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Separation of fullerenes C60 and C70 using a crystallization-based process

Authors

  • Kui S. Kwok,

    1. Dept. of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
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  • Yik C. Chan,

    1. Dept. of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
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  • Ka M. Ng,

    Corresponding author
    1. Dept. of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
    • Dept. of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
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  • Christianto Wibowo

    1. ClearWaterBay Technology Inc., 4000 W. Valley Boulevard, Suite 100, Pomona, CA 91789
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Abstract

A crystallization-based process that separates pure fullerenes C60 and C70 from their mixture using o-xylene as the solvent has been developed. Isothermal solid–liquid equilibrium phase diagrams of the C60-C70-o-xylene ternary system for a number of temperatures were first determined at 1 atm. Taking advantage of the shift in solvent-free composition of the C60-C70 double saturation point with temperature and based on the solid solution-forming phase behavior between C60 and C70, the flowsheet of a general crystallization process was then synthesized. It involved the fractionation of a C60-C70 fullerene mixture into C60-rich and C70-rich solid solutions using temperature-swing crystallization, followed by purification of the solid solutions with multistage crystallization into pure C60 and C70 solids. To demonstrate process feasibility, bench-scale batch experiments were performed using a commercially available fullerene mixture that was pretreated by adsorption to remove higher fullerenes. C60 and C70 solids of purity higher than 99 wt % were obtained. © 2009 American Institute of Chemical Engineers AIChE J, 2010

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