VERFAHREN ZUR EINENGUNG DER MOLEKULARGEWICHTSVERTEILUNG VON POLYTETRAHYDROFURAN UND VON COPOLYMERISATEN AUS TETRAHYDROFURAN UND ALKYLENOXIDEN.

摘要

Redn. of the polydispersity of polytetrahydrofuran (PTHF) (IA) and copolymers (IB) of THF and alkylene oxides (to give narrow mol. wt. distribution) involves: (1) distilling the low mol. polymer fraction off at pressures below 0.3 mbar and temps. of 200-260 deg. C; (2) mixing the distn. residue with a solvent mixt. of (a) a 1-4 C alkanol, (b) a 3-18 C hydrocarbon and (c) water, which contains 4-60 wt.% of each component a, b and c; (3) sepg. the phases formed; and (4) isolating (I) with narrower mol. wt. distribution from the phases. Pref. (a) is MeOH or EtOH; and (b) a 4-12 C aliphatic hydrocarbon, esp. a 4-7 C linear aliphatic hydrocarbon. The polymer is PTHF with an average mol. wt. of 500-300 (sic; 500-3000 according to main text).