C6H6 -> C6H6*2 = C12H12 -> C6H6 + 3O2 -> C6H6O6 (phenol) -> C6H6O6 + O2 (catalyst) -> C12H10O6 (phthalic acid)
C6H6 -> C6H6*2 = C12H12 -> C6H6 + 3O2 -> C6H6O6 (phenol) -> C6H6O6 + O2 (catalyst) -> C12H10O6 (phthalic acid)