Chapter 26 - Carbonyls and Carboxylic acids Flashcards
What are the two carbonyl compounds and what are their functional groups?
Aldehyde -CHO
Ketone -CO
What does a primary alcohol form when oxidised?
Aldehyde
Under what conditions does a primary alcohol form an aldehyde?
Distillation
Acidified dichromate
What does a secondary alcohol form when oxidised?
Ketone
Under what conditions does a secondary alcohol form a ketone?
Reflux
Acidified dichromate
What do tertiary alcohols form when oxidised?
No reaction - tertiary alcohols cannot be oxidised
What colour change occurs when acidified dichromate is reduced by the alcohols?
Orange - to - green
What do aldehydes form when oxidised? And under what conditions?
Carboxylic acids
Reflux
Acidified dichromate
What does propanal form when oxidised?
Propanoic acid
What is the observation when aldehydes are oxidised?
Colour change from orange to green
Can ketones by oxidised? And what is the observation?
No
Colour remains orange
What is an addition reaction?
2 molecules joining together making a single product
Reaction has 100% atom economy
What is a nucleophile?
An electron pair donor
What is the nucleophile attracted to on the aldehyde?
The polar bond
Oxygen atoms are more electronegative and so there are partial charges
What are the two nucleophiles?
Hydride ion
Cyanide ion
What is the reducing agent for each of the nucleophiles?
NaBH4
HCN
Can both aldehydes and ketones be reduced to alcohols?
Yes
What do aldehydes form when reduced?
Primary alcohols
What do ketones form when reduced?
Secondary alcohols
What is the mechanism for nucleophilic addition with NaBH4 (aq)?
Dative covalent bond is formed
Undergoes heterolytic fission (C=O pi bond). Forming a negatively charged intermediate
Draw out the mechanism for nucleophilic addition with HCN?
What is used to make HCN in the least dangerous way?
Sodium cyanide
Sulfuric acid
Forming HCN in situ
What is HCN useful for?
Extending carbon chain length.
