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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:
weight of evidence
Study period:
2011-06-07 to 2011-06-15
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
Version / remarks:
27 July 1995
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
Version / remarks:
30 May 2008
Deviations:
no
GLP compliance:
no
Other quality assurance:
ISO/IEC 17025 (General requirements for the competence of testing and calibration laboratories)
Type of method:
differential scanning calorimetry
Key result
Melting / freezing pt.:
-75 °C
Atm. press.:
1 013 hPa
Remarks on result:
other: Information on atmospheric pressure not stated, but ambient pressure assumed

The DSC measurements were performed twice. After cooling to -125°C at a rate of 5 K/min the sample was heated to 35°C at a rate of 10 K/min. During cooling no significant heat flows were registered. Upon heating the heat flow curve shows an exothermic cold crystallisation and an endothermic melting. The DSC curves are attached.

Conclusions:
A melting point of -75°C at 1013 hPa has been determined for the test substance using OECD 102 test method. The result is considered to be reliable.
Endpoint:
melting point/freezing point
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
2012-07-18 to 2012-08-21
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
The study is conducted in accordance to an appropriate test method and in compliance with a known quality system (ISO 9001:2008)
Qualifier:
according to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
Deviations:
no
GLP compliance:
no
Other quality assurance:
other: ISO 9001:2008
Type of method:
differential scanning calorimetry
Key result
Melting / freezing pt.:
-75.5 °C
Atm. press.:
1 013 hPa
Melting / freezing pt.:
< -100 °C
Atm. press.:
1 013 hPa
Remarks on result:
other: Since there was no change observed in the DSC during the cooling process, freezing temperature was reported as <–100 °C (< 173 K)

Melting Temperature:

For DSC measurement the test substance was cooled with liquid nitrogen. The measurement was carried out in an atmosphere of nitrogen (30 ml/min). The registration of the measurement starts at –130°C (~ 143 K) with a rate of 10 K/min and ends at +400°C (673 K).

The DSC diagrams show an exothermic process which started at about –115°C (~ 158 K) and ending at about –100°C (~ 173 K). The author interpreted this as a kind of crystallization process, so that a solid phase results. The solid phase melts with an endothermic reaction at about –75.5°C (197.7 K) onset temperature.

Freezing Temperature:

For testing the freezing characteristics an additional DSC test was carried out. For this the liquid test substance was measured when cooling to –100°C (~ 173 K). The measurement was carried out in an atmosphere of nitrogen (30 ml/min). The registration of the measurement starts at +25°C (~ 298 K) with a rate of –5 K/min and ends at –100°C (~ 173 K). There was no change observed in the DSC diagram during the cooling process. The freezing temperature was therefore considered <–100°C (< 173 K).

After application of heat at –100°C (~ 173 K) with a rate of 5 K/min there is an exothermic reaction followed by an endothermic peak which looks similar to the process which was described under “Melting Temperature".

Results:

Test

Melting temperature

1

-75.5°C (197.7 K)

2

-75.4°C (197.6 K)

Mean

-75.5°C (197.7 K)

 

Test

Freezing temperature

1

<-100°C (<193 K)

Approximate accuracy of the instrument: ± 0.5 K (up to 600 K)

Conclusions:
A melting point of -75.5°C at 1013 hPa has been determined for the test substance using OECD 102 test method. The result is considered to be reliable.

Description of key information

Melting point: -75 to -75.5°C at 1013 hPa (OECD 102)

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
-75 °C

Additional information

Two reliable measured results are available for the registered substance. Melting point values of -75°C and -75.5°C at 1013 hPa were determined for the substance using Differential Scanning Calorimetry (DSC) in accordance with OECD Test Guideline 102. The results are considered to be reliable and are used as weight of evidence.

In a secondary source to which reliability could not be assigned, a limit melting point value of <-74°C was reported for the test substance.