Polycarbonate Ether Polyol Synthesis via DMC Catalyst
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Solution Overview
Problem
Existing methods for preparing polycarbonate ether polyols require high pressures of carbon dioxide, exceeding industrial equipment limits, and struggle to achieve appreciable incorporation of carbon dioxide under lower pressures, limiting the control of ether and carbonate linkages and molecular weight, which affects the properties and processing of polyurethanes.
Innovation Solution
A method using a double metal cyanide (DMC) catalyst with a specific formula (I) and a starter compound to react epoxide and carbon dioxide at pressures between 1 and 60 bar, allowing for the preparation of polycarbonate ether polyols with controlled ether and carbonate linkages and molecular weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high pressures of carbon dioxide (40 bar or above) are used to achieve appreciable incorporation of carbon dioxide in polycarbonate ether polyols, then the proportion of carbonate linkages increases, but the equipment requirements exceed typical industrial polyether polyol equipment limits (up to 10 bar)
Solution Approach 1:
The patent changes the chemical parameters of the catalyst system by combining a DMC catalyst with a metal salen complex catalyst and specific additives. This catalytic parameter change enables the reaction to proceed at lower CO2 pressures (1-10 bar) while maintaining high carbonate linkage incorporation (≥20 wt% CO2), thus resolving the contradiction between CO2 incorporation and pressure requirements
Solution Approach 2:
The patent introduces intermediary substances including a metal salen complex catalyst (with specific ligand structures), additives, and co-catalysts that mediate the reaction between epoxide and CO2. These intermediaries facilitate carbonate linkage formation at lower pressures by providing alternative reaction pathways with lower activation energy requirements
2Stability of the object's composition
If the ratio of ether linkages to carbonate linkages is controlled to improve polyol properties, then the molecular weight and polydispersity become harder to control, affecting processing ease
Solution Approach 1:
The patent employs feedback control through the catalyst system where the metal salen complex and DMC catalyst work synergistically to regulate chain growth. The catalyst system responds to reaction conditions and maintains optimal ether/carbonate linkage ratios while controlling molecular weight and polydispersity within desired ranges, enabling simultaneous control of multiple parameters
Solution Approach 2:
The patent changes multiple catalytic parameters simultaneously - using a dual catalyst system with specific metal salen complexes and DMC catalysts, adjusting additive concentrations, and optimizing reaction conditions. These parameter changes enable coordinated control of linkage ratio, molecular weight, and polydispersity, resolving the contradiction between composition control and manufacturing precision
3Quantity of substance
If appreciable incorporation of carbon dioxide (≥20 wt% CO2) is achieved under low pressures, then the proportion of carbonate linkages reaches ~0.5 or higher, but existing DMC catalyst systems cannot achieve this without high pressure equipment
Solution Approach 1:
The patent fundamentally changes the catalytic parameters by introducing metal salen complex catalysts in combination with DMC catalysts and specific additives. This parameter change enables the reaction to achieve ≥20 wt% CO2 incorporation at low pressures (1-10 bar), making the process compatible with standard industrial equipment and improving ease of manufacture
Solution Approach 2:
The patent introduces metal salen complex catalysts and additives as intermediaries that facilitate high CO2 incorporation at low pressures. These intermediaries create efficient reaction pathways that do not require high-pressure equipment, thus improving ease of manufacture while achieving the desired CO2 incorporation levels
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
Enables the production of polycarbonate ether polyols with tailored properties and molecular weight under industrially feasible pressures, suitable for use in polyurethane production, improving UV stability, hydrolytic stability, and mechanical strength.
Implementation Method 1
reacting an epoxide and carbon dioxide in the presence of a double metal cyanide (DMC) catalyst and a metal salen complex, and a starter compound
Data Source
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AI summary
The present invention relates to a polycarbonate ether polyol obtainable by a process comprising reacting carbon dioxide and an epoxide in the presence of a double metal cyanide (DMC) catalyst, a catalyst of formula (I), and a starter compound. The catalyst of formula (I) is as follows: