American Cyanamid Company

Charles Richard Witschonke

Arthur Maurice Schiller

Mark Allan Higgins

Dae Suk Song

Richard Joseph Duffy

Robert Rabinowitz

A process for inhibiting scale formation using a low molecular weight hydrolyzed polyacrylamide prepared by a process involving simultaneously and continuously charging separate streams of acrylamide monomer, ammonium persulfate (as catalyst) and mercaptoalkanoic acid (as chain transfer agent) to a reaction zone containing water under reflux, the rate of charging being such that the heat of polymerization is sufficient to maintain reflux in the reaction zone without exceeding the capacity of the condenser to remove the heat of reaction, and then reacting the polymer product with sufficient aqueous caustic to hydrolyze from about 60 to 90% of the amide groups in the polymer product.

Low molecular weight hydrolyzed polyacrylamide used as a scale inhibitor

A low molecular weight hydrolyzed polyacrylamide having exceptional effectiveness as a scale-inhibiting agent is prepared by a process involving simultaneously and continuously charging separate streams of acrylamide monomer, ammonium persulfate (as catalyst) and mercaptoalkanoic acid (as chain transfer agent) to a reaction zone containing water under reflux, the rate of charging being such that the heat of polymerization is sufficient to maintain reflux in the reaction zone without exceeding the capacity of the condenser to remove the heat of reaction, and then reacting the polymer product with sufficient aqueous caustic to hydrolyze from about 60 to 90% of the amide groups in the polymer product.

Low molecular weight hydrolyzed polyacrylamide and use thereof as scale

Aqueous solutions of Mannich bases of polyvinylamides are stabilized against viscosity increase and gelation by addition thereto of an effective amount of a formaldehyde scavenger.

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Noroton, CT, United States of America

Charles Richard Witschonke