Alcohols and Phenols
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What are alcohols?
They are organic molecules that contain the functional group OH
Suffix
Usually “-ol” unless there are higher priority functional groups like amines or aldehydes. Then we use the prefix “hydroxy-“
Melting and boiling point
both high because of the hydrogen bonding. this increases with additional hydroxyl groups (OH groups)
Are alcohols strongly or weakly acidic?
weakly with pKa of 15-17 (weaker than water)
How can an acid be made stronger?
by adding electron-withdrawing substituents
How can an acid be made weaker?
by adding electron-donating substituents
What is the conjugate base of an alcohol called?
Alkoxide weaker acid = stronger conjugate base
How to turn an alcohol into a ketone
add an oxidant
How to turn an alcohol into an aldehyde
add an oxidant
How to turn an alcohol into an ether
add an alkyl halide or acid or base
Oxidation
increase in the number of bonds to electronegative element or decrease in number of bonds to hydrogen
Reduction
decrease in the number of bonds to electronegative element or increase in number of bonds to hydrogen
Oxidation of alcohol
Primary alcohol (OH goes to aldehyde or carboxylic acid) secondary alcohol (OH to ketone) tertiary alcohol (cannot go further)
Oxidizing agent
PCC turning hydroxyls into carbonyls (is not strong enough to go to carboxylic acid)
Oxidizing agent that is strong
Na2Cr2O7 (sodium dichromate), potassium dichromate, chromium trioxide (CrO3) -metal and several oxygens
Protecting groups
stop the alcohol from being so reactive EX) silyl ethers, mesylate, tosylate
Phenol
Hydroxyl group added to an aromatic benzene ring
Are phenols or alcohols more acidic?
phenols because of their ring (pKa of 10)