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Physical & Chemical properties

Melting point / freezing point

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Endpoint:
melting point/freezing point
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2003
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
The study was conducted similarly to internationally recognised method, but experimental details are lacking. Test substance is adequately specified with purity. Therefore validation applies with restrictions.
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
Qualifier:
equivalent or similar to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
GLP compliance:
no
Type of method:
method to determine freezing temperature
Key result
Melting / freezing pt.:
27.3 °C
Atm. press.:
981 mBar
Remarks on result:
other: accuracy +/- 2°C

A seed crystal was needed to initiate crystallization.

Conclusions:
As seeding was needed, it is anticipated that the substance undergoes supercooling.
Executive summary:

The freezing point of the test item was determined with cooling curve method, similarly to OECD 102 / EU A1 guideline. Measurement was performed in triplicate, and a seed crystal was used to initiate crystallization.

The freezing temperature of the test item has been determined to be 27.3°C.
Endpoint:
melting point/freezing point
Type of information:
not specified
Adequacy of study:
supporting study
Study period:
No data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Remarks:
Data comes from peer-reviewed sources, but only the result is provided. Therefore validation applies with restrictions.
Principles of method if other than guideline:
no data
GLP compliance:
not specified
Melting / freezing pt.:
33 °C
Remarks on result:
other: 91 °F; trans isomer
Melting / freezing pt.:
-10 °C
Remarks on result:
other: -50 °F; mixture

None

Executive summary:

The melting point of the test substance is 33 °C (91 °F) (trans) and -10 °C (-50 °F) (mixture).

Description of key information

For the trans isomer, melting ca 33°C (lit.) and freezing ca 27°C (exp.), with supercooling anticipated.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
27 °C

Additional information

A reliable experimental study, conducted according to OECD/EU-like freezing method is available. Despite restrictions due to lack of experimental details, it is considered as a key study. The result is retained as key data, but it should be noted that the liquid-solid transition was obtained with crystal seeding.

Supporting reliable literature provides a melting value (i.e. assumed to be solid-liquid transition) of 33°C for the trans isomer, which is consistent with the above study on the corresponding substance dossier.

A much lower value (-10°C) is proposed for the mixture of cis and trans isomer. Considering the difference between isomers, the fact that seeding was needed to obtain freezing, and sample description of the substance tested as a liquid (see 4.1), suppercooling phenomenon is supposed.