University:
Eastern Kentucky University
Course:
CHE 361 | Organic Chemistry I
Academic year:

2020
Views:

282

Pages:

1
Author:

blakestar2o1o

Organic Chemistry 8: Carboxylic Acid Description and Properties Carboxylic acids contain a carbonyl and a hydroxyl group connected to the same carbon. They are always terminal groups. Nomenclature: Suffix –oic acid. Salts are named with the suffix –oate, and dicarboxylic acids are –dioic acids Physical Carboxylic acids are polar and hydrogen bond well, Properties: resulting in high BP. They often exist as dimers in solution. Acidity: The acidity of a carb acid is enhanced by the resonance between its oxygen atoms. The acidity can be further enhanced by substituents that are electron-withdrawing, and decreased by substituents that are electron-donating b-dicarboxylic Like other 1,3-dicarbonyl compounds, they have an aAcids: hydrogen that is also highly acidic a-proton is the most acidic due to resonance Carboxylic Acid Synthesis via Oxidation Reactions of Carboxylic Acids Oxidation: Carboxylic acids can be made by the oxidation of 1° alcohols or aldehydes or the oxidation of 1° or 2° alkyl groups using an oxidizing agent like KMnO4, Na2Cr2O7, K2Cr2O7, or CrO3. Nucleophilic Acyl A common reaction in carboxylic acids. Nucleophile Substitution: attacks the electrophilic carbonyl carbon, opening the carbonyl and forming a tetrahedral intermediate. The carbonyl reforms, kicking off the L.G. Nucleophiles: Ammonia / Amine: Forms an amide. Amides are given the suffix –amide. Cyclic amides are called lactams. Alcohol: Forms an ester. Esters are given the suffix – oate. Cyclic esters are called lactones. Carboxylic Acid: Forms an anhydride. Both linear and cyclic anhydrides are given the suffix anyhydride. Reduction: Carboxylic acids can be reduced to a 1° alcohol with a strong reducing agent like LiAlH4. Aldehyde intermediates are formed, but are also reduced to 1° alcohols. NaBH4 is not strong enough to reduce a carboxylic acid Decarboxylation: b-dicarboxylic acids and other b-keto acids can undergo spontaneous decarboxylation when heated, losing a carbon as CO2. This reaction proceeds via a six-membered cyclic intermediate Saponification: Mixing long-chain carboxylic acids (fatty acids) with a strong base results in the formation of a salt we call soap. Soaps contain a hydrophilic carboxylate head and hydrophobic alkyl chain tail. They organize in hydrophilic environments to form micelles. A micelle dissolves nonpolar organic molecules in its interior, and can be solvated with water due to its exterior shell of hydrophilic groups. Reduction of Carboxylic Acid Yields a 1° Alcohol Micelle: Polar heads, non-polar tails. The non-polar tails dissolve non-polar molecules such as grease Amide Synthesis Nucleophilic Acyl Substitution Anhydride Synthesis Acid Halide Synthesis Ester Synthesis