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Help me identify peaks in H NMR please!

  1. Oct 8, 2009 #1
    CHM238L - Identifying Peaks of H NMR spectra

    1. The problem statement, all variables and given/known data

    The experiment is "Reducing Benzil using Sodium Borohydride".
    The experiment itself was simple enough and when I finished, I got a melting point of 134-136 C, which is indicative of benzoin (135-137) rather than meso-hydrobenzoin (137-139), however my thin layer chromatography revealed that my sample was nearly identical to meso-hydrobenzoin, and I tend to believe that moreso than the melting point. It's possible my sample wasn't pure.

    So, I also ran the NMR of my sample and got a spectra for it, but I am having trouble identifying the peaks. Please help me out here!

    Here is the picture of the 1H NMR spectra.
    http://img246.imageshack.us/img246/5873/95924000.jpg" [Broken]

    2. Relevant equations
    This is a picture of the reaction and the 5 possible products. I circled Meso-Hydrobenzoin, which is what I believe to have after my TLC test.
    http://img515.imageshack.us/img515/8025/41232169.jpg" [Broken]


    3. The attempt at a solution
    I cleaned the NMR tube a few days in advance. I'm not sure if there is any H2O or Acetone showing in the spectra... I tried integrating the big peak at ~7.2 at 10, and I get way too many hydrogens.
    It should have 14 hydrogens only if it is meso-hydrobenzoin.

    Thanks in advance!
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Oct 8, 2009 #2
    Is this too difficult for people?
    I'm much better at identifying the structures in Carbon 13 NMR, honestly.
    I don't like hydrogen NMR.

    This is for a lab report for an experiment I did last week that's due tomorrow.
    I've got the rest of the lab report done, just need to verify what I have with my NMR.
    Help please :p
     
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