> Computer calculations by colleagues at the University of California, Los Angeles, revealed DMSO knocks off the carboxylic acid group. “Once that happens it causes the entire molecule to fall apart in a cascade of reactions,” Dichtel says.
Big if true. I'm slightly skeptical that just decarboxylating PFAS causes the rest of the backbone to "fall apart" - I would expect it to form CF3[CF2]· (carbon radical) which would readily react with water to form -H or -OH, which is basically back to square one. But maybe it can eliminate HF in the presence of UV, forming CF3[CH2]CF=CFOH, which gets hydrolyzed, oxidized, then cleaved, but boy is that an unfavorable process.
(edit: skimmed the paper, I was pretty close. Forms CF3[CF2]- which goes to CF3[CH2]CF=CF2 which then gets hydrolyzed, but...DMSO/NaOH at 80-120°C ...yikes. This is the ochem equivalent of "nuke the site from orbit", very few compounds survive these conditions)
I've been out of the chemistry game for a few years now so I'm a bit rusty but gut instinct is that this is far from a slam dunk. But anything to reduce FC's is a boon to the world, so I'm hopeful this is a breakthrough.
Edit2:
> This high fluoride recovery indicates that most of the perfluoroalkyl fluorines were defluorinated and mineralized rather than being transformed to smaller-chain PFAS or being lost as volatile fluorocarbons.
So the surprising thing isn't the decarboxylation, it's that NaOH encourages the perflourylalkenes to cleave at sites away from the alpha (splitting, rather than carbon-by-carbon), which is neat. Still doesn't touch PFOS, unfortunately.