Element 61 - Sub- and Super-Critical Fluids

An introduction to Element 61: Sub- and Super-Critical Fluids, from the Periodic Table of the Elements of Green and Sustainable Chemistry, Solvents and Super-Critical Fluids series.

"There are compressible gases that at a certain temperature and under a certain pressure, collectively their critical point, become fluids that are neither gas nor liquid but rather a “super-critical fluid”. While these fluids have been known for centuries it was only in recent decades that new discoveries showed some of them could be excellent solvents. Carbon dioxide is the most highly studied of these and has been demonstrated at large scale to be a useful solvent for everything from synthesis to extraction, cleaning, and analysis.

The green advantages of these supercritical fluids are numerous including lack of toxicity for water and carbon dioxide, lack of flammability, tunability, and the possibility of ‘infinite recyclability’ by cycling pressure. (Note: The use of carbon dioxide as a solvent does not require the generation of new CO2 and therefore does not contribute to greenhouse gas emissions.)"
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Adapted from and inspired by Anastas, P. T.; Zimmerman, J. B. (2020.) The Periodic Table of the Elements of Green and Sustainable Chemistry. Press Zero.

Video produced by the Center for Green Chemistry and Green Engineering at Yale University.

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Thumbnail image source: "Teal Gas Tanks" - Daniil Prikhno/Pexels