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A fascinating piece of chemistry. I like everything about the article except the claim, near the beginning, that it melts into two different liquid forms. I wou
by mcherm 7y ago
A fascinating piece of chemistry. I like everything about the article except the claim, near the beginning, that it melts into two different liquid forms. I would have preferred to express it as two different melting processes (one catalyzed by tiny amounts of impurities, the other not catalyzed).
Normally, it is chemical reactions that get catalyzed, not state changes, but the behavior of this chemical is an exception.
- kortex 7y agoNo, it is truly a different chemical form, as evidenced by the shift in NMR spectrum. Isomers often have an energy barrier between the two forms which can be overcome under certain conditions. Infamously, thalidomide easily converted between isomers, even if it was prepared chirally, it would convert in-vivo to the teratogenic form, due to a loose alpha hydrogen. Usually, it's something like a chemical rearrangement, like the alpha hydrogen popping off then another attaching, inverting chirality. At some point, this barrier can be low enough that it's very sensitive to these rearrangements, even a tiny fraction of acid or base can swing it.