Phenols Flashcards
What is a phenol and how is reactivity dif to benzene
OH group directly attached to benzene ring, lp of electrons on oxygen delocalised with electron charge cloud of arene ring so delocalised bonding increases reactivity as electron density higher
How is phenol different to carboxylic acid in terms of reactions as acid
Cannot react with sodium carbonate which COOH can as not strong enough
What does phenol produce when reacted with sodium metal/NaOH and how this differs to phenol in terms of properties
Sodium phenoxide (benzene ring with O-andNa+ attached), more soluble than phenol so phenol dissolves on addition of NaOH
How does reaction with bromine differ between phenol and benzene and why
Add bromine water at room temp, do not need FeBr3 catalyst like benzene and undergoes multiple substitutions while benzene only adds one Br
-as in phenol lp of electrons on oxygen is partially delocalised into ring so electron density in ring greater making it less stable and bromine more polarised
What is produced by bromination of phenol and what is observed
2,4,6-tribromophenol and HBr
-white precip and smell of antiseptic, decolourises bromine water
What are phenols used in production of
Plastics and antiseptics
State and colour of phenol
Almost colourless crystalline solid with low mp
Why is phenol more acidic than other alcohols
As conjugate base C6H5O- is more stable due to delocalisation and O-H bond more polar and weaker due to increased electronegativity of oxygen so more able to donate hydrogen ion
How is C-O bond different to other alcohols, how can this be seen and what does this mean
Shorter (IR spectroscopy) as some electron density between oxygen and delocalised electron ring, makes OH substitution unlikely
Why is substitution at 2,4,6 positions
As electron density greatest here due to pi and p orbital overlap
How is nitration of phenols different
No catalyst and use dilute nitric acid
