains in the final product. Those having a function as a foam-enhancing agent for sulfates are preferable.
Examples of the compound having an amide group satisfying this condition include N, N-dimethylalkaneamide having an alkyl group having 8 to 20 carbon atoms and N, N-diethanolalkaneamide having an alkyl group having 8 to 20 carbon atoms. Aliphatic amide compounds may be mentioned. More specifically, N, N-dimethylpelargonamide, N, N-dimethylcaprinamide, N, N-dimethylundecylamide, N, N-dimethyllaurinamide, N, N-dimethyltridecylamide, N, N- Dimethylmyristinamide, N, N-dimethylpentadecylamide, N, N-dimethylpalmitinamide, N, N-dimethylheptadecylamide, N,
N, N-dimethyl alkane amides such as N-dimethyl stearamide, N, N-dimethyl nonadecane amide, N, N-dimethyl araquinamide, N, N-diethanol pelargonamide, N, N-diethanol caprinamide, N, N-diethanol undecylamide, N, N
-Diethanollaurinamide, N, N-diethanoltridecylamide, N, N-diethanolmyristinamide, N, N-diethanolpentadecylamide, N,
N-diethanolpalmitinamide, N, N-diethanolheptadecylamide, N, N-diethanolstearinamide, N, N-diethanolnonadecaneamide,
N, N-diethanol alkanamide, such as N, N-diethanol araquinamide, is mentioned.

Of these N, N-dimethylalkaneamides or N, N-diethanolalkaneamides, the most preferable ones are N, N-dimethyllaurinamide, N, N-dimethyllaurinamide,
N-diethanol laurinamide, alkane having 8 carbon atoms
So-called N, N-diethanolalkanamide having a palm composition and N, N-dimethylalkaneamide having a palm composition, which are composed of a mixture of

Although amines also form a complex with a sulfating agent, the resulting complex is stable and has a poor sulfating ability, so that sulfation of hydroxyl groups cannot be carried out efficiently. Further, since the complex is too stable and has no effect of trapping the free acid, the amount of 1,4-dioxane as a by-product cannot be reduced. Therefore,
It is not suitable for use in the sulfation according to the invention. As the sulfating agent that can be used in the present invention, known ones can be used, and examples thereof include chlorosulfonic acid, sulfur trioxide and concentrated sulfuric acid. Of these, sulfur trioxide is particularly preferable for industrial use from the viewpoint of yield and the like.

First, polyoxyethylene ether is treated with a sulfating agent in the presence of a compound having an amide group to be sulfated. As the sulfation method, a thin film sulfation method, which is excellent in suppressing the by-production of 1,4-dioxane, is used. The thin film type sulfating apparatus used in the thin film type sulfating method is not particularly limited, and examples thereof include Falling Film Reacter (manufactured by Balestra Co., Ltd.).

The amount of the compound having an amide group used in the method of the present invention is 1 to 300 mol% based on the polyoxyethylene ether used. However, if only considering the suppression of by-production of 1,4-dioxane during sulfation, the more effective the use of polyoxyethylene ether, the higher the suppression effect, but the presence of an amide group. From the viewpoint of reducing the load when the compound is removed after neutralization or preventing the decrease of the purity of the polyoxyethylene ether sulfate obtained when the compound is used without removing it, 2 to 100 mol% is preferable, and 3 is particularly preferable. ~
30 mol% is preferable.

The amount of the sulfating agent used is from 0.9 to 1 mol per hydroxyl group in the polyoxyethylene ether used.
It is 0.99 mol, more preferably 0.95 to 0.98 mol. If it is less than 0.9 mol, the reaction rate of sulfation is lowered, which is not preferable, and if it is more than 0.99 mol, 1,4-dioxane is rapidly produced as a by-product, which is not preferable. When sulfur trioxide is used as the sulfating agent, it is used as gaseous sulfur trioxide diluted with an inert gas.
Nitrogen or air is used as the inert gas from the viewpoint of price and the like, but it is industrially preferable to use air. The concentration of sulfur trioxide in the inert gas is 1.5
˜4.0% by volume is preferred.

The sulfation temperature is 70 ° C. or lower, preferably 20 to 60 ° C., more preferably 40 to 60 ° C.
Here, the present invention is characterized in that a compound having an amide group is simultaneously present at the time of sulfation. However, even if a compound having an amide group is added to the reaction system immediately after sulfation, the effect is small. -The dioxane by-product can be suppressed to some extent.

The polyoxyethylene ether sulfated as described above can be converted to the corresponding salt by treating with a basic substance. The basic substance for neutralizing the sulfate by converting it to a salt is not particularly limited, but hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide; alkalis such as magnesium hydroxide and calcium hydroxide. Earth metal hydroxides; alkali metal carbonates such as sodium carbonate and potassium carbonate; alkaline earth metal carbonates such as magnesium carbonate and calcium carbonate; ammonia; lower alkylamines such as methylamine and ethylamine; hydroxymethyl Examples thereof include lower hydroxyalkylamines such as amine and hydroxyethylamine. Among these basic substances, sodium hydroxide, potassium hydroxide or lower alkanolamines are particularly preferable in consideration of reactivity and availability. Here, the time to neutralize should be as short as possible.
It is preferable from the viewpoint of suppressing the by-production of 1,4-dioxane. The neutralization method is not particularly limited.

The polyoxyethylene ether sulfate produced by the above production method does not require any particular purification because the content of 1,4-dioxane is extremely small. However, depending on the application, a lower content of polyoxyethylene ether sulfate can be obtained by applying a known purification method.

[0025]

Function: General formula (I) RO- (CH ₂ CH ₂ O) _n H (I) (wherein R is a hydrocarbon residue, n is the average number of moles added, and is 1
A polyoxyethylene ether represented by the following formula) is treated with a sulfating agent in the presence of a compound having an amide group using a thin-film sulfating apparatus to be sulfated, and then converted into a salt. If polyoxyethylene ether sulfate is produced, the production of oxonium ions is suppressed,
The content of 1,4-dioxane, which can be harmful to health, is reduced.

Further, the compound having an amide group is 1,3
By using dimethyl-2-imidazolidinone, the content of 1,4-dioxane is further reduced. Furthermore, a compound having an amide group is represented by the general formula (II)

[0027]

[Chemical 3]

(In the formula, R ¹ , R ² and R ³ are the same or different and each is an alkyl group having 1 to 20 carbon atoms which may be substituted with a hydrogen atom or a hydroxyl group, or R ¹ and R ² or R 3.
³ , or R ² and R ³ may together form a ring) to form an amide compound.
The dioxane content is reduced. In addition, a compound having an amide group is converted into N, N-dimethylformamide, N,
N-dimethylacetamide, N-methylformamide,
N, N-dimethylalkaneamide having 8 to 20 carbon atoms, N, N-dihydroxyethylalkaneamide having 8 to 20 carbon atoms, or N-methylpyrrolidone activator foam-increasing effect agent or amide which itself functions as activator. By selecting from compounds having a group, there are advantages such as omission of purification cost.

Furthermore, by using sulfur trioxide as the sulfating agent, industrialization is easy and the yield of polyoxyethylene ether sulfate is improved.

[0030]

EXAMPLES Examples will be shown below, but the present invention is not limited to these examples. Example 1 Polyoxyethylene having an average molecular weight of 330 and a hydroxyl value of 170 was obtained by adding 3 moles of —CH ₂ CH ₂ O— groups to a natural alcohol having 12 and 14 carbon atoms and having an average carbon number of 12.8. A mixture of N, N-dimethylformamide (DMF) as a compound having ether and amide group is a thin film type sulfation reactor (internal diameter 14 mmφ, length 4 m)
Introduced. Here, polyoxyethylene ether is 3.96 kg / hr (12 mol / hr), and DMF is 0.
0877 kg (1.2 mol / h, 10 mol% based on polyoxyethylene ether) were introduced.

Further, SO ₃ having a concentration of 2.0% by volume diluted with air was introduced into the thin film type sulfation reactor to carry out the sulfation reaction. Here, SO ₃ is 0.941 kg (1
It was introduced at 1.76 mol / hour, that is, 0.98 mol times with respect to the hydroxyl group of polyoxyethylene ether. The temperature during sulfation was 40 to 50 ° C. After completion of the reaction, gas-liquid separation was performed with a cyclone, and the obtained sulfated product was added dropwise to an aqueous sodium hydroxide solution to neutralize the pH of the aqueous solution to 7-9. The amount of 1,4-dioxane was 5 ppm with respect to the polyoxyethylene ether sulfate in the obtained aqueous solution of polyoxyethylene ether sulfate.

The reaction conditions, the reaction rate of sulfation, the amount of 1,4-dioxane, etc. are summarized in Table 1. Example 2 N, N-dimethylacetamide (DMA) was used as a compound having an amide group, and 0.105 kg (1.
2 mol / hr, 10 for polyoxyethylene ether
Mol%), except that it is introduced into the thin film sulfation reactor.
A polyoxyethylene ether sulfate was produced in the same manner as in Example 1.

The amount of 1,4-dioxane was 6 ppm based on the polyoxyethylene ether sulfate in the obtained polyoxyethylene ether sulfate aqueous solution. The reaction conditions, the reaction rate of sulfation, the amount of 1,4-dioxane, etc. are summarized in Table 1. Example 3 N-methylformamide is used as a compound having an amide group and is introduced into a thin film sulfation reactor at 0.071 kg (1.2 mol / hr, 10 mol% based on polyoxyethylene ether) per hour. A polyoxyethylene ether sulfate was produced in the same manner as in Example 1 except for the above.

The amount of 1,4-dioxane was 11 ppm with respect to the polyoxyethylene ether sulfate in the obtained polyoxyethylene ether sulfate aqueous solution. The reaction conditions, the reaction rate of sulfation, the amount of 1,4-dioxane, etc. are summarized in Table 1. Example 4 Using N-methylpyrrolidone as a compound having an amide group, 0.119 kg / hr (1.2 mol / hr, 10 mol% based on polyoxyethylene ether) was introduced into a thin film sulfation reactor. A polyoxyethylene ether sulfate was produced in the same manner as in Example 1 except for the above.

The amount of 1,4-dioxane was 7 ppm based on the polyoxyethylene ether sulfate in the obtained polyoxyethylene ether sulfate aqueous solution. The reaction conditions, the reaction rate of sulfation, the amount of 1,4-dioxane, etc. are summarized in Table 1. Example 5 1,3-Dimethyl-2- as a compound having an amide group
0.137 per hour using imidazolidinone (DMI)
A polyoxyethylene ether sulfate was produced in the same manner as in Example 1 except that kg (1.2 mol / hr, 10 mol% based on polyoxyethylene ether) was introduced into the thin film sulfation reactor. .

The amount of 1,4-dioxane was 8 ppm with respect to the polyoxyethylene ether sulfate in the obtained polyoxyethylene ether sulfate aqueous solution. The reaction conditions, the reaction rate of sulfation, the amount of 1,4-dioxane, etc. are summarized in Table 1. Example 6 N, N-dimethyllaurinamide was used as a compound having an amide group, and 0.273 kg (1.2 mol / hr) per hour was used.
(10 mol% relative to polyoxyethylene ether)
Example 1 except that it is introduced into the thin film sulfation reactor at
A polyoxyethylene ether sulfate was prepared in the same manner as in.

The amount of 1,4-dioxane was 10 ppm with respect to the polyoxyethylene ether sulfate in the obtained polyoxyethylene ether sulfate aqueous solution. The reaction conditions, the reaction rate of sulfation, the amount of 1,4-dioxane, etc. are summarized in Table 1. Example 7 N, N-diethanollaurinamide was used as a compound having an amide group, and 0.345 kg / hr (1.2 mol / hr, 10 mol% based on polyoxyethylene ether) was used as a thin film sulfation reactor. A polyoxyethylene ether sulfate was produced in the same manner as in Example 1 except that the polyoxyethylene ether sulfate was introduced into.

The amount of 1,4-dioxane was 8 ppm based on the polyoxyethylene ether sulfate in the obtained polyoxyethylene ether sulfate aqueous solution. The reaction conditions, the reaction rate of sulfation, the amount of 1,4-dioxane, etc. are summarized in Table 1. Example 8 N, N-diethanol coconut composition amide (C8-18, average molecular weight 293) was used as a compound having an amide group, and 0.352 kg / hr (1.2 mol / hr, relative to polyoxyethylene ether) was used. Polyoxyethylene ether sulfate was produced in the same manner as in Example 1 except that the polyoxyethylene ether sulfate was introduced into the thin film type sulfation reactor at 10 mol%.

The amount of 1,4-dioxane was 7 ppm based on the polyoxyethylene ether sulfate in the obtained polyoxyethylene ether sulfate aqueous solution. The reaction conditions, the reaction rate of sulfation, the amount of 1,4-dioxane, etc. are summarized in Table 1. Examples 9 to 11 The amount of DMF added was 3 mol% (Example 9), 30 mol% (Example 10), and 1 mol based on polyoxyethylene ether.
A polyoxyethylene ether sulfate was produced in the same manner as in Example 1 except that the amount was changed to 00 mol% (Example 11).

The amount of 1,4-dioxane based on the polyoxyethylene ether sulfate in the obtained aqueous solution of polyoxyethylene ether sulfate was 12 ppm and 3 p, respectively.
pm was 1 ppm or less. The reaction conditions, the reaction rate of sulfation, the amount of 1,4-dioxane, and the like are summarized in Table 2.

Comparative Example 1 Triethylamine was used in place of the compound having an amide group, and 0.121 kg / hr (1.2 mol / hr, 10 mol% based on polyoxyethylene ether) was added to a thin film sulfation reactor. A polyoxyethylene ether sulfate was produced in the same manner as in Example 1 except that it was introduced.

The amount of 1,4-dioxane was 23 ppm based on the polyoxyethylene ether sulfate in the obtained polyoxyethylene ether sulfate aqueous solution. The reaction conditions, the reaction rate of sulfation, the amount of 1,4-dioxane, and the like are summarized in Table 2. Comparative Example 2 A polyoxyethylene ether sulfate was produced in the same manner as in Example 1 except that the sulfation reaction was carried out without using a compound having an amide group.

The amount of 1,4-dioxane was 25 ppm with respect to the polyoxyethylene ether sulfate in the obtained aqueous solution of polyoxyethylene ether sulfate. The reaction conditions, the reaction rate of sulfation, the amount of 1,4-dioxane, and the like are summarized in Table 2.

[0044]

[Table 1]

[0045]

[Table 2]

In the above table, the active ingredient of ether sulfate was measured by the Epton method, and the sulfation reaction rate was calculated from the analysis value by the Epton method. Also, 1,4-
The amount of dioxane by-product was quantified by a calibration curve method using gas chromatography. As is clear from Tables 1 and 2, when the thin-film type sulfation reactor is used, the by-production of 1,4-dioxane is suppressed by introducing the compound having an amide group.

[0047]

INDUSTRIAL APPLICABILITY General formula (I) RO- (CH ₂ CH ₂ O) _n H (I) (wherein R is a hydrocarbon residue, n is the average number of moles added, and is 1
A polyoxyethylene ether represented by the following formula) is treated with a sulfating agent in the presence of a compound having an amide group using a thin-film sulfating apparatus to be sulfated, and then converted into a salt. When a polyoxyethylene ether sulfate is produced, the production of oxonium ions can be suppressed, and the content of 1,4-dioxane, which may be harmful to health, can be reduced.

Further, the compound having an amide group is 1,3
-Dimethyl-2-imidazolidinone gives 1,4
-The content of dioxane is further reduced. Furthermore, a compound having an amide group is represented by the general formula (II)

[0049]

[Chemical 4]

(In the formula, R ¹ , R ² and R ³ are the same or different and each is an alkyl group having 1 to 20 carbon atoms which may be substituted with a hydrogen atom or a hydroxyl group, or R ¹ , R ² or R 3.
³ , or R ² and R ³ may together form a ring) to form an amide compound.
-The content of dioxane can be reduced. Also,
The compound having an amide group is converted into N, N-dimethylformamide, N, N-dimethylacetamide, N-methylformamide, N, N-dimethylalkaneamide having 8 to 20 carbon atoms, and N, N- having 8 to 20 carbon atoms. By selecting from a foaming effect agent of an activator of dihydroxyethylalkanamide or N-methylpyrrolidone or a compound having an amide group which itself functions as an activator, there is an advantage that purification cost can be omitted.

Further, by using sulfur trioxide as the sulfating agent, industrialization is easy and the yield of polyoxyethylene ether sulfate is improved.

Claims (5)

[Claims] 1. General formula (I) RO- (CH ₂ CH ₂ O) _n H (I) (wherein R is a hydrocarbon residue, and n is the average number of moles added, 1
A polyoxyethylene ether represented by the formula (2) to 20) is treated with a sulfating agent in the presence of a compound having an amide group using a thin-film sulfating device to be sulfated, and then converted into a salt. A method for producing a polyoxyethylene ether sulfate characterized by the following. 2. The method according to claim 1, wherein the compound having an amide group is 1,3-dimethyl-2-imidazolidinone. 3. A compound having an amide group has the general formula (I
I) [Chemical formula 1] (In the formula, R ¹ , R ² and R ³ are the same or different and have 1 to 2 carbon atoms which may be substituted with a hydrogen atom or a hydroxyl group.
An alkyl group of 0, or R ¹ and R ² or R ³ , or R ²
And R ³ together may form a ring) and the amide compound. 4. The compound having an amide group is N, N-dimethylformamide, N, N-dimethylacetamide,
The method according to claim 3, which is N-methylformamide, N, N-dimethylalkaneamide having 8 to 20 carbon atoms, N, N-dihydroxyethylalkanamide having 8 to 20 carbon atoms, or N-methylpyrrolidone. 5. The sulfating agent is sulfur trioxide.
The manufacturing method described.