This invention relates to novel double metal cyanide catalysts and to a process for the production of these double metal cyanide catalysts. These DMC catalysts can be used to prepare polyoxyalkylene polyols which have low amounts of high molecular weight tail compared polyoxyalkylene polyols prepared from DMC catalysts of the prior art.

According to one embodiment, a catalyst system that reduces polymeric fouling may comprise at least one titanate compound, at least one aluminum compound, and at least one antifouling agent or a derivative thereof. The antifouling agent may comprise a structure comprising a central aluminum molecule bound to an R1 group, bound to an R2 group, and bound to an R3 group. One or more of the chemical groups R1, R2, and R3 may be antifouling groups comprising the structure O((CH.sub.2).sub.nO).sub.mR4, where n is an integer from 1 to 20, m is an integer from 1 to 100, and R4 is a hydrocarbyl group. The chemical groups R1, R2, or R3 that do not comprise the antifouling group, if any, may be hydrocarbyl groups.

The present invention relates to a process for preparing a double metal cyanide (DMC) catalyst, comprising the reaction of an aqueous solution of a cyanide-free metal salt, an aqueous solution of an alkaline metal cyanide salt, an organic complex ligand and optionally a complex-forming component, wherein the metal cyanide salt is one or more compound(s) and is selected from the group consisting of potassium hexacyanocobaltat(III), potassium hexacyanoferrate(II), potassium hexacyanoferrate(III), calcium hexacyanocobaltate(III) and lithium hexacyanocobaltat(III), where the organic complex ligand is one or more compound(s) and is selected from the group consisting of dimethoxyethane, tert-butanol, 2-methyl-3-buten-2-ol, 2-methyl-3-butyn-2-ol, ethylene glycol mono-tert-butyl ether and 3-methyl-3-oxetanemethanol, and wherein the alkaline metal cyanide salt used has an alkalinity by the titration method disclosed in the Experimental of between 0.700% and 3.000% by weight of sodium hydroxide (NaOH) based on the total weight of the alkaline metal cyanide salt used. The invention further relates to double metal cyanide (DMC) catalysts obtainable by the process according to the invention and to the use of DMC catalysts for preparation of polyoxyalkylene polyols.

The present invention relates to an improved process for preparing double metal cyanide (DMC) catalysts for the preparation of polyoxyalkylene polyols, preferably polyether polyols and/or polyether carbonate polyols. The invention further provides DMC catalysts which are obtainable by this process and for the use of the catalysts according to the invention for preparing polyoxyalkylene polyols.

A ceramic catalyst filter, a filtering system including the same, and a method of manufacturing the same. The ceramic catalyst filter includes: a single body ceramic filter including a first surface for blocking a first material and a second surface for removing the second material passing through the first surface; and a photocatalyst thin film including nanometer-scale grains coated on a surface of the ceramic filter.

The present invention is directed to providing a method of preparing a heterogeneous linear carbonate, including: performing a transesterification reaction of dimethyl carbonate (DMC) and ethanol (EtOH) in the presence of a catalyst, wherein the catalyst is an amine-based compound having a boiling point of 150 C. or more.