Phenols

Phenols are often used as what?

Antiseptics and disinfectants

What is the overall reaction for the bromination of phenol?

What are the observations for the bromination of phenol? How does this compare to benzene?

Orange solution to a white solid/ precipitate in a colourless solution

Benzene: orange solution to colourless solution

What are the reaction conditions for the bromination of phenol?

Room temperature and pressure

NO halogen carrier

Why is phenol bromination at the 2 and 4 position?

The hydroxyl group is a 2 and 4 directing group

Why is a halogen carrier required for the bromination of benzene but not phenol?

Phenol is more reactive than benzene: has a higher electron density

The lone pair on oxygen from the hydroxyl group in phenol is delocalised into the ring

The hydroxyl group can activate the aromatic ring which increases its electron density

Phenol is able to induce a dipole in bromine:

ELECTROPHILE IS MORE POLARISED

What is the overall reaction for the nitration of phenol?

What are the reaction conditions for the nitration of phenol?

Room temperature and pressure

DILUTE nitric acid

No sulfuric acid

Why doesn’t trisbustituion take place when phenol is nitrated?

Nitro group is a deactivating group

Nitro group reduces the electron density of the aromatic ring by drawing π electrons from the aromatic ring towards it

The aromatic ring is less susceptible to electrophilic attack

Why is phenol partially soluble in water?

The hydroxyl group can form hydrogen bonds with water molecules

The aromatic ring is non-polar so can’t form hydrogen bonds with water

What is the observation when universal indicator is added to phenol? Why?

Orange colour

Phenol is a weak acid

It partially dissociated in aqueous solution: higher concentration of phenol that the phenoxide ion

What is the observation when phenol reacts with NaOH? Why?

Phenol completely dissolves

Soluble salt and water is formed

What is the equation for the partial dissociation of phenol?

What is the equation for the reaction between phenol and NaOH?

Why can’t phenol react with weak bases? What are examples of weak bases?

Since it is a very weak acid

E.g sodium carbonate or calcium carbonate

How acidic is phenol compared to alcohols and carboxylic acids?

Phenol is more acidic than alcohols but less acidic than carboxylix acids

How do you test for phenol?

indicator - orange

no reaction with carbonate

OR

bromine water - white precipitate in a colourless solution