Pages in this set

Page 1

Preview of page 1
CH4 11.2 Aldehydes and ketones




















a)
Aldehydes and ketones can be formed
by the oxidation of alcohols using
K2Cr2O7/H+.
Primary alcohols oxidise to an aldehyde
(Mild conditions in order not to oxidise
to carboxylic acid)
Secondary alcohols oxidise to a ketone.
b)
Aldehydes can be oxidised to
carboxylic acids where…

Page 2

Preview of page 2
The carbonyl group can be reduced by lithium tetrahydridoaluminate(III)(LiAlH4)
and sodium tetrahydridoborate (NaBH4)(III).
LiAlH4 must be aqueous and usually is dissolved in methanol
NaBH4 mus be anhydrous and is usually reacted with an ether
Aldehydes reduce to primary alcohols.
Ketones reduce to secondary alcohols.
(d) Additionelimination (condensation) reactions.
In these…

Page 3

Preview of page 3
Positive result: A pale yellow precipitate with a strong antiseptic smell
(triiodomethane/ CHI3/ iodoform)
Positive for: Methyl groups: ethanol CH3CH2OH and all alcohols with the 2ol
structure CHOHCH3 and the aldehyde ethanal CH3CHO and all ketones with
the 2one structure RCOCH3 ('methyl ketones')










Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all resources »