Catalytic Production of Monomers for Sustainable Polymers from Carbon Dioxide and Diols

Polymers, better known as plastics, are widespread in modern society as they are light, strong, and cheap. Their demand is dramatically increasing and in 2013, 299 megatonnes of plastics were produced worldwide, a 46.5% increase compared to 2002 (source: plasticseurope). However, polymers are regarded as unsustainable as they are environmentally persistent and their production is dependent on finite fossil-based resources. In 2013, 99.5% of plastics were still produced from oil (source: europeanbioplastics). There is therefore an urgent need for further research into the production of sustainable plastics. Additionally, in 2014, 32.3 gigatonnes of waste carbon dioxide (CO2) were released into the atmosphere (source: International Energy Agency). Therefore, polymers made from a cheap and renewable resource like CO2 are highly desirable products. The aim of this proposal is to utilise CO2 as a raw material in the synthesis of cyclic carbonate monomers, which are the building blocks of polycarbonate polymers. Polycarbonates are furthermore promising materials for numerous applications, including as thermoplastics, binders for photovoltaics, polymer electrolytes, adhesives, tissue engineering scaffolds and drug delivery carriers. The current method used to produce cyclic carbonate monomers employs phosgene, a toxic and energy intensive reagent. Replacing phosgene by CO2 is an exciting scientific challenge that has the potential to transform the economy and impact the environment. Building on our published preliminary results and using an experimental and computational approach, this project will develop catalysts for the synthesis of cyclic carbonate monomers directly from CO2 and diols, abundant molecules that can be sourced from nature. These catalysts will ultimately be used to transform carbohydrates from biomass and food waste into new monomers that cannot be accessed using traditional phosgene reagents. This process will provide a vital step towards the valorisation of CO2 and the derivatisation of renewable feedstock like carbohydrates into novel sustainable materials that could generate significant wealth within the UK.