A process for the removal of by-products from a phenolic mixture, which process may include the following steps: subjecting a phenolic mixture to extractive distillation to produce an initial phenolic mixture, contacting the initial phenolic mixture containing phenol and one or more by products with a catalyst to produce a first purified phenol product mixture, and distilling the first purified phenol product mixture to produce a second purified phenol product mixture; wherein the extractive distillation is carried out in two columns, a higher pressure column and a lower pressure column.