Carboxylic Acid Derivatives Flashcards
What do ammonia and amines act as in reactions with acyl chlorides?
Nucleophiles
They donate a pair of electrons from the nitrogen atom to an electron-deficient species.
What is formed when ammonia reacts with acyl chlorides?
Primary amide
The nitrogen atom in a primary amide is attached to one carbon atom.
What is the reaction product of ethanoyl chloride and ammonia?
Ethanamide and ammonium chloride
What type of amide is formed when a primary amine reacts with an acyl chloride?
Secondary amide
The nitrogen atom in a secondary amide is attached to two carbon atoms.
What is the name of the secondary amide formed from methylamine and ethanoyl chloride?
N-methylethanamide
How do acid anhydrides react compared to acyl chlorides?
They react in a similar way but are less reactive
Useful for laboratory preparations where acyl chlorides may be too reactive.
What is the equation for the formation of phenyl ethanoate from ethanoic anhydride and phenol?
2(CH3CO)2O + C6H5OH → CH3COOC6H5 + CH3COOH
What are the two steps in the mechanism of acyl chloride reactions with nucleophiles?
Addition followed by elimination
What is the product when acyl chlorides react with alcohols?
Esters
What is formed when acyl chlorides react with water?
Carboxylic acids
This reaction produces dense steamy hydrogen chloride fumes.
What is the process of hydrolysis of esters?
Chemical breakdown of a compound in the presence of water or in aqueous solution.
What is required for acid hydrolysis of an ester?
Heating under reflux with dilute aqueous acid
What is the product of the acid hydrolysis of an ester?
Carboxylic acid and an alcohol
What is alkaline hydrolysis also known as?
Saponification
What does alkaline hydrolysis of an ester produce?
Carboxylate ion and an alcohol
How can acyl chlorides be prepared?
By reaction with thionyl chloride (SOCl2)
The other products, SO2 and HCl, are evolved as gases.
What is the reaction for the formation of propanoyl chloride from propanoic acid?
Propanoic acid + SOCl2 → Propanoyl chloride + SO2 + HCl
What is esterification?
The reaction of an alcohol with a carboxylic acid to form an ester
What acts as a catalyst in the esterification process?
Concentrated sulfuric acid
What is the molecular formula for ethyl propanoate?
C5H10O2
What is a characteristic smell of many esters?
Fruity smell
What is the first step in making ethyl propanoate in the laboratory?
Mix ethanol with propanoic acid and concentrated sulfuric acid
What is the purpose of adding aqueous sodium carbonate after the ester formation?
To neutralize acids in the mixture
What do ammonia and amines act as in reactions with acyl chlorides?
Nucleophiles
They donate a pair of electrons on the nitrogen atom to an electron-deficient species.
What type of amide is formed when ammonia reacts with acyl chlorides?
Primary amide
In a primary amide, the nitrogen atom is attached to one carbon atom.
What is the reaction product of ethanoyl chloride and ammonia?
Ethanamide and ammonium chloride
The reaction shows ammonia converting ethanoyl chloride into a primary amide.
What type of amide is formed when a primary amine reacts with an acyl chloride?
Secondary amide
In a secondary amide, the nitrogen atom is attached to two carbon atoms.
What is the name of the secondary amide formed from the reaction of ethanoyl chloride and methylamine?
N-methylethanamide
This indicates that the methyl group is attached to the nitrogen atom.
How do acid anhydrides react compared to acyl chlorides?
They react in a similar way but are less reactive
Useful for laboratory preparations where acyl chlorides may be too reactive.
What is the reaction equation for the formation of phenyl ethanoate from ethanoic anhydride and phenol?
2(CH3CO)2O + C6H5OH → CH3COOC6H5 + CH3COOH
This shows the conversion of ethanoic anhydride and phenol into phenyl ethanoate and ethanoic acid.
What are the two steps in the mechanism of acyl chloride reactions with nucleophiles?
Addition and elimination
This mechanism shows how nucleophiles interact with acyl chlorides.
What happens in the addition step of the nucleophilic addition-elimination mechanism?
The nucleophile donates a lone pair to the carbon atom in the C=O group
A dative covalent bond is formed, leading to a negatively charged intermediate.
What occurs during the elimination step of the nucleophilic addition-elimination mechanism?
The C=O double bond is reformed, and a chloride ion is removed
A proton is also lost to complete the elimination.
True or False: Acyl chlorides undergo substitution reactions with nucleophiles.
False
Acyl chlorides undergo nucleophilic addition-elimination, which is different from substitution.
