ORGANIC SPECTROSCOPY INTERNATIONAL: 1H NMR n-propylbenzene

n-propylbenzene

Moving downfield, we see the expected sequence of signals: a, primary (3H); b, secondary (2H), c, benzylic (2H), d, aromatic (5H). Signals a and c are each split into a triplet by the two secondary protons H(b). The five protons adjacent to the secondary protons - three o none side and tow on the other - are, of course, not equivalent. But the coupling constants J(ab) and J(bc) are nearly identical, and signal b appears as a sextet (5 + 1 peaks). The coupling constants are not exactly the same, however, as shown by the broadening of the six peaks.