Reactions of alcohols - experimental details

Question 1

What is used to oxidise alcohols?

Answer 1

a solution of potassium dichromate,

acidified with dilute sulfurice acid

it is the oxidising agent

Question 2

What occurs when the potassium dichromate solution is added to an alcohol?

Answer 2

the organge dicromate (IV) ions are reduce to green chromium(III) ions

Question 3

What is used to oxidise 1º alcohols to an aldehyde

Answer 3

dilute acid and less potatssium dichromate(VI) than is needed for complete oxidation to carboxylic acid is used

Question 4

How is the 1º alcohol oxidised to an aldehyde?

Answer 4

mixture is heated gently

the receiver cooled in ice to reduce the evaporation of the product

aldehydes have relatively low boiling points and distils off

this stops it from being oxidised further to a carboxylic acid

unreacted alcohols remain in the flask

Question 5

What is the equation for the oxidation of ethanol to ethanal?

Answer 5

CH₃CH₂OH (l) + [O] → CH₃CHO (g) + H₂0 (l)

[O} is used to represent oxygen from the oxidising agent

Question 6

What is used to oxidise a 1º alcohol to a carboxylic acid?

Answer 6

concentrated sulfuric acid and excess potassium dichromate(VI) is used to complete the reaction

Question 7

How is the oxidation to a carboxylic acid carried out?

Answer 7

the mixture is refluxed

reflux means that vapour condenses and drips back into the reaction flask (looks like a big ol bong)

any alcohol or aldehyde will condense and drip back into the flask until, eventually it is all oxidised to the acid

Question 8

How is ethanoic acid seperated from the reaction mixture?

Answer 8

distillation like dys

CH₃CH₂OH (l) + 2[O] → CH₃COOH (g) + H₂O (l)