Synthesis of novel promising materials via impregnation of crosslinked polymeric networks with metal complexes in supercritical carbon dioxide

Three types of polymers, phenol-formaldehyde copolymer and polypropyleneimine and polyamidoamine dendrimers, are synthesized using the polycondensation method. Mesoporous polymeric networks are formed by treating the above dendrimers with crosslinking agents. Impregnation of polymeric networks with rhodium acetylacetonate in supercritical carbon dioxide has been carried out for the first time and its optimal conditions have been determined. Using Raman spectroscopy, it has been shown that the metal content in polymer networks falls in the range 0.3–2.0 mass % depending on the type of the polymer and the crosslinking agent and on the crosslinking degree. Polymer samples including rhodium nanoparticles have been prepared by reducing immobilized rhodium acetylacetonate with molecular hydrogen. According to the preliminary data, the resulting samples possess extremely high activity as catalysts for hydrogenation of unsaturated compounds.