3.3.5.2 Oxidation of alcohols

• Primary alcohol can change into

  Aldehyde and carboxylic acid
• How do we remove an aldehyde from a mixture

  Distillation
• Process of removing an aldehyde from mixture

  Heat reaction mixture, aldehyde turns into a vapour, condenses into a liquid, drops into flask
• How do we make a carboxylic acid separate

  Heated under reflux
• Why are COOH heated under reflux

  Any aldehyde will turn into a vapour and will condense in a condenser drop back into the reaction mixture and oxidise COOH
• How do we separate an aldehyde from COOH

  Distillation
• Aldehyde

  Distillation
• Ketone

  Reflux
• Carboxylic acid

  Reflux
• What can we add in oxidation of alcohols

  Acidified potassium dichromate
• Why is mixture heated

  Increase rate of reaction
• How do we prevent ketones from being lost in a system

  Condenser
• Use of a condenser

  Water inside keeps it coo so when ketones pass through it cools down until it condenses into liquid
• What is left after secondary alcohols under reflux and what is left

  Ketones some acidified potassium dichromate
• Why do we use a thermometer?

  Ensure temperature of mixture remains below the boiling point of alcohol
• Electrophile

  Lone pair acceptor
• Nucleophile

  Lone pair donator
• Why can't teritary alcohols be oxidised

  No hydrogen atoms bonded to the carbon with the OH group, remains orange
• How to distinguish aldehydes and ketones

  Fehlings solution and tollens reagent
• Observation change in fehlings solution

  Blue to red in presence of aldehydes, but no reaction if a ketone is present, heat gently
• Observation change in tollens reagent

  Silver mirror coats the inside of the test tube in presence of aldehydes, no reaction of ketones, heated gently
• What is the use of antibumping granules

  Prevents rigorous and uneven boiling
• What is it collected with ice in a beaker

  Keeps it below the boiling point distillate the yield