How can I distinguish 1-bromobutane and 2-bromobutane by their IR spectrums?

In the 1-bromobutane spectrum I think the $\ce{-CH3}$ peak is shorter, but I don't know if that is actually reasonable or just a fluke.

In the spectrum that I think is 2-bromobutane there is an additional peak at around $1290$. What might this be?

The only alkyl halide peaks we discussed in class was the $\ce{C-Br}$ stretch $600-750$. They both seem to have this (although they do look different). How can I distinguish?

  • $\begingroup$ Meh, with NMR it would be crystal clear. $\endgroup$ – Mithoron Apr 7 '19 at 23:34
  • $\begingroup$ Sure would! Unfortunately this is an IR problem set. $\endgroup$ – Noah Harris Apr 7 '19 at 23:49
  • $\begingroup$ From NIST database 1-bromobutane and 2-bromobutane in the gas phase. $\endgroup$ – MaxW Apr 8 '19 at 1:07
  • $\begingroup$ I did see the different spectrum on SDBS, but I'm more interested in given just the two spectrum and the two compounds, how can you tell which goes with which? $\endgroup$ – Noah Harris Apr 8 '19 at 14:50

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