Phenol preparing, reactions, physical properties

Phenol is an oxygen substituted organic compound. Phenol is an insoluble compound in water. Phenol has a characteristic smell and can act as a germicidal. Preparing phenol, reactions of phenol, characteristics of phenol are sections you have to learn under phenol lesson.

phenol molecule
Fig 01: phenol molecule

Physical properties of phenol

  • colourless, crystalline solid.
  • Phenol turns into pink colour when it is exposed to the air.
  • Melting point: 430C
  • Boiling point : 1820C
  • There is the characteristic carbolic acid smell

Phenol in water

Phenol makes hydrogen bonds with water. Therefore phenol should dissolve in water. Adding more phenol into the water will make separate layers of both substances.

Phenol dissolve in ether and ethanol very well.

Uses of phenol

  • Dilute solutions of phenol is used as germicides.
  • As a raw material of dyes, pharmaceutical, detol, bakelight.
  • to manufacture herbicide

Preparation of phenol

Prepare phenol from benzene

We cannot synthesis phenol from benzene in a single step. We have to follow several steps to prepare phenol from benzne.

  1. Benzene is translated into the nitrobenzene by adding concentrated H2SO4 and Concentrated HNO3 at 400C.
  2. Aniline is prepared by nitrobenzene. Zn, concentrated HCl as added to the nitrobenzene and then add excess NaOH to the given aniline salt to get release aniline.
  3. NaNO2(aq) and concentrated HCl(aq) is added into the aniline between 0-50C. It will produce benzene diazonium chloride.
  4. Finally, water is added to the benzene diazonium chloride at higher temperatures than 100C.
phenol from benzene, nitrobenzene and aniline

Reactions of phenol

Phenol with sodium hydroxide reaction

Phenol is a weaker acid than carbonic acid. Phenol react with sodium hydroxide (NaOH) and give sodium phenoxides. This reaction can be used identify phenol and alcohols because alcohols do not react with NaOH.

Sodium phenoxide - C6H5O-Na+

Phenol and sodium carbonate reaction

Phenol does not react with sodium carbonate (Na2CO3)

Phenol and sodium bicarbonate reaction

Phenol does not react with sodium carbonate (NaHCO3)

Phenol and ferric chloride

Phenol gives violet colour with ferric chloride(FeCl3). This reaction is characteristic of all compounds containing the group -C(OH)=C. This reaction can be used to identify phenol from other compounds.

Reactions of phenol

Phenol is ortho para activator and a weak acid. Electrons density of benzene ring in phenol is much higher than benzene. Therefore substitutions reactions of phenol occurs much easier than benzene. Phenol reactions are explained below.

  1. Phenol and strong metals reaction/li>
  2. with strong alkalis
  3. Phenol and halogen
  4. Phenol with dilute and concentrated nitric acid

Phenol and strong metals reaction

Phenol reacts strong metals such as sodium, potassium to give hydrogen gas and sodium phenoxide. This indicates, phenol has acidic characteristics.

Phenol and sodium reaction

Phenol and aqueous NaOH reaction

Phenol reacts with NaOH(aq) to give H2O and sodium phenoxide.

Phenol reacts with KOH(aq) to give H2O and potassium phenoxide.

This reaction is used to identify phenol and alcohols. Alcohols do not react with aqueous NaOH or KOH.

Phenol and sodium hydroxide reaction

Note: Phenol do not react with Na2CO3 or NaHCO3.

Phenol and halogen reaction

Phenol reacts with halogens easily and give precipitates. Also we don't need to add lewis acids such AlCl3.

Phenol and aqueous bromine reaction

2,4,6-tribromophenol is given as the product. Aqueous Br2 solution is yellow brown in colour. When phenol is added to the Br2(aq) solution, the white precipitate, 2,4,6-tribromophenol is formed.

Phenol and aqueous bromine reaction

Phenol and dilute nitric acid reaction

Phenol and dilute nitric acid react to give a mixture of ortho-nitrophenol and para-nitrophenol. This shows phenol is a strong activator because we do not need concentrated HNO3 or heating.

Phenol and dilute nitric acid reaction

Phenol with acid chloride or acid anhydride reaction

Phenyl esters are given as given.

Phenol and acid chloride reaction

Phenol reacts with ethanoyl chloride to give phenyl ethanoate / phenyl acetate.

Phenol and acid chloride reaction

Phenol and acid anhydride

Phenol and acid anhydride reaction

Phenol reactions summary

phenol reactions summary

Organic chemistry tutorials


Halogen derivatives organic compounds

Oxygen derivatives of organic compounds

Nitrogen derivatives of organic compounds