5.4.2 Organic Nitrogen Compounds: Amines, Amides, Amino Acids and Proteins Flashcards
What is an amine?
Ammonia with at least one of the hydrogens substituted with an organic group.
Give an example of a tertiary amine.
Trimethlyamine
Give an example of an aromatic amine.
Phenylamine.
How do the smells of amines compare to that of ammonia.
More fishy.
What happens when you add small amines to water?
They dissolve to form alkaline solutions.
What makes small amines very soluble in water?
They hydrogen bonds that it forms with water.
What happens to solubility of an amine as you increase the length of the carbon chain? Why?
It decreases because the london forces between amines increase.
Give the equation to show ethylamine dissolving in water.
CH3CH2NH2(aq) + H2O(l) ⇌ CH3CH2NH3+(aq) + OH-(aq)
What happens when you react an acid with an amine?
They form salts. The lone pair on the nitrogen atom forms a dative covalent bond with the H+ ion.
Give the equation for the reaction between ethyl amine and hydrochloric acid.
CH3CH2NH2 + HCl → CH3CH2NH3+Cl-
What do amines form with copper(II) ions?
Complex ions.
What happens when you add a small amount of methyl amine solution to copper(II) sulfate solution?
Insoluble copper hydroxide forms.
What happens when you add a large amount of methyl amine solution to copper(II) sulfate solution?
A deep blue solution forms.
Why might copper complex with large amine ligands be different form small ones?
They can’t fit six around the copper ion.
What happens when amines are reacted with acyl chlorides?
An H atom on the amine is swapper for the acyl group to produce an N-substituded amide and HCl which then goes on to react again to produce a salt.
Give the overall equation for the reaction between ethanoyl chloride and butylamine.
CH3COCl + 2C4H9NH2 → CH3CONHC4H9 + [C4H9NH]+Cl-
What are the conditions required for creating N-substidued amides?
Add ethanoyl chloride to a concentrated aqueous solution of amine.
Describe the reaction and product of the acylation of amines.
The reaction is violent and a mixture of white solid products is formed.
What happens when you add a primary amine to a halogenoalkane?
The lone pair of electrons attack the δ+ carbon on the haloalkane, displacing the chlorine and making salt. The Chlorine then removes an H to make Hal and a secondary amine. This could repeat to make a tertiary amine.
Why might products from the acylation of phenylamine be stained brown?
Unreacted phenylamine.
What functional group do amides have?
-CONH2
Why do amides behave differently from amines?
Because the carbonyl group draws electrons away from the rest of the group.
What is the difference between an amide and an N-substituted amide?
On an N-sub amide one of the hydrogens on the nitrogen is replaced with an alkyl group.
What is the name of H2NCONH2?
Urea.
What is the product of the reaciotn between ethanoyl chloride and ammonia?
Ethanamide (and HCl which goes on to make a salt).
How can you make aromatic amines?
Reducing nitro commands.
What is the first step of the reduction of a nitro compound?
Heat it with tin and concentrated HCl under reflux to make an ammonium salt.
What is the second set of the reduction of a nitro compound?
Add sodium hydroxide to remove an H+ form the salt, giving an aromatic amine.
Name the catalyst used when reducing nitrobenzene.
Tin, Sn.
What name the products of reducing nitrobenzene.
Phenylamine and H2O.
What is the azo group?
-N=N-
Where is the azo group commonly found?
Manmade azo dyes.
What does the azo group link in most azo dyes?
Two aromatic groups.
Why are two aromatic groups linked by the azo group very stable?
The azo group forms part of the delocalised electron system.
How are different colours of azo dyes created?
Combining different phenols and amines.
What causes the colours of azo dyes?
The light absorption by the delocalised system.