THERMAL STABILITY AT ELEVATED PRESSURE - AN INVESTIGATION USING DIFFERENTIAL SCANNING CALORIMETRY

During laboratory scale development of a new chemical process which is to be operated at elevated pressure a material was found to undergo an unexpected thermal decomposition. Initial DSC testing had indicated that melting appeared to be a pre-requisite for decomposition and based upon this and the fact that melting points are elevated at increased pressures the material had been expected to be thermally stable under the proposed operating conditions. The unexpected thermal decomposition resulted in a more extensive investigation into the thermal stability of the material being performed. Work was carried out primarily at ambient pressure in order to obtain an understanding of the mode of decomposition. The work was then extended to pressures of up to 30 bar and although this gave us a further insight into the decomposition it failed to simulate the process conditions which could reach 600 bar. A collaboration with The University of Aberdeen has enabled DSC measurements to be carried out at 500 bar confirming predictions about the melting point behaviour but also giving an unexpected view of the thermal decomposition. A second collaboration with The University of Huddersfield provided a further insight into the thermal decomposition of the material.