Aldehydes And Ketones Flashcards
What group do aldehydes and ketones contain and what is their difference?
They contain the carbonyl group (C=O). They differ in that aldehydes have a carbon atom and a hydrogen atom bonded to the carbon of the carbonyl group, while keto es have two carbon atoms bonded to the carbon of the carbonyl group
From the oxidisation of which alcohols can aldehydes and ketones be prepared?
Aldehydes can be prepared by the oxidisation of primary alcohols. Ketones can be prepared by the oxidation of secondary alcohols
What type of reaction is the addition of hydrogen cyanide to both aldehydes and ketones and what does it produce?
A nucleophillic addition reaction that produces hydroxynitriles
What is the nucleophile in hydrogen cyanide?
:CN-
What is the mechainsm for the nucleophillic addition across the C=O bond?
Check snap camera roll
Why do we usually use potassium cyanide followed by an acid such as sulfuric or hydrochloric acid instead of hydrogen cyanide?
Because the reaction is easier and potassium cyanide is less toxic. Hydrogen cuanide is also a very weak acid and the degree of ionisation is very small
Why is a racemic mixture formed when the cyanide nucleophile attacks and makes a chiral product?
Because the carbonyl bond is planar in shape and so the cyanide molecule has an equal likelihood of attacking from either side of the molecule
What do reduction reactions do with carboxylic acids, ketones and aldehydes?
They reduce aldehydes to primary alcohols and ketones to secondary alcohols
They reduce carboxylic acids to primary alcohols but first reduce them to aldehydes
What are the strong reducing agents that reduce aldehydes and ketoned and how are they represented?
Lithium tetrahydrioaluminate
Sodium tetrahydrioborate
And they are represented by [H]
What sort of reactions are the reductions of aldehydes and ketones?
Nucelophillic addition reactions
What is the nucleophile in reduction reactions?
The :H-
What us the mechanism for the nucleophillic addition reduction reaction for aldehydes and ketones?
Check snap camera roll
