# 6: Carboxylic Acids and Esters

• 6.1: Prelude to Organic Acids and Bases and Some of Their Derivatives
Organic acids have been known for ages. Prehistoric people likely made acetic acid when their fermentation reactions went awry and produced vinegar instead of wine. The Sumerians (2900–1800 BCE) used vinegar as a condiment, a preservative, an antibiotic, and a detergent.
• 6.2: Carboxylic Acids - Structures and Names
Simple carboxylic acids are best known by common names based on Latin and Greek words that describe their source (e.g., formic acid, Latin formica, meaning “ant”). Greek letters, not numbers, designate the position of substituted acids in the common naming convention. IUPAC names are derived from the LCC of the parent hydrocarbon with the -e ending of the parent alkane replaced by the suffix -oic and the word acid.
• 6.3: The Formation of Carboxylic Acids
Whether in the laboratory or in the body, the oxidation of aldehydes or primary alcohols forms carboxylic acids.
• 6.4: Physical Properties of Carboxylic Acids
Carboxylic acids have high boiling points compared to other substances of comparable molar mass. Boiling points increase with molar mass. Carboxylic acids having one to four carbon atoms are completely miscible with water. Solubility decreases with molar mass.
• 6.5: Chemical Properties of Carboxylic Acids- Ionization and Neutralization
Soluble carboxylic acids are weak acids in aqueous solutions. Carboxylic acids neutralize bases to form salts.
• 6.6: Esters - Structures and Names
An ester has an OR group attached to the carbon atom of a carbonyl group.
• 6.7: Physical Properties of Esters
Esters have polar bonds but do not engage in hydrogen bonding and are therefore intermediate in boiling points between the nonpolar alkanes and the alcohols, which engage in hydrogen bonding. Ester molecules can engage in hydrogen bonding with water, so esters of low molar mass are therefore somewhat soluble in water.
• 6.8: Preparation of Esters
Esters are made by the reaction of a carboxylic acid with an alcohol, a process that is called esterification.
• 6.9: Hydrolysis of Esters
Hydrolysis is a most important reaction of esters. Acidic hydrolysis of an ester gives a carboxylic acid and an alcohol. Basic hydrolysis of an ester gives a carboxylate salt and an alcohol.
• 6.10: Esters of Phosphoric Acid
Inorganic acids such as $$H_3PO_4$$ form esters. The esters of phosphoric acid are especially important in biochemistry.