13 C NMR...One for your eye

Ethanal or AcetaldehydeEthanoic acid or Acetic acidEthanol or Ethyl alcohol

Since all three preceding C-13 spectra are fully proton decoupled, the carbon atoms appear as narrow singlets (single peaks). Note that the carbons in methyl groups (–CH₃, indicated as C2 next to peaks) of all three compounds have a chemical shift rather upfield (close to the right) in the spectra not too far from about 20 ppm. The carbon in themethylene group (–CH₂–, indicated as C1) in ethanol is brought further downfield to 58 ppm because that carbon is bonded directly to the oxygen in the hydroxyl group (–OH). Note that the carbonyl group (–CO–, indicated as C1) carbons in acetaldehyde and acetic acid are downfield at the left side of the spectrum, the carbonyl region between about 160 and 220 ppm.