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 [alkaline] alkylene oxide and an initiator having at least one reactive hydrogen which is reactive to the [alkaline] 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 [alkaline] 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 [alkaline] alkylene oxide in the second spiral reaction tube.

In the claims:  
     
         14 . (amended) A continuous process of forming polyether polyols comprising the steps of: 
 a) 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 said alkylene oxide;    b) providing a plurality of spiral shaped reaction tubes operably connected to each other in series and each having an internal diameter between 0.25 and 3.0 inches, a spiral diameter of between 2 feet and 10 feet, said spiral shaped reaction tubes promoting a pseudo-turbulent flow of said initial reaction mixture;    c) continuously flowing said initial reaction mixture through said first of said spiral shaped reaction tubes to form a reaction product;    d) flowing said reaction product into a second of said spiral shaped reaction tubes adjacent to said first of said spiral reaction tubes and adding a catalyst and an alkylene oxide to said reaction product;    e) surrounding said plurality of spiral shaped reaction tubes with a heat exchange medium, said heat exchange medium establishing and maintaining a reaction temperature within said plurality of spiral shaped reaction tubes of between 130° C. and 250° C.; and    f) maintaining a pressure in said spiral shaped reaction tubes of between 200 to 1500 pounds per square inch.    
     
     
         18 . (amended) A continuous process as recited in claim  14  wherein, step c) further comprises adding said catalyst to said initial reaction mixture in said first of said spiral shaped reaction tubes.  
     
     
         19 . (amended) A continuous process as recited in claim  14  further comprising the steps of adding additional amounts of said catalyst and said alkylene oxide to others of said spiral shaped reaction tubes.  
     
     
         20 . (amended) A continuous process as recited in claim  14  wherein step e) further comprises the additional steps of establishing and maintaining a first reaction temperature in a first plurality of spiral shaped reaction tubes and establishing and maintaining a second reaction temperature in a second plurality of spiral shaped reaction tubes, said second reaction temperature being greater than said first reaction temperature.  
     
     
         21 . (new) A continuous process as recited in claim  14  wherein the spiral reaction tubes curve in a continuous spiral, in the absence of substantially linear tubes.  
     
     
         22 . (new) A continuous process as recited in claim  14  wherein the spiral reaction tubes provide fluid flow from a first spiral reaction tube inlet to a first spiral reaction tube outlet, in the absence of any fluid flow out of said outlet into said inlet.  
     
     
         23 . (new) A continuous process as recited in claim  14  wherein the spiral reaction tubes comprise a continuously curved wall, said wall being continuously curved in x, y and z planes.