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Activation and Utilization of CO2 Using Ionic Liquid or Amine-Functionalized Basic Nanocrystalline Zeolites for the Synthesis of Cyclic Carbonates and Quinazoline-2,4(1H,3H)‑dione

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journal contribution
posted on 30.06.2017, 00:00 by Bhaskar Sarmah, Rajendra Srivastava
CO2 was activated and used as a reactant for the preparation of cyclic carbonates and quinazoline-2,4­(1H,3H)-dione using functionalized basic nanocrystalline zeolite Nano-ZSM-5 as catalysts. Nano-ZSM-5 was treated with aqueous NH3 solution to prepare basic Nano-ZSM-5. The surface basicity of the basic Nano-ZSM-5 was systematically varied by the surface modification with various amines and basic ionic liquids. Powder X-ray diffraction, N2 adsorption–desorption, scanning/transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, 29Si and 13C cross polarized-magic angle spin NMR, elemental analysis, and temperature-programmed desorption techniques were used to characterize the materials. Kinetic (rate constant, activation energy) and thermodynamic parameters (change in enthalpy, free energy, and entropy) were calculated for the cycloaddition reaction of CO2 to epichlorohydrin and 2-aminobenzonitrile by varying the reaction parameters. Basic Nano-ZSM-5 functionalized with methylimidazolium hydroxide exhibited remarkable high activity and selectivity in the preparation of cyclic carbonates and quinazoline-2,4­(1H,3H)-dione. The catalyst was separated and recycled with no significant loss in the activity. In this study mesoporous zeolite was made basic and then the basic property of the nanocrystalline zeolite surface was systemically tuned using various functional amines and ionic liquids under one umbrella.