IBDP Chemistry: Carbonxylic Acid Derivatives - Acyl Chlorides

• In this chapter of IBDP Chemistry, it named after the parent carboxylic acid from which it is derived
• Remove the ‘-oic acid’ suffix and replace with ‘-oyl chloride’ for the COCl bond system
• e.g. propanoic acid to propanoyl chloride
• Very reactive and so very useful in organic synthesis
• They are easily converted into carboxylic acid derivatives e.g. esters and amides with good yields
• React with nucleophiles by losing the chloride ion whilst retaining the C=O double bond

• In this chapter of IBDP Chemistry, it must be prepared in a fume cupboard as the products are harmful- produce SO2 and HCl as gases
• Prepared from their parent carboxylic acid + thionyl chloride (SOCl2)
• e.g. propanoic acid(aq) + thionyl chloride(aq)  --> propanoyl chloride(aq) + SO2(g) + HCl(g)

Acyl chloride + alcohol --> ester + HCl (hydrogen chloride gas)

• In this chapter of IBDP Chemistry, it is esterification reaction
• Alcoholic conditions
• e.g. ethanoyl chloride + propan-1-ol --> propyl ethanoate + HCl

Acyl chloride + phenol --> phenyl ester + HCl

• Carboxylic acids are not reactive enough to form esters with phenols
• Acyl chlorides and acid anhydrides are both much more reactive than carboxylic acids

e.g. ethanoyl chloride + phenol --> phenylethanoate + HCl

• Hydrolysis
• React instantly in cold water
• Violent reaction takes place- evolution of dense, steamy hydrogen chloride fumes (white)
• Very exothermic

Acyl chloride + water --> carboxylic acid + hydrogen chloride

• e.g. ethanoyl chloride + water --> ethanoic acid + HCl

• In this chapter of IBDP Chemistry, ammonia can act as a nucleophile by donating the lone pair of electrons on the Nitrogen atom to an electron deficient species to form primary amides

Acyl chloride + ammonia --> primary amide + ammonium chloride

• A primary amide is when the Nitrogen atom is attached to one Carbon only and 2 Hydrogen atoms
• e.g. ethanoyl chloride + ammonia --> ethanamide + ammonium chloride

This is the end of this topic.