Amines (needs completing with physics and maths tutour) Flashcards
What is the reactivity of amines like?
Very reactive
What are the boiling points of like and why? Compare bp of amines to comparable alcohols
Contain H bonding so have a high bp
Bp of amines less than comparable alcohols due to lower electronegativity to Oxygen
What is the solubility of amines like?
Primary amines with carbon length < 4 soluble in water and alcohol due to H bonds
Phenylamines not very soluble due to no H bonds in benzene ring
When reacting amines, what can the lone pair bond with?
H+ ion to act as a base
Electron deficient carbon to act as a nucleophile
Trend in base strength of amines + why?
Primary amines stronger than ammonia
Secondary amines stronger than primary
Secondary amines stronger than tertiary (insoluble)
Surrounding carbons exert a positive inductive effect than increases electron density in N atom and pushes lone pair out to be more readily accepted
Why are phenylamines a weak base?
Delocalised ring withdraws electrons away from the N atom making the lone pair not as available
Negative inductive effect
What 2 methods can be used to produce amines?
Nucleophilic substitution using halogenoalkane
Reduction of Nitrile or nitrobenzene
What is the product of reaction ammonia with halogenalkane + why?
Produces primary amine + ammonium salt
NH3 + RX –> [RNH3]^+X^-
[RNH3]^+X^- + NH3 –> RNH2 + [NH4]^+X^-
When reacting ammonia, what should you keep in mind about its properties?
Its lone pairs make it a nucleophile
When forming a primary amine from ammonia and halogenoalkane, what is the issue with this reaction?
The primary amide can further react with halogenalkanes to produce secondary, tertiary and quanternary amides.
When making primary amides from nucelophillic substitution, what can we do to increase the yield of primary amides due to multiple substitution reactions?
Add excess ammonia
What are the 2 steps, reactants and conditions to forming amines by reduction of nitriles?
Halogenalkanes react with cyanide in aqueous ethanol via nucleophillic substitution
Nitrile reduced to primary amine using H2 and a nickel catalyst
What are the 2 steps and conditions for the production of phenylamine?
Benzene reacted with conc. nitric and sulfuric acid catalyst to produce nitrobenzene + water
Nitrobenzene redueced to phenylamine using tin catalyst and HCl reducing agent
(C6H5NO2 + 6[H] –> C6H5NH2 + 2H2O)
What are the uses of quanternary amines?
Cationic surfactants
What are the uses of amines?
Nylon, dyes and drugs
