Bio-Based Solvents for Organic Synthesis

Scrutiny over solvent selection in the chemical industry has risen in recent decades, popularising research into neoteric solvent systems such as ionic liquids and supercritical fluids. More recently bio-based solvent products have been considered as replacements for conventional petroleum derived solvents. Because they bear a close resemblance to existing solvent products, bio-based solvents can be readily absorbed into the fine chemical industries. This work develops a methodology for identifying reactions of concern with respect to current solvent selection practice, and then implementing a high performance bio-based solvent substitute.

In this thesis, kinetic studies of heteroatom alkylation, amidation, and esterification are documented, and the solvent effect dictating the rate of each reaction ascertained. With the ideal properties for the solvent known, bio-based solvent candidates were screened for suitability in each case study. This process, which employs computational tools, was also applied to model the productivity of the Biginelli reaction as a representative multi-component heterocycle synthesis. A strong case is made for limonene and p-cymene as bio-based solvents for all but heteroatom alkylation from the case studies listed above. Alkylations with nitrogen nucleophiles are instead suited to high polarity solvents, and to this end some bio-based amides were investigated.