JPS63189407A - Production of water-soluble polystyrenesulfonic acid - Google Patents

Abstract

PURPOSE:To obtain the titled compound having high purity and low organic solvent content and to reutilize the solvent, by sulfonating a polystyrene in a halogenated hydrocarbon solvent and separating produced polystyrenesulfonic acid from the reaction mixture using a specific method. CONSTITUTION:A polystyrene having an average molecular weight of 200-50,000 is sulfonated in a halogenated hydrocarbon solvent (preferably methylene dichloride, etc.). The obtained sulfonation reaction product is stirred to disperse the polystyrenesulfonic acid to particles having an average diameter of 5-500mu and the particles are subjected to centrifugal separation under a condition to satisfy 1<=A<=20 and the formula [wherein A is amount (pts.wt.) of the halogenated hydrocarbon per 1pt.wt. of the polystyrene used as the raw material, G is centrifugal force (G) and T is time (min) of centrifugal separation treatment] to obtain the objective compound. The centrifugal separation is preferably centrifugal filtration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing highly pure water-soluble polystyrene sulfonic acid in high yield.

[Conventional technology]

As a method of sulfonating polystyrene to obtain a water-soluble polystyrene sulfonate, in a halogenated hydrocarbon solvent, chlorsulfonic acid, sulfuric anhydride, or a complex of sulfuric anhydride and an inorganic or organic compound is used as a sulfonating agent,
Methods of sulfonation using various crosslinking inhibitors are known.

When polystyrene is sulfonated by such a method, the polystyrene sulfonic acid becomes insoluble in the reaction solvent, and when the reaction product is allowed to stand still, the polystyrene sulfonic acid precipitates and separates. Therefore, the reaction solvent has conventionally been separated from the reaction product by filtration, distillation, etc., but in the conventional method, (I) It is difficult to handle the filtered solid polystyrene sulfonic acid; Recovery rate decreases.

(II) Since the filtered polystyrene sulfonic acid contains a considerable amount of solvent, further means for separating the solvent may be required depending on the application.

(iii) If unreacted polystyrene or polystyrene with a low sulfonic acid group introduction rate remains in the solvent and the solvent is to be reused, it is necessary to purify the solvent.

(iv) The equipment becomes larger and the energy cost is high.

There were drawbacks such as.

[Problem that the invention seeks to solve]

Therefore, the present invention can produce water-soluble polystyrene sulfonic acid with a low organic solvent content in high yield, and can separate the organic solvent from highly purified water-soluble polystyrene sulfonic acid that does not contain water-insoluble impurities in a short time. Furthermore, it is an object of the present invention to provide a method that has high separation efficiency and allows the separated organic solvent to be reused as it is.

[Means for solving problems]

The present invention discloses that when polystyrene sulfonic acid in a reaction product obtained by sulfonating polystyrene in a halogenated hydrocarbon solvent is dispersed into particles with a specific particle size and centrifuged under specific conditions, the desired This was done based on the knowledge that water-soluble polystyrene sulfonic acid can be easily separated from an organic solvent and the above problems can be solved.

That is, in the present invention, the average molecular weight is 200 to 50,00
0 polystyrene was sulfonated in a halogenated hydrocarbon solvent, the resulting sulfonated reaction product was stirred to make polystyrene sulfonic acid into a dispersed state with an average particle size of 5 to 500μ, and then the following conditions (I) and ( II): 1-(A<20 (I) (wherein, Δ
is the amount of halogenated hydrocarbon (parts by weight) per part by weight of the raw material polystyrene, G is the centrifugal force (CG), and T is the centrifugation time (minutes). ) Provided is a method for producing water-soluble polystyrene sulfonic acid, which is characterized by centrifuging under conditions that satisfy the following.

The polystyrene used as a raw material in the present invention has an average molecular weight in the range of 200 to 50,000. In other words, if the average molecular weight exceeds 50,000, the viscosity of the reaction system becomes high, making handling difficult. On the other hand, if the average molecular weight is less than 200, polymerization reactions occur simultaneously due to the presence of unreacted styrene monomer. This is because the amount of water-insoluble sulfonated substances increases.

In the present invention, the polystyrene is dissolved in a halogenated hydrocarbon solvent and then sulfonated by a conventional method. The halogenated hydrocarbon solvent used here is preferably an aliphatic halogenated hydrocarbon having 1 to 2 carbon atoms, specifically methylene dichloride, 1,2-dichloroethane, ethyl chloride, carbon tetrachloride, 1,1- dichloroethane,
1.1゜2.2-tetrachloroethane, chloroform,
Examples include those that are inert to sulfonating agents such as ethylene dipromide. And the halogenated hydrocarbon solvent 10
It is preferable to add and dissolve 5 to 100 parts by weight, preferably 20 to 40 parts by weight, of polystyrene per 0 parts by weight.

In the above sulfonation, it is preferable to use SO'+ as the sulfonation agent. That is, liquid SO5, gaseous SO3
For example, gaseous 5O8 (diluted gas 5O2) diluted with an inert gas such as nitrogen gas or dehumidified air, and liquid 5O1 (diluted liquid 5O2) is used. Here, the diluent gas SO5 has 5 ports and a degree of 1 to 12% by volume, preferably 3 to 4% by volume, and the diluent liquid 303 has an SOs concentration of 1 to 59wt%, preferably 5 to 12% by volume. 10 wt% is used.

In the present invention, the sulfonating agent has an SO3 content of 0.7 to 2.0 (mole ratio) per unit of monomer constituting polystyrene.
, preferably in an amount of 1.0 to 1.5.

The sulfonation reaction can be carried out using any reactor, but it is best to use one equipped with a stirrer with a shearing force of 0.05 (N/caf) or more.
It is preferable to conduct the reaction at a temperature of 0 to 80°C, preferably 20 to 40°C, and it is desirable that the residence time of the raw material solution in the reactor is 1 to 60 minutes, preferably 5 to 40 minutes.

In the present invention, the sulfonation reaction product is stirred as described above, and polystyrene sulfonic acid, which is an insoluble component in the product, has an average particle size of 5 to 500 μm, preferably 80 to 4 μm.
00μ dispersion, and as it is, the above formulas (I) and (II
) Perform centrifugation under conditions that satisfy the following conditions. In addition, when using a sulfonation reactor equipped with a stirrer, adjust the stirring power so that the average particle size of the limbs at the end of the reaction is within the above range, and centrifuge immediately after the sulfonation reaction. It's okay.

The average particle size of polystyrene sulfonic acid during centrifugation is extremely important in terms of increasing the separation efficiency of organic solvents, and the amount of organic solvent represented by A in Bunmu (I) is also important for adjusting the particle size. Important in terms of ease and separation efficiency. A in formula (I) is particularly preferably 4 to 9.

Furthermore, in formula (II), GXT/ (AX 103) needs to be 0.1 to 10, preferably 0.
7-7. That is, if it is less than 0.1, the separation efficiency of polystyrene sulfonic acid decreases, while if it exceeds 10, it is not preferred for industrial processes.

In the present invention, centrifugation is performed so as to satisfy the conditions of the above formulas (I) and (I Centrifugal sedimentation is used to separate particles, centrifugal filtration is performed by installing a filter medium on the inner surface of a perforated rotating body that operates at a constant angular velocity, and filling is present in wet powder and granular materials in a piled up state. Centrifugal separation is performed using centrifugal dehydration, which separates the liquid by gravity, centrifugal force, etc.

Among these, centrifugal filtration is preferred. When performing centrifugation, 300-3000G, preferably 500-2
The most effective method is to apply a centrifugal force of 000 G, and the time from when the sulfonation reaction product is supplied to the centrifuge until it is separated is 0.5 minutes to 15 minutes.
minutes, preferably 1 minute to 10 minutes. That is, if the centrifugal force is less than 300G, the separation of the solvent will be poor;
Above 0G, the effect is not so great that it is not practical.

If the separation time is less than 0.5 minutes, the separation will be poor, and if it exceeds 15 minutes, it will be inefficient and impractical. Normally, the type of filter media used when performing centrifugal filtration has a liquid flow rate of 5 to 1
It is preferable to select a material made of 5CC/Cll11SeC.

In the present invention, water-soluble polystyrene sulfonic acid can be obtained by the above-mentioned operation, but it is also possible to further remove the trace amount of organic solvent remaining in the sulfonic acid by known means such as vacuum drying and turn it into powder. can.

In addition, the polystyrene sulfonic acid obtained by the method of the present invention can be dissolved in water and then neutralized with an alkali, or directly dissolved and neutralized in alkaline water to obtain a water-soluble polystyrene sulfonate. . The alkaline agents used here include alkali metal hydroxides or carbonates such as caustic soda and caustic potash, alkaline earth metal hydroxides or carbonates such as magnesium hydroxide and calcium hydroxide, ammonium hydroxide, and alkanols. Examples include amines. Neutralization can be carried out by conventional methods.

〔Effect of the invention〕

According to the present invention, water-soluble polystyrene sulfonic acid with low organic solvent content and high purity can be produced in high yield, and the organic solvent can be reused, so the production method of the present invention is industrially extremely advantageous.・It is a law.

Therefore, polystyrene sulfonic acid or its salt obtained by this method can be used as an antistatic agent for paper, a water reducer for concrete,
Widely used as a dispersant.

Next, the present invention will be explained with reference to Examples, but the present invention is not limited thereto.

Example 1 polystyrene with an average molecular weight of 4,500 or 10,000
．． The raw material was dissolved in 2-dichloroethane solvent, liquid S03 was used as the sulfonating agent, and the SO5 molar ratio was 1.
0, reaction temperature 30℃, reaction vessel with stirrer (shear force 1
．． Sulfonation was carried out at 5N/cI11> to obtain a sulfonated product in which polystyrene sulfonic acid was dispersed with a specific average particle diameter. This was immediately centrifuged using a centrifugal filtration type centrifuge (Mitsubishi Kakoki Gl 1 (Z-40Si type)) under the conditions shown in Table 1 to obtain polystyrene sulfonic acid.

Then, add an equal amount of water to the polystyrene sulfonic acid to dissolve the polystyrene sulfonic acid, and add 15% NaOH to the polystyrene sulfonic acid.
The solution was neutralized to pH 7.0 to obtain water-soluble sodium polystyrene sulfonate.

The conditions and results are summarized in Table 1. Furthermore, experiment No.
In Nos. 6 and 7, polystyrene with an average molecular weight of 1ioooo was used, and in the others, polystyrene with an average molecular weight of ff14,500 was used.

Claims (1)

[Claims] Polystyrene with an average molecular weight of 200 to 50,000 is sulfonated in a halogenated hydrocarbon solvent, and the resulting sulfonated reaction product is stirred to disperse polystyrene sulfonic acid with an average particle size of 5 to 500μ. state, then the following condition (I
) and (II): 1≦A≦20...(I) 0.1≦[G×T]/[10^3×A]≦10...(
II) (where A is the amount of halogenated hydrocarbon [parts by weight] per part by weight of raw material polystyrene, G is centrifugal force [G], and T is centrifugation time [minutes]). A method for producing water-soluble polystyrene sulfonic acid, which comprises centrifugation.