acyl chlorides and acid anhydrides
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how does the reactivity of acyl chlorides compare to that of carboxylic acids?
much more reactive because of the Cl and OCOCH3 groups which are classified as good leaving groups
how do we name acyl chlorides?
the primary suffix name for an acid chloride is based on the longest carbon chain name + ‘oyl chloride’ for the COCl bond eg ethanoyl chloride, propanoyl chloride etc (there is no stable methanoyl chloride)
what happens when acyl chlorides react with a range of compounds?
the Cl is substituted by an O or N group and steamy fumes of HCl given off in each case
what is produced when an acyl chloride reacts with water?
carboxylic acid and steamy fumes of HCl gas
what is produced when an acyl chloride reacts with alcohol?
esters and steamy fumes of HCl gas
what is produced when acyl chlorides react with aqueous ammonia?
amides and steamy fumes of HCl the HCl will then react further with excess ammonia to produce a salt (eg ammonium cloride)
what is produced when acyl chlorides are reacted with amines at room temp?
N-substituted amides and steamy fumes of HCl gas the HCl will then react further with excess amine to produce a salt (eg methyl ammonium chloride)
what is the order of nucleophile reactivity with acyl chlorides?
primary amine ammonia alcohol water
what are the reactions of acyl chlorides?
nucleophilic addition-elimination mechanisms
what is the difference between amines and amides
an amine is an organic compound, related to ammonia, that contains a N atom bonded to one or more alkyl groups an amide is an organic compound that contains a carbonyl group bonded to a nitrogen atom
what is the test for acyl chlorides?
add water/ alcohol and look for steamy white fumes to be given off
what is important about the nucleophiles in acyl chloride reactions?
nucleophiles also have a hydrogen attached to the lone-paired element
how are acid anhydrides formed?
when 2 of the same carboxylic acids combine and release a water molecule
how do we name acid anhydrides?
remove acid and replace with anhydride eg methanoic anhydride propanoic anhydride
what are the reactions of acid anhydrides generally?
all reactions are nucleophilic addition-elimination just like acyl chlorides, they react vigorously with water, alcohol, ammonia and amines, just LESS VIGOROUSLY instead of producing HCl, they produce their carboxylic acids ( as no Cl is present in acid anhydrides)
what is produced when an acid anhydride is reacted with water?
2 carboxylic acids
what is produced when acid anhydrides are reacted with alcohols?
ester + carboxylic acid eg ethanoic anhydride +methanol ——-> methyl ethanoate + ethanoic acid
what is produced when acid anhydrides are reacted with ammonia?
amide and carboxylic acid eg ethanoic anhydride + ammonia ——> ethanamide + ethanoic acid
what is produced when an acid anhydride is reacted with an amine?
N-substituted amide and a carbixylci acid eg ethanoic anhydride + methyl amine ——-> N-methylethanamide + ethanoic acid