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US 5,175,193 AGranted
Process for the preparation of weakly acid cation exchange resins
AssigneeBayer Aktiengesellschaft
InventorsHarold Heller, Friedrich Werner, Alfred Mitschker, Herbert V. Diehl, Axel Schafer
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Abstract
The invention relates to an environment-friendly process for the preparation of weakly acid cation exchange resins by hydrolysis of crosslinked acrylonitrile bead polymers with an alkaline hydrolizing agent at elevated temperature, according to which the bead polymer and alkaline hydrolizing agent are brought together at elevated temperature only.
Claims6
A process for the preparation of a weakly acid cation exchange resin by alkaline hydrolysis of a cross-linked acrylonitrile bead polymer prepared by polymerization of
- A. from 80 to 98% by weight of monoethylenically unsaturated monomer;
- and
- B. from 20 to 2% by weight of ethylenically polyunsaturated crosslinking agent;
- the above percentages being based on the sum A+B;
- with the proviso that monomer A comprises (i) at least 70% by weight (based on monomer A) of acrylonitrile (ii) from 2 to 0% by weight (based on monomer A) of acrylic and/or methacrylic acid C.sub.1-4 -alkyl ester, and (iii) the balance (based on monomer A) of monoethylenically unsaturated monomer other than (i) and (ii), said process comprising suspending cross-linked acrylonitrile bead polymer in alkaline hydrolysing agent at a temperature in the range of from 105.degree. to 200.degree. C. to effect hydrolysis and separating off the beads from the alkaline hydrolysing agent after the hydrolysis has ended.
2 more elements
Dependencies are inferred from the claim text.