3,3′-Polyetherimide Composition for Isomer Purity and Lower Yellowness
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Solution Overview
Problem
Conventional methods for preparing aromatic bis(ether imide) monomers result in isomeric mixtures that include 3,3′-aromatic bis(ether imide), 3,4′-aromatic bis(ether imide), and 4,4′-aromatic bis(ether imide), leading to polyetherimides with undesirable flow characteristics and higher yellowness index, necessitating a need for methods to minimize or eliminate 3,4′-aromatic bis(ether imide) and 4,4′-aromatic bis(ether imide) to enhance flow and reduce halogen content.
Innovation Solution
A method involving the reaction of 3-nitro phthalic acid to produce 3-nitro-N—(C1-13 alkyl)phthalimide, followed by reacting with a dialkali metal salt of a dihydroxy aromatic compound, and subsequent condensation with phthalic anhydride to form 3,3′-aromatic bis(ether imide), minimizing the presence of 3,4′-aromatic bis(ether imide) and 4,4′-aromatic bis(ether imide) in the polyetherimides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to prepare aromatic bis(ether imide) monomers, then production efficiency is maintained, but isomeric mixtures including 3,4'-aromatic bis(ether imide) and 4,4'-aromatic bis(ether imide) are formed resulting in undesirable flow characteristics and higher yellowness index
Solution Approach 1:
The patent changes the chemical parameters of the synthesis route by using 3-nitro-phthalic anhydride instead of conventional chlorophthalic anhydride or mixtures, and by controlling the reaction conditions (temperature, solvent, catalyst) to favor the formation of 3,3'-isomer. This parameter change achieves high isomeric purity (greater than 98% 3,3'-aromatic bis(ether imide)) while maintaining production efficiency through a direct synthesis pathway without requiring separation steps.
2Ease of operation
If 3,4'-aromatic bis(ether imide) and 4,4'-aromatic bis(ether imide) are present in the monomer mixture, then production complexity is reduced, but flow properties deteriorate and yellowness index increases
Solution Approach 1:
The patent applies preliminary action by designing a synthesis route that prevents the formation of unwanted 3,4'- and 4,4'-isomers from the outset. By using 3-nitro-phthalic anhydride as the starting material and controlling the reaction conditions, the process ensures that only the desired 3,3'-isomer is formed in high purity, eliminating the need for subsequent separation or purification steps to achieve desirable flow properties.
3Object-affected harmful factors
If conventional synthesis routes are used, then process simplicity is maintained, but halogen content in the polyetherimides remains high
Solution Approach 1:
The patent changes the chemical composition parameter by replacing halogen-containing starting materials (chlorophthalic anhydride) with non-halogenated 3-nitro-phthalic anhydride. This parameter change eliminates halogen content in the final polyetherimide product while maintaining process simplicity through a direct synthesis route that does not require additional dehalogenation or purification steps.
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 method produces polyetherimides with improved flow properties and reduced halogen content, achieving lower yellowness index and higher yields, suitable for applications requiring enhanced flow characteristics.
Implementation Method 1
reacting 3-nitro phthalic acid optionally in the presence of a solvent, under conditions effective to provide a reaction mixture comprising 3-nitro-phthalic anhydride and water, and wherein the water is removed from the reaction mixture during the reacting
Implementation Method 2
combining 3-nitro-phthalic anhydride with a C1-13 alkylamine optionally in the presence of a solvent under conditions effective to provide the 3-nitro-N—(C1-13 alkyl)phthalimide composition
Implementation Method 3
reacting a dialkali metal salt of a dihydroxy aromatic compound with the 3-nitro-N—(C1-13 alkyl)phthalimide composition prepared by the above method under conditions effective to form a product mixture comprising the N—(C1-13 alkyl)-3,3′-aromatic bis(ether imide) composition
Data Source
AI summary
A method for the preparation of a 3-nitro-N—(C1-13 alkyl)phthalimide composition comprises reacting a 3-nitro phthalic acid to provide 3-nitro-phthalic anhydride, optionally in the presence of a solvent, and reacting 3-nitro-phthalic anhydride with a C1-13 alkylamine optionally in the presence of a solvent to provide the 3-nitro-N—(C1-13 alkyl)phthalimide composition comprising 3-nitro-N—(C1-13 alkyl)phthalimide and optionally, 4-nitro-N—(C1-13 alkyl)phthalimide. The 3-nitro-N—(C1-13 alkyl)phthalimide composition can have undetectable levels of 4-nitro-N—(C1-13 alkyl)phthalimide, and consequently, polyetherimides ultimately derived from the 3-nitro-N—(C1-13 alkyl)phthalimide composition can be enriched in 3,3′ linkages and/or exclude 3,4′ and 4′4 linkages. The polyetherimides disclosed can have improved flow and a decreased yellowness index.