| 摘要 |
TRIMERIZATION CATALYSTS, A PROCESS FOR THEIR PREPARATION AND THEIR USE FOR THE PREPARATION OF POLYISOCYANATES CONTAINING ISOCYANURATE GROUPS The present invention relates to trimerization catalysts which are suitable for heterogeneous catalysis and are based on quaternary ammonium or phosphonium fluorides adsorbed on porous carrier materials, characterized in that the carrier material is an adsorbent having a particle size (90%) of 0.1 to 10 mm, a pore volume of 0.4 to 1.4 ml/g, an average pore diameter of 7 to 50 nm and a specific surface area (BET) of 100 to 700 m2/g. The present invention also relates to a process for the preparation of these catalysts by stirring together an alkali metal fluoride and a quaternary ammonium or phosphonium salt in the presence of an alcoholic solvent, removing any precipitate formed by filtration and adsorbing the resulting homogeneous catalyst solution onto the previously described carrier material, optionally after further dilution of the solution with an alkaline solvent. Finally, the present invention relates to the use of the catalysts for the preparation of polyisocyanates containing isocyanurate groups by trimerizing at least a portion of the isocyanate groups of organic diisocyanates. |
