Free-radical polymerization of itaconic acid in the presence of choline salts: Mechanism of persulfate decomposition

• Mechanism of choline-activated decomposition of persulfate was investigated.
• Radical-chain redox mechanism was proposed to explain activation effect of choline.
• The presence of choline allows synthesis of poly(itaconic acid) with higher Mw.

Kinetics of decomposition of persulfate activated by choline in aqueous solution has been studied. Additionally, the products of choline degradation were analyzed by 1H NMR spectroscopy, and betaine aldehyde was identified as the main oxidation product. Thus, radical-chain redox mechanism is postulated to explain experimental results. The mechanism was successfully verified using kinetic modeling approach. Moreover, it was found that due to formation of complex of itaconic acid and choline chloride, the salt solubility of the acid in water was increased. Finally, free-radical polymerization of itaconic acid initiated by persulfate in aqueous solution of the choline salt yielded poly(itaconic acid) with higher molecular weight and increased polydispersity.

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