PL - Amines and amides Flashcards
What are amines?
Organic derivatives of ammonia.
How is a primary amine formed?
If one of the hydrogens in ammonia (NH3) is replaced with an organic group, R.
How do small amines smell?
Similar to ammonia, with a slightly ‘fishy’ twist.
How do larger amines smell?
Very ‘fishy’.
Are amines acidic of basic?
Basic.
How can you test for amines?
See whether it turns a piece of damp red litmus paper blue (as amines are basic).
You can confirm that the unknown compound is an amine by reacting it with a small amount of acyl chloride - if it’s and amine, white fumes of HCL gas will be given off.
How do you name a primary amine?
Find and name the longest alkane chain attached to the amine group, take off the final ‘e’ and add ‘-amine’ to the end.
If the carbon chain is more than 2 carbons long, you should include a number to show which carbon the amine group is attached to. Number the carbon chain so that the amine group has the smallest possible number.
Then use the suffix ‘-amine’ or prefix ‘amino-‘.
What is it called if the molecule has 2 amine groups?
A diamine.
What is a diamine?
A molecule that has 2 amine groups.
How do you name diamine?
In the same way as primary amines except you use the suffix ‘-diamine’, and keep the final ‘e’ of the alkane stem.
Why is an amine a base?
Because it has a lone pair of electrons.
They act as bases because they accept protons, forming a cation (a positively charged ion).
Where’s the lone pair of electrons in an amine?
On the nitrogen atoms that can form a dative covalent (coordinate) bond with an H+ ion.
How can you neutralise an amine?
By reacting it with an acid to make an ammonium salt.
What is the general equation for the neutralisation of an amine?
RNH2 + HX –> RNH3+X-
What are amides?
Carboxylic acid derivatives.
Why do amides behave differently from amines?
Because the carbonyl group in amides pulls electrons away from the rest of the -CONH2 group.
What are the different types of amides?
Primary and secondary.
Whether an amide is a primary or secondary amide depends on what?
How many carbon atoms the nitrogen is bonded to.
How many carbon atoms is the N bonded to in a primary amide?
1
How many carbon atoms is the N bonded to in a secondary amide?
2
How do you name primary amides?
Use the stem of the carbon chain, followed by -amide.
How do you name secondary amides?
Use the stem of the carbon chain, followed by -amide.
Also, use the prefix N-alkyl- to describe the alkyl chain that is attached directly to the nitrogen atom.
E.g. N-ethylpropanamide.
Under what conditions can amides be hydrolysed?
Acidic or basic.
How can you hydrolyse an amide?
- Heat it with a dilute acid to get a carboxylic acid and an ammonium salt.
OR…
- Heat it with a dilute alkali to get a carboxylate ion and ammonia gas given off.
What will heating a secondary amide with dilute acid produce?
A carboxylic acid and the salt of a primary amine.
What will heating a secondary amide with dilute alkali produce?
A salt of the carboxylic and an amine.
What will heating a primary amide with dilute acid produce?
A carboxylic acid and an ammonium salt.
What will heating a primary amide with dilute alkali produce?
A carboxylate ion and ammonia gas.
