SCH4U Date:______
Carboxylic Acids
Carboxylic Acids
· An organic compound, containing a carboxyl group.
· A carboxyl group is a functional group consisting of a hydroxyl group (-OH) attached to the carbon atom of a carbonyl group (-C=O).
· A carboxyl group is often written in its condensed form (-COOH)
Naming Carboxylic Acids
· Take the name of the alkane or alkene with the same number of carbon atoms as the longest chain in the acid.
· Remove the “e” and add –oic acid.
· For example, an acid with one carbon is methanoic acid, with two carbons is ethanoic acid and so on.
· Many of these acids have common names
o Methanoic acid is also know as formic acid
o Ethanoic acid is also know as acetic acid or vinegar
Properties of Carboxylic Acids
· Turns litmus paper red.
· React in neutralization reactions with bases
· Carboxyl groups make these molecules polar and capable of forming hydrogen bonds with water. This also accounts for their high boiling points.
· Smaller acids are water soluble. Acids with hydrocarbon chains larger then four are relatively insoluble in water.
Reactions of Carboxylic Acids
· Aldehydes are oxidized to produce carboxylic acids.
Esters
Esters:
· an organic compound that contains a carbonyl group bonded to an oxygen atom.
· responsible for the many odours of fruits and flowers
· synthetic esters are often added to cosmetics and perfumes
Esterfication:
· Esters are formed from a condensation reaction between and acid and an alcohol forming the ester and water.
· This is a condensation reaction because water is formed.
· It is also a neutralization reaction because the acid reacts with a base (the alcohol) to form water.
· An acid catalyst and heat are generally required for the reaction to proceed.
· The reverse reaction splits an ester into an acid and alcohol. Seeing as this reaction requires water it is called a hydrolysis reaction.
Naming Esters
1. The first part comes from the alcohol
2. The second part comes form the carboxylic acid and the ending of the acid is changed from -oic acid to –oate.
For example the reaction of ethanol and butanoic acid forms the ester ethyl butanoate.
Name the following esters:
a. CH3CH2CH2COOCH2CH2CH2CH2CH3 / b.Draw the structural reaction equation for the reaction of butanoic acid and ethanol
Reaction and Properties of Esters:
· Esters contain a carbonyl group, but no carboxyl group like a carboxylic acid.
· Therefore intermolecular forces are weaker in esters, yielding lower boiling points and decreased solubility in water when compared to carboxylic acids.
· Esters are not acidic, unlike carboxylic acids.