Chapter 2, Problem 75IP

Interpretation Introduction

Signals that confirms the complete hydrolysis of the acetate groups has to be described.

Concept introduction:

IR spectroscopy is the study of absorption of infrared radiation, which causes vibrational transition in a molecule.

Principle of IR spectroscopy

• Molecules are made up of atoms linked by chemical bonds. The movement of atoms is like spring and balls (vibration).
• This characteristic vibration is called natural frequency of vibration.

$C=O$ bond stretch appear in the range $1750-1735c{m}^{-1}$ for normal aliphatic ester.

Conjugation of $C=O$ stretch with phenyl will appears in the range $1740-1715c{m}^{-1}$.

$O-H$ stretching signal is broad, at $3400-3300c{m}^{-1}$