Semiclathrate hydrates of methane + tetraalkylammonium hydroxides

Equilibrium Phase Relations and Dissociation Enthalpies of Tri-n-butylalkenylphosphonium Bromide Semiclathrate Hydrates

“…Different SCHs have to be used depending on the intended use. For example, the usage of SCHs in the air conditioning system, shipping boxes for medicine and/or fresh foods, and cooling systems of data centers and lithium-ion batteries for electric vehicle is expected. − As a way of tuning the equilibrium temperature of SCH, the replacement of anions has been well known and widely used. ,, Carboxylate anions with the different size of alkyl heads have been actively investigated. ,− As another way for tuning, the modification of quaternary onium cation as well as anion replacement has been investigated. ,− We recently reported the thermodynamic properties of tri- n -butylalkylphosphonium bromide (P444R-Br) SCHs, which exhibit a different size and shape of alkyl groups in phosphonium cations . In a previous study, propyl (R = 3), butyl (R = 4), and pentyl (R = 5) groups were adopted for the normal alkyl groups of the P444R-Br SCHs (the cation structures are shown in Figure ).…”

Phase equilibrium temperature and dissociation enthalpy in the tri-n-butylalkylphosphonium bromide semiclathrate hydrate systems

“…ammonium or phosphonium, has been well known as the typical cation change and the difference has been discussed in several papers (Kobori et al, 2015;Muromachi et al, 2014). Besides, binary systems of water + salts of quaternary ammonium cation composed of the same sort of alkyl group, such as tetramethylammonium, tetraethylammonium, tetra-n-propylammonium, tetra-n-pentylammonium (tetra-n-amylammonium), and tetraisopentylammonium (tetraisoamylammonium), have been also demonstrated (Su et al, 2016(Su et al, , 2017. From the literature, the butyl and isopentyl groups are preferable for clathrate hydrate formation.…”