Kinetic and Mechanistic Aspects of Ethylene and Acrylates Catalytic Copolymerization in Solution and in Emulsion

Ethylene was copolymerized with acrylates in solution and in emulsion using sulfonated arylphosphine Pd-based catalysts. The copolymerization of C2H4 and methyl acrylate in toluene was slowed by the σ-coordination of the acrylate on Pd. The substitution of pyridine by itself was shown to proceed via an associative mechanism with activation parameters ΔH‡ = 16.8 kJ/mol and ΔS‡ = −98 J mol−1 K−1 whereas the activation parameters for the substitution of pyridine by methyl acrylate were found to be ΔH‡ = 18.1 kJ/mol and ΔS‡ = −87 J mol−1 K−1. Using these Pd-based catalysts in an emulsion polymerization process, latexes of copolymers of ethylene with various acrylates having particle diameters ∼200 nm were obtained for the first time. Their solid contents did not exceed 5% because of the low activity of the catalyst resulting from the coordination of water and from the slow decomposition of the active site by water.