Patent ID: 6927268

Claim:
A process for producing a water-absorbent resin, which is a neutralized salt and is obtained by polymerizing at least one monomer component including acrylic acid and/cr its salt as major components, wherein said acrylic acid aud/or its salt is produced by a process comprising the steps of (i) obtaining acrylic acid by catalytic gas-base oxidation of propylene and/or propane, where the obtained acrylic acid contains impurities and/or byproducts and includes protoanemonin as an impurity or byproduct, (ii) reducing a protoanemonin content of said acrylic acid to not more than 10 ppm, and then (iii) subjecting at least 50 mol % of said acrylic acid and/or its salt obtained in step (ii) to alkali treatment, where the mixture of said acrylic acid and/or its salt and said alkali is a solution containing 0.5 to 20 ppm of oxygen.