Reactivity of Ionic Liquids: Reductive Effect of [C4C1im]BF4 to Form Particles of Red Amorphous Selenium and Bi2Se3 from Oxide Precursors

Temperature-induced change in reactivity of the frequently used ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([C4 C1 im]BF4 ) is presented as a prerequisite for the rational screening of reaction courses in material synthesis. [C4 C1 im]BF4 becomes active with oxidic precursor compounds in reduction reaction at ϑ≥200 °C, even without the addition of an external reducing agent. The reaction mechanism of forming red amorphous selenium from SeO2 is investigated as a model system and can be described similarly to the Riley oxidation. The reactive species but-1-ene, which is formed during the decomposition of [C4 C1 im]BF4 , reacts with SeO2 and form but-3-en-2-one, water, and selenium. Elucidation of the mechanism was achieved by thermoanalytical investigations. The monotropic phase transition of selenium was analyzed by the differential scanning calorimetry. Beyond, the suitability of the single source oxide precursor Bi2 Se3 O9 for the synthesis of Bi2 Se3 particles was confirmed. Identification, characterization of formed solids succeeded by using light microscopy, XRD, SEM, and EDX.