Spectroscopic investigation, cage occupancy, and gas storage capacity of hydroquinone clathrates formed with H2S-N2 and COS-N2 binary gas mixtures

Lee, Jun Young; Lee, Seo Hee; Yoon, Sang Jun; Yoon, Ji-Ho

doi:10.1007/s11814-017-0184-0

Cited by 5 publications

(6 citation statements)

References 32 publications

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“…The lattice parameters for βform HQ clathrates are similar to those of N 2 -loaded HQ clathrates, supporting similar behaviors for N 2 and CO. 31 Because NMR peak intensity is inherently proportional to a corresponding atomic state and because the atomic signal of the hydroxyl-substituted carbon is split into three components of relative intensity (2:3:1), 7 the signals at around 148.8 ppm can be used to calculate the relative amounts of the α and β forms (that is, conversion yields) after deconvolution of the overlapped peaks and peak fitting. 19,37 Figure 4 shows the conversion yields of HQ samples prepared with (CO + H 2 ) gas mixtures at three experimental pressures of 40, 60, and 80 bar. As illustrated in the figure, the conversion yields primarily increase as the CO concentrations in the gas mixtures increase or as the formation pressures increase.…”

Section: Energy and Fuelsmentioning

confidence: 99%

Spectroscopic Studies on the Formation and Guest Behaviors of Hydroquinone Clathrate with Binary CO and H₂ Gas Mixtures

Lee

Yoon

et al. 2018

Energy Fuels

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Syngas clathrate compounds were for the first time investigated using hydroquinone (HQ) with binary CO and H2 gas mixtures as syngas replicas. In combination with X-ray diffraction and Raman spectroscopy, solid-state 13C 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 HQ under standard temperature and pressure conditions, respectively, when cross-checked with solid-state NMR and elemental analysis methods.

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Section: Energy and Fuelsmentioning

confidence: 99%

Spectroscopic Studies on the Formation and Guest Behaviors of Hydroquinone Clathrate with Binary CO and H₂ Gas Mixtures

Lee

Yoon

et al. 2018

Energy Fuels

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“…Recently, organic clathrates, in particular HQ clathrates, have been reported as a potentially good medium for gas separation and storage because HQ has some advantages over water molecules when forming clathrate compounds. 6,7 HQ is a crystalline solid substance with three distinct crystal structures: α, β, and γ forms have been reported thus far. The α form is stable at ambient pressure and temperature and has a rhombohedral space group (R3) with lattice parameters a = 38.46 Å and c = 5.650 Å.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, specific gas components can be separated from gas mixtures as a result of their selectivity (or preference) for the cage occupation. Recently, organic clathrates, in particular HQ clathrates, have been reported as a potentially good medium for gas separation and storage because HQ has some advantages over water molecules when forming clathrate compounds. , …”

Section: Introductionmentioning

confidence: 99%

Swapping and Enhancement of Guest Occupancies in Hydroquinone Clathrates Using CH₄ and CO₂

et al. 2019

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In this study, we investigated guest behaviors of CO2 and CH4 molecules during the initial formation of hydroquinone (HQ) clathrates and then the swapping reactions of guest-loaded HQ. Two experimental pressures of 3.0 and 5.0 MPa were selected for both formation and swapping reactions at room temperature, both of which are known to be in the stability region of HQ clathrates. Prepared samples were analyzed by a series of spectroscopic measurements to obtain qualitative and quantitative information on guest molecules in clathrate cages. After the initial formation, CO2 molecules showed higher cage occupancies of 90.1 ± 3.9 and 99.4 ± 2.7%, with full conversion into the clathrate form, compared to the values of 61.9 ± 4.2 and 64.6 ± 4.5% with incomplete conversion for CH4 molecules at 3.0 and 5.0 MPa, respectively. In the subsequent swapping reactions, 72–77% of CH4 molecules in guest-loaded HQ clathrate are replaced with CO2, while only 6–9% of CO2 molecules are replaced with CH4 molecules. The experimental results demonstrated that kinetic behaviors of CO2 molecules are better favored than CH4 molecules in HQ clathrates, even though their thermodynamic equilibria are almost identical.

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“…To minimize dissociation of the clathrate out of the formation conditions, pressure release and sample collection were performed right before all the measurements. Basically, the same experimental procedures as our previous reports were used in this study [10][11][12][13].…”

Section: Methodsmentioning

confidence: 99%

“…Moreover, the clathrate compound prepared from HQ was found to be applicable to gas separation. Unlike a gas hydrate, because the HQ clathrate only has one type of cavity structure, it can easily achieve the selective separation of a speci c component from various gas mixtures [12,13].…”

Section: Introductionmentioning

confidence: 99%

Formation Behaviors and Selective Separation of the Binary (SF6+N2) Gas Mixtures Using Hydroquinone Clathrate

Yoon,

Lee

2023

Preprint

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After reacting hydroquinone (HQ) powder with pure sulfur hexafluoride (SF6) and nitrogen (N2), and binary gas mixtures of (SF6 + N2) with various compositions at experimental pressures of 20 bar and 40 bar, the HQ samples are analyzed using a series of analytic methods to obtain both qualitative and quantitative information. As a result, it was found that N2 can be enclathrated into cavities of the formed HQ clathrate if the simplified partial pressure of N2 is sufficiently large (occupation of 10% per one cavity when the simplified partial pressure is 32 bar, and occupation of 40% per one cavity when the pressure of pure N2 is 40 bar). In addition, additional experiments were performed to evaluate the N2 storage in the clathrate depending on the experimental pressure. When the pressure of pure N2 was increased up to 80 bar, the occupation per one clathrate cage was calculated to be 55%, which corresponded to 18.7 L of N2 at STP conditions per 1 kg of HQ. Because higher pressure is required to form the HQ clathrate and the stored amount of gas molecules is smaller compared with other technologies such as adsorption or hydrate-based process, a lot of additional investigations will be necessary, focusing on reducing energy consumption and increasing the gas storage.

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Spectroscopic investigation, cage occupancy, and gas storage capacity of hydroquinone clathrates formed with H2S-N2 and COS-N2 binary gas mixtures

Cited by 5 publications

References 32 publications

Spectroscopic Studies on the Formation and Guest Behaviors of Hydroquinone Clathrate with Binary CO and H₂ Gas Mixtures

Spectroscopic Studies on the Formation and Guest Behaviors of Hydroquinone Clathrate with Binary CO and H₂ Gas Mixtures

Swapping and Enhancement of Guest Occupancies in Hydroquinone Clathrates Using CH₄ and CO₂

Formation Behaviors and Selective Separation of the Binary (SF6+N2) Gas Mixtures Using Hydroquinone Clathrate

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Spectroscopic investigation, cage occupancy, and gas storage capacity of hydroquinone clathrates formed with H2S-N2 and COS-N2 binary gas mixtures

Cited by 5 publications

References 32 publications

Spectroscopic Studies on the Formation and Guest Behaviors of Hydroquinone Clathrate with Binary CO and H2 Gas Mixtures

Spectroscopic Studies on the Formation and Guest Behaviors of Hydroquinone Clathrate with Binary CO and H2 Gas Mixtures

Swapping and Enhancement of Guest Occupancies in Hydroquinone Clathrates Using CH4 and CO2

Formation Behaviors and Selective Separation of the Binary (SF6+N2) Gas Mixtures Using Hydroquinone Clathrate

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Spectroscopic Studies on the Formation and Guest Behaviors of Hydroquinone Clathrate with Binary CO and H₂ Gas Mixtures

Spectroscopic Studies on the Formation and Guest Behaviors of Hydroquinone Clathrate with Binary CO and H₂ Gas Mixtures

Swapping and Enhancement of Guest Occupancies in Hydroquinone Clathrates Using CH₄ and CO₂