Chapter 27, Problem 64IAE

Interpretation Introduction

(a)

Interpretation:

The principal product formed when $\text{but-1-ene}$ undergoes reaction with $\text{dil}{\text{.H}}_{\text{2}}{\text{SO}}_4$ should be predicted and written.

Concept introduction:

The general mechanism of electrophilic addition is as follows:

Step1: Alkene pi electrons abstract a proton from the acid and attack occurs through that carbon that leads to the more stable carbocation.

Step2: Then the nucleophilic part of reagent adds to the carbocation to give the addition product.

These steps can be illustrated as follows:

Interpretation Introduction

(b)

Interpretation:

The principal product formed in the monochlorination of propane should be predicted and written.

Concept introduction:

The reaction between chlorine and propane under ultraviolet light is the monohalogenation reaction. This is essentially a substitution reaction. Every possible monochlorinated products are formed. The major one is the one where chlorine is attached at the terminal carbon.

The principal product in the halogenation of alkanes such as propane is governed by the regioselectivity. It has been found that for chlorination of alkanes, tertiary alkanes are more reactive than secondary which in turn are more reactive than primary.

Interpretation Introduction

(c)

Interpretation:

The principal product when isopropyl alcohol is heated with benzoic acid should be predicted and written.

Concept introduction:

Heating alcohol and acid involve esterification reaction and an ester is formed along with the release of a water molecule.

The reaction can be illustrated as:

Where ${\text{R}}^{\text{'}}$ and ${\text{R}}^{\text{'}\text{'}}$ indicate different alkyl groups.

The general mechanistic pathway for esterification as proposed by Fischer is as follows:

Interpretation Introduction

(d)

Interpretation:

The principal product when $\text{butan-2-ol}$ is oxidized in the presence of dichromate ions should be indicated.

Concept introduction:

Oxidation of alcohols can be done with an oxidizing reagent.

Tertiary alcohols cannot be oxidized as they do not have hydrogen; the secondary alcohols are oxidized to ketones and no further oxidation is possible since ketones do not have any hydrogen that can be lost in an oxidation reaction.

While the primary alcohols oxidized to aldehydes as they have two hydrogen atoms. The aldehydes thus formed can again be oxidized to corresponding acids.

The general formula of a tertiary, secondary and primary alcohol is represented as follows: