1. Why is the chemical shift for the Hydrogen(h) protons on the glycerol backbon

Question

1. Why is the chemical shift for the Hydrogen(h) protons on the glycerol backbone around 5.30 ppm? Explain (photos on bottom)

2. The Hydrogen (g) protons have one next door neighbor, and yet their splitting pattern is not the typical doublet. What contribution factor can you conclude is playing a role in causing this atypical splitting pattern? (photos on bottom)

Experimental NMR

http://postimg.org/image/wl2o0tmy7/full/

Fat Equations

http://postimg.org/image/4md3npapb/

Food Package label

http://postimg.org/image/b2m2dsj8v/

Given NMR

http://postimg.org/image/k94d12ohb/

Explanation / Answer

The hydrogen shift near 5.3 is due to presence of ester group in the given fatty acid

The hydrogen marked bold

H-C-OOCH-R

Shows the peak near 5 in nmr spectrum due to deshielding due to presence of electronegative element (oxygen of ester)

2) The Hg protons are two different protons

They are stereochemically different from each other so they will also cause splitting of the other

So inspite of splitting due to only neighbour carbon protons they also experience spliting due to protons on the same carbon and hence we obtain multiplets

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