PURPOSE: To recover diphenyl useful as a dyeing carrier, antifungal agent, etc., for citrus fruits from a diphenyl-containing fraction in high purity and yield, by passing through an azeotropic distillation step with diethylene glycol, cooling and crystallization step of the azeotropic fraction and recrystallization step.

CONSTITUTION: A diphenyl-containing fraction, e.g. coal tar fraction having 220W280°C boiling point, is subjected to azeotropic distillation with diethylene glycol to collect an azeotropic fraction of the diphenyl with the diethylene glycol and remove impurities other than ethylnaphthalenes, e.g. indoles, etc., inseparable by ordinary distillation because of the boiling point extremely close to that of diphenyl. The above-mentioned azeotropic fraction is then cooled to separate depositing crystal substances and ethylnaphthalenes remaining in the afore-mentioned fraction are removed. Furthermore, the obtained crystals are recrstallized in the presence of a solvent to afford the aimed high-purity diphenyl in high yield from the diphenyl-containing fraction obtained by distilling coal tar.