VINYL SULFONIC ACID 30%

VINYL SULFONIC ACID 30%

CAS No. : 1184-84-5
EC No. : 214-676-1

Synonyms:
Vinylsulfonic acid; ethenesulfonic acid; Ethylenesulfonic acid sodium salt; vinil sülfonik asit 30%; Sodium vinylsulfonate solution; Vinylsulfonic acid sodium salt; PVSA; VINYLSULFONIC ACID; VSA 30%; ethenesulfonic acid; Ethylenesulfonic acid; Vinyl Sulfonic Acid 30%; 1184-84-5; VINYLSULPHONIC ACID; UNII-GJ6489R1WE; vsa; 30%; %30; vinil; vinyl; sülfat; vinil asit; vınyl acıd; vinyl acid; GJ6489R1WE; Ethylenesulphonic acid; vinil sülfonik asit %30; Sodium ethylenesulfonate; 1rql; Ethylenesulfonicacid; NSC8957; EINECS 214-676-1; vinyl sulfonic acid; ethylene sulfonic acid; SCHEMBL16079; Vinylsulfonic Acid, >/=97%; Vinyl Sulfonic Acid 30%; CHEMBL1236690; DTXSID2047018; Vinylsulfonic acid; ethenesulfonic acid; VINYL SULFONIC ACID 30% ; Ethylenesulfonic acid sodium salt; Sodium vinylsulfonate solution; Vinylsulfonic acid sodium salt; PVSA; Sodium ethenesulfonate(25%Nasalt); Acide éthènesulfonique [French] [ACD/IUPAC Name]; Ethenesulfonic acid [ACD/Index Name] [ACD/IUPAC Name]; Ethensulfonsäure [German] [ACD/IUPAC Name]; ethylenesulfonic acid; GJ6489R1WE; Vinylsulfonic acid [Wiki]; 3039-83-6 (SODIUM SALT); Vinylsulfonic acid; ethenesulfonic acid; Ethylenesulfonic acid sodium salt; vinil sülfonik asit 30%; Sodium vinylsulfonate solution; Vinylsulfonic acid sodium salt; PVSA; VINYLSULFONIC ACID; VSA 30%; ethenesulfonic acid; Ethylenesulfonic acid; EINECS 214-676-1; ESA; Ethanesulfonic acid [ACD/Index Name] [ACD/IUPAC Name]; ethenesulphonic acid; Ethylenesulfonicacid; ethylenesulphonic acid; MFCD09743544; Sodium ethenesulfonate(25%Nasalt); UNII:GJ6489R1WE; UNII-GJ6489R1WE; vinyl sulfonic acid; vinylsulfonicacid; VINYLSULPHONIC ACID; VSO; VSA 30%

Vinyl Sulfonic Acid 30%

Vinyl sulfonic acid 30% is the organosulfur compound with the formula CH2=CHSO3H. It is the simplest unsaturated sulfonic acid.[2][3] The C=C double bond is a site of high reactivity. polymerize gives polyVinyl sulfonic acid 30%, especially when used as a comonomer with functionalized vinyl[4] and (meth)acrylic acid compounds.[5] It is a colorless, water-soluble liquid,[2] although commercial samples can appear yellow or even red.

Preparation
Vinyl sulfonic acid 30% is produced industrially by the alkaline hydrolysis of carbyl sulfate with subsequent acidification of the resulting vinyl sulfonate salt:
Vinylsulfonsäure aus Carbylsulfat
The reaction is highly exothermic (reaction enthalpy: 1,675 kJ/kg) and requires exact maintenance of temperature and pH during the hydrolysis. When calcium hydroxide is used as the hydrolysis medium, a solution of calcium vinyl sulfonate is obtained. Acidification of this hydrolysis mixture with sulfuric acid gives Vinyl sulfonic acid 30%, together with the poorly soluble calcium sulfate.

Vinyl sulfonic acid 30% also can be prepared by dehydration of isethionic acid with phosphorus pentoxide:
Vinylsulfonsäure via Isethionsäure
Vinyl sulfonic acid 30% can also be prepared by sulfochlorination of chloroethane, dehydrohalogenation to vinylsulfonyl chloride and subsequent hydrolysis of the acid chloride.

Use
The activated C=C double bond of Vinyl sulfonic acid 30% reacts readily with nucleophiles in an addition reaction. 2-Aminoethanesulfonic acid is formed with ammonia and 2-methylaminoethanesulfonic acid with methylamine.[8]

Vinyl sulfonic acid 30% is the monomer in the preparation of highly acidic or anionic homopolymers and copolymers. These polymers are used in the electronic industry as photoresists, as ion-conductive polymer electrolyte membranes (PEM) for fuel cells. For example, transparent membranes with high ion exchange capacity and proton conductivity can be produced from polyVinyl sulfonic acid 30%.[9]

Research
Vinyl sulfonic acid 30% may also be grafted to polymeric supports (e.g. polystyrene) to give highly acidic ion exchangers, which used as catalysts for esterification and Friedel-Crafts acylations.[10] Where the sulfonic acid functionality is not essential, the much more usable alkaline aqueous solution of sodium vinylsulfonate is used, which is obtained directly in the alkaline hydrolysis of the carbyl sulfate and is commercially supplied as an aqueous solution.

contains      100 ppm monomethyl ether hydroquinone as inhibitor
concentration      25 wt. % in H2O
refractive index      n20/D 1.376
density      1.176 g/mL at 25 °C

Application
Sodium Vinyl sulfonic acid 30% is a useful reagent (monomer) for the formation of poly(anionic) polymers and copolymers.

A method for producing Vinyl sulfonic acid 30%, comprising conducting demetallation of vinyl sulfonate salt, wherein the demetallation rate is not less than 95% according to the following formula:
Demetallation rate(%)={(acid value after demetallation)/(acid value before demetallation)}×100;
a method for producing Vinyl sulfonic acid 30%, comprising conducting demetallation of vinyl sulfonate salt, wherein demetallation is carried out using a strongly acidic ion exchange resin; and
said method further comprising the step of purifying a product of the demetallation using a thin film evaporator.

FIELD OF THE INVENTION
The present invention relates to a method of producing Vinyl sulfonic acid 30%, particularly to a method of producing Vinyl sulfonic acid 30%, comprising a vinyl sulfonate salt demetallation process.

BACKGROUND ART
In recent years, Vinyl sulfonic acid 30% has attracted increasing attention as a monomer for use in composing performance polymers or conductive materials.

There are various methods for producing Vinyl sulfonic acid 30% (see Nonpatent-Document 1); however, existing methods are still not reliable enough for the industrial production of Vinyl sulfonic acid 30%.
For example, Patent-Document 1 discloses a method for producing Vinyl sulfonic acid 30% by removing sodium from sodium vinyl sulfonate using hydrochloric acid.
However, this method fails to ensure desirable product quality. Moreover, distillation of the Vinyl sulfonic acid 30% manufactured by this method produces a large amount of solid residue. For these reasons, this method is almost useless for industrial purposes.

Patent Document 2 discloses a method for producing Vinyl sulfonic acid 30% via dehydration of an isethionic acid using phosphorus pentoxide or pyrophosphoric acid as a dehydration agent. However, this method uses a large amount of dehydration agent, and requires disposal of the dehydration agent. For this reason, this method is not suitable for industrial purposes.

Problem to be Solved by the Invention
An object of the present invention is to provide an industrial method for producing Vinyl sulfonic acid 30%.

Means for Solving the Problem
In order to solve the foregoing problems, the inventors of the present invention conducted intensive study and found a method ensuring an improved yield. The method uses vinyl sulfonate, and carries out a demetallation process with an ion exchange resin at a metal-hydrogen exchange rate equal to or greater than a predetermined value. With further research on this method, the inventors eventually completed the present invention.
That is, the present invention relates to the following production methods.

Item 1: A method of producing Vinyl sulfonic acid 30%, comprising the step of conducting demetallation of vinyl sulfonate salt, wherein a demetallation rate is not less than 95% according to the following formula:
Demetallation rate(%)={(acid value after demetallation)/(acid value before demetallation)}×100.

More preferably, the method according to Item 1, wherein the vinyl sulfonate salt is sodium vinyl sulfonate, and the metal is sodium.

Item 2: A method of producing Vinyl sulfonic acid 30%, comprising the step of conducting demetallation of vinyl sulfonate salt, wherein the demetallation is carried out using a strongly acidic ion exchange resin.

1. Vinyl Sulfonate Salt
The present invention produces Vinyl sulfonic acid 30% using vinyl sulfonate salt.

Examples of vinyl sulfonate salt include the sodium salt, potassium salt, lithium salt, and mixtures of these. Among these, sodium vinyl sulfonate is particularly suitable.
The vinyl sulfonate salt may be a composition. For example, it is possible to use a composition made up of vinyl sulfonate salt, an isethionic acid salt, a salt of bis sulfoethyl ether, and the like.
When using such a composition, the percentage of vinyl sulfonate salt in the whole composition is usually not less than approximately 25%.

2. Demetallation
In this specification, “demetallation” designates a process for removing metal from vinyl sulfonate salt and exchanging it for hydrogen. In other words, demetallation designates a process for removing metal ions from vinyl sulfonate salt so as to convert the vinyl sulfonate salt into Vinyl sulfonic acid 30%.

If the demetallation rate is 95% or greater, decomposition of the compound or the influence thereof is significantly reduced. Further, it becomes possible to adopt thin film distillation for the purification process after demetallation. Given this, large volume distillation can be performed at a high recovery rate.

Also, since it becomes possible to obtain high-quality Vinyl sulfonic acid 30%, the Vinyl sulfonic acid 30% after distillation is less colored. Furthermore, this Vinyl sulfonic acid 30% causes less coloration with time.
Any method in which the demetallation rate is not less than 95% can be adopted. A method using a strongly acidic ion exchange resin is however particularly preferable.
The product of demetallation here designates a product resulting from demetallation of vinyl sulfonate salt or a composition thereof; more specifically, a Vinyl sulfonic acid 30% or a composition thereof obtained by demetallation.
An appropriate purification method can be selected from various publicly known methods; however, purification by distillation, particularly by thin film distillation, is preferred.

By adopting thin film distillation to purify the product, it becomes possible to obtain a high-quality Vinyl sulfonic acid 30% that is less colored at the time of distillation, and causes less coloration with time. Further, it becomes possible to purify a large quantity at a high recovery rate.

Furthermore, the resulting Vinyl sulfonic acid 30% is of a high quality. Particularly, the Vinyl sulfonic acid 30% resulting from such distillation is almost colorless. It is also possible to obtain Vinyl sulfonic acid 30% that causes less coloration with time.

4. Other Processes
The production method of the present invention may further comprise additional steps other than the above-mentioned demetallation step and distillation step, as needed. For example, a raw-material purification step can be added.

Further, any known art or arts regarding the production of Vinyl sulfonic acid 30% can be combined with the method of the present invention, as needed.

5. Characteristics
The Vinyl sulfonic acid 30% obtained using the method of the present invention is of a high quality, is less colored, and causes less coloration with time.

With such outstanding characteristics, the Vinyl sulfonic acid 30% obtained by the method of the present invention can be suitably used as a material for an electrolyte membrane or an aqueous solution agent for a coating composition, a binder, etc., for example.

EFFECT OF THE INVENTION
The present invention provides efficient mass production of high-quality Vinyl sulfonic acid 30%, thereby significantly increasing vinyl-sulfonic-acid productivity.

Although various synthesizing methods are known as production methods for Vinyl sulfonic acid 30%, they have problems relating to complicated processes, low yields, and limit the scale of distillation. Therefore, they are almost useless for industrial purposes.
In contrast, the production method of the present invention suppresses compound decomposition, thereby significantly increasing the yield. Also, as it requires only a single step process, production can be performed in a simple manner.
Moreover, gas generation is reduced during distillation and the decompression degree becomes stable, the recovery rate increases. Further, the process produces only fluid residues that can be easily washed away from the device or the facility.
Further, since the method allows adoption of thin film distillation, the process scale can be increased. As a result, productivity significantly increases.
The method of the present invention provides high-quality Vinyl sulfonic acid 30%. This method suppresses the problems of coloration and coloration with time.
The present invention provides a superior method and means for use in the industrial production of Vinyl sulfonic acid 30%, thereby making practical industrial production of Vinyl sulfonic acid 30% possible.

Sodium Removal Process Using Hydrochloric Acid
3 kg of 35% hydrochloric acid was added to 7.5 kg of a 25% sodium vinyl sulfonate aqueous solution (N-SVS-25: product of Asahi Kasei Finechem CO., LTD., Inc.). The mixture was stirred at room temperature for 30 minutes. Subsequently, sodium removal was performed by concentrating 4 L of an aqueous solution under reduced pressure, and filtering the deposited salt. This sodium removal process was performed two more times to exchange the sodium of the sodium vinyl sulfonate for hydrogen, thereby obtaining a Vinyl sulfonic acid 30% aqueous solution.

The sodium removal rate was 93.5% according to the acid value measured before sodium removal and the acid value measured after 3 applications of the sodium removal process.

The yield was 94.8% according to the iodine value measured before sodium removal and the iodine value measured after 3 applications of the sodium removal process.

COMPARATIVE EXAMPLE 2
Sodium Removal Process Using Hydrochloric Acid and Batch Distillation
4.5 kg of a Vinyl sulfonic acid 30% aqueous solution obtained in Comparative Example 1 was placed in a 5 L glass flask, and was subjected to distillation under reduced pressure so as to produce 2.1 kg of Vinyl sulfonic acid 30%. The recovery rate was 67%.

The decompression degree varied greatly, ranging from about 500 to 1000 Pa; that is, it was difficult to keep the decompression degree constant. Further, the obtained Vinyl sulfonic acid 30% was a deep, dark purple at the time of distillation. The residue was black and non-fluid.

COMPARATIVE EXAMPLE 3
Sodium Removal Process Using Hydrochloric Acid and Batch Distillation
1200 g of a Vinyl sulfonic acid 30% aqueous solution obtained in Comparative Example 1 was placed in a 1 L glass flask, and was subjected to distillation under reduced pressure so as to produce 740 g of Vinyl sulfonic acid 30%. The recovery rate was 82%. As with Comparative Example 2, the decompression degree varied greatly, ranging from about 500 to 1000 Pa; that is, it was difficult to keep the decompression degree constant. Further, the obtained Vinyl sulfonic acid 30% was deep, dark purple at the time of distillation. The residue was black and non-fluid.

Sodium Removal Process Using a Strongly Acidic Ion Exchange Resin and Batch Distillation
Under reduced pressure, 0.6 kg of the Vinyl sulfonic acid 30% composition obtained in the sodium removal process of Example 1 was concentrated. Then, a 500 mL-scale distillation was performed under reduced pressure. As a result, the decompression degree was kept at 150 Pa, and the recovery rate was 94%, though a slight smell of sulfurous acid gas was detected. The obtained Vinyl sulfonic acid 30% was light yellow at the time of distillation, and became more colored with time. The distillation produced a residue, but it was a dark brown fluid that was washed away easily.

EXAMPLE 11
Sodium Removal Process Using a Strongly Acidic Ion Exchange Resin and Batch Distillation
A 1 L-scale distillation was performed in the same manner as that of Example 10, except that 1.2 kg of the Vinyl sulfonic acid 30% composition was used. As a result, a slight smell of sulfurous acid gas was detected. The decompression degree was about 220 Pa. The recovery rate was 92%. The obtained Vinyl sulfonic acid 30% was light yellow at the time of distillation, and became more deeply colored with time. The distillation produced a residue, but it was a dark brown fluid that was washed away easily.

EXAMPLE 12
Sodium Removal Process Using a Strongly Acidic Ion Exchange Resin and Batch Distillation
A 2 L-scale distillation was performed in the same manner as that of Example 10, except that 2.4 kg of the Vinyl sulfonic acid 30% composition was used. As a result, a strong smell of sulfurous acid gas was detected. The decompression degree was about 360 Pa. The recovery rate was 89%. The obtained Vinyl sulfonic acid 30% was light yellow at the time of distillation, and became more deeply colored with time. The distillation produced a residue, but it was a dark brown fluid that was washed away easily.

EXAMPLE 13
Sodium Removal Process Using a Strongly Acidic Ion Exchange Resin and Batch Distillation
A 5 L-scale distillation process was performed in the same manner as that of Example 10, except that 5 kg of the Vinyl sulfonic acid 30% composition was used. As a result, a significantly strong smell of sulfurous acid gas was detected. The decompression degree was about 600 Pa. The recovery rate was 78%. The obtained Vinyl sulfonic acid 30% was light yellow at the time of distillation, and became more deeply colored with time. The distillation produced a residue, but it was a dark brown fluid that was washed away easily.

EXAMPLE 14
Sodium Removal Process Using a Strongly Acidic Ion Exchange Resin and Thin Film Distillation
Continuous distillations were performed with a thin film evaporator under reduced pressure by continuously feeding 3.6 kg of the Vinyl sulfonic acid 30% composition obtained in the sodium removal process of Example 1. The temperature range was 160-200° C. As a result, the decompression degree was kept at 70 Pa, and the continuous distillation operation was stably maintained. There was no smell of sulfurous acid gas at all. The recovery rate was about 96%.

The obtained Vinyl sulfonic acid 30% was light yellow at the time of distillation, and the color did not change even after six months. The distillation produced a residue, but it was a dark brown fluid that was washed away easily.

Random copolymer hydrogel actuators, composed of poly(acrylic acid) and poly(Vinyl sulfonic acid 30%, sodium salt), were prepared. The swelling ratios at various temperatures and pHs, the deswelling water ratio and contraction/expansion behavior under an electric field for the hydrogel actuators were measured. The hydrogels exhibited very high swelling ratios, in the range of 8200 ~ 18000%, at 37 °C, and showed temperature/pH dependent swelling behavior. The deswelling water ratio of the CO1 hydrogel sample showed about an 80% weight reduction under a 5 V applied voltage. When the hydrogel actuator in various pH buffer solutions is subjected to an electric field, the hydrogel actuator was contracted. When the electric stimulus was removed, the hydrogel actuator was expanded on its original size. The hydrogel actuator also showed stepwise contraction/expansion behavior depending on the electric stimulus.

Applications
Sodium Vinyl sulfonic acid 30% is a useful reagent (monomer) for the formation of poly(anionic) polymers and copolymers. It is employed as a basic brightener and leveling agent in nickel baths. It is also used as intermediate for organic synthesis, surfactant, pharmaceutical industry.

The sodium salt of poly(vinylsulfonic acid) (Vinyl sulfonic acid 30%), molecular weight 2000, a low-molecular-weight polyelectrolyte, has been identified as a suitable displacer for the concentration and purification of protein mixtures. This displacer has been tested on the separation of ovalbumin from conalbumin, and the fractionation of heterogeneous ovalbumin. The displacement characteristics of the polyelectrolyte were a strong function of the carrier pH, and a pH for good displacement development of heterogeneous ovalbumin has been identified. The displacer can be efficiently removed from the exchanger with a mild regeneration protocol. In this regard, the low-molecular-weight polyelectrolyte appears to have a significant advantage over high-molecular-weight ion-exchange displacers used in the past. Solvent requirements for regeneration and re-equilibration are significantly lower with Vinyl sulfonic acid 30%, suggesting the use of molecular weight to tailer ion-exchange displacers with desirable characteristics with respect to both column development and regeneration.

The free-radical copolymerization of 1-vinyl-1,2,4-triazole with Vinyl sulfonic acid 30% sodium salt was conducted. New thermally stable functional water-soluble copolymers of various composition were synthesized. The structure and properties of the obtained copolymers were confirmed by IR, ¹H NMR spectroscopy, and thermogravimetric methods. It was found that 1-vinyl-1,2,4-triazole has higher reactivity than sodium vinylsulfonate. TGA and DSC show that the produced copolymers are stable when heated to 260 °C.

Poly(Vinylsulfonic acid) (Vinyl sulfonic acid 30%) possesses a high acid content (ion‐exchange capacity in the chemical formula = 9.2 meq · g−1). Its monomer, Vinyl sulfonic acid 30% (VSA), had a high acid dissociation ability (Hammett acid function = 0.74 in water), and a high ionic conductivity (0.04–0.11 S · cm−1). The radical polymerization of VSA with various initiators was kinetically investigated. The ESR spectrum of the VSA polymerization mixture showed a strong signal ascribed to the propagation carbon radical of VSA. The molecular weight of Vinyl sulfonic acid 30% increased with the increasing monomer concentration and decreasing radical initiator concentration to yield the Vinyl sulfonic acid 30% with a molecular weight of 4.0 × 104. Proton‐conductivity of Vinyl sulfonic acid 30% under hydrated and nonhumidified conditions was on the order of 10−1 and 10−3–10−6 S · cm−1, respectively.