摘要 |
<p>The double metal cyanide complex, e.g. metal hexacyanometallate, catalysts obtained by reacting metal salts and alkali metal cyanometallates are not easily separated from the reaction mixture because the particle size is too small to allow filtration under normal conditions. Centrifugation, dialysis, or conversion to a filterable metal hydroxide salt are the methods previously described for separating the alkali metal salt formed during reaction from the catalyst. Forming the complex in the presence of an inert filter-aid has been found to give a filterable catalyst which can be washed clean of the alkali metal salt and can be used without further treatment in the catalysis of the formation of propylene oxide polyols.</p> |