Question

A student monitored the reaction progress of the reduction of 4-Nitrobenzaldehyde to 4-Nitrobenzyl alcohol using TLC. 30% ethyl acetate in petroleum ether was used as the elution solvent. TLC plates available in the laboratory were coated with the common absorbent silica gel (SiO₂.xH₂O) which contains polar hydroxyl (OH^-) groups.

t solvent front || 0 SM - Staring material CP1 - Crude Product 1 CP2 - Crude Product 2 -- -- -- -- - --- SM CP1 CP2 X = 1.8 cm, y=3.4 cm, z= 5.7 cm

1. c. The crude product moves slower than the starting material with the mobile

phase in the TLC plate. Briefly explain a possible reason for the

observation based on the chemical structures of the two compounds.

(Hint: consider the intermolecular interactions)

1. d. If the student decided to switch the TLC elution solvent to 100%

ethyl acetate, sketch the view of developed TLC plate you would

expect to observe.

Answer 1

C. 1.4. Nitrobe Nitrobenzyl alcohol is a polar molecule and always remains below the starting materia MONO cil Ell intramolecular hydrogen bond affect Ro ralue ? stacting material a=N&... HTO d. It TLC runs in 1001 ELOAC the picture will be different as increase in polarity both snoeting material and Crude product runs with sowent front. Scanned with CamScanner SM LP (p