Polymerization of purified acrylamide monomer, the resulting polyacrylamide, and process for flocculating suspended solids therewith

Claim 1

A PROCESS FOR PREPARING A HIGH MOLECULAR WEIGHT WATER SWELLABLE AND DISPERSIBLE HOMOPOLYMER FROM ACRYLAMIDE MONOMER, THE ACRYLAMIDE MONOMER BEING PREPARED BY HYDRATION OF ACRYLONITRILE WITH SULFURIC ACID FOLLOWED BY NEUTRALIZATION, THE ACRYLAMIDE MONOMER CONTAINING IMPURITIES LESS VOLATILE THAN ACRYLAMIDE MONOMER SELECTED FROM THE GROUP CONSISTING OF INORGANIC SALTS AND ORGANIC OLEFINIC SUBSTANCES COPOLYMERIZABLE WITH ACRYLAMIDE MONOMER, COMPRISING THE STEPS OF REMOVING THE IMPURITIES FROM THE ACRYLAMIDE MONOMER BY SUBLIMATION, AND HOMOPOLYMERIZING AND PURIFIED ACRYLAMIDE MONOMER IN AN AQUEOUS MEDIUM CONTAINING INITIALLY ABOUT 2.5-40% BY WEIGHT OF ACRYLAMIDE MONOMER IN THE PRESENCE OF A FREE RADICAL CATALYST AT LEAST ONE SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF (1) FREE AMMONIA IN AN AMOUNT OF ABOUT 1X10-3 TO 3X10-1 MOL PER MOL OF ACRYLAMIDE MONOMER AND IN A CONCENTRATION NOT EXCEEDING ABOUT 1.0 MOLAR AND (2) AMMONIUM CARBONATE, AMMONIUM BICARBONATE AND ALKALI METAL HYDROXIDES, CARBONATES AND BICARBONATES IN AN AMOUNT TO PROVIDE A PH OF ABOUT 7.5 TO 10 TO PRODUCE A HIGH MOLECULAR WEIGHT WATER SWELLABLE AND DISPERSIBLE HOMOPOLYMERIZATION PRODUCT WHICH PRODUCES A HIGHLY VISCOUS AQUEOUS MEDIUM WHEN DISPERSED IN WATER.