Why is phenol not soluble in water

Experiments:
Experiment: burning phenol
Experiment: Solubility of phenol

Phenol in crystalline form
(Photo: Helene)


Pure phenol forms colorless, needle-shaped crystals that have a typical hospital smell. It melts at 43 C and boils at 182 C.
If phenol is left to stand in the air for a long time, it turns slightly pink due to oxidation, but this does not interfere with most experiments.

Because of its high carbon content, phenol burns with a glowing, sooty flame. This incomplete combustion is typical for all aromatics. In the case of phenol, even elemental carbon remains. If you continue to heat it vigorously, you can observe a bright glow of the solid (-> experiment). This glow gave the phenol its name (Greek. phainen: to shine; on phenomenon, appearance).

Phenol is only slightly soluble in water. It acts as a weak acid. The water solubility increases sharply with increasing temperature.
Phenol dissolves well in petrol and also in Ethanol (-> attempt). This is where the large hydrophobic / lipophilic hydrocarbon residue has an effect. It works particularly well in a alkaline ethanol solution. The reason for this is that phenol has the properties of a Br nsted acid. It forms negatively charged anions that can easily be dissolved in polar solvents.

Since phenol is toxic (-> on the toxicity of phenol), it goes without saying that it should be removed quickly from the skin if it comes into contact with it. The solubility behavior shows that an alkaline ethanol solution is much better suited for this than, for example, water.


Further texts on the subject of `` phenols ''