Download alkanones

Our Plan For Today
Aim: We are going to learn about the structures
of aldehydes and ketones and how to name them.
• Recap on oxidation of alcohols
• Aldehydes (alkanals) and Ketones
(alkanones)
• Naming aldehydes and ketones.
Recap on Oxidation of Alcohols
• Oxidised by acidified potassium dichromate.
• The alcohol is oxidised to form an aldehyde
which is a member of the alkanal homologus
series.
[O]

ethanol
+ H2O
ethanal
Secondary Alcohols
• Oxidised by acidified potassium dichromate.
• When a secondary alcohol is oxidised a ketone
is produced, they belong to the homologus
series, the alkanones.
[O]

propan-2-ol
+ H2O
propanone
Tertiary Alcohols

Tertiary alcohols
are not readily
oxidised
Aldehydes - Alkanals
carbonyl group
butanal
Aldehydes can be categorised by the presence
of a C=O known as a carbonyl group.
In an aldehyde the carbonyl group (C=O) is at
the end of a carbon chain.
They are a member of a homologus series called
the alkanals, which ends in –anal.
Naming Alkanals
H CH3 H H O
5
4
3
2
1
H–C–C–C–C–C–H
4-methylpentanal
H H H H
Number your carbons from the carbonyl end.
Name any branches
Ketones - Alkanones
H O H H H
H – C – C – C – C – C- H
H
H H H
For a ketone, the carbonyl group (C=O) is attached
to two other carbon atoms and is found mid-chain.
They are a member of a homologus series called
the alkanones, which ends in –one.
The position of the carbonyl group must be
indicated in the name e.g pentan-2-one.
Individual Tasks
• Stick in both sheets of appendix 2.11
• Turn to page 21 of your work booklets and
complete the tables for the straight chain
alkanals and alkanones with up to 6 carbon
atoms.
• Exercise 2.5 on page 29 of your work booklets