Narrowing the molecular weight distribution of polytetrahydrofuran

A process for narrowing the molecular weight distribution of polytetrahydrofuran which has been obtained by polymerization of tetrahydrofuran using a cationic catalyst, which method comprises:

• heating the polytetrahydrofuran for depolymerization in the presence of a bleaching earth or a zeolite as a catalyst while simultaneously distilling off tetrahydrofuran, at a temperature from 80.degree. to 280.degree. C., said initial polytetrahydrofuran to be depolymerized having a number average molecular weight of from 650 to 3000, a molecular weight distribution (Mw/Mn) of from 1.5 to 4 and a viscosity of from 1 to 70 poise (at 40.degree. C.), and said heating being carried out for a period of time sufficient only to depolymerize from 10 to 40% by weight of the initial polytetrahydrofuran and to produce a reduced molecular weight distribution (Mw/Mn) of from 1.2 to 2.5.