Preparing a Sample of Organic Liquid: Will need Quickfit apparatus- 1) pearshaped/ round bottom flask, 2) receiver, 3) screw- tap adapter, 4) condenser
and 5) still head.
• Reflux: The continual boiling and condensing of a reaction mixture back to
the original container so contents of the flask don’t boil dry.
• Heating under Reflux: Will need pear- shaped/ round bottom flask,
condenser, heat source (Bunsen burner, tripod and gauze) and stand and
clamp.
• Process: Vapour from mixture rises up tube of condenser. Outer jacket
containing cold water, condenses vapour and drips back into flask.
• Heating: Water bath can be used if reaction below 100oC. For flammable
liquids, heating mantle can be used so no naked flame in case apparatus leak.
• Anti- Bumping Granules: They are added for smooth boiling. Otherwise large
bubbles will form, making glassware jump violently.
• Condenser: Never put stopper in top of condenser- closed system, pressure
would build up as heated air expanded, causing apparatus to explode.
• Rubber Tubing: Water always enters the condenser at the bottom and leaves
at the top to ensure outer jacket is full.
• Distillation:
– Reactions might be incomplete or may produce by-products
alongside desired product.
– Once reflux complete, the product needs to be purified to remove
any remaining reactants or by products- the impurities.
• Setting Up: Condenser horizontal unlike reflux. Water should enter
condenser at the closest point to receiver adapter so condenser fills
with water and promote more efficient cooling. Flask is used to collect
the distillate so apparatus not airtight.
• Process: Heat flask. The different liquids have different boiling points.
One with lowest boiling point is most volatile and will boil first.
Vapour reaches cold condenser, where it condenses to liquid. Liquid
drips into collecting flask.
• Ice beaker/ under receiving flask to keep cool for proper condensing.
Purifying Organic Products: If this happens, will see an organic layer and
aqueous layer inside collection flask.
• Separating Funnel: Add water to identify aqueous layer as it increases in
volume. Use separating funnel to separate organic and aqueous layers.
Bottom layer can be run off into conical flask.
• Removing Acid: If used acids or acid catalysts. Can remove by adding
aqueous sodium carbonate or sodium Hydrogencarbonate in separating
funnel, which will react with acid and release carbon dioxide.
• Tap in separating funnel needs to be slowly opened, to release any gas
pressure built up. Aqueous sodium carbonate layer removed from organic layer with separating
funnel.
• Polarities of substance present- what would end up in a particular layer.
• Can also use sodium carbonate to remove HCl from waste gases. Or can use any alkali, base or
carbonate.
• Drying Organic Product: May be some water left in organic liquid product. Traces of water
removed by adding drying agent- anhydrous inorganic salt. It readily takes up water to become
hydrated. E.g. anhydrous calcium chloride CaCl2 used for drying hydrocarbons.
• Process: If solid has all stuck together in lump, still water left so add more drying agent until solid
dispersed in solution as fine powder. Decant liquid from solid and liquid should be clear.
• Redistillation: Sometimes organic liquids have boiling points close together, so sample may still
contain organic impurities. Only distil product at specific boiling point of the compound trying to
make. The narrower the boiling range, the purer the product.
• Should re- distil after any of these methods, if question mentions any temperature range.
• Concentrated sulphuric acid is corrosive. Butan-1- ol is flammable.
• When ‘liquid mixture containing organic products and acid catalysts’. Need to do a number of
purification techniques. Liquid = separating funnel and anhydrous salt. Mixture = Redistillation.
– Use of separating funnel to separate organic and aqueous layers.
– Drying with anhydrous salt e.g. calcium chloride or magnesium sulphate.
– Redistillation.