Registration Dossier

Administrative data

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

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2019
Report Date:
2019

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
GLP compliance:
yes (incl. certificate)
Type of method:
differential scanning calorimetry

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: crystalline

Results and discussion

Melting / freezing point
Key result
Melting / freezing pt.:
91 °C
Atm. press.:
1 013 hPa
Remarks on result:
other: shows amorphous behavior

Any other information on results incl. tables

Results in detail

Melting temperature

The test item had a melting range starting at about 50 °C ranging up to 95 °C with a pronounced peak at 91 °C in the 1st heating after drying at 75 °C for 30 minutes.

Determination

Onset temperature

[°C]

Peak temperature

[°C]

End temperature

[°C]

5

~ 50

91.6

94.5

6

~ 50

91.1

94.6

Mean value

~ 50

91

95

Observed thermal processes

Besides the pronounced peak at 91 °C in the 1st heating there was a small peak at about 65 °C, which is probably the result of the drying step. The melting process was visually verified by monitoring the test item within a melting point capillary tube.

In the pretests it was observed that during cooling down to -50 °C the test item did not recrystallize. In the 2nd heating the test item did no longer exhibit any pronounced endothermal signals in the range >30 °C, meaning melting processes were no longer observed.

A previous TG/DSC-Test (non-GLP) was run up to 600 °C to survey the thermal behavior of the test item. This test showed a decreasing TG-signal, starting at about 60 °C with a steep decrease starting at about 174 °C and reaching total weight loss at 273 °C. The weight loss was accompanied by an endothermal signal

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Pretests

Discussion

The DSC-measurement Test 1 was performed as an overview of the thermal behavior, showing the beginning decomposition of the test item starting at about 155 °C. The measurement showed a

broad exothermal peak with a maximum at 95 °C.

The DSC curve in Test 2 was recorded with a lower heating rate and exhibited a broad exothermal signal with two peak maxima at 73 °C and 92 °C. Because of the broad shape, especially of the first peak, we suspected it tobe residual water. To remove the residual water a 30-minute drying step at 60 °C was performed in Test 3.

This led to a broad melting peak with only one maximum at 91 °C.

In the resulting 1st heating curve of Test 4 again two peak maxima at 71 °C and 92 °C are visible. Afterwards a quick five-minute annealing step was performed at 94 °C, slightly above the peak maxima observed in the tests before.

In all the performed analyses the test item did no longer depict the same melting behavior in the 2nd heating after being melted during the 1st heating. During cooling down to -50 °C between the 1st and 2nd heating the test item did not recrystallize. We assume that it is no longer the original test item and is no longer in the same state as provided. Therefore, the DSC curves in the 2nd heating were not analyzed in detail.

Applicant's summary and conclusion