Amines and Amides Flashcards
Order of base strength (increasing)
Aromatic –> Ammonia –> Aliphatic (1y–>3y)
What determines base strength
Availability of nitrogen lone pairs so they can accept a proton
Why are aromatic amines weakest bases?
Lone pairs on nitrogen are partially delocalised which decreases electron density and lone pair is less available
What makes aliphatic amines stronger bases?
Alkyl groups push electrons away from themselves which increases electron density on nitrogen making the lone pairs more available
Uses of Quaternary ammonium salts
Used as cationic surfactants and therefore used in fabric cleaners and hair products
Two ways of making amines
Reducing nitriles, heating halogenalkanes with ammonia
What’s a con to the amine prepration method of heating halogenalkanes with ammonia
A mixture of amines and ammonium salts are produced (low atom economy)
Main product with excess ammonia
1y Amine
Main product with excess haloalkane
4y Ammonium salt
Reducing agent used in nitrile reduction
LiAlH4 (lithium aluminium hydride)
Equation for reduction of nitriles and conditions
R-CH2-C≡N + 4[H] —> R-CH2-CH2NH2, dilute acid
Why Catalytic hydrogenation may be used instead to reduce nitriles?
LiAlH4 is too expensive
Equation for catalytic hydrogenation of nitriles and conditions
R-CH2-C≡N +2H2 —> R-CH2-CH2NH2
H2 gas, Nickelt catalyst, High temperature and pressure
Reducing nitrocompounds into aromatic amines conditions + equation
Heat mixture of tin metal, conc. HCl and the Nitrocompound under reflux, add NaOH to formed salt
Benzene-NO2 + 6[H] —> Benzene-NH2 + 2H2O
What is an N-substituted amide
An amide where one of the hydrogens on nitrogen is replaced by an alkyl group
