RSD TAN - TSU and RSD
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Introduction 3 Instruments have their strong and weak points and not one can always give the complete solution. But ‘Safety Calorimeters’ are designed to investigate exothermic materials and ought to reliably indicate exothermic data from samples undergoing significant exothermic reaction. Some samples are easy to evaluate, for example DTBP. Others may be more challenging – for example samples that may sublime. This report shows results from DSC, TSu and RSD of methyl hydrazinocarboxylate or methyl hydrazinyl carboxylate. This known exothermic material is also referred to as Methyl Carbazate Clearly shown is the melting near 75 o C and there is a very small exotherm starting at 140 o C. This exotherm completes before the next exotherm starts above 180 o C, this exotherm leads in to a major complex exothermic region. The test typical of DSC is with a 5mg sample at 5°C/min. The melting is shown but there is no indication of an exotherm. It appears there may be some exotherm but this is soon replaced by endothermic activity. Clearly the pressure rise indicates a gas producing reaction is occurring – and close inspection of the pressure trace indicates pressure rise from below 100 o C. Careful inspection of the temperature trace shows some non- linearity below 100 o C, the trace shows curvature. Issues with the TSu are that the thermal control is from the furnace and there is a significant metal heat sink outside the hot zone causing heat loss – potential reflux or distillation of a volatile sample. Experimental An RSD test was carried out under conditions similar to those used for the TSu test to give as good a comparison as possible (3grams of sample heated at 2C/min in an ARC- bomb). An empty ARC-bomb was used aas a ‘reference’. The RSD test was concluded at a lower pressure than that of the TSu test and the system then cooled. Results The results are shown in the series of graphs overleaf. The melting peak is shown and the start of the exothermic decomposition is shown. The RSD data clearly has no issue with reflux or condensation and gives normal safety screen data. DSC and TSu data from the sample Rapid Screening Device - RSD™ Technical Application Note 999 Comparison of Data: Tsu and RSD
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Comparison of data from THT RSD and HEL TSU instruments
Transcript of RSD TAN - TSU and RSD
Introduction 3 Instruments have their strong and weak points and not one can always give the complete solution. But ‘Safety Calorimeters’ are designed to investigate exothermic materials and ought to reliably indicate exothermic data from samples undergoing significant exothermic reaction. Some samples are easy to evaluate, for example DTBP. Others may be more challenging – for example samples that may sublime. This report shows results from DSC, TSu and RSD of methyl hydrazinocarboxylate or methyl hydrazinyl carboxylate. This known exothermic material is also referred to as Methyl Carbazate Clearly shown is the melting near 75oC and there is a very small exotherm starting at 140oC. This exotherm completes before the next exotherm starts above 180oC, this exotherm leads in to a major complex exothermic region. The test typical of DSC is with a 5mg sample at 5°C/min. The melting is shown but there is no indication of an exotherm. It appears there may be some exotherm but this is soon replaced by endothermic activity. Clearly the pressure rise indicates a gas producing reaction is occurring – and close inspection of the pressure trace indicates pressure rise from below 100oC. Careful inspection of the temperature trace shows some non-linearity below 100oC, the trace shows curvature.
Issues with the TSu are that the thermal control is from the furnace and there is a significant metal heat sink outside the hot zone causing heat loss – potential reflux or distillation of a volatile sample. Experimental An RSD test was carried out under conditions similar to those used for the TSu test to give as good a comparison as possible (3grams of sample heated at 2C/min in an ARC-bomb). An empty ARC-bomb was used aas a ‘reference’. The RSD test was concluded at a lower pressure than that of the TSu test and the system then cooled. Results The results are shown in the series of graphs overleaf. The melting peak is shown and the start of the exothermic decomposition is shown. The RSD data clearly has no issue with reflux or condensation and gives normal safety screen data.
DSC and TSu data from the sample
Rapid Screening Device - RSD™ Technical Application Note 999
Comparison of Data: Tsu and RSD
Discussion and Conclusions The full temperature profile as recorded by the RSD is shown in the first graph. The two graphs below zoom the ranges of interest. An advantage of the RSD is the possibility of difference plots—ie temperature (or pressure) of sample versus reference. Such plots highlight onset and stability information. The temperature difference against ‘reference’ temperature gives clear information on the onset of exothermic activity.
Pressure data is also very valuable. The pressure data may be plotted against time or against the reference temperature. The data shows operation of the RSD and its ability to perform with problematic materials!
Rapid Screening Device - RSD™ Technical Application Note 999
Comparison of Data: Tsu and RSD
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