Chapter 16 - Organic Synthesis Flashcards
What apparatus is needed for heating under reflux?
- round bottom or pear shaped flask
- condenser
- rubber tubing
- stand and clamp
- heat source (usually Bunsen, tripod and gauze or heating mantle)
What apparatus is needed for distillation?
- round bottom or pear shaped flask
- condenser
- rubber tubing
- heat source
- stand and clamp
- screw cap adaptor
- receiver adaptor
- still head
- thermometer
What is the procedure for drying an organic liquid?
- Add organic liquid to a conical flask and use a spatula to add some of drying agent to liquid and gently swirl the contents to mix together.
- Place a stopper on the flask to prevent your product from evaporating away, and leave for about 10 minutes.
- If the solid has all stuck together in a lump, there is still some water present. Add more drying agent until some solid is dispersed in the solution as a fine powder.
- Decant the liquid from the solid into another flask, if this liquid is dry it should be clear.
What are 2 common inorganic salts used for general drying of organic liquids?
Anhydrous calcium sulfate (CaSO4)
Anhydrous magnesium sulfate (MgSO4)
What common inorganic salt is used to dry hydrocarbon organic liquids?
Anhydrous calcium chloride (CaCl2)
How can you separate an organic layer from water using a separating funnel?
- Pour liquids into funnel and invert to mix, ensuring tap is closed and stopper is on
- Allow layers to settle then add some water to see which layer increases in volume - this is the aqueous layer
- Place conical flask under funnel and open tap until whole of lower layer has left funnel.
- Now collect the second layer in a separate conical flask
How can you remove acid impurities from an organic product?
Add aqueous sodium carbonate and shake mixture in separating funnel. Tap must be slowly opened to release gas pressure from CO2 formed by sodium carbonate. Finally the aqueous sodium carbonate layer is removed and the organic layer washed with water before running both layers off into 2 separate flasks
What is redistillation and why might it be needed?
Redistillation is when distillation appratus is cleaned and dried and set up again so that a second distillation can be carried out.
Needed because sometimes organic liquids have boiling points that are relatively close together, so prepared sample may still contain some organic impurities
What is organic synthesis?
The preparation of complex molecules from simple starting materials
What does the term ‘target molecule’ mean?
Used to describe the compound that the chemist is attempting to prepare by organic synthesis
What is the type of reaction for the conversion of an alkane to haloalkane, and what reagents/conditions are required?
Free radical substitution
Reagents: halogen
Conditions: UV light
What is the type of reaction for the conversion of an alkene to alkane, and what reagents/conditions are required?
Hydrogenation/addition
Reagents: H2
Conditions: Nickel catalyst
What is the type of reaction for the conversion of an alkene to haloalkane, and what reagents/conditions are required?
Electrophillic addition
Reagents: hydrogen halide
Conditions: n/a
What is the type of reaction for the conversion of an alkene to dihaloalkane, and what reagents/conditions are required?
Electrophillic addition
Reagents: halogen
Conditions: n/a
What is the type of reaction for the conversion of a haloalkane to alcohol, and what reagents/conditions are required?
Nucleophillic substitution
Reagents: NaOH or KOH (aq)
Conditions: heated under reflux
