Phenols Flashcards
properties of phenols
crystalline solid
melting point of 43 degrees
airly soluble in water, forming a weak acid solution called carbonic acid
obtained from CoalTar
acidic property of phenol
2 lone pairs of electrons on the oxygen (one is a 2p orbital which becomes partially delocalized around the ring)
the oxyen will exert a stronger pull on the bonding pair of the OH bond
results in: the OH bond becoming weaker, the H atom becoming more positive
the C-O bond becoming stronger
how do deactivating groups increase the acidity of phenol?
they pull the electrons away from the ring which results in electrons from the oxygen drifting more into the ring and away from the hydrogen
this will weaken to OH bond, making the compound a stronger acid
which reactions involve the breaking of the OH bonds
- Reaction with NaOH
- Esterification
what happens when Na is added to a solution of phenol?
Na atoms replace the hydrogen of the OH group and H2 is evolved
reaction with NaOH
phenol reacts readily with NaOH, forming sodium phenoxide and water
reactions with other organic compounds are performed by dissolving them in NaOH first
esterification of phenols
reacting phenol with the acyl chloride
reactions involving the breaking of the C-OH bond
there are no reactions in which the C-OH bond is broken, meanin that the C-OH bond is partially double bonded
no reaction with SOCl2 or POCl5
reactions involving the ring (reaction with bromine)
when phenol is added to aqueous bromine, a white precipitate of 2,4,6-tribromophenol is formed
what happens during the reaction with Bromine?
slight effervescence due to HBr gas formed
white precipitate is formed
reddish brown colour of the bromine will disappear
test for phenols
add a few drops of FeCl3 solution to phenol and a violet colour will appear
uses of phenols
manufacture of carbonic soap
manufacture of aspirin
manufacture of dyes
manufacture of bakelite
