Carboxylic acids Flashcards
Preparation of Carboxylic acids
- Oxidation of primary alcohols or aldehydes
- Hydrolysis of nitriles
- Hydrolysis of ester
- Iodoform reaction of methyl ketone or ethanal
Oxidation of primary alcohols or aldehydes
Reagents: acidified potassium dichromate
Condition: heat under reflux
Observation: orange to green
Hydrolysis of nitriles
Condition: acid or alkaline conditions, heat under reflux
nitrile + H+ –> carboxylic acid + NH4+
nitrile + OH- –> carboxylate anion + NH3
carboxylate anion + H+ (excess strong acid) –> carboxylic acid
Hydrolysis of ester
Condition: acid or alkaline conditions, heat under reflux
ester + H+ –> carboxylic acid + alcohol
ester + OH- –> carboxylic acid anion + alcohol
carboxylic acid anion + H+ (excess strong acid) –> carboxylic acid
Iodoform reaction of methyl ketone or ethanal
Reagents: iodine and NaOH or KI and NaClO then excess strong acid
Condition: warm gently
With LiAlH4
Type of reaction: reduction
Conditions: in dry ether then acid workup
Change in functional group: carboxylic acid –> primary alcohol
With bases
Type of reaction: acid-base reaction
metal hydroxide + acid –> salt + water
metal oxide + acid –> salt + water
metal carbonate + acid –> salt + CO2 + water
ammonia + acid –> ammonium salt
With PCl5 or SOCl2
Type of reaction: addition-elimination
Condition: anhydrous
Change in functional group: carboxylic acid –> acyl chloride
carboxylic acid + PCl5 –> acyl chloride + POCl3 + HCl
carboxylic acid + SOCl2 –> acyl chloride + SO2 + HCl
With alcohols
Type of reaction: esterification
Condition: heat under reflux, sulfuric acid catalyst
carboxylic acid + alcohol ⇌ ester + water
With chlorine
Type of reaction: free radical substitution
Conditions: UV light
Change in functional group: carboxylic acid –> chlorocarboxylic acid
