Polymerization kinetics of acrylonitrile by oxidation: Reduction system using potassium persulfate/ascorbic acid in an aqueous medium

Abstract

The kinetics of acrylonitrile polymerization initiated by free radicals formed in situ in a potassium persulfate/ascorbic acid redox system was investigated in an aqueous sulfuric acid medium in the temperature range of 40-70 C. The rate of polymerization and the rate of the disappearance of potassium persulfate were measured. A kinetic scheme involving the production of initiating radicals from the oxidation of ascorbic acid by potassium persulfate ions and termination exclusively by the interaction of chain radicals with persulfate ions is proposed. The effects of some water-miscible organic solvents on the rate of polymerization were investigated. The temperature dependence of the rate was studied. A possible mechanism consistent with the experimental data is proposed.

Iron-Based Redox Polymerization of Acrylic Acid for Direct Synthesis of Hydrogel/Membranes and Metal Nanoparticles for Water Treatment

“…This polymerization is done in solution and/or using a bath to prevent overheating which gives a proper control of temperature 5 to arrest polymer gelation. 6–8 This acid-redox polymerization includes strong oxidants like persulfates, perphosphates or peroxides and one or two reducing agents to initiate radicals.…”

“…One process for making these hydrogels is an acid redox polymerization because the process has high conversion (≥98%) and results in high-molecular-weight hydrogels. This polymerization is done in solution and/or using a bath to prevent overheating, which provides proper control of temperature to arrest polymer gelation. − This acid redox polymerization includes strong oxidants such as persulfates, perphosphates, or peroxides and one or two reducing agents to initiate radicals. The reducing agents act as accelerants and can be either inorganic salts from metals such as iron, copper, manganese, or sodium , or organic salts.…”

Preparation and characterization of a foam regulator with ultra‐high molecular weight

“…As shown in Figure (c,d), excessive reductants or oxidants lead more oxidants to be reduced or more reductants to be oxidized, less primary radicals generated to initiate monomers lead to low conversion rate and intrinsic viscosity. When the ratio of oxidant and reductant is 3:1, they need less activation energy, that is, 41.87 kJ/mol, which is much lower than 140.3KJ/mol, the thermal initiator needs . So low initiation temperature makes less side reaction and higher molecular weight.…”