6.2.5 Organic Synthesis

Question 1

Apparatus for filtration under reduced pressure

Answer 1

Büchner funnel
Büchner flask
Pressure tubing
Filter paper
Vacuum pump

Question 2

Steps in filtration under reduced pressure

Answer 2

Connect apparatus to vacuum pump, place filter paper and wet with solvent
Pour reaction mixture
Rinse beaker with solvent
Rinse crystals and leave to dry

Question 3

Why would you filter under reduced pressure

Answer 3

To separate a solid product from a solvent or liquid reaction mixture

Question 4

How to carry out recrystallisation

Answer 4

Add minimum volume of hot solvent to dissolve impure solid
Allow solution to cool to reform crystals
Filter under reduced pressure
Use melting point apparatus to determine purity and compare with data book values