Smart
materials reversibly changing properties in response to a
stimuli are promising for a broad array of applications. In this article,
we report the use of trichloroacetic acid (TCA) as fuel to create
new types of time-controlled materials switching reversibly from a
gel to a solution (gel–sol–gel cycle). Applying various
neutral amines as organogelators, TCA addition induces amine protonation,
switching the system to a solution, while TCA decarboxylation over
time enables a return to the initial gel state. Consequently, the
newly obtained materials possess interesting time-dependent properties
applied in the generation of remoldable objects, as an erasing ink,
as chiroptical switches, or for the generation of new types of electrical
systems.
Amine purification have for long been dominated by tedious stepwise processes involving the generation of large amounts of undesired waste. Inspired by recent work on out of equilibrium molecular machinery, using trichloroacetic acid (TCA), we disclose a purification technique considerably decreasing the number of operations and the waste generation required for such purifications. At first, TCA triggers the precipitation of the amines through their protonated salt formation, enabling the separation with the impurities. From these amine salts, simple decarboxylation of TCA liberates volatile CO2 and chloroform affording directly the pure amines. Through this approach, a broad range of diversely substituted amines could be isolated with success.
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