Thermal decomposition of Yttrium 2-methylbutyrate in argon

The thermal decomposition of yttrium 2-methylbutyrate (Y(C₄H₉CO₂)₃) under argon gas flow has been investigated by means of simultaneous thermogravimetry and differential thermal analysis, FTIR-spectroscopy (solid residue and evolved gas analysis), mass spectrometry, hot-stage optical microscopy and X-ray diffraction with a standard laboratory Cu-tube source as well as with a high-energy synchrotron radiation source. At least one structural transition occurs in the solid state between 100 °C and 160 °C. The decomposition of the Y 2-methylbutyrate salt takes place above 400 °C. A first stage results in the formation of Y₂O₂CO₃ between 400 °C and 490 °C. This decomposition step is accompanied by the release of CO₂, a symmetrical ketone (3,5-dimethyl-4-heptanone), as well as probably a terminal alkyne, which could not be unambiguously identified. At higher temperature, Y₂O₂CO₃ is slowly converted to Y₂O₃ with release of CO₂, while some carbonaceous residue is eliminated via combustion. The TG trace reaches the final plateau at about 1200 °C.