Perfluoropolyether Purification via Supercritical CO2 Chromatography
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Solution Overview
Problem
Current methods for preparing a composition with a high ratio of perfluoropolyether having a carboxyl group at one terminal are inefficient, particularly due to the use of ion-exchange resins which require excessive fluorine solvent and result in poor manufacturing efficiency and product properties, especially when dealing with polymers of larger molecular weights.
Innovation Solution
The method involves subjecting a mixture of perfluoropolyethers to chromatography using supercritical or subcritical carbon dioxide as the moving phase and silica gel as the stationary phase, allowing for the selective separation and collection of perfluoropolyethers with a carboxyl group at one terminal at a higher ratio, thereby increasing the content of one-terminal functionalized polymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ion-exchange resin method is used to separate perfluoropolyethers, then one-terminal functionalized polymer can be obtained, but excessive fluorine solvent is required and manufacturing efficiency deteriorates
Solution Approach 1:
The patent changes the separation parameter from chemical adsorption (ion-exchange resin) to physical chromatography based on solubility differences in supercritical carbon dioxide. By controlling pressure and temperature parameters, the method achieves separation without requiring excessive fluorine solvent, thus improving manufacturing efficiency while maintaining separation purity
Solution Approach 2:
The patent replaces the chemical adsorption mechanism of ion-exchange resin with a physical separation mechanism using supercritical fluid chromatography. This substitution eliminates the need for large amounts of fluorine solvent and reduces manufacturing complexity, thereby improving productivity without sacrificing separation effectiveness
2Manufacturing precision
If ion-exchange resin method is used, then separation can be achieved, but fluorine solvent consumption increases and product properties deteriorate
Solution Approach 1:
The patent utilizes pressure and temperature parameter changes to control the solubility of perfluoropolyethers in supercritical carbon dioxide. By adjusting these parameters, the method achieves effective separation with minimal fluorine solvent consumption, preventing substance loss while maintaining separation capability
Solution Approach 2:
The patent introduces supercritical carbon dioxide as an intermediary solvent that enables separation based on solubility differences. This intermediary approach replaces the need for large amounts of fluorine solvent used in ion-exchange resin methods, reducing substance loss while achieving the same separation effect
3Manufacturing precision
If conventional distillation method is used, then separation based on boiling point difference is achieved, but application is limited to polymers with narrow molecular weight distribution
Solution Approach 1:
The patent changes the separation mechanism from boiling point-based distillation to solubility-based supercritical fluid chromatography. This parameter change allows the method to handle polymers with wide molecular weight distributions, significantly expanding adaptability while maintaining separation selectivity through controlled pressure and temperature parameters
4Manufacturing precision
If fluorine solvent-based adsorption method is used, then non-functionalized polymers can be removed, but manufacturing complexity increases and environmental burden increases
Solution Approach 1:
The patent replaces complex chemical adsorption processes using fluorine solvents and ion-exchange resins with a simpler supercritical fluid chromatography system. This substitution uses carbon dioxide as the mobile phase, eliminating the need for complex solvent recovery systems and reducing overall process complexity while maintaining purification effectiveness
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 efficiently and selectively increases the ratio of perfluoropolyether with a carboxyl group at one terminal, reduces the use of fluorine solvent, and is suitable for mass production, improving product properties and applicability to polymers with wide molecular weight distributions.
Implementation Method 1
subjecting a mixture of perfluoropolyethers to chromatography using supercritical or subcritical carbon dioxide as the moving phase and silica gel as the stationary phase
Implementation Method 2
subjecting the composition to chromatography in which a moving phase is a supercritical or subcritical state carbon dioxide and a stationary phase is silica gel
Data Source
AI summary
An object of the present invention is to provide a method for efficiently and highly selectively preparing a composition comprising a perfluoropolyether having a carboxyl group at one terminal at a higher ratio. The present invention provides a method for increasing a ratio of a perfluoropolyether having a carboxyl group at one terminal, relative to a total amount of the perfluoropolyether having a carboxyl group at one terminal and a perfluoropolyether having carboxyl groups at both terminals in a composition comprising these perfluoropolyethers, wherein the method comprises a step of subjecting the composition to chromatography in which a moving phase is supercritical or subcritical state carbon dioxide of the specific temperature and the specific pressure, and a stationary phase is silica gel to thereby collect a fraction containing the perfluoropolyether having a carboxyl group at one terminal at a higher ratio. Further, present invention provides for increasing a ratio of a perfluoropolyether having a carboxyl group at one terminal, relative to a total amount of the perfluoropolyether having a carboxyl group at one terminal, a perfluoropolyether having carboxyl groups at both terminals and a perfluoropolyether having no carboxyl group at any terminal perfluoropolyether, in a composition comprising these perfluoropolyethers, wherein the method comprises a step of subjecting the composition to chromatography in which a moving phase is supercritical or subcritical state carbon dioxide of the specific temperature and the specific pressure, and a stationary phase is silica gel to thereby collect a fraction containing the perfluoropolyether having a carboxyl group at one terminal at a higher ratio.