Isomers: More Student Teaching Lab Manuals

We have developed two documents which show how the Spinsolve benchtop NMR spectrometer can be used in Chemistry Education to introduce students to NMR. In these laboratories students measure the 1D proton NMR spectra of isomers of C4H8O2: ethyl acetate, butyric acid and isobutyric acid.

Isomers

The first experiment, Distinguishing between the isomers of C4H8O2, is aimed at students who have very recently been introduced to NMR spectroscopy and encourages them to use the concepts they learn in class to think about the structure of the molecule and predict how the spectrum will look. The second experiment, Identification of the isomers of C4H8O2, is a more advanced experiment using the same spectra where students determine the structure of the molecule with only the 1D proton NMR spectrum.

Ethyl acetate example:

EthylacetateH
Predictions:

PositionIntegrationSplittingChemical Shift
12Three nearest neighbours that are equivalent – quartetSingle bond to oxygen – deshielded
23Two nearest neighbours that are equivalent – tripletSaturated alkyl group far from ester group – shielded
2′3No nearest neighbours – singletAdjacent to the carbon of a carbonyl – slightly deshielded

A list of all available Student Teaching Lab Manuals can be found here.