JP2527599B2 - Method for producing amidoalkanesulfonic acid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improved process for producing amidoalkanesulfonic acid used as a dispersant for copolymers of acrylamide and lime soap.

[Conventional technology]

The following formula (I) (In the formula, R ¹ is a hydrocarbon group, and R ² , R ³ , R ⁴ and R ⁵ are each independently hydrogen or an optionally substituted hydrocarbon group.) Is represented by amidoalkanesulfonic acid. Is abbreviated.

For the production of amidoalkanesulfonic acid, a method in which sulfur trioxide or 100% sulfuric acid and nitrile are mixed and an olefin is added and reacted (US Pat. No. 3,235,549
No. 3,500,707, British Patent No. 1,070,779), a method of reacting a vinyl group-containing chloride with a nitrile in the presence of sulfuric acid (JP-A-56-103145), an alkanol,
Method of reacting fuming sulfuric acid and nitrile in glacial acetic acid or methylene chloride (European Patent No. 0170485), method of reacting β-hydroxyalkanesulfonic acid and nitrile in sulfuric acid (PCT International Application No. 8400165), and nitrile , A method of reacting fuming sulfuric acid or sulfuric acid and an olefin (US Pat. No. 3,544,597, German Patent Application Publication No. 2,523,616, Japanese Patent Publication No. 50-30059) and the like are disclosed.

[Problems to be solved by the invention]

However, most of these methods use a special raw material or easily cause coloring due to the high reactivity of the raw material, and require a reaction temperature below the freezing point to suppress the coloring.

Among these methods, the method described in Japanese Examined Patent Publication No. Sho 50-30059 uses industrially inexpensive raw materials and carries out the reaction under relatively mild conditions. It is necessary to mix nitrile with fuming sulfuric acid or sulfuric acid at a temperature of -30 ° C or less), and then add olefin while raising the temperature to 50 to 60 ° C, and the yield and purity are not constant, and there are many cases where coloring occurs. However, the need for refrigeration equipment and the material and strength of the reactor can be a problem. It is considered that the product color cannot be removed by any method other than recrystallization.

As for the purity of the product, as described in JP-A-54-106427, high purity is required when the product is used as a copolymer. Therefore, a method of recrystallizing and purifying the product has been devised, but generally, there are few kinds of solvents that dissolve the amidoalkanesulfonic acid appropriately, and there is a problem in the stability of the compound in the solvent. In JP-A-54-106427, recrystallization is carried out in hydrous acetic acid. However, hydroacetic acid is industrially difficult to handle because it easily corrodes the equipment.

Therefore, there has been a demand for a method for producing an amidoalkanesulfonic acid, which allows a reaction under mild conditions and does not require any particular purification of the product.

[Means for solving problems]

The present inventors have conducted extensive studies to overcome the above-mentioned drawbacks of the prior art and produce a high-quality amidoalkanesulfonic acid in a high yield and economically without requiring recrystallization.

As a result, when nitrile, olefin and sulfur trioxide, fuming sulfuric acid or sulfuric acid, and optionally water, are reacted to produce amidoalkanesulfonic acid,
At least 1% by weight of carboxylic acid amide to nitrile before formation of amidoalkanesulfonic acid or its precursor
When present, the reaction proceeds and the amidoalkanesulfonic acid is separated from the reaction mixture, washed with the nitrile, and simply dried to give a high yield of high quality amidoalkanesulfonic acid that requires virtually no further purification. It was found that there is no effect even if the carboxylic acid amide is added after the formation of the amidoalkanesulfonic acid or its precursor.

The present invention is based on the above new knowledge, and includes nitrile, olefin and sulfur trioxide, fuming sulfuric acid or sulfuric acid,
In the method for producing an amidoalkanesulfonic acid of the formula (I) by reacting amide alkanesulfonic acid or a precursor thereof with at least 1% by weight of carboxylic acid amide with respect to the nitrile. The method for producing amidoalkanesulfonic acid is characterized by reacting in the presence of

Nitrile is represented by the formula R ¹ -CN (wherein R ¹ has the same meaning as defined above), and examples thereof include R ¹ being methyl, ethyl, propyl,
Butyl, hexyl, octyl, saturated nitrile that is a saturated hydrocarbon group such as dodecyl group, unsaturated nitrile that is an unsaturated hydrocarbon group such as vinyl, allyl, ethynyl, propargyl group, phenyl, tolyl, xylyl, benzyl group, etc. Examples thereof include aromatic nitrile which is an aromatic group.

The olefin is an aliphatic compound having an unsaturated bond in the molecule, and the hydrocarbon group may have a substituent.

The carboxylic acid amide includes, for example, an amide represented by the formula R ¹ -CONH ₂ (wherein R ¹ has the same meaning as described above) and a mono- or dialkylated amide of the amino group. The hydrocarbon group of R ¹ is the same as in the above-mentioned nitrile, and an alkylated example of the amino group includes amidoalkane produced by the Ritter reaction from the above-mentioned nitrile and olefin.

Nitrile, olefin and sulfur trioxide in the present invention, fuming sulfuric acid or sulfuric acid, and optionally water,
The amidoalkanesulfonic acid is optionally formed via the intramolecular anhydride of its precursor, amidoalkanesulfonic acid, that is, a 2-dioxy-1,2,5-oxathiazine compound.

The above precursor is converted to amidoalkanesulfonic acid by reaction with water.

In the process of the present invention, at least 1% by weight of carboxylic acid amide, based on the nitrile, is present in the reaction mixture before the formation of the amidoalkanesulfonic acid or its precursor. The preferred amount of carboxylic acid amide is 1 to 10% based on the nitrile.

The carboxylic acid amide may be an amide corresponding to a partial hydrolyzate of the raw material nitrile, and the amide may be present in the reaction mixture by previously hydrolyzing a part of the nitrile. In the latter case, it is advantageous in the subsequent reaction operation to carry out the hydrolysis using sulfuric acid.

As described above, in the present invention, nitrile, olefin and sulfur trioxide, fuming sulfuric acid or sulfuric acid are reacted in the presence of a carboxylic acid amide.

According to one aspect of the invention, fuming sulfuric acid is added to the mixture of nitrile and carboxylic acid amide at 0 ° C to 5 ° C, the mixture is heated to 30-60 ° C and then the olefin is added. The reaction is usually completed in 30 minutes to 1 hour. The theoretical amount of water is then added to the reaction mixture before the amidoalkanesulfonic acid is separated off.

According to another embodiment, the nitrile and 90-100% concentrated sulfuric acid are mixed in
Accumulate at least 1% by weight of the carboxylic acid amide in the mixture by mixing at 0-60 ° C and holding at that temperature for 30-90 minutes, followed by addition of olefin at the same temperature to react. The subsequent steps are similar to those described above.

In the latter embodiment, the mixing and reaction of the raw materials is 30-60.
It can be carried out at a constant temperature in the range of ° C. Therefore, it is possible to avoid the two-step operation of the reaction at a high temperature following the low-temperature reaction in the conventional method.

Thus, when acrylonitrile is used as the nitrile, isobutene is used as the olefin, and acrylamide or N-tert-butylacrylamide is used as the carboxylic acid amide, 2-acrylamido-2-methylpropanesulfonic acid is obtained as the amidoalkanesulfonic acid. The yield from isobutene is 80%, the purity is 97% or more by high performance liquid chromatography, and the hue of 25% aqueous solution (AP
HA) 15 or less can be obtained.

Hereinafter, the present invention will be further described in the form of examples, and comparative examples will be given to compare with the present invention.

Example 1 A four-necked flask equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer and a gas inlet tube was kept under a nitrogen atmosphere, and 573.0 g of acrylonitrile and 12.6 g of acrylamide were put therein. While maintaining the mixture at 0 ° C to 5 ° C, 104.3 g of 6.3% fuming sulfuric acid was added dropwise to obtain a clear solution. Immediately raise the temperature to 50 ° C and add 56.0 g of isobutene to 3
It was introduced in 0 minutes. After the introduction, stir for 30 minutes at 50 ℃,
Subsequently, 2.2 g of water was added and cooled. 165.0 g of the formed precipitate was removed, washed with acrylonitrile and dried.
2-acrylamido-2-methylpropanesulfonic acid was obtained as colorless crystals. Yield 79.7% (based on isobutene; the same in the following examples and comparative examples).

The purity of this crystal by high performance liquid chromatography (HPLC) is 98.2%, and its 25% aqueous solution hue (APHA)
Was 5.

Example 2 Using the same reactor as in Example 1, 53.1 g of acrylonitrile and 1.2 g of acrylamide were dissolved in liquid sulfur dioxide kept at -40 ° C. 80.0g in this solution at the same temperature
After adding dropwise liquid sulfur trioxide (Nisso Metal Chemical Co., Ltd., trade name Nisso Sulfan), 125.0 g of isobutene was introduced at -30 to -40 ° C, and stirring was continued for 3 hours at that temperature. It was After adding 20.0 g of water, the reaction solution was concentrated, and the precipitated crystals were collected, washed with acrylonitrile and dried to obtain 150.0 g of 2-acrylamido-2-methylpropanesulfonic acid as colorless crystals.

The purity of this crystal was 98.2% (HPLC), and the hue (APHA) of a 25% aqueous solution was 15.

Example 3 487.1 g of acrylonitrile was placed in the same reaction vessel as in Example 1 and 108.0 g of 98% sulfuric acid was added dropwise while maintaining at 40 ° C. under a nitrogen atmosphere. When the stirring was continued for 70 minutes, 10.7 g of acrylamide accumulated in the reaction mixture. Then 56.0 g of isobutene were introduced into the reaction mixture at the same temperature for 30 minutes.
After the introduction was complete, the mixture was stirred for 60 minutes at that temperature, then 2.0 g of water were added and then cooled. Remove the resulting precipitate,
After washing with acrylonitrile and drying, 161.1 g of 2-
Acrylamide-2-methylpropanesulfonic acid was obtained as colorless crystals. Yield 77.8%.

The purity of this crystal was 98.8% (HPLC), and the hue (APHA) of a 25% aqueous solution was 10.

Example 4 Instead of acrylonitrile, acetonitrile 376.8 g, 98
The reaction operation was performed in the same manner as in Example 3 except that 109.7 g of 96.5% sulfuric acid was used instead of the% sulfuric acid to obtain 156.0 g of 2-acetamido-2-methylpropanesulfonic acid as colorless crystals. Yield 80.0%.

The purity of this crystal was 98.5% (HPLC), and the hue (APHA) of a 25% aqueous solution was 5.

Example 5 125.5 g of 2-acrylamidopropanesulfonic acid was obtained as colorless crystals by performing the same reaction procedure as in Example 3 except that the isobutene was changed to 42.0 g of propylene. Yield 6
5.0%.

The purity of this crystal was 98.0% (HPLC), and the hue (APHA) of a 25% aqueous solution was 5.

The data obtained by carrying out the reaction procedure of Example 1 while changing the type and amount of carboxylic acid amide and the concentration and amount of fuming sulfuric acid are shown in the table below. In the table, the yield column shows the yield of 2-acrylamido-2-methylpropanesulfonic acid.

Comparative Example 1 2-Acrylamido-2-methylpropanesulfonic acid (198.9 g) was obtained as pale yellow crystals by the same procedure as in Example 1 except that acrylamide was not added.
Yield 96.1%.

The purity of this crystal was 91.3% (HPLC), and the hue (APHA) of a 25% aqueous solution was 100.

Comparative Example 2 382.0 g of acrylonitrile was placed in the same reaction apparatus as in Example 1 and 6.3% fuming sulfuric acid was added while keeping the temperature at -30 ° C under a nitrogen atmosphere.
8.6g was added.

Then, 56.0 g of isobutene was added to the reaction mixture at a temperature of -30
The mixture was introduced into the mixture while the temperature was raised from 50 ° C to 50 ° C. After the total amount of isobutene had been introduced, the reaction mixture was kept stirring at 50 ° C. for 60 minutes, 1.3 g of water was added and cooled. The resulting precipitate was separated, washed with acrylonitrile and dried to give 175.1 g of 2-acrylamido-2-methylpropanesulfonic acid as pale yellow crystals. Yield 84.6%.

The purity of this crystal was 93.4% (HPLC), and the hue (APHA) of a 25% aqueous solution was 100.

Comparative Example 3 In the method of Example 1, the reaction was carried out without adding acrylamide in the same manner as in Comparative Example 1 until the introduction of isobutene, the mixture was stirred at 50 ° C. for 60 minutes, and then 12.6 g of acrylamide was added, Then 1.3 g of water was added and cooled. The resulting precipitate was separated, washed with acrylonitrile, and then dried to obtain a pale yellow crystal of 2-acrylamido-2-2-methylpropanesulfonic acid. The crystal purity and hue were similar to those of the product of Comparative Example 1.

〔The invention's effect〕

According to the present invention, a high-quality amidoalkanesulfonic acid, which has been difficult to produce in the past, can be obtained in a high yield by a simple reaction operation.

Claims (3)

(57) [Claims] 1. A nitrile, an olefin and sulfur trioxide, fuming sulfuric acid or sulfuric acid, and optionally water, are reacted to give the following formula: (Wherein R ¹ is a hydrocarbon group, and R ² , R ³ , R ⁴ and R ⁵ are each independently hydrogen or an optionally substituted hydrocarbon group) to produce an amidoalkanesulfonic acid. The method for producing an amidoalkanesulfonic acid according to claim 1, wherein the amidoalkanesulfonic acid or a precursor thereof is produced in the presence of at least 1% by weight of a carboxylic acid amide with respect to the nitrile. 2. The method according to claim 1, wherein the carboxylic acid amide is a carboxylic acid amide which can be derived from a starting nitrile. 3. The process according to claim 1, wherein the carboxamide is present in the reaction mixture by pre-hydrolyzing part of the starting nitrile.