Organic N-Protic Bronsted Acid Catalyst Polymerization
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Solution Overview
Problem
Current methods for polymerizing alkylene oxides with H-functional starter compounds, such as polyurethane production, face issues with high cyclic by-product formation, thermal instability, and the need for non-polymeric catalysts that are free from heavy metals and easily synthesizable, while maintaining reactivity and selectivity.
Innovation Solution
A process involving the use of organic n-protic Bronsted acids with a degree of protolysis between 0 and the maximum number of transferrable protons, where n is 2, 3, or 4, to catalyze the addition of compounds like alkylene oxides, lactones, or cyclic anhydrides onto H-functional starter compounds, reducing cyclic by-products and enhancing chemical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cationic polymerization of alkylene oxides is performed using Lewis acids or Bronsted superacids, then polymerization rate is significantly higher, but cyclic by-products such as dioxanes and crown ethers are formed in high proportions (15-25%)
Solution Approach 1:
The invention changes the chemical parameters of the catalyst system by using organic n-protic Bronsted acids with specific degree of protolysis (0 < D ≤ 1.0) instead of traditional Lewis acids or Bronsted superacids. This parameter change maintains high polymerization activity while fundamentally altering the reaction pathway to prevent cyclic by-product formation, resolving the contradiction between productivity and harmful by-products
Solution Approach 2:
The invention employs simple, commercially available organic acids (such as sulfuric acid, trifluoromethanesulfonic acid) that can be easily handled and disposed of, replacing complex, expensive, and hazardous Bronsted superacids. These acids provide sufficient catalytic activity for short-duration industrial processes while minimizing environmental and safety concerns
2Stability of the object's composition
If thermally labile H-functional starter compounds are used, then product stability is improved, but degradation occurs during polymerization
Solution Approach 1:
The invention changes the temperature parameter of the polymerization process by conducting reactions at lower temperatures (0-100°C, preferably 20-60°C) using organic n-protic Bronsted acids as catalysts. This temperature reduction preserves the stability of thermally labile starter compounds while maintaining adequate polymerization rates, preventing degradation that would occur at higher temperatures
Solution Approach 2:
The organic n-protic Bronsted acid acts as an intermediary catalyst that enables polymerization at milder conditions. The acid facilitates the reaction between alkylene oxides and thermally sensitive starter compounds without requiring high temperatures that would cause degradation, thus mediating between reactivity and stability requirements
3Productivity
If polymeric perfluorinated sulfonic acid catalysts are used, then catalysis is achieved, but high proportion of oligomeric cyclic ether by-products are formed and only partial conversion results
Solution Approach 1:
The invention replaces complex polymeric perfluorinated sulfonic acid catalysts with simple, small-molecule organic acids that are commercially available and easily handled. These simpler catalysts achieve comparable or superior catalytic activity without the side reactions that produce oligomeric cyclic ether by-products, eliminating the need for complex catalyst preparation and conditioning procedures
Solution Approach 2:
The invention extracts the essential catalytic function (proton donation) from the complex polymeric structure of perfluorinated sulfonic acids, using only the active acidic component in the form of simple organic acids. This extraction removes the problematic polymeric structure that leads to by-product formation while retaining the beneficial catalytic activity
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
This approach enables more selective and efficient chain extension of thermally labile starter compounds with alkylene oxides, minimizing unwanted by-products and degradation, while using catalysts that are commercially available and easy to condition, thus improving the production of polymeric ring-opening products like polyols and polyurethane polymers.
Implementation Method 1
a process for adding a compound (A) onto an H-functional starter compound (BH) in the presence of a catalyst... wherein the catalyst comprises an organic, n-protic Bronsted acid (C)
Data Source
AI summary
The invention relates to a method for adding a compound (A) to an H-functional starting compound (BH) in the presence of a catalyst, wherein the at least one compound (A) is selected from at least one group consisting of alkylene oxide (A-1), lactone (A-2), lactide (A-3), cyclic acetal (A-4), lactam (A-5), cyclic anhydride (A-6), and oxygen-containing heterocycle compound (A-7) different from (A-1), (A-2), (A-3), (A-4), and (A-6), wherein the catalyst comprises an organic, n-protic Brønsted acid (C), wherein n ≥ 2 and is an element of the natural numbers and the degree of protolysis D is 0 < D < n, with n as the maximum number of transferable protons and D as the calculated proton fraction of the organic, n-protic Brønsted acid (C). The invention further relates to an n-protic Brønsted acid (C) having a degree of protolysis D of 0 < D < n, wherein n is the maximum number of transferable protons, with n = 2, 3 or 4, and D is the calculated proton fraction of the organic, n-protic Brønsted acid (C).