Abstract: The invention is related to petrochemistry and is useful in the process of combined production of phenol and acetone by the cumene method. The method is a two stage process which minimizes waste water volume, diminishes equipment corrosion and minimizes consumption of cumene. In the first stage, the phenol tar is treated with a 2-5% water solution of a water soluble amine at a ratio of 1:1.5-1:4.0 to produce two layers, water and organic. At the second stage the water layer from the first stage is thermotreated. As a result, water soluble amino phenate decomposes to amine and phenol. Gaseous amine is removed from the system and then recycled to the first stage. The phenol water solution obtained from the thermotreatment is extracted by standard extraction agents (e.g. diisopropylether, cumene).The water layer from the phenol extraction is about 50-95% of the original water solution employed in the first stage and is then saturated with the amine and recycled to the first stage.