Amines Flashcards
What are amines
Are organic compounds that contain one or more organic groups attached to the nitrogen
What is the general formula of saturated mono-amines
CnH2n+1NH2
What are primary amines
Nitrogen attached to only one organic group
What are seconary amines
Nitrogen attached to two organic groups
What are tertiary amines
Nitrogen attached to three organic groups
What are quaternary amines
Nitrogen attached to 4 organic groups (+ve charge)
How do you name primary amines
Using the prefix amino.
How do you name secondary and tertiary amines
N-alkylaminoalkanes. e.g. N-methylamino-1-propane
What are the physical properties of primary and secondary amines
They can form hydrogen bonds between molecules so have higher boiling points (like alcohols)
What are the physical properties of tertiary amines
Are subject only to van der Waals forces, but have permanent dipoles so strong attraction
Why do amines have higher boiling points that alkanes
They have permanent dipoles so the attraction is stronger than in alkanes
Which size amines give higher boiling points and why
Larger amines give higher boiling points. The larger the molecule the greater the surface area the more van der Waals forces the higher the boiling point
Why are amines basic
The lone pair on the nitrogen can become protonated. This makes amines weak bases
What do amines form when protonated
Alkylammonium salts (e.g. ethlyammonium salt)
What is the significance of the fact that amines can form alkylammonium salts
The ammonium salts are much more water-soluble than amines so this can be used to purify amines
How can you form amines
By nucleophilic substitution of halogenoalkanes using ammonia
Why is the mechanism either Sn1 or Sn2
Depends on whether the halogenoalkane is primary, secondary or tertiary. Primary = Sn2, Secondary = Sn1 & Sn2, Tertiary = Sn1
Describe the mechanism of forming amines by nucleophilic substitution of halogenoalkanes using ammonia
Ammonia (nucleophile) attacks bromometane (electrophile). Forms CH3NH2 + HBr. CH3NH2 (nucleophile) attacks bromomethane forms N-methylaminomethane and HBr. CH3NCHCH3 (nucleophile) attacks bromomethane (electrophile) forms N-dimethyl-aminomethane. N-dimethylaminomethane (nucleophile) attacks bromomethane (electrophile) forms quaternary amine.
Describe the nature of the reaction of forming amines by nucleophilic substitution of halogenoalkanes using ammonia
The reaction is not reliable and makes a mixture of products
How do you form an aminde
Reaction of an amine with a carboxylic acid derivative
What is produced when you react an amine with acyl chloride
Amide and HCl
Why are amides not nucleophilic or basic
Resonance stabilised the amide meaning that it is unreactive (not basic or nucleophilic)
How do you form a polyamide
Reaction of a di-amine with a di-acid derivative
