Continuous preparation of polytetrahydrofuran by a transesterification cascade with specific destruction of foam

US5981688A · kind A · utility

Assignee

• BASF SE

Inventors

• Heinz Auer · Neulußheim, DE
• Klaus Beiser · Eppelsheim, DE
• Jurgen Ciprian · Ludwigshafen, DE
• Lothar Franz · Ludwigshafen, DE
• Wolfgang Franzischka · Bischofswerda, DE
• Ulrich-Dieter Pessel · Heidelberg, DE
• Werner Weinle · Friedelsheim, DE

Key dates

• Filing date: Sep 23, 1998
• Grant date: Nov 9, 1999
• Expiry date: Sep 23, 2018

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01J2219/0025
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A process for preparing hydroxyl-containing polymers and, in particular, a process for preparing polytetrahydrofuran with terminal hydroxyl groups from the corresponding acyloxy-containing polymers by transesterification with alcohols is carried out continuously in at least one stirred vessel, with the foam produced in the transesterification being fed tangentially to a cylindrical container, preferably a cyclone separator, at an adequate velocity to destroy the foam. The liquid phase which separates out is recycled through a line to the at least one stirred vessel. This continuous process is preferably carried out in a cascade of stirred vessels, in which each stirred vessel or a subunit of at least two stirred vessels can in each case be coupled to a cylindrical container, preferably in the form of a cyclone separator.