Abstract:

Thermotropic layered phase transition compounds decylammonium tetrachlorozincate((n-C16H33NH3)2ZnCl4, C16Zn) and hexadecylammonium tetrachlorozincate((n-C18H37NH3)2ZnCl4,C18Zn) were synthesized, and a series of their mixtures were prepared from absolute ethanol. The compounds exhibit high enthalpy solid-solid phase transition in the temperature range of 340~370 K. Subsolidus binary phase diagram of C16ZnC18Zn was established by differential thermal analysis and X-ray diffraction. In the phase diagram, new material (nC16H33NH3)(n-C18H37NH3)ZnCl4 at w(C16Zn)=41.11% and two eutectoid invariants at w(C16Zn)=16.19% and w(C16Zn)=63.07% are observed. Two eutectic point temperatures are about 356 K and 353 K. In contrast to other similar system, there are three noticeable solid solution ranges(α, β, γ) at the left, right, and middle boundary of the phase diagram, respectively.

Key words: decylammonium tetrachlorozincate, hexadecylammonium tetrachlorozincate, Phase diagram, differential thermal analysis, X-ray diffraction