Patent ID: 6878802
Filing Date: 2005-04-12
Classification: C08G

Abstract:
1. A process for preparing an alcoholic solution of polytetrahydrofuran having terminal OH groups (PTHF) from the corresponding polytetraxmethylene ether having acyloxy end groups by transesterification with alcohols in the presence of an alkali or alkali earth metal 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 alkali or alkali earth metal ions, wherein the removal of the alkali or alkali earth metal ions is carried out in a fully continuous ion exchange unit which comprises: a plurality of ion exchange cells which are arranged on a rotary platform and are each provided with a distribution element and a collection element and a central valve having a stator disk and a rotor disk via which the introduction and discharge of all liquid streams into or out of the ion exchange unit occurs, and feed and discharge lines from the distribution or collection element of each ion exchange cell to the central valve.