Molybdenum, bis(N,N-dibutylcarbamodithioato-κS,κS')dioxodi-μ-thioxodi-, stereoisomer

Melting point / freezing point

Link to relevant study record(s)

Reference

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Version / remarks:

July 1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Version / remarks:

May 2008 (Commission Regulation (EC) No 440/2008)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7200 (Melting Point / Melting Range)

Version / remarks:

March 1998

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

differential scanning calorimetry

Key result

Melting / freezing pt.:

270.3 °C

Atm. press.:

1 013.25 hPa

Decomposition:

yes

Remarks:

Reaction and/or decomposition of the test item was observed during DSC experiments during and after melting.

Preliminary Test

The TGA curve of the test item is shown in Figure 1 in the attached document "S-600 - Melting and Boiling Temperature.pdf". Starting at 325°C, the weight of the sample decreased significantly. At 341°C, the sample weight had decreased by 25%. After the experiment, black residue was observed on the lid of the sample container and a black residue remained in the sample container (original colour: yellow). The change of the colour indicated reaction and/or decomposition of the test item.

Main Study

After the first experiment, a black molten residue (original colour: yellow) remained in the sample container. Three endothermic peaks were observed:

one between 150°C and 200°C;

one between 225°C and 300°C. The extrapolated onset temperature of this peak was 269.590°C. This endothermic effect was most likely obtained due to melting of the test item; and

one starting at 300°C (this endothermic effect was due to reaction and/or decomposition of the test item).

In order to investigate the endothermic peak between 225°C and 300°C, Experiment 2 was stopped directly after the endothermic effect at a temperature of 285°C. The extrapolated onset temperature was 271.066°C. A brown molten residue remained in the sample container after the experiment. The appearance of the residue demonstrated that melting in combination with reaction and/or decomposition was the reason for the endothermic effect.

In order to investigate the endothermic peak between 150°C and 200°C, Experiment 3 was stopped directly after the endothermic peak. After the experiment, the sample appeared to have been unchanged, i.e. no decomposition and/or melting were observed. Therefore, the reason for the endothermic effect was unknown.

The melting temperature was determined as the mean melting temperature of Experiment 1 (269.590°C) and Experiment 2 (271.066°C). The difference between the melting temperatures obtained in Experiment 1 and 2 was > 0.5°C, which is caused by the reaction and/or decomposition that was observed during melting.

 

DSC curves are shown in the attached document "S-600 - Melting and Boiling Temperature.pdf"). 

Conclusions:

The melting temperature of the test item was 270.3°C (543.5K).
Reaction and/or decomposition of the test item was observed during DSC experiments during and after melting.

Description of key information

melting point 270.3°C at 1013.25 hPa (OECD 102, EU A.1, OPPTS 830.7200)

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:

270.3 °C

Additional information

Reaction and/or decomposition of the test item was observed during and after melting.