Catalyst systems for polycondensation reactions

Abstract

The invention pertains to new catalyst systems for polycondensation reactions, for example for producing polyethylene terephthalate. In accordance with the invention, complex compounds with hydrotalcite-analogous structures of general formula [M(II) 1−x M(III) x (OH) 2 ] x+ (A n− x/n ).mH 2 O are used, wherein M(II) represents divalent metals, preferably Mg or Zn or NI or Cu or Fe(II) or Co, and M(III) represents trivalent metals, for example Al or Fe(III), and A represents anions, preferably carbonates or borates. These catalysts can be calcinated and can be used in combination with phosphorus compounds that contain at least one hydrolyzable phosphorus-oxygen bond.

1 . Catalyst systems for polycondensation reactions, characterized in that they are untreated or calcinated hydrotalcite-analogous derivatives of the general formula  
       [M(II) 1−x M(III) x (OH) 2 ] x+ (A n−   x/n ).mH 2 O  
       wherein M(II): divalent metals, M(III): trivalent metals, and A: anions, alone or in combination with phosphorus compounds that contain at least one hydrolyzable phosphorus-oxygen bond.  
     
     
         2 . Catalyst systems for polycondensation reactions in accordance with  claim 1 , characterized in that M(II) is Mg or Zn or Ni or Cu or Fe(II) or Co.  
     
     
         3 . Catalyst systems for polycondensation reactions according to claims  1  or  2 , characterized in that M(III) is Al or Fe(III).  
     
     
         4 . Catalyst systems for polycondensation reactions according to any of  claims 1  to  3 , characterized in that A are carbonates, titanyls or borates.  
     
     
         5 . Catalyst systems for polycondensation reactions according to any of  claims 1  to  4 , characterized in that the calcination of the hydrotalcite-analogous compounds is carried out at temperatures of 200° C. to 800° C., preferably at 400° C. to 650° C.  
     
     
         6 . Catalyst systems for polycondensation reactions in accordance with any of  claims 1  to  5 , characterized in that the polycondensation is carried out with the catalysts under vacuum in liquid phase at temperatures of 230° C. to 280° C. and in solid phase at temperatures of 170 to 240° C.  
     
     
         7 . Catalyst systems for polycondensation reactions in accordance with any of claims  1  through  6 , characterized in that the particle sizes of the hydrotalcites used are in the range of 0.1 to 50 μm, preferably 0.5 to 5 μm.  
     
     
         8 . Catalyst systems for polycondensation reactions in accordance with  claim 1 , characterized in that as the phosphorus compounds, phosphoric acid esters or esters of phosphorous acid are used.  
     
     
         9 . Catalyst systems for polycondensation reactions in accordance with  claim 8 , characterized in that the catalyst system is used in the proportion, hydrotalcite to phosphorus compound, of 1:0.5 to 1:4, preferably of 1:1 to 1:2.  
     
     
         10 . A polycondensation product made using a catalyst as described in any of claims  1  through  9  characterized in that the product is substantially free of heavy metals.  
     
     
         11 . A polycondensation product as in  claim 10  further characterized in that the product is suitable for use in bottles, sheets, films or fibers.