Broadening the scope of Pd-catalyzed oscillatory carbonylation reactions: solvent, substrate, catalyst

On our way to producing all-polymeric self-oscillatory materials, we have expanded the horizons of oscillatory carbonylation reactions by searching for alternative substrates, solvents and even catalysts. In this paper, we demonstrate that pH oscillations in carbonylation reactions have the potential to occur in a broad range of aliphatic alcohol solutions when using either a small molecule substrate (phenylacetylene) or a polymeric substrate (pegylated alkyne) with either a small molecule catalyst (Pd-diacetate) or a non-leaching polymeric catalyst (Pd-polyacrylate). The alcohols studied are methanol, ethanol, 1-propanol, 1-butanol and 1-hexanol. In this carbonylation reaction an alcohol serves as both the solvent and as a reactant. The resulting oscillations suggest that carbonylation reactions have strong potential for the discovery and development of new oscillatory chemical systems. Replacing methanol, commonly used in oscillatory carbonylation processes, with ethanol is an important step in enhancing the biocompatibility of these systems. Furthermore, showing that oscillations in pH are feasible in ethanol solutions when polymeric substrate and polymeric catalyst are used supports the vision of employing oscillatory chemical reactions to build oscillatory materials.