NMR Spectroscopy Hi! I\'m stuck on the following questions (please see picture a

Question

NMR Spectroscopy

Hi! I'm stuck on the following questions (please see picture above for the H-NMR spectrum for this problem). Please give brief explanations so I can understand this better :) Thank you!

-Consider the multiplet at 4.0-4.4ppm, which does not include the central glycerol CH. Which proton(s) in the structure of vegetable oil is responsible for the multiplet? From a first glance, what coupling pattern would you expect for these protons, and why is the actual peak significantly more complicated? The integration does not need to be scaled.

-Which proton(s) in the structure of vegetable oil is responsible for the multiplet at 5.2-5.45 ppm? What does the integration of this peak tell you?

-Which peak(s) could be responsible for the alpha-hydrogens in the acyl chain? Why?

Explanation / Answer

a) the peak at 4.0 ppm usualy arises due to attachement of proton bearing crbon attached to a hetero atom in this case its the one on either sides of glycerol CH proton the multiplet is due to long range coupling i guess it would be doublet of triplet or tripet of doublet if the spectra is well resolved with two J values.

b) The peaks at 5.2 -5.45 ppm are ccorresponding to the alkenyl protons present in the acyl chain of the vegetable oil.The integration tells how many alkeny protons are there in turn tell how many double bonded unsaturations are there in the oil.

c)The alpha hydrogens in acyl chain would appear as triplet in a well resolved spectra at 2.0-2.3 ppm since its attached to an electron withdrawing crbonyl group.

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