Question

Identify this compound (label all major functional groups on IR spectra).

SAMPLE 100- % TRANSMITTANCE 4000 1000 3500 3000 2000 1500 2500 WAVENUMBERS 600.1

Answer 1

Solution:

A- The band in the region 3050-3020 cm-1 exhibit aromatic C-H stretching vibration.

SAMPLE 100- % TRANSMITTANCE 4000 3500 3000 2000 1500 1000 2500 WAVENUMBERS 600.1

B- The bands observed around at 2920 and 2880 cm-1 represent assymmetric and symmetric C-H stretching vibrations respectively of the methyl group.

C- The bands in the region 2000-1600 cm-1 indicates aromatic overtones or combination bands, which represents the presence of 1,4-disubstituted benzene.

D- The bands at 1510 and 1460 cm-1 reveals the presence of C=C ring stretching vibration.

E- The bands occurs at 1100, 1045 and 1020 cm-1 corresponds to In-plane C-H bending vibration of aromatic ring.

F- The intense band at 805 cm-1 indicates C-H out of plane bending vibrations of p-disubstituted benzene ring.

Based on the above IR spectral values, the spectrum of compound is p-xylene (1,4-dimethylbenzene).