Method for producing double metal cyanide catalysts

A process for preparing a double metal cyanide (DMC) catalyst comprising:

• (i) reacting, in the presence of a peroxide, an aqueous solution of a cyanide-free metal salt, an aqueous solution of a metal cyanide salt, an organic complex ligand, and optionally a complex-forming component, to form a dispersion;
• (ii) separating a solid from the dispersion obtained from (i) thereby providing an isolated solid;
• (iii) washing the isolated solid by means of redispersion or filtercake washing to obtain a washed isolated solid, and
• (iv) drying the washed isolated solid to obtain the DMC catalyst,
• wherein the reaction in step i) is effected using a mixing nozzle,
• wherein the organic complex ligand comprises dimethoxyethane, tert-butanol, 2-methyl-3-buten-2-ol, 2-methyl-3-butyn-2-ol, ethylene glycol mono-tert-butyl ether 3-methyl-3-oxetanemethanol, or a mixture thereof, and
• wherein double metal cyanide compounds of the formula (I) are present in the DMC catalyst
• Mx[M′x,(CN)y]z (I),
• where
• M comprises Zn(II), Fe(II), Ni(II), Mn(II), Co(II), Sr(II), Sn(II), Pb(II), Cu(II), or a mixture thereof
• and
• M′ comprises Fe(II), Fe(III), Co(II), Co(III), Cr(II), Cr(III), Mn(II), Mn(III), Ir(III), Ni(II), Rh(III), Ru(II), V(IV), V(V), or a mixture thereof
• and
• x, x′, y and z are integers and are selected such as to ensure the electronic neutrality of the double metal cyanide compound.