Patent ID: 7544766

Claim:
A process for preparing polytetrahydrofuran, polytetrahydrofuran copolymer, polytetrahydrofuran diester or polytetrahydrofuran monoester in a polymerization reactor by polymerizing tetrahydrofuran in the presence of at least one telogen and/or comonomer and of an acidic heterogeneous catalyst, not encompassing heteropolyacids, and based on activated sheet silicates or mixed metal oxides in a fluidized catalyst bed at temperatures from 0 to 80° C., wherein the fluidized bed is operated at the fluidizing point with an expansion factor of the catalyst bed being less than or equal to 1.15 or wherein the fluidized bed is operated as an expanded fluidized bed with the expansion factor of the catalyst bed being from 1.01 to 4, wherein the fluidization is carried out such that no significant amounts of catalyst are discharged from the polymerization reactor, and wherein the reactor is operated in circulation and the ratio of circulation to feed is less than or equal to 200/1.