Evaluation of Complex Formation during polymerization of Acrylamide Initiated by Ce(IV) Aminopolycarboxylate Ligands

Abstract

The aqueous polymerisation of acrylamide initiated by Ce(IV)aminopolycarboxylate

ligands (APCL) like glycine (GLY), iminodiacetic

acid (IDA), nitrilotriacetic acid (NTA), 1,2-diaminocyclohexanetetraacetic

acid (CDTA), ethylenediaminetetraacetic acid

(EDTA), and diethylenetriamine pentaacetic acid (DTPA) are investigated.

These APC ligands form stable complexes with Ce(IV). In the presence

of monomer acrylamide these complexes get decomposed to form ligand

radicals (R) which initiated the polymerisation reaction. Such a type of

system is characterised by the formation constant 'K' and decomposition

(disproportionation) constant k_d. K and k_d values are evaluated for the

above six systems, by determining the rate of disappearance of Ce(IV) in

the polymerisation experiment in which the concentration of the ligand is

varied keeping [Ce(IV)] as constant. The complex formation is supported

by the absorption spectra.