Energy & Fuels, Vol.32, No.6, 6863-6868, 2018
Spectroscopic Studies on the Formation and Guest Behaviors of Hydroquinone Clathrate with Binary CO and H-2 Gas Mixtures
Syngas clathrate compounds were for the first time investigated using hydroquinone (HQ) with binary CO and H-2 gas mixtures as syngas replicas. In combination with X-ray diffraction and Raman spectroscopy, solid-state C-13 magic angle spinning nuclear magnetic resonance (NMR) measurements revealed that HQ molecules with the syngas mixtures were converted into the clathrate form with selective enclathration of CO partially or completely, depending upon the experimental pressure and the CO concentration. When formed with gas mixtures of 50% and higher CO concentrations at 80 bar, more than 95% HQ molecules were converted to HQ clathrates. The cage occupancy and stored amounts of CO molecules in the solid clathrates were estimated to be 20-50% and 13.6-33.9 L of CO/kg of HQunder standard temperature and pressure conditions, respectively, when cross-checked with solid-state NMR and elemental analysis methods.