Control of fluidity and miscibility of a binary liquid mixture by the liquid-liquid transition

Matter in its liquid state is convenient for processing and controlling chemical reactions, owing to its fluidity. Recently much evidence has been accumulated for the existence of a liquid–liquid transition (LLT) in single-component liquids. Here, we report that we can control, by the LLT of a molecular liquid, triphenyl phosphite (TPP), the fluidity and miscibility of its mixture with another molecular liquid. For a mixture of TPP with toluene or aniline, we find that both liquid I and II mix well and liquid II remains in a ‘liquid’ state, in contrast to pure TPP, where liquid II is a non-ergodic amorphous state. This is the first example of a ‘true’ LLT in a molecular liquid. Furthermore, we find demixing induced by the LLT for a mixture of TPP with diethyl ether or ethanol. These findings will open a new phase of research towards various applications of the LLT. Recent work has provided evidence for the existence of a liquid–liquid transition (LLT) in some single-component fluids. It is now shown that the LLT can be used to control the fluidity and miscibility of triphenyl phosphite with another molecular liquid, demonstrating the possibility of the first definite application for exploiting this phenomenon.