Journey of Chemistry

Nitrogenous compounds and amines

Major difference

Types of amines

Basicity

Alkylamine is the strongest base because the alkyl is a electron donating group which will repel the lone pair in the nitrogen atom thus it is more available to form bonds with protons/hydrogen ions
Ammonia has no effect
Phenylamine is the weakest because P orbitals in the phenylamine overlaps with the pi system and lone pair gets delocalised and makes it less readily available to form co-ordinate bonding

Reaction with amonia

Reagent : Ammonia in ethanol

Condition : Heat under reflux in excess

Product : Amine and HX

halogenoalkane chapter

Reaction with primary amines

Reagent : Halogenoalkane

Condition : in ethanol

Product : Substituted amine and HX

Reduction of amides

Reagent : Amide

Condition : LiAlH4 in dry ether or H2 with nickel catalyst

Product : Amines and water

Reduction of nitriles

Reagent : nitriles, KCN in ethanol

Condition : LiAlH4 in dry ether, refluxed or H2 with nickel catalyst

Product : Amines

Preparation of phenylamines

Reagent : nitrobenzene

Condition : With tin(Sn), conc HCL, heat and NaOH

Product : phenylamine and water

Diazotisation

Chapter 25

The presence of groups determine the colour of the dye

Amino acids

Contains COOH
Contains NH2
2-amino-carboxylic acids are the building blocks that make up protein
Structural formula RCH(NH2 )COOH
R group can vary
When R is H, simplest amino acid is glycine (aminoethanoic acid

Characteristic

R group can be acidic (another carboxylic acid group)

EX:COOH

R group can be basic (another amine group)

EX: NH2

R group can be neutral (another alkyl group)

EX: CH3

Amino acids will undergo most of the reactions of amines and carboxylic acids
The ion (the interaction within itself) is called zwitterion (NH3 + and COO- ) which is amphoteric
Strong intermolecular forces of attraction (crystalline solids) soluble in water
Always solid at 20°C because they have relatively high melting points for organic compounds because of the strong electrostatic forces of attraction between the oppositely charged parts of the zwitterion ion.

Zwitterion

Have a amphoteric nature
Acts as a buffer solution

Peptides

Condensation reaction forms peptide bonds
Can be hydrolised

Amides

Structural formula is RCONH2
Amines are basic because they can accept protons
But amides are neutral because oxygen is very electronegative attracts the electrons in the N atom thus its charge density decreases and cannot form bonds with protons/H+

Preparation of amides

Condition : room temperature

Both reactions releases white fumes of HCl
If excess amine, it will react with HCl to make its salt. Ex: C2H5NH3+ Cl-

Naming of amides

N- is used in naming amide to denote which alkyl or aryl group are bonded to the nitrogen atom
N-ethylbutanamide, C3H7CONHC2H5
(C2H5) has replaced an H atom
If H atom is replaced by another alkyl or aryl group, two N’s are used
C3H7CON(C2H5)2 is called N,N-diethylbutanamide

Hydrolysis of substituted amines

-CONH- group can be broken
By hydrolysis with acid or alkali
The product of hydrolysis are carboxylic acids and a primary amine
The amine formed will react with excess acid to form ammonium salt
With an alkali, the products are salt of carboxylic acid and primary amine

Hydrolysis of unsubstituted amines

If reflux with acid, products are corresponding carboxylic acid and ammonia.The ammonia reacts with excess acid to make ammonium salt
If reflux with alkali, the products will be salt of carboxylic acid and ammonia

Electrophoresis

A sample is placed on absorbent paper/ gel supported on a solid base (glass plate)
A buffer solution carries the ions along
The rate of movement depends on the size and charge
Larger ions move slowly
Highly charged ions move quickly
A series of lines/bands appear once a chemical is applied
UV light used to see the bands with the use of ninhydrin spray (electropherogram)

Diagram and speed

When separating a mixture of proteins, they are treated with chemicals to make them all negatively charged
All of the proteins will migrate with the same direction, towards the positive electrode but larger proteins move slowly
Lysine has a total of +1, glycine is neutral and glutamic acid is -1 thus lycine and glutamic acid will travel further than glycine

Nylon

polyamide
biodegradable under base and acidic condition
6,6 nylon and 6,10 nylon indicates the number of carbon atoms of the monomers

Kevlar

polyamide
high mp bp
Contain benzene rings
Have hydrogen bonding

Terylene

Polyester

PLA

Polyester

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