3.3.11 - Amines Flashcards
Amines are produced when…
One or more of the hydrogen atoms in ammonia is replaced with an organic group. They can be 1º, 2º, or 3º amines depending on how many hydrogens are replaced
Reaction mechanism for halogenoalkane with ammonia to form amines
Nucleophilic substitution
Products when one mole of halogenoalkane reacts with two moles of ammonia
Primary amine and an ammonium salt
Efficiency of nucleophilic substitution of amines
Low efficiency
To achieve only the primary amine in nucleophilic substitution…
Excess ammonia is added, or mixture of products can be separated using fractional distillation
Amines can also be produced by…
Reducing nitriles via hydrogenation
Reaction conditions for reduction of nitriles
LiAlH4, a reducing agent, and acidic conditions or a combination of hydrogen and nickel
Equation of reduction of nitriles via LiAlH4
R-C=N: –> R-CH2-NH2
Aromatic amines can be produced by…
The reduction of nitrobenzene using concentrated hydrochloric acid and a tin catalyst
Cationic sufactants
These molecules are complexes with a positive and negative end
Uses of cationic surfactants
Conditioners as the two ends are attracted to different substances, preventing static building up on surfaces
Base strength of amines
Weak bases because the lone electron pair on the nitrogen atom can accept protons
Base strength of amines is dependent on…
How available the electron pair is on the molecule. The more available the electrons, the more likely it is to accept a proton meaning it as a stronger base
The inductive effect
In an organic molecule, different functional groups can affect how available a lone electron pair is by changing electron density around the bond
Benzene rings and electron density
Draw electron density away from the nitrogen making it ‘less available’
