Phenol to benzene | phenol distillation with zinc dust
Phenol to benzene organic conversion has only a single step. Phenol is distilled with zinc powder to prepare benzene.
Preparation of benzene from phenol
The -OH group of the phenol is eliminated and Zn is oxidized to zinc oxide ( ZnO ) when benzene is prepared.
Is phenol to benzene reaction is oxidizing reducing reaction?
Yes. Phenol and Zn powder distillation reaction is oxidizing reducing reaction (redox reaction). Zn is oxidized to ZnO. The carbon atom which is connected to -OH, is reduced.
Phenol reduction
Phenols can be reduced by distillation with more reagents such as Hydrogen iodide (HI) and red phosphorus as zinc dust. But these methods are quite poor and are seldom feasible. Catalytic hydrogenation has also been used, but the corresponding cyclohexanol is a side product. So we cannot get clean product from these reagents.
Differences of physical properties of phenol and benzene
There are differences in properties of phenol and benzene. That can used to identify phenol and benzene.
- Both phenol, benzene are liquids in room temperature.
- Both phenol and benzene are colourless liquids.
- Phenol has weak acidic characteristic, benzene does not have acidic characteristics.
- Phenol can make hydrogen bonds.
- Phenol has higher boiling point than benzene.
- Both Phenol and benzene are insoluble compounds in water.
How to identify phenol and benzene?
Here, we are going to consider about some reactions of benzene and phenol.
Phenol reacts with sodium metal and give hydrogen gas. But benzene does not react with sodium.
Phenol reacts with NaOH(aq), but benzene does not react with NaOH(aq).
Phenol gives 2,4,6-tribromophenol white precipitate with bromine liquid.
Questions asked on phenol to benzene
Will oxidation numbers be changed during the reaction?
The carbon atom which is joint with -OH group is oxidized when benzene is given because that carbon atom is joint with a hydrogen atom.
Are there a change in physcal state during phenol to benzene?
Both phenol and benzene are liquids ar room temperature. But, the reagent zinc exist in solid state at room temperature.
What is the colour of zinc oxide ( ZnO ) ?
Zinc oxide is white powder. On heating it is changed to yellow colour. When cooling back, again it takes white colour.
Is there a gas phase in phenol to benzene
No, both phenol and benzene are liquid states at room temperature.