Ethyl acetate is highlighted as a common solvent found in fingernail polish, plastics, and lacquers.
Learning Objective:
Describe the boiling points and solubility of esters.
Draw condensed structural and line-angle formulas for products from acid and base hydrolysis.
Esters exhibit:
Higher boiling points than alkanes and ethers.
Lower boiling points than alcohols and carboxylic acids of similar molecular weight.
Unlike alcohols, esters lack hydroxyl groups, which prevents them from forming hydrogen bonds with themselves, impacting their boiling points.
Esters are soluble in water if they contain 2 to 5 carbon atoms.
As the carbon chain length exceeds five, solubility decreases.
The carbonyl group's partially negative oxygen can form hydrogen bonds with water's partially positive hydrogen atoms, contributing to solubility.
In acid hydrolysis, the following occurs:
An ester reacts with water to create:
A carboxylic acid.
An alcohol.
A water molecule donates a group, converting the carbonyl functional group into a carboxyl group.
Requires an acid catalyst and heat for the reaction to proceed.
Aspirin, when stored for extended periods, can undergo hydrolysis when exposed to water and heat, exemplifying the concept of ester hydrolysis in practical applications.
Base hydrolysis, or saponification:
Involves the reaction of an ester with a strong base (e.g., NaOH) in heat.
Produces:
A carboxylate salt.
An alcohol.
Ethyl acetate is used as a solvent in multiple products.
Task: Write the balanced chemical equation for hydrolysis of ethyl acetate with NaOH.
Given: Ethyl acetate, NaOH
Need: Base hydrolysis equation.
Expected products: Carboxylate ion and alcohol.
Reiteration of the task and the components involved in writing the balanced equation for the hydrolysis of ethyl acetate with NaOH focusing on the same details as the Learning Check.
Task: Write the balanced equations for the reactions of methyl acetate:
A: With water, heat, and an acid catalyst.
B: With KOH and heat.
Similar task as above, requesting balanced equations for the reactions of methyl acetate in two separate conditions.
Carboxyl Group:
Esters can form hydrogen bonds and are soluble in water when containing up to 5 carbon atoms.
Relationship Overview:
Carboxylic acids and esters are connected through hydrolysis and saponification reactions, revealing the transformative nature of these compounds.
Carboxylic acids can dissolve in strong bases to form carboxylate salts and dissociate as weak acids, while esters are products of these reactions.