In water, distillation causes fractioning of the $\ce{^{18}O}/\ce{^{16}O}$ oxygen isotopes (Wikipedia).

Does something similar happen to the $\ce{^{13}C}/\ce{^{12}C}$ and possibly $\ce{^{14}C}$ isotopes in alcohol when it is distilled out of a watery brew?

  • 2
    $\begingroup$ Looking at the percentage differences of the different isomers may be instructive. $\endgroup$ – TAR86 Oct 11 at 5:04
  • $\begingroup$ Yes, It does. But the effect would be weaker, because of smaller relative mass difference of isotopes, and of the ethanol mokecule. Additionally, different mass of C atoms has much lower impact on ethanol intermolecular bonding, than has O mass on water bonding. $\endgroup$ – Poutnik Oct 11 at 7:34
  • $\begingroup$ @Poutnik Selection among ethanol molecules might be limited, since most of ethanol evaporates out of the brew and water (with a bit of ethanol) stays behind. When evaporating water partially, as with Oxygen, all molecules are subject to selection. I wonder if fractioning still takes place for carbon. $\endgroup$ – HannesH Oct 11 at 22:33
  • $\begingroup$ The first ethanol fractions are enriched by 12C. As most of ethanol is evaporated, the last fractions are in contrary impoverished, with total balance about neutral. $\endgroup$ – Poutnik Oct 12 at 4:00
  • $\begingroup$ @TAR86 Can you expand on that? How would the enrichements of isomers relate to that of isotopes? $\endgroup$ – HannesH Oct 12 at 18:10

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