Organic synthesis Flashcards
What is Quickfit apparatus? (2 points).
- Apparatus designed to fit together and provide a good seal.
- Each joint is thinly layered in grease to allow a good fit but ensures the equipment comes apart easily afterwards.
Definition of reflux (3 points).
- Continuous evaporation and condensation.
- Heating under reflux enables a liquid to be continuously boiled whilst the reaction takes place.
- This prevents components from escaping the flask from boiling dry.
Why are anti-bumping granules added?
To ensure the boiling is smooth.
Draw a labelled diagram of quick-fit apparatus for a reflux experiment
*Refer to organic synsthesis notes
Why is water going into the condensor at the bottom?
For more efficient cooling.
Definition of distillation
A method used to separate a pure liquid from impurities.
Draw a labelled diagram for a distillation experiment
*Refer to organic synsthesis notes
What is the separated liquid in distillation called?
The distillate
What are the 3 steps for the preparation and purification of an organic liquid?
- Use of a separating funnel.
- Drying with an anhydrous salt.
- Redistillation.
What are the two layers seen when preparing an organic liquid?
Organic and a water layer.
What peice of equipment is used to separate the two layers?
A separting funnel
Describe how to separate the organic and water layer (3 points).
- To confirm which layer is which, add distilled water and observe which layer gets bigger.
- Once the layers are separate, place a beaker or conical flask under the tap of the funnel and open the tap to allow the bottom layer to run out.
- Use a separate beaker to collect the other layer in the same way. (The densities of the liquids will depend which layer is at the bottom).
Describe how to clean the product by removing any acid (4 points).
- Place the organic layer back into the separating funnel and add aqueous sodium carbonate solution to neutralise any acid present.
- Place the stopper in the neck of the funnel and shake to mix the aqueous and organic layers.
- The stopper needs to be released frequently as gas (carbon dioxide) is being produced, so the pressure needs to be released.
- Clamp the funnel in an upright position and leave the liquids to separate. Run off the organic layer as before.
Defintion of a drying agent
An anhydrous inorganic salt that readily takes up water to become hydrated.
What are the 3 examples of drying agents?
- Anhydrous calcium chloride (CaCl2).
- Anhydrous calcium sulfate (CaSO4).
- Anhydrous magnesium sulfate (MgSO4).
Describe how to dry the product (6 points).
- Using a spatula, add some of the drying agent to the organic liquid in the beaker.
- Mix the contents and cover the beaker if the liquid is volatile.
- Leave for about 10 minutes.
- If the solid has formed into a lump, there is still some water present, so add more solid and mix again.
- Do this until some solid remains as powder.
- The solid could be removed once drying has taken place by filtration.
Describe how the product would be re-distilled (5 points).
- The product may need to be distilled again as organic liquids sometimes have similiar boiling points.
- The distillation apparatus is cleaned, dried and set up as before.
- During the distillation, only the target product is collected.
- To ensure this, only collect the product using the boiling point of the desired product.
- The narrower the boiling point range, the purer the product.
EXAM: Describe the preparation and purification of organic liquids
- Separate the two layers
Use a separating funnel.
Two layers: organic and aqueous.
Look out for densities; lower density is upper layer and higher density will sink, so is the lower layer. If necessary- remove any acid.
Add aqueous sodium carbonate.
Open stopper frequently to avoid build up of pressure- build up of gas (CO2(g)). - Add a drying agent.
Anhydrous: HAVE TO NAME.
Remove by filtration. - Distillation.
To separate organic product.
Only collect liquid at a temperature of biling point of desired product.
Definition of organic synthesis
The preparation of complex molecules from simple starting materials.
Definition of target molecule
Describes the compound that the chemist is attempting to prepare by organic synthesis.
