Acyl Chlorides & Acid Anhydrides
Acyl chlorides are derivatives of carboxylic acids by the
substitution of the -OH group for a chlorine atom. The functional
group for acyl chlorides is COCl, with all names ending in -oyl
chloride.
Acid anhydrides are also derivatives of carboxylic acids formed by
substitution of the -OH group by an alkanoate. The functional
group for acid anhydrides is R(CO)O(CO)R, with all names ending in
-oic anhydride.
E.g.
Propanoyl Chloride Propanoic Anhydride
Nucleophilic Addition - Elimination
Due to the difference in electronegativity bet ween the oxygen
atoms and the carbon atoms, there is a dipole present. The carbon
is partially positive so it attracts nucleophiles readily.
When an acyl chloride reacts with a nucleophile it substitutes its
Cl and misty fumes of HCl are given off. Acid anyhydrides produce
a similar reaction as acyl chlorides but a carboxylic acid is formed
instead of HCl.
Different nucleophiles produce different products in nucleophilic
addition - Elimination reactions.
, Reactions Of Acyl Chlorides & Acid Anhydrides With Water
Acyl chlorides & acid anhydrides react with cold water to form
carboxylic acids.
E.g. Propanoyl Chloride To Form Propanoic Acid
*Misty fumes of HCl are also produced in this reaction.
E.g. Ethanoic Anhydride To Form 2 Molecules Of Ethanoic Acid
Reactions Of Acyl Chlorides & Acid Anhydrides With
Alcohols
Acyl chlorides & acid anhydrides react with alcohols at room
temperature to form esters as the product.
E.g. Ethanoyl Chloride To Form Methyl Ethanoate
Acyl chlorides are derivatives of carboxylic acids by the
substitution of the -OH group for a chlorine atom. The functional
group for acyl chlorides is COCl, with all names ending in -oyl
chloride.
Acid anhydrides are also derivatives of carboxylic acids formed by
substitution of the -OH group by an alkanoate. The functional
group for acid anhydrides is R(CO)O(CO)R, with all names ending in
-oic anhydride.
E.g.
Propanoyl Chloride Propanoic Anhydride
Nucleophilic Addition - Elimination
Due to the difference in electronegativity bet ween the oxygen
atoms and the carbon atoms, there is a dipole present. The carbon
is partially positive so it attracts nucleophiles readily.
When an acyl chloride reacts with a nucleophile it substitutes its
Cl and misty fumes of HCl are given off. Acid anyhydrides produce
a similar reaction as acyl chlorides but a carboxylic acid is formed
instead of HCl.
Different nucleophiles produce different products in nucleophilic
addition - Elimination reactions.
, Reactions Of Acyl Chlorides & Acid Anhydrides With Water
Acyl chlorides & acid anhydrides react with cold water to form
carboxylic acids.
E.g. Propanoyl Chloride To Form Propanoic Acid
*Misty fumes of HCl are also produced in this reaction.
E.g. Ethanoic Anhydride To Form 2 Molecules Of Ethanoic Acid
Reactions Of Acyl Chlorides & Acid Anhydrides With
Alcohols
Acyl chlorides & acid anhydrides react with alcohols at room
temperature to form esters as the product.
E.g. Ethanoyl Chloride To Form Methyl Ethanoate
