The invention provides a process for preparing polytetrahydrofuran,
tetrahydrofuran copolymers, their monoesters or diesters and the
monoesters or diesters of polytetrahydrofuran having a low color number
in the presence of a catalyst, which comprises converting crude
tetrahydrofuran which has been prepared in a manner per se into pure
tetrahydrofuran by distillation, subsequently subjecting the latter to
essentially complete hydrogenation and using the high-purity
tetrahydrofuran obtained in this way for the polymerization directly
after its preparation.