how can a phenol be separated from a mixture of a phenol & a neutral compound using acid-base extraction?

Answer 1

Phenols are acidic, thus adding a base (e.g. NaOH) would titrate the phenol out, while the neutral compound will not react with the base. :)

Answer 2

First you make the water basic (pH > 10). Then you extract 3 times with an organic solvent such as Methylene Chloride. By making the water basic you are turning phenol into a salt which is water soluble and not organic soluble. If you do 3 extractions under this condition you will extract the neutral compound but leave the salt of phenol in the aqueous layer. After these three extractions, make the water acidic (pH<3) and extract 3 more times. By making the water acidic, you are changing the phenolic salt back to phenol which is more soluble in the organic solvent then the aqueous layer. If you evporate the solvent you will have each of the pure compounds.

Answer 3

You must define if the neutral compound is volatile, dissolves in water, or what. For example suppose that it is volatile. Phenol is a weak acid, so you add a base, NaOH, to the mixture. Phenol reacts to form a non-volatile salt:

C6H5OH + NaOH -> C6H5ONa + H2O

Then you heat the mixture and the volatile neutral compound evaporates. You get the solid salt C6H5ONa. Then add a strong acid and you get phenol back:

C6H5ONa + HCl -> C6H5OH + NaCl

Answer 4

if you are planning to extract an acid in an organic solution, i would suggest that you add base to that to make it hydrophilic and then shake it up with water. by doing this your acid will be transferred to the aquas section