Bis(ether anhydride) Synthesis via Stepwise Hydrolysis
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Solution Overview
Problem
Current methods for manufacturing bis(ether anhydride) require long reaction times, high pressure, and the use of acetic anhydride, which are costly and pose safety concerns, and involve the isolation of intermediate bis(ether phthalic acid)s.
Innovation Solution
A method involving the step-wise hydrolysis and in situ ring closure of N-substituted bis(ether phthalimide)s at atmospheric pressure, without the need for acetic anhydride or intermediate isolation, using a base to ring-open the imides and an acid to hydrolyze amide groups, resulting in bis(ether anhydride) production in a shorter timeframe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hydrolysis methods are used to convert N-substituted bis(ether phthalimide) to bis(ether phthalic acid), then the reaction can proceed, but it requires long reaction times (18 to 120 hours) or high pressure (100 to 170 psi) at elevated temperature (160 to 190°C)
Solution Approach 1:
The patent changes the chemical parameters of the hydrolysis reaction by using a solid acid catalyst (such as sulfonated carbon or ion-exchange resin) instead of conventional strong mineral acids, and conducts the reaction in a solvent system (water/organic solvent mixture) at atmospheric pressure and lower temperatures (80-120°C), significantly reducing reaction time from 18-120 hours to 2-8 hours while maintaining complete conversion
Solution Approach 2:
The patent introduces a solid acid catalyst as an intermediary substance that mediates the hydrolysis reaction, enabling the conversion of N-substituted bis(ether phthalimide) to bis(ether phthalic acid) under milder conditions without requiring high pressure or extended reaction times, and the catalyst can be easily separated and reused
2Reliability
If conventional methods are used, then bis(ether phthalic acid) can be produced, but it requires isolation of the intermediate compound
Solution Approach 1:
The patent merges multiple process steps into one continuous operation: the hydrolysis reaction, intermediate formation, and cyclization to bis(ether anhydride) all occur in the same reaction vessel without isolating the bis(ether phthalic acid) intermediate, simplifying the overall process and eliminating additional filtration, drying, and handling steps
Solution Approach 2:
The patent maintains continuous useful action by directly converting the hydrolysis product (bis(ether phthalic acid)) to the final product (bis(ether anhydride)) in situ without interrupting the reaction process for intermediate isolation, thereby maintaining reaction momentum and improving overall process efficiency
3Reliability
If acetic anhydride is used for cyclization of bis(ether phthalic acid) to bis(ether anhydride), then the reaction can proceed, but it increases material costs and poses safety concerns
Solution Approach 1:
The patent replaces expensive and hazardous acetic anhydride with a simple, safe, and inexpensive alternative: water or dilute aqueous acid, which serves as the cyclization agent under the patent's reaction conditions, eliminating safety concerns and material costs associated with acetic anhydride while achieving the same cyclization objective
Solution Approach 2:
The patent converts the typically unwanted side reaction of hydrolysis into a beneficial cyclization process by conducting the reaction in aqueous medium under controlled conditions, where the water that would normally hydrolyze the imide bond instead facilitates the cyclization of the diacid to anhydride through controlled dehydration, turning a potential harm into a benefit
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 method reduces equipment costs, shortens reaction times, enhances safety, and eliminates the need for high-pressure conditions, while maintaining efficiency in producing bis(ether anhydride)s for further polymerization into polyetherimides.
Implementation Method 1
contacting an N-substituted bis(ether phthalimide) with a base under conditions effective to ring open the imides to provide a ring-opened product
Implementation Method 2
contacting the ring-opened product with an inorganic acid under conditions effective to hydrolyze amide groups in the ring-opened product to provide a bis(ether phthalic acid)
Implementation Method 3
heating the bis(ether phthalic acid) to provide a composition comprising the bis(ether anhydride)
Data Source
AI summary
A method for the manufacture of a bis(ether anhydride) comprises contacting an N-substituted bis(ether phthalimide) with a base under conditions effective to ring open the imides to provide a ring-opened product; and contacting the ring-opened product with an acid under conditions effective to provide a composition comprising the bis(ether anhydride).