SULFONATION PROCESS

Abstract

Provided is a method for reacting a resin with sulfuric acid comprising the step of heating a reaction mixture to a temperature of 80 C. or higher, wherein said reaction mixture comprises (a) a collection of copolymer particles (A), (b) sulfuric acid, and (c) a collection of solid particles (B) different from said copolymer particles (A), wherein said solid particles (B) have BET surface area of 50 m.sup.2/g to 5,000 m.sup.2/g.

Claims

1. A method for reacting a resin with sulfuric acid comprising the step of heating a reaction mixture to a temperature of 80 C. or higher, wherein said reaction mixture comprises (a) a collection of copolymer particles (A), (b) sulfuric acid, and (c) a collection of solid particles (B) different from said copolymer particles (A), wherein said solid particles (B) have BET surface area of 50 m.sup.2/g to 5,000 m.sup.2/g.

2. The method of claim 1, wherein said copolymer particles (A) comprise one or more vinyl polymers that comprise polymerized units of acrylonitrile or methacrylonitrile or a combination thereof.

3. The method of claim 1, wherein said copolymer particles (A) comprise one or more vinyl polymers that comprise polymerized units of one or more vinyl aromatic monomer.

4. The method of claim 1, wherein said sulfuric acid is in the form of oleum.

5. The method of claim 1, wherein said solid particles (B) comprise activated carbon particles.

6. The method of claim 5, wherein said activated carbon particles are powdered carbon particles.

7. The method of claim 1, wherein said method further comprises the step, after said heating, of separating said copolymer particles (A) from said sulfuric acid and said solid particles (B).

8. The method of claim 1, wherein the volume average particle diameter of the solid particles (B) is 200 m or less.

Description

EXAMPLE 1

With and Without Activated carbon

[0046] In each reaction mixture, 10 g of Resin1 was mixed with 150 mL of oleum. Activated carbon was added to some of the reaction mixtures as shown below. Reaction mixtures were heated to 125 C. and held at 125 C. for 6 hours with vigorous stirring. Resulting mixtures were then cooled to below room temperature, and then, while stirring was maintained, dilute sulfuric acid was added, followed by deionized water. Then the resin was decanted, and then the resin was chromatographically washed with 500 ml of water. The resin was mixed with 50 mL of deionized water and allowed to stand for 30 days at approximately 22 C. Then 5 mL of the water was removed and placed into a cuvette of 1 cm path length, which was placed in a UV-VIS spectrophotometer, and the absorbance was measured at wavelength of 420 nm.

[0047] Results were as follows:

TABLE-US-00001 Activated Water Retention Capacity.sup.(2) Example Carbon (g) Absorbance (%) (meq/g) 1-C.sup.(1) 0 0.563 50.5 4.97 2 1 0.409 50.8 5.00 3 2 0.233 50.8 5.03 .sup.(1)Example 1-C is a comparative example. .sup.(2)H-form cation-exchange capacity
The use of activated carbon significantly reduced the color throw of the resin, as shown by the low absorbance numbers. The water retention and the capacity of the resins was not significantly changed by the use of the activated carbon.