Chapter 7, Problem 7.45P

Interpretation Introduction

Interpretation:

Using the appropriate bond energies, ${\text{ΔH}}_{\text{rxn}}^{\text{0}}$ for the given reaction is to be estimated. The more stable form that is imine or enamine is to be determined.

Concept introduction:

Aldehydes and ketones can exist in two forms, i.e., keto-enol form. In the enol form, the species has a carbon atom that is simultaneously a part of a $\text{C = C}$ bond, characteristic of an alkene and is bonded to OH, characteristic of an alcohol. In the keto form, the hydrogen atom attached to carbon atom that is adjacent to the $\text{C = O}$ group, called alpha hydrogen. In a keto-enol tautomerization, the keto form is in equilibrium with its enol form via proton transfer steps. The imines can also exhibit this type of tautomerization. By calculating the energy of the molecule or the enthalpy of the reaction using bond energies, the stability of particular form (keto or enol) can be determined. The molecule having more enthalpy of reaction is more stable.