Chapter 17: Carboxylic Acids
Table of Contents:
Structure
The functional group for carboxylic acid is COOH, also written as CO2H.
Nomenclature
Find the longest continuous carbon chain containing COOH group and number starting from the carbon that contains the functional group.
End the name in "oic acid".
Physical Properties
Carboxylic acids are polar, and have much higher boiling point than alcohols and aldehydes of similar mass. They are capable of hydrogen bonding and are very soluble in water
Acidity
Electron withdrawing groups (EWG) such as halogens make carboxylic acids more acidic.
The more EWG are on the carboxylic acid molecule and the closer they are to the COOH group, the more acidic it is.
Preparation of Carboxylic Acids
Grignard reagent with CO2 produces a carboxylic acid.
Product: Get rid of MgX and attach the carbon that had MgX to COOH.
Note: You get one EXTRA carbon going from the reactant to the product
Reactions of Carboxylic Acids
Reduction of Carboxylic Acid using lithium aluminum hydride
Reagent: LiAlH4
Product: Turn COOH into CH2OH
Fischer Esterification
Reagent: ROH, H+
Product: Turn OH on the carboxylic acid into OR (from the alcohol)
Formation of Methyl Esters Using Diazomethane
Reagent: CH2N2
Product: Turn OH on the carboxylic acid into OCH3
Mechanism
Conversion of Carboxylic Acids into Acid Chlorides
Reagent: SOCl2
Product: Turn OH on the COOH into Cl
Decarboxylation
Decarboxylation is a reaction where COOH group is lost completely from the molecule.
Decarboxylation only occurs if the molecule is beta-ketoacid. This means there is a carbonyl group (C=O) one carbon away from the COOH group.
Decarboxylation Mechanism
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