Carboxylic Acids And Esters Flashcards
Explain the 3 methods for esterification, identifying any positives / negatives for each
1) Alcohol + Carboxylic Acid ROH + RCOOH —> RCOOR + H2O Reversible reaction via nucleophilic addition-elimination under reflux and presence of H2SO4 ❌Requires Filtration ❌Requires acid catalyst
2) Acid Anhydrides + Alcohol RCOOOR + ROH —> RCOOR + RCOOH ✅Irreversible Used in industry as it is a: ✅Fast reaction ✅with no catalyst needed
3) Acyl Chlorides + Alcohol RCOCl + ROH —> RCOOR + HCl ✅Irreversible ❌Acyl Chlorides very unstable ❌Need to be made close to time of reaction
Explain the formation of Acyl Chlorides
Acyl Chlorides are made from Carboxylic acids reacting with a chlorinating agent:
2RCOOH + SOCl2 —> 2RCOCl + SO2 + H2O
Identify which method is used in industry and why
Acid Anhydrides + Alcohol RCOOOR + ROH —> RCOOR + RCOOH ✅Irreversible Used in industry as it is a: ✅Fast reaction ✅with no catalyst needed
Explain the hydrolysis of esters using a dilute acid and using a dilute alkali
1) Dilute acid
Acid catalysed hydrolysis is an equilibrium reaction that is the reverse of an esterification process
RCOOR + H2O —> RCOOH + ROH
2) Dilute Alkali
Always irreversible since salt produced cannot react with the alcohol
RCOOR + 2OH- —> RCOO- + RO- + H2O
Explain the solubility of Carboxylic Acids
They are polar molecules that exhibit hydrogen bonding and so are very soluble in water. Because of this, they also partially dissociate and so are considered acids. It also means that they have a high melting and boiling point
Explain the reactions for carboxylic acids with metals and bases
1) Aqueous alkalis
Carboxylic acids react with aqueous alkalis to form soluble salts
RCOOH + NaOH —> RCOO-Na+ + H2O
2) Metal Carbonates
React to form soluble salts + CO2
2RCOOH —> Na2CO3 —> 2RCOO-Na+ + CO2
3) Metal Oxides
React to form soluble salts
2RCOOH + CuO —> (RCOO-)2Cu +H2O
