Continuous process for the production of polyether polyols

Abstract

A continuous alkoxylation process for the production of polyether polyols is disclosed. The process comprises the use of a plurality of reaction modules each having an outer tube and an inner tube with annular chamber between them. A spiral reaction tube is spaced from the inner tube and winds around the inner tube within the annular chamber. The spiral reaction tube includes an inlet and an outlet, each of which extend through said outer tube. A heat exchange medium flows through the annular chamber and controls the reaction temperature in the spiral reaction tube. The process comprises continuously forming an initial reaction mixture of at least one alkylene oxide and an initiator having at least one reactive hydrogen which is reactive to the alkylene oxide. Continuously flowing the initial reaction mixture through a first spiral reaction tube having an internal diameter and a spiral diameter that promote a pseudo-turbulent flow of the initial reaction mixture through the first spiral reaction tube to form a reaction product. Then flowing the reaction product into a second spiral reaction tube and adding a catalyst and an alkylene oxide to the reaction product, the second spiral reaction tube having an internal diameter and a spiral diameter that promote a pseudo-turbulent flow of the reaction product, the catalyst and the alkylene oxide in the second spiral reaction tube.