Chapter 17, Problem 17.20P

(a)

Interpretation Introduction

Interpretation:

Show how to prepare pentanoic acid from 1-Pentanol.

Concept introduction:

Carboxylic acid can be prepared from various ways; oxidation of aldehyde is one of the important methods to prepare carboxylic acid.

Carboxylic acid on further oxidation removes the carboxyl carbon as carbon dioxide.

Depending on the reaction conditions, the oxidation state of the remaining organic structure may be higher, lower or unchanged.

Carboxylic acid can be prepared from primary alcohol by oxidation using strong oxidizing agents like chromic acid, $K_{2}C{r}_2{O}_7$

$\text{Primary}\text{alcohol}\stackrel{Oxidation}{\to }\text{Aldehyde}\stackrel{Oxidation}{\to }\text{Carboxylic}\text{acid}$

(b)

Interpretation Introduction

Interpretation:

Show how to prepare pentanoic acid from Pentanal.

Concept introduction:

Carboxylic acid can be prepared from various ways; oxidation of aldehyde is one of the important methods to prepare carboxylic acid.

Aldehyde and ketones are one such an important group in the organic compounds. Both of these compounds contain carbonyl group $\text{C=O}$.

In aldehyde $\text{C=O}$ attach with hydrogen and R. $\left(R-CHO\right)$

In ketone $\text{C=O}$ attach with two R groups, they can be represented as $R-CO-R^{\text{'}}$

Aldehyde readily undergoes oxidation to carboxylic acids.

Tollens’ reagent is an ammoniac silver nitrate solution which can be used to detect the presence of aldehyde in an unknown compound.

As the oxidation of the aldehyde proceeds by Tollens’ reagent, silver metal is deposited on the walls of the reaction flask as a shiny mirror.

The reaction can be represented as follows,

$RCHO+\underset{Tollens\text{'}reagent}{2Ag{\left(N{H}_3\right)}_2^{+}}+2O{H}^{-}\to RCO{O}^{-}+N{H}_4^{+}+2Ag+3N{H}_3+H_{2}O$

(c)

Interpretation Introduction

Interpretation:

Show how to prepare pentanoic acid from 1-Pentene.

Concept introduction:

Carboxylic acid can be prepared from various ways; oxidation of aldehyde is one of the important methods to prepare carboxylic acid.

Aldehyde and ketones are one such an important group in the organic compounds. Both of these compounds contain carbonyl group $\text{C=O}$.

In aldehyde $\text{C=O}$ attach with hydrogen and R. $\left(R-CHO\right)$

In ketone $\text{C=O}$ attach with two R groups, they can be represented as $R-CO-R^{\text{'}}$

Carboxylic acid can be prepared from primary alcohol by oxidation using strong oxidizing agents like chromic acid, $K_{2}C{r}_2{O}_7$

$\text{Primary}\text{alcohol}\stackrel{Oxidation}{\to }\text{Aldehyde}\stackrel{Oxidation}{\to }\text{Carboxylic}\text{acid}$

 Alkenes on acid catalyzed hydration will give alcohol.

(d)

Interpretation Introduction

Interpretation:

Show how to prepare pentanoic acid from 1-Butanol.

Concept introduction:

Alkyl or aryl magnesium halides (RMgX) are known as Grignard reagent. The Grignard reaction is an organometallic chemical reaction in which the Grignard reagent act as nucleophile and attack electrophilic carbon atom that are present within polar bonds to yield a carbon-carbon bond.

Synthesis of Grignard reagent is shown below,

$\underset{Alkyl/arylhalide}{R-X}+Mg\stackrel{Ether}{\to }\underset{Grignardreagent}{RMgX}$

The alkyl halide can be prepared from alcohol through different methods, preparing alkyl halide using halogens is one of the important methods and it is shown below,

$R-H+B{r}_2\stackrel{hv}{\to }R-Br+HBr$

Addition of a Grignard reagent to carbon dioxide followed by protonation will produce carboxylic acid.

(e)

Interpretation Introduction

Interpretation:

Show how to prepare pentanoic acid from 1-Bromopropane.

Concept introduction:

Alkyl or aryl magnesium halides (RMgX) are known as Grignard reagent. The Grignard reaction is an organometallic chemical reaction in which the Grignard reagent act as nucleophile and attack electrophilic carbon atom that are present within polar bonds to yield a carbon-carbon bond.

Synthesis of Grignard reagent is shown below,

$\underset{Alkyl/arylhalide}{R-X}+Mg\stackrel{Ether}{\to }\underset{Grignardreagent}{RMgX}$

The alkyl halide can be prepared from alcohol through different methods, preparing alkyl halide using halogens is one of the important methods and it is shown below,

$R-H+B{r}_2\stackrel{hv}{\to }R-Br+HBr$

Addition of a Grignard reagent to carbon dioxide followed by protonation will produce carboxylic acid.

(f)

Interpretation Introduction

Interpretation:

Show how to prepare pentanoic acid from 1-Hexene.

Concept introduction:

Carboxylic acid can be prepared from various ways; oxidation of aldehyde is one of the important methods to prepare carboxylic acid.

Aldehyde and ketones are one such an important group in the organic compounds. Both of these compounds contain carbonyl group $\text{C=O}$.

In aldehyde $\text{C=O}$ attach with hydrogen and R. $\left(R-CHO\right)$

In ketone $\text{C=O}$ attach with two R groups, they can be represented as $R-CO-R^{\text{'}}$

The reaction of alkenes with ozone to form an ozonide, followed by hydrolysis of the ozonide to produce aldehyde and or ketone is known as ozonolysis.