Anionic polymerization of vinyl monomers with xanthates

Abstract

AbstractThe polymerization of vinyl monomers with various xanthates (potassium tert‐butylxanthate, potassium benzylxanthate, zinc n‐butylxanthate, etc.) were carried out at 0°C in dimethylformamide. N‐Phenylmaleimide, acrylonitrile, methyl vinyl ketone, and methyl methacrylate were found to undergo polymerization with potassium tert‐butylxanthate; however, styrene, methyl acrylate, and acrylamide were not polymerized with this xanthate. In the anionic polymerization of methyl vinyl ketone with potassium tert‐butylxanthate, the rate of the polymerization was found to be proportional to the catalyst concentration and to the square of the monomer concentration. The activation energy of methyl vinyl ketone polymerization was 2.9 kcal/mole. In the polymerization, the order of monomer reactivity was as follows: N‐phenylmaleimide > methyl vinyl ketone > acrylonitrile > methyl methacrylate. The initiation ability of xanthates increased with increasing basicity of the alkoxide group and with decreasing electronegativity of the metal ion in the series, lithium, sodium, and potassium tert‐butylxanthate. The relative effects of the aprotic polar solvents on the reactivity of potassium tert‐butylxanthate was also determined as follows: diethylene glycol dimethyl ether > dimethylsulfoxide > hexamethylphosphoramide > dimethylformamide > tetrahydrofuran (for methyl vinyl ketone); dimethyl sulfoxide > hexamethylphosphoramide > dimethylformamide ≅ diethylene glycol dimethyl ether (for acrylonitrile).