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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:
From 18 July to 23 August 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
The study was conducted according to an internationally recognised method, and under GLP. The substance is considered to be adequately characterised. Therefore full validation applies.
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
Principles of method if other than guideline:
Not applicable
GLP compliance:
yes (incl. certificate)
Remarks:
GLP compliance programme (inspected on 13-14 October 2014 / signed on 8 April 2015)
Type of method:
capillary method
Key result
Melting / freezing pt.:
>= 53.4 - <= 60.7 °C
Remarks on result:
other: main of 2 determinations with capillary method

RESULTS

Different methods were performed to determine the melting point of this substance: DSC and capillary method pre-tests. Then capillary method as a main test was chosen.

Pre-test for melting range following capillary method

Table 4.2.1.-  Values Pre-Test for melting range following capillary method

Begin of melting process

End of melting process

60.0 °C

72.0°C

The test item melted to a red-brownliquid. After cooling down the test item was a red-brown solid. Some of the test item was taken to grind, the test item was visually looked like the original state.

Security Pre-test for the DSC instrument

The crucible was found visually unchanged after reaching a temperature of 420°C. The weight was recorded with 48.81 mg (2.72 mg residue). After further heating to 600°C and cooling down the crucible was bloated. The weight was recorded with 46.47 mg (0.38 mg residue). After heating and weighing of 600 °C the crucible was opened, a black residue (like charcoal) was visible.

Calibration

After calibration with indium and zinc the measurement of indium yielded the following values:

Table 4.2.2.-Values DSC Indium

ExpectedMelting point

Measured

Melting point

Expected

Energy

Measured

Energy

Assessment

156.6 ± 1.0°C

156.29 °C

28.45 ± 1.0 J/g

28.78 J/g

OK

 

The measurement of indium after calibration met the validity criteria.

Results with DSC method

Table 4.2.3.- Values Observations

Mass test item

Mass crucible (before measurement):

Mass crucible (after measurement):

Observations

First

Measurement

1.10 mg

46.29 mg

46.22 mg

After the test the crucible was visually unchanged. The crucible was opened, a red-brown glassy mass was visible.

Second

Measurement

2.96 mg

48.88 mg

48.84 mg

After the test the crucible was visually unchanged

Third

Measurement

3.12 mg

49.08 mg

48.97 mg

After the test the crucible was visually unchanged

Fourth

Measurement

3.00 mg

48.76 mg

48.63 mg

After the test the crucible was visually unchanged

 

DSC measurements show no reliable results, the determination of the Melting Point with the Capillary Method was performed.

Results Melting Point with the Capillary Method (main test)

Table 4.2.4.- Values Melting Point with the Capillary Method

Melting point/range

Begin

End

First Determination

53.5 °C (326.7 K)

60.6 °C (333.8 K)

Second Determination

53.3 °C (326.5 K)

60.7 °C (333.9 K)

 

The test item melted to a red-brown liquid. After cooling down the test item was a red-brown solid looked like the original state.

 

Melting range: 53.4 °C to 60.7 °C (326.6 K to 333.9 K)

Standard deviation: 0.14 (begin); 0.07 (end)

Estimated accuracy: ± 0.2 °C

Validity melting point

All validity criteria are presented in the following table.

Table 4.2.5.- Validity melting point

Parameter

Criterion

Found

Assessment

Difference between duplicate determinations

<=0.5 K

0.1 K

valid

Difference between begin and end of melting process

<=0.5 K

5.2 K

melting range is stated

 

The validity criterion “difference between duplicate determinations” was met. The test item showed a melting range, no melting point. As the test item consists of a mixture, this is considered as normal.

Conclusions:
The melting range was determined as 53.4 °C to 60.7 °C (326.6 K to 333.9 K)
Executive summary:

The melting point test with the substance was performed under GLP according to OECD 102 / EU A1 guideline, using capillary method.

At first one experiment was conducted via DSC (differential scanning calorimetry). As no significant events were observed, the capillary method was conducted as a main test. The melting range was determined as 53.4 °C to 60.7 °C (326.6 K to 333.9 K) with capillary method. These values are the means from two independent determinations.

Description of key information

The melting range was determined as 53.4 °C to 60.7 °C (326.6 K to 333.9 K)

Key value for chemical safety assessment

Additional information

A reliable GLP experimental study, conducted according to a recognized OECD/EC guidelines using capillary method, is available.

It is considered as a key study. The result is retained as key data.