2-3-2　TBAB, TBAC のゲストモル分率により変化するセミクラスレートハイドレートの熱特性

抄録

We investigated the thermodynamic properties of semiclathrate hydrates (SCH) depending on tetragonal tetra-n-butyl ammonium bromide (TBAB) and tetra-n-butyl ammonium chloride (TBAC) guest mole fractions by ion chromatography and differential scanning calorimetry. TBAB mole fraction rates in TBAB + TBAC mixed SCH (y^hTBAB) are lower than those in mixed aqueous solutions; it means that Cl⁻ with a smaller size difference to a water molecule is more easily incorporated into the host frameworks of SCH than Br⁻ in mixed SCH systems. The melting points of mixed SCH were observed at 286–289K, and the maxima are around y^hTBAB = 0.1–0.3 in each hydration number. Dissociation enthalpies per guest moles increase linearly from 154kJ mol^–1 to 188kJ mol^–1 primarily depending on increasing hydration numbers.