Chapter 19, Problem 35P

Draw the structure of a wax formed from palmitic acid $\left[{\text{CH}}_{\text{3}}{\left({\text{CH}}_{\text{2}}\right)}_{\text{14}}\text{COOH}\right]$ and each alcohol.

a. ${\text{CH}}_{\text{3}}{\left({\text{CH}}_{\text{2}}\right)}_{\text{21}}\text{OH}$

b. ${\text{CH}}_{\text{3}}{\left({\text{CH}}_{\text{2}}\right)}_{\text{11}}\text{OH}$

C. ${\text{CH}}_{\text{3}}{\left({\text{CH}}_{\text{2}}\right)}_{\text{9}}\text{OH}$

Interpretation Introduction

(a)

Interpretation:

The structure of wax formed by the reaction of ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COOH}$ and ${\text{CH}}_{\text{3}}\text{-(CH}\text{)}{}_{\text{21}}\text{-OH}$ should be drawn.

Concept Introduction:

The general reaction of wax formation of fatty acid and higher alcohols can be written as:

  ${\text{R-CH}}_{\text{2}}{\text{-COOH + HO-CH}}_{\text{2}}\text{-R }\stackrel{}{\to }{\text{R-CH}}_{\text{2}}{\text{-COO-CH}}_{\text{2}}{\text{-R + H}}_{\text{2}}\text{O}$

Answer to Problem 35P

The skeleton formula of wax is ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COO-(CH}\text{)}{}_{\text{21}}{\text{-CH}}_{\text{3}}$.

Explanation of Solution

Fatty acids are long chain carboxylic acids, which consist of two parts; long hydrocarbon chains and polar −COOH group. Waxes are good example of hydrolyzable lipids, which 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 general reaction of wax formation of fatty acid and higher alcohols can be written as:

  ${\text{R-CH}}_{\text{2}}{\text{-COOH + HO-CH}}_{\text{2}}\text{-R }\stackrel{}{\to }{\text{R-CH}}_{\text{2}}{\text{-COO-CH}}_{\text{2}}{\text{-R + H}}_{\text{2}}\text{O}$

Hence, the reaction of ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COOH}$ and ${\text{CH}}_{\text{3}}\text{-(CH}\text{)}{}_{\text{21}}\text{-OH}$ for the formation of wax must be written as:

  ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}{\text{-COOH + CH}}_{\text{3}}\text{-(CH}\text{)}{}_{\text{21}}\text{-OH}\stackrel{}{\to }{\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COO-(CH}\text{)}{}_{\text{21}}{\text{-CH}}_{\text{3}}{\text{ + H}}_{\text{2}}\text{O}$

Interpretation Introduction

(b)

Interpretation:

The structure of wax formed by the reaction of ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COOH}$ and ${\text{CH}}_{\text{3}}\text{-(CH}\text{)}{}_{\text{11}}\text{-OH}$ should be drawn.

Concept Introduction:

The general reaction of wax formation of fatty acid and higher alcohols can be written as:

  ${\text{R-CH}}_{\text{2}}{\text{-COOH + HO-CH}}_{\text{2}}\text{-R }\stackrel{}{\to }{\text{R-CH}}_{\text{2}}{\text{-COO-CH}}_{\text{2}}{\text{-R + H}}_{\text{2}}\text{O}$

Answer to Problem 35P

The skeleton formula of wax is ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COO-(CH}\text{)}{}_{\text{11}}{\text{-CH}}_{\text{3}}$.

Explanation of Solution

Fatty acids are long chain carboxylic acids, which consist of two parts, i.e., long hydrocarbon chains and polar −COOH group. Waxes are good example of hydrolyzable lipids, which 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 general reaction of wax formation of fatty acid and higher alcohols can be written as:

  ${\text{R-CH}}_{\text{2}}{\text{-COOH + HO-CH}}_{\text{2}}\text{-R }\stackrel{}{\to }{\text{R-CH}}_{\text{2}}{\text{-COO-CH}}_{\text{2}}{\text{-R + H}}_{\text{2}}\text{O}$

Hence, the reaction of ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COOH}$ and ${\text{CH}}_{\text{3}}\text{-(CH}\text{)}{}_{\text{11}}\text{-OH}$ for the formation of wax must be written as:

  ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}{\text{-COOH + CH}}_{\text{3}}\text{-(CH}\text{)}{}_{\text{11}}\text{-OH}\stackrel{}{\to }{\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COO-(CH}\text{)}{}_{\text{11}}{\text{-CH}}_{\text{3}}{\text{ + H}}_{\text{2}}\text{O}$

Interpretation Introduction

(c)

Interpretation:

The structure of wax formed by the reaction of ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COOH}$ and ${\text{CH}}_{\text{3}}\text{-(CH}\text{)}{}_{\text{9}}\text{-OH}$ should be drawn.

Concept Introduction:

The general reaction of wax formation of fatty acid and higher alcohols can be written as:

  ${\text{R-CH}}_{\text{2}}{\text{-COOH + HO-CH}}_{\text{2}}\text{-R }\stackrel{}{\to }{\text{R-CH}}_{\text{2}}{\text{-COO-CH}}_{\text{2}}{\text{-R + H}}_{\text{2}}\text{O}$

Answer to Problem 35P

The skeleton formula of wax is ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COO-(CH}\text{)}{}_{\text{9}}{\text{-CH}}_{\text{3}}$.

Explanation of Solution

Fatty acids are long chain carboxylic acids, which consist of two parts, i.e., long hydrocarbon chains and polar −COOH group. Waxes are good example of hydrolyzable lipids, which 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 general reaction of wax formation of fatty acid and higher alcohols can be written as:

  ${\text{R-CH}}_{\text{2}}{\text{-COOH + HO-CH}}_{\text{2}}\text{-R }\stackrel{}{\to }{\text{R-CH}}_{\text{2}}{\text{-COO-CH}}_{\text{2}}{\text{-R + H}}_{\text{2}}\text{O}$

Hence, the reaction of ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COOH}$ and ${\text{CH}}_{\text{3}}\text{-(CH}\text{)}{}_{\text{9}}\text{-OH}$ for the formation of wax must be written as:

  ${\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}{\text{-COOH + CH}}_{\text{3}}\text{-(CH}\text{)}{}_9\text{-OH}\stackrel{}{\to }{\text{CH}}_{\text{3}}\text{-}{(\text{CH})}_{14}\text{-COO-(CH}\text{)}{}_{\text{9}}{\text{-CH}}_{\text{3}}{\text{ + H}}_{\text{2}}\text{O}$