26.1 Carbonyl compounds Flashcards
What is the formula of the aldehyde group
CHO
What is the formula of the ketone group
CO
What is the suffix for aldehydes
______al
what is the suffix for a ketone
_________one
what is the suffix for a dialdehyde (2 aldehyde groups on a carbon chain)
______dial
what is the suffix for a diketone (2 ketone groups on a carbon chain)
_______dione
what is the suffix for a carbonyl group attached to a benzene ring?
_____carbaldehyde
What is the prefix and suffix when both a hydroxy snd a carbonyl group are on a C chain
hydroxy_____al
hydroxy_______one
What are the reagants and conditions for the oxidation of aldehydes to form carboxylic acids
-K2Cr2O7/H2SO4 (potassium dichromate and sulfuric acid)
-Under reflux
Do ketones undergo oxidation
no, the C is making both C-C bonds and C=O have high enthalpy values so are unlikely to break
Why is there a difference in reactions of alkenes and carbonyl functional groups
-C=C bond in alkenes is non-polar, reacts with electrophiles by electrophilic addition
-C=O bond in carbonyl compounds is polar so react with some nucleophiles in a nucleophilic addition reaction
Why is a carbonyl compound a polar molecule
-oxygen is more electronegative than carbon so the electron density in the double bond lies closer to the oxygen atom making the oxygen end slightly negative
What is the C=O bond in carbonyl compounds made up of
- a sigma bond
-a pi bond
When reacting carbonyl compound with NaBH4 what is the role of NaBH4?
it is used as a reducing agent
What are the reagents and conditions required for reducing an aldehyde
-compound is warmed with NaBH4 in aqueous solution
(NaBH4/H2O)
What are aldehydes reduced to
primary alcohols
What is the symbol used for a reducing agent
[H]
What are ketones reduced to
secondary alcohols
What are the properties of hydrogen cyanide (HCN)
-colourless
-extremely toxic
-volatile as it is a small covalent compound
-boils slightly at room temperature
How do we reduce to toxicity of HCN (hydrogen cyanide)
-it is mixed with NaCN to lower volatility and increase boiling point
Why is the reaction of hydrogen cyanide (HCN) with carbonyl compounds very useful
as it increases the length of a carbon chain
What are the reagents used for the reaction of carbonyl compounds with HCN (hydrogen cyanide)
H2SO4 (sulfuric acid)
NaCN (sodium cyanide)
H2SO4/NaCN
What does the reaction of carbonyl compounds with HCN produce?
hydroxynitriles
What happens during the reaction of carbonyl compounds with HCN?
The double bond breaks from the C=O to form a C-O which reacts with a hydrogen ion (H+) to produce an alcohol group (OH). The :-CN forms a bond with the C from a carbonyl group
What are the steps for the nucleophilic addition mechanism for reaction of carbonyl compounds with NaBH4/H20?
- The lone pair of electrons from the hydride ion :H- is attracted and donated to the elctropostive carbon atom in the C=O bond
- A dative covalent bond is formed between the hydride ion and the carbon of the C=O bond
- The pi-bond in the C=O bond breaks by heterolytic fission forming a negatively charged intermediate
- The oxygen atom of the intermediate donates a lone pair of electrons to a hydrogen atom in a water molecule. The intermediate has been pronated to form an alcohol
What is optical isomerism
non rotational, non-superimposable, mirror images, producing a racemic mixture (50/50)
What are the steps for the nucleophilic addition mechanism for reaction of carbonyl compounds with
NaCN/H+?
- The lone pair of electrons from the cyanide ion :-CN is attracted and donated to the the electropositive carbon atom and a dative covalent bond forms
- the pi-bond in the C=O bond breaks by heterolytic fission forming a negatively charged intermediate
- the intermediate is pronated by donating a lone pair of electrons to a hydrogen atom to form a product
- the product is hydroxynitrile
