I. S. Terekhova

Clathrate Hydrates of Tetrabutylammonium and Tetraisoamylammonium Halides

Clathrate formation was considered for two series of systems: (C4H9)4NG–H2O and i‐C5H11)4NG–H2O G = F-, Cl-, Br-, I-). Clathrate hydrates of tetraisoamylammonium halides were shown to melt at higher temperatures than those of the butyl series. In passing from fluoride to bromide, the stability of compounds of the butyl series falls significantly and tetrabutylammonium iodide does not produce polyhydrates. In the isoamyl series, the melting points of polyhydrates vary insignificantly for different halides. In addition, the highest melting hydrate of tetraisoamylammonium bromide melts at a slightly higher temperature than chloride hydrates, indicating not only a hydrophilic effect of the anion on clathrate formation.

Effect of size and shape of cations and anions on clathrate formation in the system: Halogenides of quaterly ammonium bases and water

Abstract The effect of the hydrophobic and hydrophilic inclusion on the structure, stoichiometry and stability of polyhydrates of halogenides of quaternary ammonium bases is discussed. Phase diagrams of binary systems H2O-(i-C5H11)4−k(C4H9)kNA (k = 0, 1, 2, 3, 4; A = F−, Br−), H2O-(C4H9)4NA, −(i-C5H11)4NA (A = F−, Cl−, Br−, I−) and some structural and physico-chemical characteristics of polyhydrates forming in these systems are presented. A comparative analysis of presented data is given.

Clathrate formation in the tetraisoamylammonium propionate-water system

In this paper we examine clathrate formation in the tetraisoamylammonium propionate-water binary system. We have found formation of four polyhydrates, two of which are metastable over the whole temperature range studied. All polyhydrate crystals were isolated and their compositions and densities determined; for (i-C5H11)4NC2H5COO·36.5H2O, unit cell parameters were additionally found. The results are compared with data for tetra-n-butylammonium carboxylate polyhydrates, and the structure of the title compounds is suggested. It is confirmed that the isoamyl radical stabilizes the tetradecahedral void of the clathrate hydrate framework better than the n-butyl radical.