Production of polytetrahydrofuran with terminal hydroxyl groups by changing the continuous and dispersed phase

US6300467A · kind A · utility

Assignee

• BASF SE

Inventors

• Heinz Auer · Neulußheim, DE
• Jurgen Ciprian · Ludwigshafen, DE
• Lothar Franz · Ludwigshafen, DE
• Wolfgang Franzischka · Bischofswerda, DE
• Gabriele Iffland · Heidelberg, DE
• Alexander Weck · Freinsheim, DE
• Werner Weinle · Friedelsheim, DE

Key dates

• Filing date: Mar 29, 2000
• Grant date: Oct 9, 2001
• Expiry date: Mar 29, 2020

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G65/3312
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The present 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 an alkali metal- or alkaline earth metal-containing catalyst, which entails the appropriate acyloxy-containing polymer being introduced together with the alcohol and the catalyst into a first prereactor (I) and converted therein at least partly to the hydroxyl-containing polymer, and the reaction solution being fed into the upper zone (IIa) of a distillation column (II) into whose lower zone (IIb) alcohol in vapor phase is additionally fed. This involves a phase exchange at the coherent and the disperse phase at the transition from the prereactor to the distillation column. Preferably, in addition to the first prereactor, a further 3 prereactors are used which serve as holdup reactors.