Sugar Alcohol Polyarylether Copolymers via Single-Stage Carbonate Synthesis
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Solution Overview
Problem
Existing methods for preparing polyarylether polymers, such as the hydroxide and carbonate methods, are prone to errors, complex, and expensive due to the need for precise stoichiometric control, leading to reduced molecular weights and increased costs, and the resulting polymers have limitations in hydrophilicity and membrane applications.
Innovation Solution
A process involving a reaction mixture comprising dihalodiphenylsulfone, sugar alcohols like isosorbide, aromatic dihydroxyl compounds, and a carbonate component, conducted in a single stage without intermediate isolation, to produce polyarylether copolymers with high molecular weights and improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the hydroxide method is used to prepare polyarylether polymers, then the polymers can be produced with controlled molecular weight, but the process becomes complex and expensive due to the need for precise stoichiometric control and two-stage synthesis
Solution Approach 1:
The patent combines the deprotonation step and polycondensation step into a single reaction stage by using carbonate as both the base for deprotonation and the reaction medium. This eliminates the need for separate isolation and purification steps between deprotonation and polycondensation, thereby simplifying the overall process while maintaining molecular weight control.
Solution Approach 2:
The carbonate component serves multiple functions simultaneously: it acts as the base for deprotonation of the aromatic dihydroxyl compound, as the solvent for the reaction, and as the medium for polycondensation. This multi-functionality reduces the number of reagents and steps required, simplifying the process while maintaining precision.
2Manufacturing precision
If the hydroxide method is used with strong bases, then deprotonation can be achieved, but the strong bases cleave ether links formed in polycondensation, leading to decreased molecular weight
Solution Approach 1:
The patent changes the chemical nature of the base from strong base (hydroxide) to mild base (carbonate). This parameter change in base strength prevents the cleavage of ether links while still achieving sufficient deprotonation of the aromatic dihydroxyl compound, thereby maintaining molecular weight.
3Manufacturing precision
If precise stoichiometric control is maintained in the hydroxide method, then molecular weight can be preserved, but the measurement complexity and cost increase significantly
Solution Approach 1:
The carbonate method is inherently more tolerant of stoichiometric variations, allowing the reaction to proceed effectively without precise control. The carbonate excess can vary in a wide regime without decreasing molecular weights, and the reaction control is simplified, making the process more self-regulating and less dependent on precise measurement.
4Adaptability or versatility
If bio-based diols like sugar alcohols are incorporated to improve hydrophilicity, then membrane compatibility improves, but the molecular weight and polymer properties may be compromised
Solution Approach 1:
The patent changes the chemical environment by using carbonate instead of hydroxide as the base, creating milder reaction conditions that are compatible with bio-based diols like sugar alcohols. This allows the incorporation of these hydrophilic monomers while maintaining high molecular weights and good polymer properties that were previously compromised.
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 yields polyarylether copolymers with reduced chloride content, good water permeability, molecular weight cut-off, and improved tensile properties, suitable for membrane applications with reduced fouling tendency.
Implementation Method 1
the aromatic dihydroxyl compound and the aromatic dihalogen compound are reacted together in the presence of carbonates, preferably potassium carbonate... to form the diphenolate dianion from the aromatic dihydroxyl compound in the reaction mixture
Implementation Method 2
The deprotonated aromatic dihydroxyl compound is subsequently reacted with the aromatic dihalogen compound. The polyarylether polymer is formed in the second step
Implementation Method 3
In general, N,N-dimethylacetamide, DMF, N-Ethylpyrrolidone or NMP is used here as solvent and toluene or chlorobenzene is added as azeotroping agent for the removal of water. Before the actual polycondensation reaction in the carbonate method, an azeotrope of toluene and water is distilled off from the reaction mixture
Data Source
AI summary
The present invention relates to a process for the preparation of a polyarylether copolymer (P), the polyarylether copolymer (P) obtained by the process and a process for the preparation of a membrane comprising the polyaryl- ether copolymer (P) and the membrane itself.