carbonyl compounds Flashcards
why don’t carbonyl compounds react the same way as alkenes
C=O double bond is polar
C=C is not polar
What does a polar C=O bond mean for the carbonyl group
It can react with some nucleophiles- proton acceptor
What mechanism do carbonyl compounds go through
nucleophilic addition
What does reducing ketones and aldehyde make
alcohols
What reducing agent is used to turn carbonyl compounds into alcohols and conditions
NaBh4
Aldehyde or ketone warmed with NaBh4 in a aqueous solution
hydrogen cyanide chemical equation
HCN
What does an aldehyde or ketone + HCN do
gets rid of the double o bond and adds an H and CN and an OH
What catalyst is used to produce the CN
H2SO4 and NACN (sodium cyanide)
What is a group with OH and C=N called
hydroxynitriles
In the mechanism from aldehyde to alcohol what happens
- Dipoles form between the C=O
- H- with a lone pair of electrons attracts to the delta positive carbon group
- Oxygen now has a lone pair of electrons
- Water with dipoles is formed
- oxygen is attracted to the H delta positive from water
- OH is also formed
What is used to test for carbonyl groups
2,4 dinitrophenylhydrazine
what happens to 2,4 dinirtophenylhydrazine in the presence of carbonyl
yellow or orange precipitate is formed
Conditions for testing carbonyl with 2,4 DNP
dissolved in methanol and sulfuric acid as a plae orange solution called Brady’s reagent
Why does 2,4 DNP need to be dissolved
Solid can explode if there is friction
Once a compound has been determined as a carbonyl group how can you distinguish between a ketone and aldehyde
Tollens reagent - solution of silver nitrate in aqueous ammonia
Aldehyde - a silver mirror is produced
