3.9: Carboxylic Acids and Derivatives

What is the structure of a carboxylic acid? (include general formula and functional group)

• C_nH_2n+1COOH

• COOH

What is the structure of an ester?

• COO

What are some properties of carboxylic acids?

• Carboxylic acids with fewer than six carbon atoms per molecule are water-soluble as water molecules can form a H bond with the functional group

• Carboxylic acids are weak acids but will still free CO₂ from carbonates

How are esters produced? 

• Condensation reaction between an alcohol and carboxylic acid

• Presence of a concentrated strong acid catalyst

What are the uses of esters?

• Solvents

• Plasticisers

• Perfumes

• Food flavourings

What is the structure and IUPAC name for glycerol?

propane-1,2,3-triol

What are the naturally occuring esters of glycerol used for?

• Vegetable oils

• Animal fats

What is the result of hydrolysing an ester in acidic conditions?

• Reforms carboxylic acid and ester

• Reversible reaction

What is the result of hydrolysing an ester in alkaline conditions?

• Heated under reflux with dilute alkali

• Forms carboxylate salt and alcohol

• Sodium carboxylate requires further acidification to turn into a carboxylic acid

• Irreversible reaction

How is soap produced and what is the name of the process?

• Hydrolysis of vegetable oils and animal fats in alkaline conditions with aqueous NaOH

• Saponification

What is the structure of soap

Carboxylate salts of long-chain carboxylic acids, known as fatty acids

What is biodiesel made from and how is it produced?

• Mixture of natural methyl esters of long-chain carboxylic acids

• Produced using transerification

• Vegetable oils reacted with methanol in the presence of a catalyst (NaOH)

What is the structure of an acid anhydride?

What is the structure of an acyl chloride?

What is the structure of an amide?

What is the name of the mechanism of water, alcohols/ammonia/primary amines with acyl chlorides/acid anhydrides?

Nucleophilic addition-elimination

Why is ethanoic anhydride used over ethanoyl chloride in the manufacture of the drug aspirin?

• Cheaper to produce

• Less reactive so reactions can be more easily controlled

• The by-product for acid anhydrides is the less corrosive carboxylic acid compared to hydrogen chloride for acyl chlorides