CO Capture from Flue Gas Based on Tetra--butylammonium Fluoride Hydrates at Near Ambient Temperature.

Semiclathrate hydrates of tetra--butylammonium fluoride (TBAF) are potential CO capture media because they can capture CO at near ambient temperature under moderate pressure such as below 1 MPa. In addition to other semiclathrate hydrates, CO capture properties of TBAF hydrates may vary with formation conditions such as aqueous composition and pressure because of their complex hydrate structures. In this study, we investigated CO capture properties of TBAF hydrates for simulated flue gas, that is, CO + N gas, by the gas separation test with three different parameters for each pressure and aqueous composition of TBAF in mass fraction ( ).

Structure-driven CO selectivity and gas capacity of ionic clathrate hydrates.

Ionic clathrate hydrates can selectively capture small gas molecules such as CO, N, CH and H. We investigated CO + N mixed gas separation properties of ionic clathrate hydrates formed with tetra-n-butylammonium bromide (TBAB), tetra-n-butylammonium chloride (TBAC), tetra-n-butylphosphonium bromide (TBPB) and tetra-n-butylphosphonium chloride (TBPC). The results showed that CO selectivity of TBAC hydrates was remarkably higher than those of the other hydrates despite less gas capacity of TBAC hydrates.

Hyperfine resolved Fourier transform microwave and millimeter-wave spectroscopy of the iodomethyl radical, CH2I (X2B1).

Fourier-transform microwave and millimeter-wave spectra of the iodomethyl radical, CH(2)I, have been observed in the ground vibronic state in the frequency ranges 17-38 GHz and 200-610 GHz, respectively. The pi-electron radical was produced either by iodine abstraction from diiodomethane (CH(2)I(2)) or by hydrogen abstraction from iodomethane (CH(3)I). Seventy-three hyperfine resolved lines owing to the two hydrogen and to the iodine nuclei have been detected in the microwave region, including K(a) = 0 (ortho species) and K(a) = 1 (para species).

Millimeter wave spectrum of bromomethyl radical, CH2Br.

The rotational spectra of the two isotopic species of the bromomethyl radical, CH2 79Br and CH2 81Br, have been observed in their ground electronic state 2B1 in the 180-470 GHz frequency region, corresponding to a-type transitions from N=8-7 to N=21-20. The radical was produced by hydrogen abstraction of methylbromide (CH3Br) either by chlorine or by fluorine atoms in a free space cell. Hyperfine structure due to the bromine nucleus has been resolved in the observed spectra, and the rotational constants as well as the fine and hyperfine interaction constants were accurately determined for both isotopomers.

Submillimeter-wave spectra of hypoiodous acid.

Pure rotational spectra of hypoiodous acid, HOI, and its deuterated species, DOI, were measured in the frequency range of 320-670 GHz. The molecule was efficiently produced by a reaction of atomic oxygen with iodoethane. Rotational constants and centrifugal distortion constants for the molecule were determined accurately.