JP3412158B2 - Method for producing 2-acrylamide-2-methylpropanesulfonic acid polymer - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is a highly pure 2-acrylamido-2-methylpropanesulfonic acid, and
A method for producing it efficiently, and its high purity 2-
The present invention relates to a method for producing a polymer using crylamide-2-methylpropanesulfonic acid .

[0002]

2. Description of the Related Art 2-Acrylamido-2-methylpropa
In addition to being used as a dyeability improver for acrylic fibers, etc., sulfonic acid forms useful homopolymers and copolymers by polymerization. These polymers are used as a flocculant, a petroleum recovery agent, a dispersant, an adhesive, a fluidity modifier, and the like. Such 2-acrylamido-2-methylpropane
The general production method of sulphonic acid, with an excess of acrylonitrile also as a reaction solvent, is reacted with fuming sulfuric acid and isobutylene therein, the resulting 2- Accession
There is a method of directly precipitating rillamido-2-methylpropanesulfonic acid from the reaction mixture. The obtained crude crystals are washed with acrylonitrile and then dried, and if necessary, purified by suspension washing or recrystallization using a solvent. However, it is a 2-ac which can be industrially used for recrystallization.
Solvents having a high solubility in rylamido-2-methylpropanesulfonic acid are limited to water, lower alcohols, dimethylformamide and the like, and conventionally, when these solvents were used, there were the following problems.

That is, water is 2-acrylamido-2-
It has the highest solubility in methyl propane sulfonic acid , but is not suitable because it easily causes polymerization. For dimethylformamide, 2-acrylamido-2-methylpro-
Crystallization of pansulfonic acid is not easy and the boiling point is high, so it takes a long time to dry. Furthermore, with lower alcohols such as methanol, the yield is poor and the purification effect is insufficient. On the other hand, a method of recrystallizing using water-containing acetic acid having a water content of 3 to 80% by weight as a solvent is also known (JP-A-54-106).
427). However, the 2-acryl to the hydrous acetic acid
The solubility of amido-2-methylpropanesulfonic acid is low and still insufficient for efficient recrystallization.

[0004]

[Problems to be Solved by the Invention] 2-Acrylamide-
2-Methylpropanesulfonic acid can be used for various purposes as described above, but especially 2-acrylamide-2-methyl
When using rupropanesulfonic acid as a polymer for a flocculant, a petroleum recovery agent, etc., a higher molecular weight product is required. However, well-purified 2-acrylic acid
When do-2-methylpropanesulfonic acid is not used as a raw material, it is difficult to obtain such a high molecular weight polymer.
Therefore, an object of the present invention is to obtain high-purity 2-acrylamide.
2-methylpropanesulfonic acid and a method for producing more efficiently it, as well as high-purity 2-Akurirua that
It is an object of the present invention to provide a method for producing a high molecular weight polymer using mido-2-methylpropanesulfonic acid .

DISCLOSURE OF THE INVENTION The present inventors have solved the problems of the prior art and made it possible to obtain 2-acrylamido-2-methine of high purity.
As an inexpensive purification method for efficiently obtaining crystals of tylpropanesulfonic acid , as a result of diligent studies on a recrystallization purification method using water, which has the highest solubility, as a result, a remarkable effect by the addition of a specific compound to a crystal solvent system was confirmed. Found and arrived at the present invention. That is, the present invention is a crude 2-acrylamide-
Produced by recrystallizing 2-methylpropanesulfonic acid in the presence of a phenolic compound using water as a solvent.
High purity 2-acrylamido-2-methylpropane that
Acid, and a method for producing the same, and high-purity 2-A thereof
The present invention relates to a method for producing a polymer, which comprises polymerizing crylamide-2-methylpropanesulfonic acid in the presence of an azo-based polymerization initiator. Hereinafter, the present invention will be described in detail.

2-acrylamido-2-methylpropane
The method for producing the sulfonic acid is not particularly limited, but usually, as described above, it was synthesized using acrylonitrile, isobutylene and fuming sulfuric acid, and the precipitate precipitated from the reaction system was washed with acrylonitrile and dried to obtain crude 2-acrylamide-2.
-Methylpropanesulfonic acid is used. Crude crystal 2
-Acrylamido-2-methylpropanesulfonic acid is
It usually contains impurities such as acrylamide, acrylic acid and methacrylic acid in an amount of about 3,000 to 30,000 ppm. As the phenolic compound used in the present invention, for example, a compound represented by the following general formula [I] is used. Many of the phenol compounds are used as general polymerization inhibitors.

[0006]

[Chemical 1]

(In the formula, R ^{1 to} R ⁵ are hydrogen atoms, hydroxyl groups,
It represents an alkoxy group, a linear or branched alkyl group having 1 to 5 carbon atoms, an arylalkyl group, or an arylalkyl group substituted with an alkyl group or a hydroxyl group. Further, R ^{1 to} R ⁵ may be an alkyl group or an aryl group containing a hetero atom, or an alkyl group or an aryl group bound by a hetero atom. ) Specific examples of the phenolic compound include hydroquinone, p-methoxyphenol, p-hydroxytoluene, and 2,5-di-
tert-butyl hydroquinone, 2,5-di-ter
t-aluminum hydroquinone, 2,2'-methylenebis (4-ethyl-6-tert-butylphenol),
2,2'-methylenebis (4-methyl-6-tert-
Butylphenol), 4,4'-butylidene bis (6-
tert-butyl-3-methylphenol), 4,4 '
-Thiobis (6-tert-butyl-3-methylphenol), 1,1'-bis (4-hydroxyphenol)
Cyclohexane, 2,6-di-tert-butyl-4-
Examples thereof include methylphenol, mono- or tri (α-methylbenzyl) phenol, dl-α-tocopherol, butylhydroxylanisole, etc., and hydrophilic phenolic compounds such as hydroquinone and p-methoxyphenol are particularly preferable.

The amount of the phenolic compound added is approximately 2-
It is usually 0.002 to 1.0% by weight, preferably 0.0 to 1.0, with respect to crylamide-2-methylpropanesulfonic acid .
It is 1 to 0.5% by weight. 2 if less than the range
-The effect of suppressing polymerization during the purification operation of acrylamido-2-methylpropanesulfonic acid cannot be expected sufficiently. If it exceeds the range, purified 2-acryl
Purified 2-acrylamido-2 by the phenolic compound remaining in amido-2-methylpropanesulfonic acid
-It is not preferable because it may cause polymerization inhibition when further polymerizing methylpropanesulfonic acid . Water of the solvent used in the present invention is usually distilled water, but deionized water is preferred, if appropriate, such as a saturated aqueous solution of acrylonitrile 2
-It is also possible to use an aqueous solution containing a substance that does not inhibit the purification of acrylamido-2-methylpropanesulfonic acid . That is, 2-acrylamido-2-methyi
Acrylonitrile also serves as a reaction solvent during the purification of propane sulfonic acid .
It is also possible to employ a method in which a crystal slurry of rufonic acid is obtained, the phenolic compound and water are added and dissolved by heating, and then the upper acrylonitrile layer is separated and recrystallized from the lower aqueous solution.

2-acrylamido-2-me according to the present invention
Recrystallization method of chill propanesulfonic acid, crude crystals of 2-
This is a method in which a phenolic compound and water are added to acrylamido-2-methylpropanesulfonic acid and dissolved by heating, and then the temperature is lowered to recrystallize. 2-acrylamide
The melting temperature of 2-methylpropanesulfonic acid is usually 3
The temperature is 0 to 90 ° C., but it is preferable to dissolve at 40 to 60 ° C. in consideration of crystallization efficiency, monomer stability, safety and the like. In addition, since the crystallization temperature increases the crystal yield,
A low temperature of 5-20 ° C is preferred. To further increase the efficiency of recrystallization, crude 2-acrylamido-2- meth at 40-60 ° C is used.
After dissolving chillpropanesulfonic acid , the pressure in the system is reduced to evaporate and concentrate water, and the crystallization is performed while cooling by utilizing the heat of vaporization of water, and then kept at a low temperature of 5 to 10 ° C for crystallization. The method of completing the above is advantageous. 2-A thus obtained
Crystals of crylamido-2-methylpropanesulfonic acid are dried by rapid filtration or centrifugation. As a result, impurities are usually 1000 ppm or less, preferably 5
High-purity 2-acrylamido-2- methy of 00 ppm or less
Crystals of rupropanesulfonic acid are obtained.

High purity 2-acrylamido-2- of the present invention
Methyl propane sulfonic acid can be homopolymerized or copolymerized with acrylic acid or methacrylic acid and their derivatives, acrylamide, methacrylamide and their derivatives and the like. Particularly, in order to obtain a polymer having a high molecular weight, the radical polymerization initiator used is preferably an azo type polymerization initiator. For example, 2,2'-azobis- (2-amidinopropane) dihydrochloride, azobis- (N, N-dimethyleneisobutylamidine) dihydrochloride, 4,4'-
Azobis- (4-cyanovaleric acid) -2-sodium and the like can be mentioned. The amount of radical polymerization initiator used is 2-acrylamido-2-methylpropane sulfone in the case of homopolymerization.
Folic acid , or 2-acrylamide-2- in the case of copolymerization
The amount is usually 0.005 to 5% by weight, preferably 0.05 to 0.5% by weight, based on the weight of the mixture of methylpropanesulfonic acid and another copolymerizable monomer. The polymerization temperature is
It is usually selected in the range of 10 to 150 ° C. according to the molecular weight of the desired polymer. When polymerizing in the form of an aqueous solution, the preferred temperature is 40 to 80 ° C.

The polymerization method is not particularly limited, but if an aqueous solution polymerization is exemplified, a method of polymerization with stirring, a method of polymerization in an adiabatic state in a stationary container, a method of polymerization while removing heat in a sheet form, water-in-oil A method of polymerizing in a type emulsion or dispersion state is exemplified. As a method of polymerizing with stirring,
An example is a method in which oxygen is removed from an aqueous solution of a sodium salt of 2-acrylamido-2-methylpropanesulfonic acid through nitrogen gas, then a radical polymerization initiator is added, and the mixture is maintained at a predetermined temperature under a nitrogen gas stream.

[0012]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. (Crude 2-acrylamido-2-methylpropane sulfone
Example of production of acid ) 100 mol parts of acrylonitrile and 22 mol parts of fuming sulfuric acid were charged in a reactor equipped with a stirrer, a thermometer, and a gas blowing tube.
Hold at 40 ° C. 20 mol parts of isobutylene was blown thereinto over 20 minutes. During this time, the temperature in the reactor was set to -4
Hold at 5--35 ° C. After the completion of blowing, the temperature of the reaction solution was raised to 55 ° C. and kept for 60 minutes to complete the reaction. At the same time as the blowing of isobutylene ends, 2-act
Crystals of lylamido-2-methylpropanesulfonic acid began to precipitate, and a slurry was formed. The crystals were filtered, washed with acrylonitrile and dried in a vacuum dryer at 30 ° C. for 8 hours to give 2-acrylamido-2-methylpropanesulfone.
Crude acid crystals were obtained.

This 2-acrylamido-2-methylpro
Bread sulfonic acid crude crystal was analyzed by high performance liquid chromatography (hereinafter abbreviated as HPLC), 2-acrylate
Impurities other than luamido-2-methylpropanesulfonic acid (acrylamide, acrylic acid, methacrylic acid, etc.)
It contained 8,300 ppm. Example 1 In a 300 ml four-necked flask equipped with a stirrer, a cooling tube, and a thermometer, the 2-acrylamide- obtained in the above Production Example was placed.
150 g of 2-methylpropanesulfonic acid crude crystals, 0.05 g of p-methoxyphenol and 100 g of demineralized water were added, and the mixture was immersed in a warm bath at 40 ° C. and stirred. After uniformly dissolving, the cooling tube was removed and the capillary was attached. A cooling pipe and a trap were attached to the extraction side, and when about 50 g of water was distilled off while dehydrating under reduced pressure at 5 mmHg, the bath was removed, and after the boiling in the interior was stopped, the pressure was returned to normal pressure. Then 5
Crystallization was completed by immersing in a constant temperature bath at ℃. Next, the liquid containing the crystals was taken out and filtered under reduced pressure with a glass filter to obtain 5
After washing twice with 50 ml of cold water at ℃, it was further dried under reduced pressure at 35 ℃ for 8 hours, and 103 g of purified 2-acrylamide.
2-Methylpropanesulfonic acid crystals were obtained.

Table 1 shows the results of HPLC analysis of the amount of impurities in the crystals. Obtained purified 2-acrylamide-
The 2-methylpropanesulfonic acid crystals were neutralized with sodium hydroxide in an aqueous solution to give 30% by weight of 2-acrylic amine.
An aqueous solution of sodium salt of do-2-methylpropanesulfonic acid (hereinafter abbreviated as 2-acrylamido-2-methylpropanesulfonic acid- Na) was prepared. 9.06 g of this solution
Was taken in a 50 ml sealed tube, and 15.94 g of a 30 wt% acrylamide aqueous solution and 2.75 g of demineralized water were further added and uniformly dissolved. Next, 0.2 as a polymerization initiator
Wt% NN'-azobis- (2-amidinopropane)
-Adding 2.25 g of dihydrochloride aqueous solution, the total amount was 30 g. After thoroughly replacing the inside of the sealed tube with nitrogen gas and sealing it, 5
When polymerized in a constant temperature water bath of 0 ° C. for 4 hours, 25% by weight of acrylamide / 2-acrylamido-2-methyl
A propanesulfonic acid- Na copolymer was obtained. The polymerization rate at this time was measured by the bromine method. Further, the polymer was dissolved in a concentration of 0.1 g / dl, and the reduced viscosity (ηsp / c) was determined at 25 ° C. using an Ostwald viscometer. The results are shown in Table-1.

Examples 2 and 3 2-acrylamido-2-methylpropanesulfonic acid was used in the same manner as in Example 1 except that 0.05 g of the compound shown in Table 1 was used instead of p-methoxyphenol as the phenol compound. Was recrystallized and polymerized. Table of results
Shown in 1. Comparative Examples 1 and 2 2-acrylamido-2-methylpropane sulfone was used in the same manner as in Example 1 except that 0.05 g of the compound shown in Table 1 which was generally used as a polymerization inhibitor was used in place of the phenol compound. The acid was recrystallized and polymerized. The results are shown in Table-1. Comparative Example 3 2-acrylamide-2-without purification by recrystallization
The results of polymerization in the same manner as in Example 1 using crude crystals of methylpropanesulfonic acid as they are are shown in Table 1. Comparative Example 4 Polymerization was conducted in the same manner as in Example 1 except that ammonium persulfate was used instead of the azo compound as a polymerization initiator. The polymerization rate was 99.6%, and the obtained polymer had a reduced viscosity of 13.5. there were.

[0016]

[Table 1]

Example 4 A 300 ml four-necked flask equipped with a stirrer, a condenser and a thermometer was charged with 2-acrylamido-2-methylpropanone.
The crude crystals of sulfonic acid ( 150 g), p-methoxyphenol (0.05 g) and demineralized water (100 g) were added, and the mixture was immersed in a warm bath at 40 ° C and stirred. 2-acrylamido-2-methyl
After the crude crystals of lopansulfonic acid were dissolved, cool the bath to 10 ° C with stirring and stop stirring at 5 ° C.
Crystals of 2-acrylamido-2-methylpropanesulfonic acid were precipitated. After holding at 5 ° C. for 8 hours, it was filtered under reduced pressure with a glass filter. Next, 2 with 50 ml of cold water at 5 ° C
After washing twice, the obtained crystals were further dried under reduced pressure at 35 ° C. for 8 hours. The obtained crystal weighs 50.6 g, and H
The amount of impurities analyzed by PLC was 106 ppm. Polymerization was carried out in the same manner as in Example 1 using the crystals, and the polymerization rate was 100% and the reduced viscosity of the polymer was 26.7.
Met.

Comparative Example 5 100 g of 10% by weight hydrous acetic acid was placed in the same flask as in Example 4, immersed in a warm bath at 40 ° C., and 2-acrylamido-2-methylpropanesulfonic acid crude crystals were added little by little and stirred. However, since it was difficult to dissolve, the temperature of the warm bath was further set to 60 ° C., and 12 g of 2-acrylamido-2-methylpropanesulfonic acid crude crystal was dissolved. Next, a recrystallization operation was performed in the same manner as in Example 4, but the obtained crystals were only 6.6 g, the crystal yield was extremely low, and the amount of impurities was 226 ppm.

[0019]

EFFECT OF THE INVENTION High-purity 2-acrylamide-2 of the present invention
- According to the manufacturing method of methylpropanesulfonic acid, at industrially inexpensive method efficiently high-purity 2-acrylamide
Not only crystals of do-2-methylpropanesulfonic acid can be obtained, but also extremely high molecular weight (co) polymers can be obtained by using the crystals, and the application fields of water-soluble or hydrophilic polymers, etc. For example, it largely contributes to a polymer flocculant and a petroleum recovery agent.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-54-106427 (JP, A) JP-A-54-163524 (JP, A) JP-A-50-82010 (JP, A) JP-B-44- 31328 (JP, B1) (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08F 20/00 C07C 303/00 C07C 309/00 CA (STN) REGISTRY (STN)

Claims (3)

(57) [Claims] 1. Crude 2-acrylamido-2-methylpro
Pansulphonic acid, water in the presence of phenolic compounds
High-purity 2-acrylamide obtained by recrystallization as a solvent
2-methylpropanesulfonic acid is used as an azo polymerization initiator.
2-acrylamide characterized by polymerizing in the presence
A method for producing a 2-methylpropanesulfonic acid polymer. 2. High-purity 2-acrylamido-2-methyl
Impurity of propanesulfonic acid is less than 500ppm
2-Acrylamido-2-methylpropanes according to claim 1.
Method for producing rufonic acid polymer. 3. High-purity 2-acrylamido-2-methyl
Propanesulfonic acid is treated with water in the presence of an azo polymerization initiator.
Solution polymerization, 2-acrylamido-2 according to claim 1 or 2.
-A method for producing a methylpropanesulfonic acid polymer.