Chapter 19, Problem 37P

What hydrolysis products are formed when each wax is treated with aqueous sulfuric acid?

a. ${\text{CH}}_{\text{3}}{\left({\text{CH}}_{\text{2}}\right)}_{\text{16}}\text{COO}{\left({\text{CH}}_{\text{2}}\right)}_{\text{17}}{\text{CH}}_{\text{3}}$

b. ${\text{CH}}_{\text{3}}{\left({\text{CH}}_{\text{2}}\right)}_{\text{12}}\text{COO}{\left({\text{CH}}_{\text{2}}\right)}_{\text{25}}{\text{CH}}_{\text{3}}$

C. ${\text{CH}}_{\text{3}}{\left({\text{CH}}_{\text{2}}\right)}_{\text{14}}\text{COO}{\left({\text{CH}}_{\text{2}}\right)}_{\text{27}}{\text{CH}}_{\text{3}}$

Interpretation Introduction

(a)

Interpretation:

The hydrolysis products which are formed when ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{16}\text{-COO-(CH}\text{)}{}_{\text{17}}{\text{-CH}}_{\text{3}}$ wax is treated with aqueous sulfuric acid should be determined.

Concept Introduction:

The general reaction of hydrolysis of wax with aqueous sulfuric acid can be written as:

  ${\text{R-CH}}_{\text{2}}{\text{-COO-CH}}_{\text{2}}\text{-R }\stackrel{{\text{H}}_{\text{2}}{\text{SO}}_{\text{4(aq}}{}_{\text{)}}}{\to }{\text{R-CH}}_{\text{2}}{\text{-COOH + HO-CH}}_{\text{2}}\text{-R }$

Answer to Problem 37P

The hydrolysis products which are formed when ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{16}\text{-COO-(CH}\text{)}{}_{\text{17}}{\text{-CH}}_{\text{3}}$ wax is treated with aqueous sulfuric acid are ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{16}\text{-COOH}$ and ${\text{CH}}_{\text{3}}\text{-(CH}\text{)}{}_{\text{17}}\text{-OH}$.

Explanation of Solution

Waxes are composed of fatty acid and higher alcohols. They have an ester functional group which is formed between $\text{–COOH and –OH}$ functional group of the fatty acid and alcohols respectively. The hydrolysis of wax molecule leads to the formation of respective fatty acid and alcohol molecules.

The general reaction of hydrolysis of wax with aqueous sulfuric acid can be written as:

  ${\text{R-CH}}_{\text{2}}{\text{-COO-CH}}_{\text{2}}\text{-R }\stackrel{{\text{H}}_{\text{2}}{\text{SO}}_{\text{4(aq}}{}_{\text{)}}}{\to }{\text{R-CH}}_{\text{2}}{\text{-COOH + HO-CH}}_{\text{2}}\text{-R }$

The hydrolysis reaction of wax ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{16}\text{-COO-(CH}\text{)}{}_{\text{17}}{\text{-CH}}_{\text{3}}$ with aqueous sulfuric acid can be written as:

  ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{16}\text{-COO-(CH}\text{)}{}_{\text{17}}{\text{-CH}}_{\text{3}}\stackrel{{\text{H}}_{\text{2}}{\text{SO}}_{\text{4(aq}}{}_{\text{)}}}{\to }{\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{16}{\text{-COOH + CH}}_{\text{3}}\text{-(CH}\text{)}{}_{\text{17}}\text{-OH }$

Interpretation Introduction

(b)

Interpretation:

The hydrolysis products which are formed when ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{12}\text{-COO-(CH}\text{)}{}_{25}{\text{-CH}}_{\text{3}}$ wax is treated with aqueous sulfuric acid should be determined.

Concept Introduction:

The general reaction of hydrolysis of wax with aqueous sulfuric acid can be written as:

  ${\text{R-CH}}_{\text{2}}{\text{-COO-CH}}_{\text{2}}\text{-R }\stackrel{{\text{H}}_{\text{2}}{\text{SO}}_{\text{4(aq}}{}_{\text{)}}}{\to }{\text{R-CH}}_{\text{2}}{\text{-COOH + HO-CH}}_{\text{2}}\text{-R }$

Answer to Problem 37P

The hydrolysis products which are formed when ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{12}\text{-COO-(CH}\text{)}{}_{25}{\text{-CH}}_{\text{3}}$ wax is treated with aqueous sulfuric acid are ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{12}\text{-COOH}$ and ${\text{CH}}_{\text{3}}\text{-(CH}\text{)}{}_{\text{25}}\text{-OH}$.

Explanation of Solution

Waxes are composed of fatty acid and higher alcohols. They have an ester functional group which is formed between $\text{–COOH and –OH}$ functional group of the fatty acid and alcohols respectively. The hydrolysis of wax molecule leads to the formation of respective fatty acid and alcohol molecules.

The general reaction of hydrolysis of wax with aqueous sulfuric acid can be written as:

  ${\text{R-CH}}_{\text{2}}{\text{-COO-CH}}_{\text{2}}\text{-R }\stackrel{{\text{H}}_{\text{2}}{\text{SO}}_{\text{4(aq}}{}_{\text{)}}}{\to }{\text{R-CH}}_{\text{2}}{\text{-COOH + HO-CH}}_{\text{2}}\text{-R }$

The hydrolysis reaction of wax ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{12}\text{-COO-(CH}\text{)}{}_{25}{\text{-CH}}_{\text{3}}$ with aqueous sulfuric acid can be written as:

  ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{12}\text{-COO-(CH}\text{)}{}_{25}{\text{-CH}}_{\text{3}}\stackrel{{\text{H}}_{\text{2}}{\text{SO}}_{\text{4(aq}}{}_{\text{)}}}{\to }{\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{12}{\text{-COOH + CH}}_{\text{3}}\text{-(CH}\text{)}{}_{\text{25}}\text{-OH }$

Interpretation Introduction

(c)

Interpretation:

The hydrolysis products which are formed when ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COO-(CH}\text{)}{}_{27}{\text{-CH}}_{\text{3}}$ wax is treated with aqueous sulfuric acid should be determined.

Concept Introduction:

The general reaction of hydrolysis of wax with aqueous sulfuric acid can be written as:

  ${\text{R-CH}}_{\text{2}}{\text{-COO-CH}}_{\text{2}}\text{-R }\stackrel{{\text{H}}_{\text{2}}{\text{SO}}_{\text{4(aq}}{}_{\text{)}}}{\to }{\text{R-CH}}_{\text{2}}{\text{-COOH + HO-CH}}_{\text{2}}\text{-R }$

Answer to Problem 37P

The hydrolysis products which are formed when ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COO-(CH}\text{)}{}_{27}{\text{-CH}}_{\text{3}}$ wax is treated with aqueous sulfuric acid are ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COOH}$ and ${\text{CH}}_{\text{3}}\text{-(CH}\text{)}{}_{\text{27}}\text{-OH}$.

Explanation of Solution

Waxes are composed of fatty acid and higher alcohols. They have an ester functional group which is formed between $\text{–COOH and –OH}$ functional group of the fatty acid and alcohols respectively. The hydrolysis of wax molecule leads to the formation of respective fatty acid and alcohol molecules.

The general reaction of hydrolysis of wax with aqueous sulfuric acid can be written as:

  ${\text{R-CH}}_{\text{2}}{\text{-COO-CH}}_{\text{2}}\text{-R }\stackrel{{\text{H}}_{\text{2}}{\text{SO}}_{\text{4(aq}}{}_{\text{)}}}{\to }{\text{R-CH}}_{\text{2}}{\text{-COOH + HO-CH}}_{\text{2}}\text{-R }$

The hydrolysis reaction of wax ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COO-(CH}\text{)}{}_{27}{\text{-CH}}_{\text{3}}$ with aqueous sulfuric acid can be written as:

  ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COO-(CH}\text{)}{}_{27}{\text{-CH}}_{\text{3}}\stackrel{{\text{H}}_{\text{2}}{\text{SO}}_{\text{4(aq}}{}_{\text{)}}}{\to }{\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}{\text{-COOH + CH}}_{\text{3}}\text{-(CH}\text{)}{}_{\text{27}}\text{-OH }$