Stepping stones in CO₂ utilization Synthesis and evaluation of oxalic- and glycolic acid (co)polyesters

Plastic materials have become indispensable in everyday life because of their versatility, high durability, lightness and low cost. As a consequence their demand continues to increase steadily, accompanied by an increasing requirement of fossil resources, both for energy and building blocks, as about 99 % of the current feedstock for polymers is fossil-based. Unfortunately, this trend is accompanied by higher emissions by the industry and leakage during production, transport and through consumer usage and disposal. This mismanaged plastic waste causes unprecedented harm to ecosystems. The aforementioned issues prompt the need to rethink the entire plastic value chain. While for energy many options are available to decouple from fossil feedstocks, for plastic materials the only alternative carbon sources are biomass, existing plastics (via recycling) and in the long-term CO2. The fact that CO2 is naturally abundant, nontoxic, inexpensive, a non-oxidant and renewable, makes it a promising feedstock. Finally, the use of CO2 as feedstock can leade to negative emissions required to reach “net zero” in the second half of this century. The research presented in this thesis is part of the OCEAN (EU Horizon 2020 Spire program) project in which a new route to produce polymers using CO2 as circular feedstock is developed. CO2 can be electrochemically reduced to formic acid derivatives that can be subsequently converted into useful monomers such as oxalic acid and glycolic acid. We focused on investigating synthesis routes to produce polyesters based on those monomers and on studying their properties and assessing potential applications.