Sustainable Solvent Development: Exploring Bio-Based Alternatives Assisted By Computational Modelling

Solvents are the mainstay of many chemical reactions and formulations in the chemical industry. In recent years, concern regarding the potential long-term health and environmental risks of many existing solvents has vastly increased, leading to stricter legislation and pressure to discontinue their use. As such, there has been more focus on alternatives, from solvent selection guides informing users about solvent safety rankings, to research into new and existing compounds, usually from bio-available sources, which show potential as replacements. In this thesis, the development of new bio-based solvents from a pilot-scale production platform molecule is explored. The synthesis and purification of lactones derived from levoglucosenone were studied extensively. Literature syntheses were critiqued and improved upon to scale-up the production of these compounds, previously disregarded as potential solvents. Also, para-cymene was investigated as an alternative solvent for direct amidation, with promising results, and thoroughly compared with its analogue, petrochemically derived toluene. In both approaches, computational modelling was employed to guide the decision-making process, and the limitations of the techniques used as predictive tools were assessed. para-Cymene was found to be a suitable alternative to toluene for most crystalline amides, with the yield appreciably advantaged by the higher reflux temperature. The Yalkowsky approximation was shown to compare well with experimental solubilities of the amides and a flow system was put into practice. HSP of 5-membered ring lactones were predicted using HSPiP showing promise for some as NMP replacements. Furthermore, gamma-hydroxymethyl-alpha,beta-butyrolactone was made with 98% selectivity in a one-step method using an L-lysine catalyst and subsequently scaled-up to 175 g using a simplified method, then O-methylated. In initial tests, both lactones displayed good resistance to organic bases, faring better than Cyrene.