Fullerene C60 and C70 Separation via Crystallization
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Solution Overview
Problem
Current methods for separating highly pure fullerenes, such as C60 and C70, from crude fullerene mixtures are inefficient due to irreversible adsorption and lack of understanding of the underlying phase behavior, hindering large-scale commercialization.
Innovation Solution
A method involving crystallization based on the solid-liquid equilibrium phase diagram of the fullerene-solvent system, where the phase equilibrium behavior of the feed stream is manipulated to crystallize out pure fullerenes, solid solutions, or solvates in separate crystallizers, allowing for simultaneous and continuous production of highly pure fullerenes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chromatographic methods (liquid chromatography using neutral alumina, graphite, or activated charcoal) are used to separate fullerenes, then some fullerenes can be isolated in highly pure form, but large-scale separation is inefficient due to inherent losses from irreversible adsorption onto the adsorption medium
Solution Approach 1:
The patent employs crystallization (a phase transition from liquid solution to solid crystal) to separate fullerenes, replacing the adsorption-based chromatographic method. By manipulating the solid-liquid equilibrium phase behavior of the fullerene-solvent system, pure fullerene crystals are formed and separated from the solution, achieving both high purity and scalability without irreversible adsorption losses.
Solution Approach 2:
The patent changes the physical parameters of the system by utilizing phase equilibrium behavior at different temperatures and compositions. By operating at specific points on the phase diagram and controlling temperature and solvent composition, the patent achieves selective crystallization of different fullerene components, enabling efficient large-scale separation while maintaining high purity.
2Manufacturing precision
If conventional crystallization methods are used, then pure fullerene solids can be obtained from solution, but the underlying phase behavior is not understood and separation efficiency is limited
Solution Approach 1:
The patent incorporates systematic investigation and characterization of the phase equilibrium behavior of the fullerene-solvent system. By measuring and mapping the phase diagram (including solubility curves and crystallization regions), the patent establishes a feedback mechanism that guides process optimization, enabling both high purity separation and deep understanding of the underlying phase behavior.
3Manufacturing precision
If multiple sequential separation steps are used to achieve high purity fullerenes, then desired purity levels can be reached, but production time and processing complexity increase
Solution Approach 1:
The patent segments the separation process by exploiting the different phase equilibrium behaviors of various fullerene components (C60, C70, and higher fullerenes) in the solvent system. By manipulating composition and temperature to target specific regions on the phase diagram, different fullerene components crystallize at different stages, enabling simultaneous separation of multiple components in a integrated process rather than requiring multiple sequential 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
Enables the simultaneous separation of highly pure fullerenes up to 99.99% purity on a large scale with low production and separation costs, applicable to various fullerene-solvent systems.
Implementation Method 1
crystallization based on the solid-liquid equilibrium phase diagram of the fullerene-solvent system
Implementation Method 2
the phase equilibrium behavior of the feed stream is manipulated such that pure fullerenes, solid solutions or solvates are crystallized out
Data Source
AI summary
The present invention is a method for simultaneously separating two highly pure fullerenes from a mixture of fullerenes via crystallization, by (i) adjusting the amount of solvent in the mixture fed to a first crystallizer to obtain a phase equilibrium behavior so a first fullerene component of the two fullerenes, in the form of pure crystal, solid solution crystal, or solvate crystal is obtained; (ii) adjusting the amount of solvent in another mixture fed to a second crystallizer, operating at a temperature different from the first crystallizer, to obtain a phase equilibrium behavior so a second fullerene component of the two fullerenes, in the form of pure crystal, solid solution crystal, or solvate crystal is obtained; and additionally (iii) purifying the solid solution or the solvate into highly pure fullerene, when the solid product from the crystallizers is in the form of solid solution or solvate.