Conversion of CO2 into organic carbonates: a venture into catalysis, reaction design and product modification

A growing focus on sustainability is witnessed in today’s chemical product development. Although sustainability is a very broad concept, within the field of chemical products this primarily translates into the utilisation of renewable feedstock, safer alternatives for currently used hazardous chemicals, and biodegradable or recyclable end-products. Within the context of sustainable chemical product development, the application of carbon dioxide (CO2) as feedstock for chemical products is an interesting option as this compound has the potential to be used as low-toxic, non-flammable and inexpensive building block for the production of bulk chemicals, minerals and even polymers. Among the various opportunities for CO2-utilisation, the reaction between carbon dioxide and epoxides offers an attractive pathway as it leads to the formation of two different, yet both valuable products: cyclic and polymeric carbonates. However, this route also has its challenges, as active and selective catalysts are necessary in order to selectively obtain the desired carbonate products with high yields.
This thesis reports a research effort towards the conversion of CO2 into organic carbonates, taking the reader on a venture into the catalysis and reaction design of carbon dioxide and epoxide chemistry and post-polymerisation modification of the polycarbonate products. First, the development of a series of titanium, zirconium and iron-based compounds is discussed, combined with the evaluation of these metal complexes as catalysts for the reaction of CO2 with various epoxides. The last chapters of this thesis focus on the synthesis of several functionalized polycarbonates and their potential use in, amongst others, biomedical applications.