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Physical & Chemical properties

Melting point / freezing point

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Reference
Endpoint:
melting point/freezing point
Type of information:
experimental study
Adequacy of study:
key study
Study period:
April 29, 2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
GLP compliance:
yes
Type of method:
differential scanning calorimetry
Specific details on test material used for the study:
Identification: PARAD Substance 139
Batch: 31104251
Physical state: slightly yellowish viscous liquid
Purity: n.a. (mixture)
Key result
Atm. press.:
1 013.25 hPa
Decomposition:
yes
Decomp. temp.:
85 - 125 °C
Remarks on result:
not determinable

Details on results

- First experiment (25°C – 175°C, 20°C/minute): Between 115°C and 125°C a small shift of the base line was observed into the endothermic direction. It is not clear what process caused this effect, but it appears insignificant for this study. A large exothermic effect started at about 125°C, probably caused by reaction or decomposition of the test substance. After the experiment the sample, the consistency of the sample did not seem to have changed. Weighing showed a small amount of mass-loss (0.4%).

- Second experiment (25°C - 320°C, 20°C/minute): A large exothermic peak was observed between 105°C and about 235°C, probably caused by reaction or decomposition of test substance. Above about 235°C an endothermic was observed, which reached a maximum at about 272°C. Above 272°C the endothermic effect rapidly decreased and changed into a large exothermic effect. After the experiment, the sample had lost 59% of its mass. The residue had a black colour (original colour: slightly yellowish). The change of the colour is an indication that the test substance had reacted or decomposed. The observed endothermic effect may be caused by a combination or reaction/decomposition of test substance and evaporation of test substance or reaction products.

- Third experiment (25°C – 260°C, 20°C/minute): A very small exothermic effect was observed between 85°C and 128°C, followed by a large exothermic effect between 128°C and about 242°C. The exothermic effects are probably caused by reaction or decomposition of test substance. Above about 242°C an endothermic effect was observed. After the experiment, the sample had a yellow colour and appeared to have hardened (glassy). The sample had lost 25% of its mass. The change of the colour of the sample is an indication that the test substance had reacted or decomposed.

- Fourth and the fifth experiments (-40°C to 40°C, 10°C/minute) respectively: No significant heat effects were observed. This implies that the test substance did not solidify when cooled down to -40°C. After the experiment the consistency and the mass of the sample did not seem to have changed.

In conclusion: the test substance was a viscous liquid at room temperature. The test substance did not solidify at temperatures > or = -40°C. Therefore no melting temperature could be determined by the method used in this project. Reaction or decomposition of the test substance started in the temperature range 85°C – 125°C.

Conclusions:
Under the study conditions, the test substance did not solidify at temperatures ≥-40°C. Therefore no melting temperature could be determined by the method used in this project. Reaction or decomposition of the test substance started in the temperature range 85°C–125°C (DSC method).
Executive summary:

A study was conducted to determine the melting point/freezing point of the test substance according to OECD guideline 102 and EU Method A.1. The test substance and an inert reference were heated in a differential scanning calorimeter (DSC). The difference between the heat flow to the sample and the heat flow to the reference was recorded. Five experiments were performed. Three experiments were performed starting from 25°C and two experiments were performed starting from –40°C. The results of all experiments were combined for the conclusion.

Under the study conditions, the test substance did not solidify at temperatures ≥-40°C. Therefore no melting temperature could be determined by the method used in this project. Reaction or decomposition of the test substance started in the temperature range 85°C – 125°C (van der Baan-Treur, 2004).

Description of key information

The melting point/freezing point was determined according to OECD guideline 102 and EU Method A.1 (differential scanning calorimetry (DSC) method) (van der Baan-Treur, 2004).

Key value for chemical safety assessment

Additional information

The test substance did not solidify at temperatures -40°C. Therefore no melting temperature could be determined using the DSC method.