EXERCISES
EXERCISE 1
EXERCISE 2
EXERCISE 3
A compound with molecular formula C3H6O2 gives the following peaks in its proton
nmr spectrum:
Chemical shift
Splitting
1.1
2.2
11.8
Triplet
Quartet
Singlet
Integration
factor
3
2
1
Identify the molecule and account for the chemical shifts, splitting and
integration factors of all three peaks.
EXERCISE 4
A compound with molecular formula C5H10O2 gives the following peaks in its proton
nmr spectrum:
a)
Chemical shift
Splitting
1.2
1.3
2.3
4.1
Triplet
Triplet
Quartet
Quartet
Integration
factor
3
3
2
2
Identify the molecule and account for the chemical shifts
EXERCISE 5– Combined spectral analysis
A compound containing 58.8% carbon, 9.8% hydrogen and 31.4% oxygen is subjected
to mass spectrometry and found to give intense peaks at m/z = 43 and m/z =
57, in addition to a molecular ion peak at m/z = 102.
Infra-red analysis of the molecule showed a sharp peak at m/z = 1710 cm-1.
A proton nmr spectrum of the molecule yielded the following peaks:
Chemical shift
Splitting
0.8
1.1
2.3
3.7
Triplet
Sextet
Triplet
Singlet
Integration
factor
3
2
2
3
Deduce the structure of the molecule and account for the formation of all the
peaks the spectra.
EXERCISE 6
The two spectra below are of phenol and benzaldehyde. Assign them.
EXERCISE 7
For each spectrum below, chose between the alternative compounds. Give your reasons.
EXERCISE 8
The spectra below are of acetone, 1,2-dichloroethane, 1,1,2-trichloroethane, 2,2dimethoxypropane, 1- bromopropane and 2-bromopropane. Assign them.
EXERCISE 9
Assign the following spectra to one of the compounds listed: 1,4-dimethylbenzene, 1,4dimethoxybenzene, phenylethyne, 3-methyl-3-hydroxy-1-butyne, 2-bromobutane, 1,2dibromo-2-methylpropane.
EXERCISE 10.
Propose plausible structures for the five compounds whose proton NMR spectra are shown:
a) C4H10O2; b) C7H7Br; c) C4H9Br; d) C8H9Br
EXERCISE 11
Compound Z, C9H12, gives a proton NMR spectrum as shown below. Assign a structure.
EXERCISE 12
Two spectra are given below along with their molecular formulas. Propose a structure that
corresponds to each spectrum.
EXERCISE 13.
The integrated 1H NMR spectrum of a compound of formula C4H10O is shown. Propose a
structure consistent with the data.
EXERCISE 14
The compound whose proton NMR spectrum is shown below has the molecular formula
C3H6Br2. Propose a plausible structure.
EXERCISE 15
A compound (C10H12O2), whose spectrum appears below was isolated from a reaction
mixture containing 2-phenylethnaol and acetic acid. Propose a structure for this compound.
EXERCISE 16
The compound whose proton NMR spectrum is shown has the molecular formula
C4H7O2Cl and shows an infrared absorption peak at 1740 cm^-1. Propose a plausible
structure.
EXERCISE 17
A small plant was adding bromine across the double bond of 2-butene to make 2,3dibromobutane. A controller malfunction and allowed the reaction temperature to rise
beyond safe limits. A careful distallation of the product showed that several impurities had
formed, including the one whose NMR is shown below. Determine the structure.
EXERCISE 18
When 2-chloro-2-methylbutane is treated with a variety of strong bases, the products
always seem contain two isomers (A and B) of formula C5H10. When sodium hydroxide is
used as the base isomer B predominates. Determine the structures of A and B and explain
the experimental results.