Rapid Continuous-Flow Water-Free Synthesis of Ultrapure Ionic Liquids Assisted by Microwaves

Continuous flow synthesis of pyridinium salts accelerated by multi-objective Bayesian optimization with active learning

We report a human-in-the-loop implementation of the multi-objective experimental design via a Bayesian optimization platform (EDBO+) towards the optimization of butylpyridinium bromide synthesis under continuous flow conditions. The algorithm simultaneously optimized reaction yield and production rate (or space-time yield) and generated a well defined Pareto front. The versatility of EDBO+ was demonstrated by expanding the reaction space mid-campaign by increasing the upper temperature limit. Incorporation of continuous flow techniques enabled improved control over reaction parameters compared to common batch chemistry processes, while providing a route towards future automated syntheses and improved scalability. To that end, we applied the open-source Python module, nmrglue, for semi-automated nuclear magnetic resonance (NMR) spectroscopy analysis, and compared the acquired outputs against those obtained through manual processing methods from spectra collected on both low-field (60 MHz) and high-field (400 MHz) NMR spectrometers. The EDBO+ based model was retrained with these four different datasets and the resulting Pareto front predictions provided insight into the effect of data analysis on model predictions. Finally, quaternization of poly(4-vinylpyridine) with bromobutane illustrated the extension of continuous flow chemistry to synthesize functional materials.

Electrochemically Activated Expanded Graphite with Tailor-Made Pores for Magnesium-Organocation Hybrid Batteries

Persisting limitations of lithium-ion batteries (LIBs) in terms of safety, energy and power density, natural resources, and the price call for expeditious research to develop the "beyond Li-ion" technologies. In this regard, magnesium-organocation hybrid batteries (MOHB) hold the potential to address the above issues associated with LIBs by utilizing abundant and inexpensive elements of magnesium and carbon for the anode and cathode, respectively. Moreover, magnesium metal anode is highly energy-dense yet less susceptible to the dendrite formation, enabling safer operation compared to lithium metal anodes. In this study, we targeted to increase the capacity and rate capability of porous carbon cathode of MOHB by generating tailor-made pores, which were provided by the interlayer accommodation of solvated organic cations with controlled sizes during the electrochemical activation of expanded graphite. Our electrochemically activated expanded graphite can be used as an efficient cathode in MOHB with enhanced kinetics, specific capacitance, and cycle life.