CHAPTER 14: Unit 1. Definition
Opening Essay
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. Citric acid was discovered by an Islamic alchemist, Jabir Ibn Hayyan (also known as Geber), in the 8th century, and crystalline citric acid was first isolated from lemon juice in 1784 by the Swedish chemist Carl Wilhelm Scheele. Medieval scholars in Europe were aware that the crisp, tart flavor of citrus fruits is caused by citric acid. Naturalists of the 17th century knew that the sting of a red ant’s bite was due to an organic acid that the ant injected into the wound. The acetic acid of vinegar, the formic acid of red ants, and the citric acid of fruits all belong to the same family of compounds—carboxylic acids. Soaps are salts of long-chain carboxylic acids.
| Pickles and lemons have sour taste because of the presence of organic acid called citric acid. |
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| DefinitionLearning ObjectivesIdentify the general structure for a carboxylic acid, an ester, an amine, and an amide.Identify the functional group for a carboxylic acid, an ester, an amine, and an amide.The function al group present in carboxylic acid is the carboxyl group. A carboxyl group is composed on a hydroxyl group bonded to a carbonyl carbon atom. Thus, it contains two oxygen atoms directly bonded to the same carbon atom. |
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 Propanoic Acid |
Carboxylic Acid derivatives: Four important families of Carboxylic acid derivatives are esters, acid chlorides and acid anhydrides and amides. The group attached to the carbonyl carbon distinguishes these derivatives from each other and also from carboxylic acids.
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| Examples: Acyl Chloride and Acetic Anhydride |
 Acetic Anhydride |
 Acyl chloride |