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 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 a method for producing a double metal cyanide (DMC) catalyst, comprising the reaction of an aqueous solution of a cyanide-free metal salt, an aqueous solution of a metal cyanide salt, an organic complex ligand, optionally a complex-forming component to form a dispersion, the dispersion being produced using a mixing nozzle and a peroxide. The invention further relates to double metal cyanide (DMC) catalysts obtainable by means of the method according to the invention and to the use of DMC catalysts to produce polyoxyalkylene polyols.

The present invention relates to a method for producing a double metal cyanide (DMC) catalyst, comprising the reaction of an aqueous solution of a cyanide-free metal salt, an aqueous solution of a metal cyanide salt, an organic complex ligand, optionally a complex-forming component to form a dispersion, the dispersion being produced using a mixing nozzle and a peroxide. The invention further relates to double metal cyanide (DMC) catalysts obtainable by means of the method according to the invention and to the use of DMC catalysts to produce polyoxyalkylene polyols.

The present invention relates to: a double-metal cyanide catalyst comprising an organosilane compound as a complexing agent; a preparation method therefor; and a method for preparing polyol. The double-metal cyanide catalyst of the present invention comprises a metal salt, a metal cyanide salt, and a complexing agent, therein the complexing agent is an organosilane compound.

Polycarbonate polyols are made by copolymerizing carbon dioxide and an alkylene oxide in the presence of a starter compound and a carbonate catalyst. The process is operated in semi-batch mode by combining starter, catalyst and a small amount of alkylene oxide in a reaction vessel, pressurizing the vessel with carbon dioxide, initiating polymerization, and then feeding both carbon dioxide and alkylene oxide to the vessel under polymerization conditions without removal of product until the feeds are completed.

Polycarbonate polyols are made by copolymerizing carbon dioxide and an alkylene oxide in the presence of a starter compound and a carbonate catalyst. The process is operated in semi-batch mode by combining starter, catalyst and a small amount of alkylene oxide in a reaction vessel, pressurizing the vessel with carbon dioxide, initiating polymerization, and then feeding both carbon dioxide and alkylene oxide to the vessel under polymerization conditions without removal of product until the feeds are completed.

A process for separating a catalyst component from a catalyst-containing slurry by centrifugation including separating the catalyst component from the mother liquor of the catalyst-containing slurry using a stacked disc centrifuge equipped with an auto-discharging functionality. The solids discharge from the stacked disc centrifuge is enhanced by adding a washing solution to the bowl and the solids discharge chute of the stacked disc centrifuge.

A process for separating a catalyst component from a catalyst-containing slurry by centrifugation including separating the catalyst component from the mother liquor of the catalyst-containing slurry using a stacked disc centrifuge equipped with an auto-discharging functionality. The solids discharge from the stacked disc centrifuge is enhanced by adding a washing solution to the bowl and the solids discharge chute of the stacked disc centrifuge.

The present disclosure provides intermediates used for preparing Brivaracetam, a preparation method and a use thereof, including an intermediate compound A and an intermediate compound B and a preparation method thereof, as well as a synthetic route for using the intermediate compound B to prepare Brivaracetam. The present technical solution can obtain high-quality and high-optical purity Brivaracetam and intermediates thereof, the proportion of Brivaracetam among the four optical isomers being greater than 99.5%. In addition, neither silica gel column for separation and purification nor expensive chiral high performance liquid chromatography for resolution is required, thereby avoiding cumbersome separation and purification steps, also avoiding waste of raw materials, reducing the production cost and making it more suitable for industrial production.