Question

1. A byproduct of the catalytic transfer hydrogenation is benzene (See Figure 1) Is the reverse process (hydrogenation of benzene) favorable? Why or why not?  

2. ¹H NMR is another spectroscopic method with which the success of this reaction could be determined.

1. If you collected an ¹H NMR spectrum of olive oil, at what chemical shift range (in ppm) would the hydrogens on the carbon-carbon double bonds appear?

2. At what chemical shift range would the hydrogens on the carbon-carbon single bonds appear?

3. Given your answers for A and B above in ¹H NMR, how could you tell by specific peaks (give the shifts) in the ¹³C NMR spectra that olive oil had been hydrogenated?

Answer 1

A) 1H NMR spectrum of olive oil, around 5.3 to 5.4  ppm the hydrogens on the carbon-carbon double bonds appear

B) They appear on wide range as 0.8 , 1.3, 1.6, 2, 2.3, 2.8, 4.2,4.3, and 5.2 ppm. due to different types of hydrogen on differen carbon carbon single bond.

C) After hydrogenation of olive oil peaks at 5.3 to 5.4 ppm disappears as there is no longer carbon double bond.