Third Trimester
Formation of Acyl Halides (Using SOCl₂):
Identify Reactants:
Carboxylic acid (R-COOH)
Thionyl chloride (SOCl₂)
Reaction Mechanism:
Carboxylic acid reacts with SOCl₂.
SOCl₂ converts the -OH group of the carboxylic acid into a chlorine atom.
Products:
Acyl chloride (R-COCl)
Byproducts: sulfur dioxide (SO₂) and hydrogen chloride (HCl)
Example:
R-COOH + SOCl₂ → R-COCl + SO₂ + HCl
Esterification (Fischer Esterification):
Identify Reactants:
Carboxylic acid (R-COOH)
Alcohol (R'-OH)
Acid catalyst (e.g., H₂SO₄)
Reaction Mechanism:
Acid catalyst protonates the carboxyl group, making it more electrophilic.
Alcohol attacks the carbonyl carbon, forming a tetrahedral intermediate.
Loss of water molecule (H₂O) and formation of an ester.
Products:
Ester (R-COOR')
Water (H₂O)
Example:
R-COOH + R'-OH ⇌ R-COOR' + H₂O (catalyst: H₂SO₄)
Preparation for Both Reactions:
Set Up Reaction Conditions:
Ensure proper stoichiometry of reactants.
Use appropriate solvent if necessary (e.g., anhydrous conditions for SOCl₂ reaction).