Polyether Carbonate Polyol Dioxane Reduction via Phosphorus Stabilizer
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Solution Overview
Problem
Existing processes for preparing polyether carbonate polyols often result in high dioxanes content after thermal exposure, posing safety risks and increasing costs due to high exothermicity and pressure demands, and do not effectively stabilize the products for use in flexible polyurethane foams.
Innovation Solution
A process involving the addition of one or more alkylene oxides and carbon dioxide to H-functional starter substances in the presence of a double metal cyanide catalyst, followed by the inclusion of a phosphorus-oxygen bond containing compound, which reduces dioxanes content and stabilizes the polyether carbonate polyols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high amounts of alkylene oxide (60% by weight) are used for catalyst activation, then catalyst activity is improved, but safety risk increases due to high exothermicity
Solution Approach 1:
The patent applies partial action by using only 1-50% by weight of alkylene oxide for catalyst activation instead of the conventional 60%, which is sufficient to activate the catalyst while avoiding excessive exothermicity and safety risks
2Quantity of substance
If high pressure (up to 150 bar) is applied to increase CO2 incorporation, then CO2 content in polymer increases, but device complexity and safety demands increase
Solution Approach 1:
The patent changes the pressure parameter from conventional high pressure (150 bar) to moderate pressure (1-50 bar), while achieving comparable or superior CO2 incorporation (30-70% by weight) through optimized catalyst system and process conditions
3Productivity
If conventional catalyst systems are used, then polyether carbonate polyols are produced, but dioxanes content increases after thermal exposure
Solution Approach 1:
The patent introduces a cocatalyst (metal halide, metal carboxylate, or organic compound) as an intermediary that works synergistically with the DMC catalyst to suppress dioxanes formation during thermal exposure while maintaining high polymerization productivity
4Manufacturing precision
If solvent (toluene) is used to achieve high molecular weight, then polymer quality improves, but process time and cost increase due to solvent removal
Solution Approach 1:
The patent extracts the solvent from the process entirely, achieving high molecular weight polyether carbonate polyols through optimized catalyst system and reaction conditions without requiring toluene or other solvents, thereby eliminating the time-consuming solvent removal step
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 achieves polyether carbonate polyols with significantly reduced dioxanes content after thermal exposure, making them suitable for preparing flexible polyurethane foams while enhancing safety and reducing production costs.
Implementation Method 1
one or more alkylene oxide(s) and carbon dioxide are added onto one or more H-functional starter substance(s) in the presence of a double metal cyanide catalyst
Implementation Method 2
at least one component K is added to the obtained reaction mixture comprising the polyether carbonate polyol, wherein component K is selected from at least one compound containing a phosphorus-oxygen bond
Implementation Method 3
preparing polyether carbonate polyols by catalytic copolymerization of carbon dioxide (CO2) with alkylene oxides
Data Source
AI summary
The invention relates to a method for producing polyether carbonate polyols, (i) one or more alkylene oxide(s) and carbon dioxide being added to one or more H-functional starter substance(s) in the presence of a double metal cyanide catalyst or in the presence of a metal complex catalyst based on the metals zinc and/or cobalt, a reaction mixture containing the polyether carbonate polyol being obtained, characterized in that (ii) at least one component K is added to the obtained reaction mixture containing the polyether carbonate polyol, wherein component K is selected from at least one compound that contains a phosphorus-oxygen bond or a compound of phosphorus that can form one or more P—O bonds by reaction with OH-functional compounds.