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The kinetics of polymerization of acrylamide initiated by potassium peroxodisulfate, in the presence and absence of Ag(1) and Cu(I1) ions, was studied. The rate law for the polymerization was established. Cu(I1) ions were found to reduce both the rate and degree of polymerization. Experimental PartMaterials: Acrylamide (from American Cyanamide Co.) was recrystallized from chloroform". Potassium peroxodisulfate (from E. Merck, F. R. G.) was used without further purification. AgC104, C U ( C~O~)~, and NaC104 were prepared from the respective "AnalaR salts and perchloric acid. Water, double-distilled over alkaline permanganate and deionized, was used to prepare the reagents. The nitrogen gas, used for deaeration, was purified by passing through a "Fieser solution". Polymerization:The polymerization was conducted in a reaction tube of 100ml capacity. 25 ml of the reaction mixture containing acrylamide, metal ion, and the neutral salt were deaerated for 45min. The reaction was started by addition of a peroxodisulfate solution. The rate of monomer disappearence, R,, was followed by estimating the acrylamide concentration at various time intervals, by the bromine-addition method4). The experiments were conducted at various concentrations of monomer, catalyst, initiator, and neutral salt. The experiments with Ag(1) ions were conducted in the dark. Results and Discussion

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The mechanism of acid catalyzed decomposition of peroxodisulfate, (SzOi-) in aqueous perchlorate medium involves the hydrolysis of the species HzSzOe and HSzOB and the homolysis of the species HzS208, HSz08 and S20:-at the 0-0 bond. The overall rate law whenThe constants k' and k " contain the hydrolysis and homolysis rate constants of HSZOT and H2S208, respectively. With added Ag( I), the acid catalyzed and Ag(1) catalyzed reactions take place independently. Ag(1) catalyzed decomposition appears to involve the species AgSzOi (aq).