1. Carboxylic Acids and Derivatives Milbank High School

2. Learning Objectives/Study Questions 1.What is the general structure for a carboxylic acid? An ester? An amide? What is the functional group for each of these classes of organic molecules? 2.How are the common names of carboxylic acids, esters, and amides determined? How are these compounds named using IUPAC nomenclature? 3.Why are the boiling points of carboxylic acids higher than those of alcohols of similar molar mass? How do the boiling points of esters and amides compare with alcohols of similar molar mass?

3. Learning Objectives/Study Questions 4.How do the solubilities of carboxylic acids, esters, and amides of five carbons or less compare to the solubilities of comparable alkanes and alcohols in water? 5.How are carboxylic acids, esters, and amides prepared? 6.What typical reactions take place with carboxylic acids, esters, and amides? 7.What are some common carboxylic acids and esters and their uses? 8.What are phosphate esters? Why are they important?

4. Carboxylic Acids: The Functional Groups Carboxyl group  Combo of the carbonyl and hydroxyl groups

5. Amides/Esters: Derivatives of carboxylic acids Amides  Functional group has a nitrogen instead of an oxygen attached to the carbonyl group Esters  Like an ether and carboxylic acid

6. Common Carboxylic Acids: Structures and Names Formic acid (methanoic acid)  Ants Acetic acid (ethanoic acid)  Vinegar  Weak acid Propionic acid Butyric Acid (butanoic acid)  Rancid butter  Found in body odor

7. Benzoic Acid/Dicarboxylic acids Benzoic Acid Dicarboxylic acids  Table 16.3  Two carboxylic groups

8. Preparation of Carboxylic Acids Final oxidation products of aldehydes and/or primary alcohols Our body oxidize alcohols to acids Liver converts ethanol to acetic acid

9. Physical Properties of Carboxylic Acids Colorless liquids with disagreeable odors  Caproic acid Produced by skin bacteria Body odor, locker room smell High melting points Boiling points increase with the number of carbons 1-4 carbons: soluble in water

10. Physical Properties of Carboxylic Acids Sometimes carboxylic acids produce dimers Changes physical properties  Lower freezing points and other properties

11. Neutralization All carboxylic acids react with NaOH, KOH and other strong bases to form water- soluble salts RCOOH + NaOH(aq)  RCOO - Na + (aq) + H 2 O RCOOH + NaHCO 3 (aq)  RCOO-Na(aq) + H 2 O + CO 2 (g)

12. Esters Derivatives of carboxylic acids Widely found in nature Pleasant odors  Fruits and flowers -ic ending replaced by -ate

13. Physical Properties Boiling point: about same as those of ketones 3-5 carbons borderline for solubility (again) Uses:  Solvents (nail-polish remover)

14. Preparation of Esters: Esterification Prepared by treating carboxylic acids with an alcohol in the presence of HCl or H 2 SO 4

15. Hydrolysis Alkoxy group (-OR’) replaced by another group Basically the reverse of esterification

16. Saponification Base is used to hydrolyze an ester

17. Amides Nitrogen atom attached to a carbonyl atom Naming:  -ic or –oic replaced by –amide

18. Amides Naming Con’t  Name substituent attached to nitrogen  Indicate with N

19. Physical Properties of Amides Most are solids Colorless, odorless Soluble to about 5-6 carbons Very high boiling points  Polar nature of amide group  Formation of hydrogen bonds

20. Synthesis of Amides Addition of ammonia to a carboxylic acid

21. Hydrolysis of Amides Amide + water = carboxylic acid Can be basic or acidic