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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
Deviations:
no
Principles of method if other than guideline:
About 5 mL of the test item were filled in a test tube and cooled down using acetone and dry ice until solidification occurred. The probe of a thermocouple was placed in the centre of the sample. The temperature was measured with an appropriate thermocouple. The test was carried out in duplicate. The temperature/time curves were recorded during the cooling of the test item. Additionally, the physical state was observed visually.
GLP compliance:
no
Type of method:
method to determine freezing temperature
Melting / freezing pt.:
-56.5 °C
Remarks on result:
other: Estimated accuracy +/- 0.5°C

A pretest was done to determine that the value was well below -20°C. The test sample was cooled to -70.5°C using a dry ice and acetone bath. The solid test item was then allowed to warm up to -56.7°C, where it became liquid. The process was repeated with the test item becomming liquid at -56.3°C. The mean of the two measurements was taken as the resulting freezing point.

Supercooling was observed in the experiment.

Conclusions:
The freezing point is determined to be -56.5°C (329.7°K)

Description of key information

-56.5°C.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
-56.5 °C

Additional information

A single GLP study (Kuehne 2010) according to OECD guidelines is available and reports the meting point of trimethyl orthoformate to be -56.5°C.