Carboxylic Acids

Why are carboxylic acids soluble?

What happens to their solubility as chain length increases?

• Polar C=O + O-H bonds

• Form H bonds with water

• As chain length increases solubility decreases as non-polar C has greater affect on overall polarity

Reaction of carboxylic acid with metals

example of propanoic acid and magnesium

• Hydrogen gas + carboxylate salt

• 2CH3CH2COOH + MG —> (CH3CH2COO-)Mg2+ + H2

Reaction of carboxylic acids with metal oxides

Example using ethanoic acid and calcium oxide

• Forms salt and water

• 2CH3COOH + CaO —> (CH3COO)2-Ca2+ + H2O

Reaction of carboxylic acids with alkali

Example using ethanoic acid and sodium hydroxide

• Forms salt and water

• CH3COOH + NaOH —> CH3COO-NA+ + H2O

Reaction of carboxylic acids with carbonates

Example with ethanoic acid and sodium carbonate

• Forms salt, water and CO2

• 2CH3CHOOH + NaCO3 —> 2CH3COO-Na+ + CO2 + H2O

Describe esterification of carboxylic acids

Example using propanoic acid + ethanol

• Happens when carboxylic acids react with alcohols in presence of concentrated H2SO4

• produces ester + water

Describe alkaline hydrolysis of esters

Example using methyl enthanoate

• Esters heated under reflux with aqeous OH- ions to form carboxylate ion and alcohol

• CH3COOCH3 + NaOH- —> CH3COO-Na+ + CH3OH

Acid hydrolysis of esters

forms alcohol + carboxylic acids

What is rhe acyl chloride functional group?

COCl

Reaction of acyl chlorides with alcohols

using ethanoyl chloride + propan-1-ol as exmaple

• form esters + HCl

• CH3COCl + CH3CH2CH2OH  —> CH3COOCH2CH2CH3 + HCl

reaction of acyl chloride + phenol

forms ester + HCl

Why do acyl chlorides react with ammonia or amines and what do they make?

• N on ammonia/amines acts as nucleophile and donates lone pair of electron to electron-deficient species

• forms primary amides