Download alcohol - Portal UniMAP

Reactions:
OXIDATION & REDUCTION
ROHAZITA BAHARI
Basic need to know

Type of alcohol
What is carbonyl group
Oxidation
Reduction
Type of alcohol

PRIMARY ALCOHOL
SECONDARY ALCOHOL
TERTIARY ALCOHOL
Carbonyl group

 What is carbonyl group?
Aldehyde
Ketone
Carboxylic Acid
Ester
How to remember

L: loss
E : eO : oxidation
Says
G : gain
E : eR : reduction
oxidation

reduction
 Is the loss of electrons
(e-) and loss of
hydrogen atom
 Is the gain of electrons
(e-) and gain of
hydrogen atom
 Up charge
 Reduce charge
Example:

If I have the Fe2+ reacting to form
Fe3+, U probably learned that when the
oxidation number goes up that is
oxidation.
Fe 2+
Fe3+
A reaction involving electron
transfer

Called it as redox reaction
example:
Fe + CuSO4
FeSO4 + Cu
Oxidation-Reduction

 An oxidation reduction reaction or a redox reaction
is one which electron transfer occurs
 In organic chemistry this tends to have a significance
more on par of oxygen content
 Oxidation reactions as ones in which carbon gains
bonds to oxygen
 Reduction reactions as ones in which carbon atoms
lose bonds to oxygen.

 We can see some different functional groups here a
carboxylic acid and an aldehyde and alcohol and just
alkane.
 This is oxidation and reduction .
 So there are different compounds that will induce
different transformations so there are reducing
agents that will reduce any of these compounds in
this direction and there are oxidizing agents that will
oxidize compounds in this direction.
oxidation

Just to take a look at oxidations.
We can oxidize primary or secondary alcohols
A tertiary alcohol cannot be oxidized because that
carbon cannot already has three bonds to other
carbons.
So, there are not any bonds that can be replaced to
give carbon more bonds to oxygen.
It is going to be possible to gain more oxygen here
Example: (oxidation)
oxidation

 For oxidation, we usually used PCC, Pyridinium
chlorochromate to get aldehyde for primary
alcohols & ketone for secondary alcohols
 It is a reagent in organic synthesis used primary
for oxidation of alcohols.
 We use Jones oxidation (CrO3 + H2SO4) to get
carbocyclic acid for primary alcohols and
ketones for secondary alcohols.
oxidation

Why we can’t use tertiary alcohol to
form a carbonyl compound? (what is
carbonyl compound)
Eg:
reduction

Carbonyl compound to alcohol
Use different reducing agents and again these
have different strengths.
Sodium borohydrate (NaBH4) and Lithium
aluminum hydride (LiAlH4)
LiAlH4 more stronger than NaBH4.
NaBH4 only reduce aldehyde and ketones
LiAlH4 can reduce aldehyde, ketones
including carboxylic acid and ester.
conclusion

U need to understand the
transformation that agent is
capable of producing and be
able to apply that to any
substrate.