DMC Catalyst Preparation for Low-Viscosity Polyether Polyols
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Solution Overview
Problem
Existing processes for preparing double metal cyanide (DMC) catalysts do not achieve sufficient catalytic activity for polyoxyalkylene polyols, leading to high product viscosity and requiring high catalyst amounts, which complicates further processing and increases costs.
Innovation Solution
A process involving the reaction of cyanide-free metal salts, metal cyanide salts, and organic complex ligands with specific complex-forming components, using a mixing nozzle to create a dispersion, followed by filtration, washing, and drying, optimized for low energy consumption and scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional DMC catalyst preparation processes are used, then the catalysts achieve sufficient activity for polyether polyol preparation, but the product viscosity remains high and catalyst amounts must be increased
Solution Approach 1:
The patent applies parameter changes by optimizing the preparation temperature (26-49°C range), adjusting the molar ratios of reactants, and controlling the addition rate of catalyst components. These parameter optimizations result in DMC catalysts with enhanced activity, enabling lower catalyst concentrations (25 ppm or less) to achieve the same catalytic effect, thereby reducing the harmful effect of high product viscosity while maintaining reliable catalytic performance
2Reliability
If higher catalyst amounts are used to achieve sufficient activity, then the catalytic performance improves, but the economic viability decreases and further processing becomes more difficult
Solution Approach 1:
The patent optimizes preparation parameters including temperature (26-49°C), reactant ratios, and addition rates to produce DMC catalysts with maximum activity. This enables the use of very low catalyst concentrations (25 ppm or less) in the polyether polyol preparation, thereby maintaining high catalytic activity while significantly improving economic viability and ease of further processing by reducing catalyst removal requirements
3Reliability
If complex preparation processes are used to enhance catalyst activity, then the catalytic performance increases, but the process complexity and energy consumption increase
Solution Approach 1:
The patent employs moderate preparation temperatures (26-49°C) that balance catalyst activity enhancement with energy efficiency. This temperature range is sufficient to achieve high catalyst activity without requiring excessive energy input, thereby improving catalytic performance while maintaining low energy consumption and simplifying the preparation process compared to high-temperature methods
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process results in highly active DMC catalysts with reduced viscosity, allowing for lower catalyst usage and improved economic viability, while being simple to implement in existing industrial setups.
Implementation Method 1
the DMC catalyst dispersion being prepared using a mixing nozzle, preferably a jet disperser
Implementation Method 2
this dispersion is then filtered
Implementation Method 3
the filtercake is subsequently washed with one or more aqueous or nonaqueous solutions of the organic complex ligand
Implementation Method 4
the washed filtercake is finally dried after an optional pressing out or mechanical moisture removal
Data Source
AI summary
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.