PAG 05a: Synthesis of an organic liquid- synthesis of a haloalkane Flashcards
What type of reaction occurs when a haloalkane is formed from an alcohol?
Nucleophilic substitution
Write word and chemical equations for the formation of 2-chloro-2-methylpropane from 2-methylpropan-2-ol
2-methylpropan-2-ol + hydrochloric acid -> 2-chloro-2-methylpropane + water
CH3C(CH3)2OH + HCl -> CH3C(CH3)2Cl + H2O
What are 3 main stages in synthesis of a haloalkane from an alcohol?
- Preparation
- Separation
- Distillation
Why do 2 layers form in the separating funnel when synthesising a haloalkane from an alcohol?
The aqueous and organic layers have different densities and they are immiscible
What is purpose of anti-bumping granules?
To prevent formation of large gas bubbles that cause violent boiling.
During distillation, anti-bumping granules prevents the mixture boiling over into the condenser meaning impurities won’t contaminate the product
When producing a haloalkane from an alcohol, why is sodium hydrogen carbonate added to the organic layer after it has been separated from the aqueous layer?
To react with any leftover hydrochloric acid
Why is it important to open the stopper of the separating funnel regularly?
To release build up of pressure and reduce risk of apparatus breaking
When producing a haloalkane from an alcohol, why is anhydrous sodium sulfate added to the organic mixture after separation?
To remove water (small amounts only)- acts as a drying agent
Why is distillation used when synthesising a haloalkane from an alkane?
To separate and purify the organic product
Describe key features of the apparatus set-up for distillation
- Tilt the condenser down so any liquids flow into the beaker
- The water must enter at bottom of condenser and leave at the top for efficient cooling
- The collection flask should not be sealed to the condenser- it should not be airtight as the hot air in the system could cause the apparatus to crack
- Use a thermometer to identify when the desired product has evaporated from reaction mixture
Why might a water bath or electric heater be used instead of a Bunsen burner to heat a reaction mixture?
If reactants are flammable as using a bunsen burner would be a safety risk
What safety precautions should be taken when carrying out this practical?
-2-methylpropan-2-ol is highly fllammable and harmful if inhaled. Keep away from naked flames and keep the lab well ventilated.
- Concentrated sulfuric acid causes severe skin burs and eye damage. Use a fume cupboard and wear safety goggles and gloves.
- Take care when heating apparatus. Move hot apparatus with tongs to avoid burns.
