RP5 - Distillation of a product from a reaction, preparation of an organic liquid Flashcards
What are the 5 stages to distilling and preparing an organic liquid?
Preparation
Seperation of crude product
Purification
Dry
Final distillation
What is reflux?
The continual boiling and condensing of a reaction mixture to ensure that the reaction takes place without the contents of the flask boiling dry
Why are reactants added slowly to reflux?
Reaction is typically exothermic so adding slowly dissipates heat and prevents extreme temp rise that may form side products
What do anti bumping granules do?
Prevent large bubble formation
What is the purpose of the condenser?
Prevent the escape of vapour
When is a water bath suitable to use when heating a mixture?
When the temperature required is less than 100 degrees
Why is a bunsen burner not suitable for heating most organic mixtures?
Most mixtures are flammable
Why is anti bumping granules especially important during distillation?
Liquid may splash over into condenser, causing impure product to be formed
What are immiscible liquids?
Liquids that do not mix and form 2 layers
What method can be used to purify the product?
Solvent extraction
Describe the process of solvent extraction of an organic mixture
Place organic liquid into a seperating funnel and add sodium hydrogen carbonate solution to neutralise acid impurities
Add stopper and shake
Invert funnel and open the tap to release pressure
Allow funnel to stand and layers to seperate
Remove stopper and open tap to allow bottom layer to run into a beaker
Close tap before second layer runs into beaker
Discard aqueous layer
Place organic layer back into funnel and repeat once more
Which liquid will the bottom layer be in the separating funnel?
The one with the higher density
Describe the method to dry the organic liquid
Add spatula of anhydrous calcium chloride/ drying agent to liquid in conical flask
Swirl the mixture
Add more drying agent until liquid changes from cloudy to clear
Filter liquid into clean dry flask
If the boiling points of the reactants and products are very similar, how can they be seperated?
Fractional distillation
If the boiling point of a product in final distillation is similar to the boiling points in data books, is it pure or impure?
Pure
