Organic Practical Techniques

A basic set of Quickfit apparatus

1) round-bottom or pear-shaped flask 2) receiver 3) screw-top adaptor 4) condenser 5) still head

To overcome the activation energy and increase the rate of reaction as many are slow at room temperature

To prepare an organic liquid without boiling off the solvent, reactants or products

1) round-bottom or pear-shaped flask 2) condenser 3) rubber tubing 4) clamp and stand 5) heat source (bunsen burner with a tripod and gauze)

A water bath

A reaction under reflux to be carried out a fixed temperature

A heating mantle so that no naked flame is present, giving an added level of safety should any of the apparatus leak or crack

Anti-bumping granules so that the contents will boil smoothly - without the granules, large bubbles form at the bottom of the liquid and make the glassware vibrate or jump violently

1) apply a thin layer of grease to the ground-glass joint on the condenser 2) place the condenser carefully into the flask and gently rotate the condenser back and forth to provide a good seal

1) keep the condenser in the upright position 2) clamp it loosely to prevent breakage 3) never put the stopper in the top of the condenser bc otherwise you will have a closed system in which pressure would build up as the heated air expanded - the apparatus could explode

• It is used to connect the inlet of the condenser to the tap and the outlet into the sink • Water always enters the condenser at the bottom and leaves at the top to ensure that the outer jacket is full

A liquid to be continually boiled whilst the reaction takes place, preventing volatile contents from escaping and the flask from boiling dry

Vapour from the mixture rises up the inner tube of the condenser until it meets the outer jacket containing cold water, when it condenses and drips back into the flask

The crude product needs to be purified to remove any by-products or reactants as the reaction may not have gone to completion or produced by-products

The method used to separate pure liquid from impurities

1) round-bottom or pear-shaped flask 2) condenser 3) rubber tubing 4) heat source 5) clamp and stand 6) screw-cap adaptor 7) receiver adaptor 8) still head 9) thermometer

1) the flask is clamped by its neck and the still head is connected to the flask 2) the still head adaptor is T shaped and has two ground-glass joints, one to fit the screw-cap adaptor and one for the condenser 3) a second clamp is placed around the receiver adaptor/condenser joint, removing the need to clamp the condenser, as it will be supported sufficiently at both ends 4) a flask is used to collect the distillate so that the distillation apparatus is not completely airtight

So that the apparatus comes apart easily after the experiment

At the lowest point (the point closest to the receiver adaptor)

1) the flask is heated and the mixture in the flask starts to boil 2) the different liquids in the mixture will have different boiling point - the liquid with the lowest boiling point is the most volatile and will boil first 3) the vapour moves out of the flask up into the other parts of the apparatus, leaving behind less volatile components of the mixture 4) when the vapours reach the cold condenser, they condense and this liquid then drips into the collecting flask 5) collect the liquid in the the known boiling point range of the desired product and discard any products below the known boiling point

There will be two layer in the collection flask - one organic layer and one aqueous layer

Add some water to the mixture and the layer that gets bigger is the aqueous layer

A separating funnel