When I was a kid, age 10 or so, and a budding chemist, surprisingly retaining all eyes and limbs in my little “laboratory”, one of my favorite compounds was scary-sounding hydrofluoric acid, HF in water.
I could etch glass with it and feel like the Sorcerer’s Apprentice with a powerful thing. Fluorine compounds are now everywhere, much to our general consternation. Think of the perfluoro and polyfluoro compounds, the PFAs that are even found in polar bears now!
While the European Chemicals Agency is considering banning 10,000 fluorochemicals in everyday use – yes, 10,000 - some are still irreplaceable, such as in some drugs. They still have to be made safely, starting from the ore fluorspar. The current process to liberate fluorine in a form that’s reactive for making all those other chemicals is dangerous. It runs at 300 degrees C and generates nasty hydrofluoric acid.
Now, Immo Klose and colleagues at the University of Oxford have a better way. They treat the fluorspar ore, which is harmless calcium fluoride, with boric acid or simple silicon dioxide, plus somewhat toxic but readily controlled oxalic acid.
The result is a chemical that can insert the fluorine atom into a variety of molecules, on the way to useful products. The process runs at less than 50 degrees C, a Phoenix summer high, and even in water. There’s no free HF created. Another advantage is that the processes – from fluorspar and onward- can be run in small, decentralized facilities.
This has been an outreach activity of the Las Cruces Academy, viewable at GreatSchools.org.
Source: Nature 14 Nov. 24, pp. 359 ff.
