Method for preparing metal cyanide catalysts using insoluble metal salts
AssigneeDow Global Technologies LLC
InventorRichard M. Wehmeyer
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Abstract
Metal cyanide catalyst dispersions in initiator compounds and/or polyethers are prepared by reacting an acidic metal cyanide compound with an insoluble metal salt in a medium that is a solvent for the acidic metal cyanide compound but not the metal salt. The resulting catalyst slurry may be combined with an initiator and stripping to form a catalyst/initiator or catalyst/polyether slurry. Using this method, an active alkylene oxide polymerization catalyst is prepared, and the preparation method is greatly simplified. Further, it is not necessary to use a separate organic complexing agent in the preparation.
Claims15
A method for preparing a metal cyanide catalyst, comprising mixing an acidic metal cyanide compound with an insoluble metal salt in a solvent medium for the acidic metal cyanide compound under conditions such that the insoluble metal salt and the acidic metal cyanide compound react to form a multimetal cyanide catalyst insoluble in the solvent medium, wherein:
- a) the acidic metal cyanide compound is represented by the general formula Hw[M1(CN)r(X)t] in which M1 is a transition metal ion;
- each X represents a group other than cyanide that coordinates with the M1 ion;
- r is from 4 to 6, t is from 0 to 2, and w represents the absolute value of the valence of the M1(CN)r(X)t group;
- and
- b) the insoluble metal salt is insoluble in the solvent medium and is represented by the general formula MxAy, wherein M is a metal ion that forms an insoluble precipitate with the metal cyanide grouping M1(CN)r(X)t, A represents an anion that forms a salt of M that is insoluble in the solvent medium, and x and y are integers that balance the charges in the insoluble metal salt.
Dependencies are inferred from the claim text.