Abstract: Alkylene oxides are polymerized in the presence of a catalyst system that includes a double metal cyanide catalyst that is modified with certain metal or semi-metal compounds. At least one additive is present. The additive is an alkali metal, ammonium or quaternary ammonium salt of a monocarboxylic acid having up to 24 carbon atoms; monobasic potassium phosphate, a monobasic ammonium or quaternary ammonium phosphate, a dibasic ammonium and quaternary ammonium phosphate or phosphoric acid.

Abstract: Catalyst complexes include a zinc hexacyanocobaltate with M5 metal and M6 metal or semi-metal phases, wherein M5 metal is gallium, hafnium, manganese, titanium and/or indium and the M6 metal or semi-metal is one or more of aluminum, magnesium, manganese, scandium, molybdenum, cobalt, tungsten, iron, vanadium, tin, titanium, silicon and zinc and is different from the M5 metal. The catalysts are highly efficient propylene oxide polymerization catalysts characterized by rapid activation, short times to the onset of rapid polymerization and high polymerization rates once rapid polymerization has begun.

Abstract: Catalyst complexes include a zinc hexacyanocobaltate with M5 metal and M6 metal or semi-metal phases, wherein M5 metal is gallium, hafnium, manganese, titanium and/or indium and the M6 metal or semi-metal is one or more of aluminum, magnesium, manganese, scandium, molybdenum, cobalt, tungsten, iron, vanadium, tin, titanium, silicon and zinc and is different from the M5 metal. The catalysts are highly efficient propylene oxide polymerization catalysts characterized by rapid activation, short times to the onset of rapid polymerization and high polymerization rates once rapid polymerization has begun.