Process for the preparation of oligomeric aliphatic diols, polycarbonatediols prepared using these oligomeric aliphatic diols and their prepolymers.

摘要

A method (M1) for the production of oligomeric aliphatic diols (I) in which the reaction mixture is worked up by phase separation to give an organic phase and an aqueous phase. Independent claims are also included for: (1) a method (M2) for the production of (I) by (a) oligomerization of aliphatic diols in presence of an acid catalyst and an entraining agent, with azeotropic distillation of reaction water, (b) reaction with aqueous base, with hydrolysis of any ester which may have formed, (c) adjustment to pH 4.0-8.0 by adding non-oxidizing inorganic acid or a salt thereof and (d) phase separation, removal of water and filtration; (2) a method (M3) for the production of polycarbonate-diols (II) by reacting (I) with a sub-stoichiometric amount of a carbonate source in presence of a catalyst; and (3) a method (M4) for the production of NCO-terminated prepolymers by reacting a sub-stoichiometric amount of (II) with a polyisocyanate.