tetrahydrofuran in tetrahydrofuran byproducts: hexamethylbenzene; Ar-atmosphere; addn. of Ti-complex to excess THF cooled to -120°C, warming to room temp.; volume reduction, cooling to -30°C (crystn. of TiCl4(THF)2 ), evapn. of soln., heptane addn., filtration of second crop of TiCl4(THF)2, volume reduction, crystn. on cooling (-30°C), decantation, drying(vac.);

in toluene byproducts: hexamethylbenzene, TlAlCl4; Ar-atmosphere; addn. of TlCp to suspn. of Ti-complex, stirring (15 h, room temp.); filtration, volume reduction, pptn. on heptane addn., filtration, washing (heptane), drying (vac.);