Distinguishing propan-2-ol from ethanol using IR spectroscopy
Here is the spectrum for ethanol:



Here is the spectrum for propan-2-ol:



Here are the tabulated peak positions ($\pu{cm^{-1}}$) and percent transmittance (%T) for the two. I've tried to match the appropriate peaks.

$$
\begin{array}{cccc}%
\hline%
\text{ethanol position} &amp; \text{ethanol %T} &amp; \text{propan-2-ol position} &amp; \text{propan-2-ol %T} \\
\hline%
3358 &amp; 12 &amp; 3346 &amp; 9  \\
     &amp;    &amp; 3334 &amp; 9  \\
2974 &amp; 13 &amp; 2972 &amp; 5  \\
2927 &amp; 38 &amp; 2933 &amp; 19 \\
     &amp;    &amp; 2907 &amp; 23 \\
2887 &amp; 35 &amp; 2884 &amp; 20 \\
     &amp;    &amp; 2722 &amp; 60 \\
     &amp;    &amp; 2669 &amp; 60 \\
     &amp;    &amp; 2521 &amp; 74 \\
     &amp;    &amp; 2408 &amp; 79 \\
     &amp;    &amp; 2387 &amp; 81 \\
     &amp;    &amp; 2198 &amp; 84 \\
     &amp;    &amp; 1903 &amp; 85 \\
     &amp;    &amp; 1766 &amp; 84 \\
1455 &amp; 59 &amp; 1467 &amp; 24 \\
     &amp;    &amp; 1409 &amp; 29 \\
1381 &amp; 54 &amp; 1379 &amp; 16 \\
     &amp;    &amp; 1368 &amp; 17 \\
1330 &amp; 68 &amp; 1341 &amp; 28 \\
1274 &amp; 74 &amp; 1309 &amp; 23 \\
     &amp;    &amp; 1162 &amp; 10 \\
1090 &amp; 22 &amp; 1130 &amp; 9  \\
1050 &amp; 7  &amp; 1110 &amp; 15 \\
     &amp;    &amp; \color{red}{954}  &amp; 4  \\
881  &amp; 37 &amp; 818  &amp; 13 \\
669  &amp; 67 &amp; 660  &amp; 37 \\
     &amp;    &amp; 654  &amp; 37 \\
     &amp;    &amp; 490  &amp; 66 \\
     &amp;    &amp; 436  &amp; 68 \\
\hline%
\end{array}%
$$

One way of differentiating between the two is that I don't believe the peak at 954 wavenumbers in propan-2-ol appears in ethanol. Another better way that doesn't require looking at the fingerprint region is to see that the hydrogen-bonding peaks (the broadest ones to the left) are red-shifted in propan-2-ol compared to ethanol.