Verification of alkenes with concentrated sulphuric acid
cyclohexene F Xn R 11-22 S 9-16-23-33
sulphuric acid 96 % C R 35 S (1/2)-26-30-45
Instead of cyclohexene one can also use other alkenes.
- Cyclohexene stinks, provide for ventilation! Safety goggles!
- One adds to a test tube 4-5 drops cyclohexen.
- Now one adds approx. 0.5 concentrated sulphuric acid and sways a bit back and forth. Accompanied by a slight generation of heat a unified, turgid phase is formed which quickly becomes yellow and then after 1-2 minutes orange.
- After adding plenty of water (caution!) to the reaction mixture it can be discharged into the drainage.
Sulphuric acid combines as a 1,2-addition with the alkene. Cyclohexyl sulphuric acid is formed which dissolves in concentrated sulphuric acid.
Reaction mixture shortly after the addition of sulphuric acid.
Reaction mixture after about 2 minutes.
Derived from experiment 19.3 (D), "Sulfuric Acid", p. 266,