Biodiesel is being widely explored as an alternative to petroleum based diesel fuels. It is renewable, biodegradable, and produces fewer total emissions. The process of synthesizing biodiesel results in the co-generation of approximately 10% glycerol. This coproduct glycerol is currently viewed as a disposal problem for biodiesel producers. One potential way to add value to coproduct glycerol is to use it as a component in deep eutectic solvents (DESs). DESs are a class of solvents related to ionic liquids; they are comprised of a hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA). DESs are very polar, have novel solubility and electronic properties, have low to no volatility, can be reusable, and are often biodegradable. Implementing these reusable DESs in teaching labs will lower university solvent acquisition and disposal costs while adding value to industrial biodiesel synthesis. Previous research showed that DESs can be prepared using synthetic glycerol + choline chloride (ChCl) mixtures; our group has shown that a DES can be prepared with coproduct glycerol from acid-catalyzed (CGAC) biodiesel synthesis. This work extends our study on DESs prepared using synthetic glycerol. Eight different HBAs were evaluated using synthetic glycerol as the HBD. Of the HBAs examined, four were selected to prepare DESs with CGAC. Density and viscosity measurements confirmed the formation of DESs. Next, DESs prepared with either synthetic glycerol or CGAC were used as solvents in five reactions to determine the DESs’ viability as solvents in common organic chemistry teaching labs. Of the reactions, which included three Diels Alder reactions, an olefin cross metathesis reaction, and a ring closing metathesis reaction, the ring closing metathesis was the best candidate to use in a teaching laboratory experiment. Product formation was confirmed by GC-MS and 1H NMR. Then, DESs were successfully reused in a second ring closing metathesis reaction.

Reusable biodegradable solvents from biodiesel coproduct glycerol

2019 Spring National Meeting

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