A process is described for the recovery of phenol and biphenols from their homogeneous mixtures containing benzene, sulfolane and water, which is based on the use of an alkaline solution and benzene for the separation of biphenols from sulfolane, after removing the benzene, H2O and phenol contained in the reaction effluent. The process allows the recovery of phenol and biphenol by-products dissolved in sulfolane, directly obtaining the purified solvent containing the benzene necessary for the feeding to the reactor for the direct oxidation of benzene, as well as the biphenols dissolved in water and pure phenol.