Sample NMR Problems

Three unlabeled vials each contain a different one of the following C5H12O2 isomers A, B & C.

A. 1,3-dimethoxypropane (CH3OCH2)2CH2

B. 2,2-dimethoxypropane (CH3)2C(OCH3)2

C. diethoxymethane CH2(OC2H5)2

     

To help identify each compound and properly label its container 13C and 1H nmr spectra have been taken.
The following questions refer to this experimental data.  


Part I What prediction can be made regarding the number of 13C nmr signals expected from these compounds?
(Select one of the following)
All three compounds will have a different number of 13C nmr peaks.   .............
Two of these compounds will have the same number of 13C nmr peaks.     .......
All three of these compounds will have the same number of 13C nmr peaks.   ...

Part II Which if any of the 1H nmr spectra of these compounds would fit the following criteria?
(Enter A, B, C or X for none)
1. Which would not show any spin-spin splitting?  ..
2. Which would show a 4H quartet at δ3.5 ppm?  ...
3. Which would show a 2H quintet at δ1.7 ppm?  ...


This script written by William Reusch, Dept. of Chemistry, Michigan State University. Please send comments and corrections to whreusch@pilot.msu.edu.