Basf Aktiengesellschaft

Wulfrich Friedemann Beer

Alexander Weck

Lothar Franz

Frank-Friedrich Pape

Wolfgang Franzischka

Volkmar Menger

Axel Paul

Jürgen Ciprian

Christof Palm

Ulrich-Dieter Pessel

Klaus Beiser

In a process for preparing polytetrahydrofuran having terminal OH groups (PTHF) from the corresponding polytetramethylene ether having acyloxy end groups by transesterification with alcohols in the presence of a sodium-containing catalyst followed by passing the alcoholic PTHF solution in the presence of a catalytic amount of water directly through at least one ion exchanger to remove the sodium ions, the removal of the sodium ions is carried out in a fully continuous ion exchange unit which comprises:

Method of producing an alcoholic solutions of polyetrahydrofurane that comprises terminal OH groups

The invention relates to a process for preparing hydroxyl-containing polymers, in particular for preparing polytetrahydrofuran with terminal hydroxyl groups, from the corresponding acyloxy-containing polymers by transesterification with alcohols in the presence of a sodium-containing catalyst. In this process the polytetrahydrofuiran solution is passed in the presence of a catalytic amount of water directly through at least one ion exchanger following the transesterification in order to remove the sodium cations. The novel process makes it possible to remove the sodium cations from the sodium-containing catalyst in an economic manner and with little complexity. The residual sodium content can be reduced to values of less than 0.5 ppm.

Preparation of polytetrahydrofuran with terminal hydroxyl groups using

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Neustadt, Germany

Wulfrich Friedemann Beer