Aldehydes and Ketones ( 3.3.8) Flashcards
What can aldehydes be oxidised to
Carboxylic acids
What can ketones oxidise to
they can’t get oxidised any further
What do aldehydes get reduced to
A primary alcohol
What does a ketone get reduced to
A secondary alcohol
What condition should oxidising a primary alcohol to an aldehyde be in
Reagent : K2Cr2O7 ( acidified potassium dichromate ) or H2SO4 ( dilute sulfuric acid )
Condition : heat and distil off product
What condition should oxidising a primary alcohol to a carboxylic acid be in
reagent : K2Cr2O7 ( acidified potassium dichromate ) or H2SO4 ( dilute sulfuric acid )
condition : reflux
What condition would oxidising an aldehyde into a carboxylic acid be in
Reagent :
K2Cr2O7 ( acidified potassium dichromate )
H2SO4 ( diltute sulfuric acid )
Or Tollens reagent ( heat )
Or Fehlings solution ( heat )
Condition : heat or reflux
What condition should oxidising a secondary alcohol to a ketone be in
Reagent :
K2Cr2O7 ( acidified potassium dichromate )
H2SO4 ( dilute sulfuric acid )
Condition : heat or reflux
What is the reducing agent used to reduce aldehydes and ketones
NaBH4
what is the mechanism called for reducing aldehydes and ketones
Nucleophilic addition
why is nucleophilic addition used
The C= O bond is polar
O is more electronegative than the C . This means that the C is susceptible to attack by nucleophiles ( electron pair donors).
Why is NaBH4 used
acts as a source of hydride ions ( H-)
What is the conditions needed for reduction of aldehydes and ketones
Reagent : NaBH4 or KCN followed by dilute acids
Conditions : aqueous , heat
What products is formed when an aldehyde or a ketone is reduced with the addition of a CN- ion
Hydroxynitrile
Why is KCN used and not HCN
HCN is very poisonous
