Calorimetric and Structural Studies of Tetrabutylammonium Chloride Ionic Clathrate Hydrates

Abstract

Three ionic clathrate hydrates of different water content are formed in the binary system tetrabutylammonium chloride-water. The data on heats of fusion of these hydrates measured by DSC are presented. Single-crystal and powder X-ray diffraction studies of ionic clathrate hydrates of tetrabutylammonium chloride have been carried out. Structural justification of the occurrence of three different ionic clathrate hydrates derived from tetragonal structure-I in the (C(4)H(9))(4)NCl-H(2)O system has been found for the first time. A novel mode of hydrophilic inclusion of the halide anion with displacement of two hydrogen-bonded host water molecules has been revealed. Structural data obtained are indicative of the possibility of location of tetrabutylammonium cations in combined cavities formed with participation of D-voids.

Hydrogen and carbon dioxide adsorption with tetra‐n‐butyl ammonium semi‐clathrate hydrates for gas separations

“…The lattice constants a, b, and c were taken from the literature. 25,30,[32][33][34] The porosity parameter was determined from Eqs. 5 and 6 according to previous work.…”

“…There structure parameters were determined with X-ray study. 25,30,[32][33][34] TBAB: tetra-n-butyl ammonium bromide, TBAC: tetra-n-butyl ammonium chloride, TBAF: tetra-n-butyl ammonium fluoride. N ideal;H2O : ideal number of water molecules per unit cell, N H2O : number of non-replaced water molecules as host molecule by cation and anion of TBA salt per unit cell, N conditions and characterization of the semi-clathrate hydrates.…”

Semiclathrate-based CO2 capture from flue gas mixtures: An experimental approach with thermodynamic and Raman spectroscopic analyses

“…To avoid and overcome this concern, gas hydrate formation needs to be performed at much milder pressure and temperature conditions. Thus, extensive efforts have been undertaken to reduce hydrate equilibrium pressures or to enhance hydrate equilibrium temperatures by adding thermodynamic promoters to the system [10,12,[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] Semiclathrates, which share many physical and chemical properties with gas hydrates, could be an attractive alternative to gas hydrates because in general, they can maintain their thermodynamic stability under atmospheric pressure conditions [19,[31][32][33][34][35][36][37][38][39]. In gas hydrates, the guest molecules are not physically bonded to host water lattices, whereas in semiclathrates, guest molecules can both take part in building the host water frameworks and occupy cages after breaking part of the cage structure.…”

“…In QAS semiclathrates, anions such as Br À , Cl À , and F À are involved in forming cage structures with the host water molecules, and tetra-n-butyl ammonium (TBA) cations are incorporated into the large cages. In addition, the QAS semiclathrates have small 5 12 cages which are left vacant and thus, can be used for capturing small-sized gas molecules [19,22,23,[25][26][27][28][31][32][33][34][35][36][37][38][39][40][41]. Due to their significant thermodynamic stability and guest gas enclathrating ability, QAS semiclathrates have been investigated as an alternative to gas hydrates for gas storage and separation [23,27,31,[42][43][44][45][46][47][48].…”

Effects of Promoter on the Formation of Gas Hydrate from Blast Furnace Gas

“…완벽한 clathrate를 이루지 않고 semi-clathrate를 형성하는 TBAB (Tetra-n-butyl ammonium bromide), TBAC(Tetra-n-butyl ammonium chloride), TBAF(Tetra-n-butyl ammonium fluoride) 등을 통칭하는 TBAX와 TBPB(tetra-n-butyl phosphonium bromide) 등이 있다 [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] 3. 결과 및 고찰 Table 2에 Gas hydrate dissociation pressure for , N 2 + water system [44]; , BFG model gas + water system; and , CO 2 + water system [45].…”