(510f) Solvent Template-Directed Synthesis of Flexible and Thermosensitive Metal-Organic Framework (CPL-1) for Highly Selective C3H6/C3H8 Separation

The separation of olefins from paraffin is important for the production of industrial chemicals. A flexible and thermosensitive microporous Metal-organic framework (CPL-1) was synthesized by a solvothermal method using various sized solvents as the template. The isotherms of propylene and propane on CPL-1 materials were measured by a volumetric method. Experiments of multiple adsorption-desorption cycles were conducted to estimate reversibility of propylene on CPL-1. Results showed the C₃H₆ isotherms of all samples showed a sudden rise at the threshold pressure and attained a saturated level rapidly, indicating that the structure of CPL-1 materials could expand in response to propylene molecule at 273 K. Whereas, CPL-1 materials were not responding to propane molecule. Therefore, CPL-1 demonstrated a highly selectivity towards C₃H₆ against C₃H₈. The solvents could be divided into two groups based on the kinetic diameters: the kinetic diameters of the solvents in one group are smaller than that of C₃H₆, those in the other are greater than that of C₃H₆. And C₃H₆ gate opening pressure of CPL-1 materials synthesized by different solvents reduced with the decreasing of the kinetic diameters of two groups of solvents, separately. Among them, CPL-1 synthesized in the solvent of CH₂Cl₂, which molecular size is slightly larger than propylene, performanced the lowest C₃H₆ gate opening pressure about P/P₀=0.37. Itâ??s worth noting that the structure of thermosensitive CPL-1 could expand in response to propylene molecular at 273 K, but shrink at 298 K. Consecutive cycles of adsorption-desorption experiment showed that the desorption efficiency could reach 90% for five cycles at 298 K, P/P₀=0.9, indicating that CPL-1 had excellent regeneration property of propylene at room temperature.