Water as a reaction medium for nickel(II)-catalyzed ethylene polymerization

As the most environmentally friendly common solvent conceivable, water also possesses other unique properties as a reaction medium: it is highly polar and immiscible with most organic compounds, has a high heat capacity and also features a strong propensity for micelle formation in the presence of surfactants. These features are exploited in radical emulsion and suspension polymerization of olefinic monomers, such as butadiene, styrene and acrylates on a large scale. Also, transition metal catalysis in aqueous media involving the synthesis of low molecular weight compounds (commercialized in the Ruhrchemie/ Rhone-Poulenc hydroformylation process) is currently attracting strong interest. By contrast transition metal catalyzed coordination polymerization reactions in water have received less attention, as the common early transition metal catalysts2 are extremely sensitive to moisture