Methane capture with α-cyclodextrins

Abstract

α-cyclodextrin dissolved in water binds methane giving crystals of a 1:1 complex in up to 57 % yield. The binding constant was Ka = 21 M-1. 3A,6A,3D,6D-dianhydro-α-cyclodextrin which has a...

One-step synthesis of Ling's tetrol and its conversion into A,D-di-allo-α-cyclodextrin derivatives

“…The increased binding to methane is likely due to the decreased cavity size caused by the axial amino groups. This is evident from the comparison of the X-ray structure of the α-cyclodextrin-methane complex 24 with the corresponding model of 16 complexed with CH 4 obtained by adding the axial amino groups to the structure (Fig. 1).…”

“…Binding to the ligands methyl orange and 4-(4-hydroxyphenyl)-1-naphthalene sulfonic acid, and the gases methane and carbon dioxide was investigated using a previously described methodology. 24 The two azodyes changed the UV/VIS spectrum upon binding to cyclodextrins, so the K d values were determined simply by measuring the absorbance change at 370 or 450 nm and making Benesi–Hildebrand plots from the experimental data (Table 4). The gas binding constants were determined by measuring the absorbance change of a sample of a cyclodextrin derivative mixed with 4-(4-hydroxyphenyl)-1-naphthalene sulfonic acid in the case of methane or methyl orange in the case of carbon dioxide at different partial pressures of the gas.…”

“…The samples were prepared that consisted of phosphate buffer ( pH 7, 50 mM), 4-(4-hydroxyphenyl)-1-naphthalensulfonsyre (40 μM) and a fixed concentration of cyclodextrin ([CD] 0 = 1-4 mM) and were added to a pressure cell as previously described. 24 The spectrum was recorded with 0, 10, 20, and 30 bar of CH 4 pressure over the liquid after a 16-24-hour gas-liquid equilibration period.…”

A high efficiency gas phase photoreactor for eradication of methane from low-concentration sources

“…The low affinity of methane for surfaces interferes with the efficiency of catalytic oxidation of methane, and it also makes it difficult to capture methane using an adsorbant such as activated charcoal, zeolites or metal-organic frameworks (MOFs). One breakthrough could come in the form of carbohydrates that form clathrate type adducts with methane [23]. Finally, methane is weakly soluble in water, making separation with scrubbers very inefficient, and also creating a mass transfer barrier for biological treatment methods using methanogenic bacteria.…”

A High Efficiency Gas Phase Photoreactor for Eradication of Methane from Low-Concentration Sources

“…The low affinity of methane for surfaces interferes with the efficiency of catalytic oxidation of methane, and it also makes it difficult to capture methane using an adsorbant such as activated charcoal, zeolites or MOFs. One breakthrough could come in the form of carbohydrates that form clathrate type adducts with methane [23]. Finally, methane is weakly soluble in water, making separation with scrubbers very inefficient, and also creating a mass transfer barrier for biological treatment methods using methanogenic bacteria.…”