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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:
To be completed
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
Version / remarks:
1995
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
Version / remarks:
2008
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
differential scanning calorimetry
Specific details on test material used for the study:
- Test item: REACH substance = freeze-dried commercial product
- Analytical purity: 97.2%
- Purity test date: 08 March 2017
- Lot:bacth No.: WI6G16X07 after drying
- Expiration date of the lot/batch: 16 July 2018
- Appearance: Off-white to yellow crystals
- Storage: At room temperature
Key result
Melting / freezing pt.:
>= 137.7 - <= 141.8 °C
Atm. press.:
1 013 hPa
Decomposition:
yes

Preliminary test

Starting at 225°C, the weight of the sample decreased significantly. At 346°C, the sample weight had decreased by 25%. After the experiment, a black molten residue remained in the sample container (original colour: off-white to yellow). The change of the colour indicated reaction and/or decomposition of the test item.

Main study

In Experiment 1, an endothermic peak was observed between 25°C and 100°C. The endothermic effect was due to evaporation of volatile components (the test item contains 2.8% water). An endothermic peak was observed between 100°C and 200°C. The extrapolated onset temperature of the peak was 137.708°C. The endothermic effect was most likely obtained due to melting and reaction and/or decomposition of the test item. From 200°C, an endothermic peak followed by an exothermic peak were observed. The effects were due to reaction and/or decomposition of the test item. After the experiment, a brown molten residue remained in the sample container.

In order to investigate the melting peak, Experiment 2 was stopped directly after the melting peak. The extrapolated onset temperature was 141.808°C. After the experiment, a beige molten residue remained in the sample container (original colour: off-white to yellow). It demonstrated that melting was the reason for the endothermic effect. Based on the weight loss observed at 150°C during the preliminary test it is most likely that reaction and/or decomposition occurred during melting of the test item. A change in colour was not significant as an indication of the decomposition.

In order to investigate the melting peak, a lower heating rate of 5°C/minute was applied in Experiment 3. The extrapolated onset temperature of the melting peak could not be determined. A smaller melting peak was obtained due to reaction and/or decomposition which had occurred at lower temperatures. It demonstrated that reaction and/or decomposition occurred during melting of the test item. After the experiment, a beige molten residue remained in the sample container.

Experiment 4 was performed as a duplicate of Experiment 2. Similar results as in Experiment 2 were obtained. The extrapolated onset of the melting peak was 140.052°C. After the experiment, a beige molten residue remained in the sample container. 

 

Since reaction and/or decomposition was observed during melting a high deviation was found between the extrapolated onset temperatures. Therefore a melting range is given instead of a melting temperature. The melting range was determined as the lowest and highest melting temperature of Experiment 1 (137.708°C), Experiment 2 (141.808°C) and Experiment 4 (140.052°C).

Conclusions:
The melting point of the test item was determined to be in the range 137.7-141.8°C.
Executive summary:

The melting point of the test item (= REACH substance) was determined in a GLP-compliant study performed in accordance with EC A.1 method and OECD Guideline No. 102, using Differential Scanning Calorimetry (DSC). The melting point of the test item was determined to be in the range 137.7-141.8°C.

Description of key information

The melting point of the test item (= REACH substance) was determined in a GLP-compliant study performed in accordance with EC A.1 method and OECD Guideline No. 102, using Differential Scanning Calorimetry (DSC). The melting point of the test item was determined to be in the range 137.7-141.8°C.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
137.7 °C

Additional information

The melting point of the test item was determined in one GLP-compliant study performed in accordance with standard methods, without deviations. The study is considered as reliable (Klimisch 1) and is selected as a key study for the endpoint.