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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:
March 17 to April 02, 2014
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Justification for type of information:
The study was conducted according to an internationally recognised method, and under GLP.
Restrictions apply considering that the melting of the substance is difficult to observed and a piece of thin wire was used in order to detect melting. Otherwise, the substance is considered to be adequately characterised. Therefore validation with restrictions applies.
Qualifier:
according to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
Version / remarks:
dated 27. July 1995
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
Version / remarks:
dated 31. May 2008
Deviations:
no
Principles of method if other than guideline:
Not applicable
GLP compliance:
yes (incl. certificate)
Remarks:
inspected on 29 and 30 November 2010 / signed on 11 April 2011
Type of method:
capillary method
Key result
Melting / freezing pt.:
>= -25.5 - <= -14.7 °C
Decomposition:
no

In the pre-test, the test item was considered as liquid at 5°C and solid at - 20 °C and - 80 °C.

Table 4.2/1: Pre-Test

Room Temperature

5 °C

- 20 °C

- 80 °C

brown,

slightly viscous liquid

liquid,

more viscous

solid

solid

 

The following values were recorded during the Main test:

Table 4.2/2: Main Study

Melting point/range

Begin

End

First Determination

At approx. -19 °C, test item was in process of melting, begin

was missed because the thin wire stuck on the wall of capillary

Second Determination

- 25.3 °C (247.9 K)

- 14.4 °C (258.8 K)

Third Determination

- 25.6 °C (247.6 K)

- 14.9 °C (258.3 K)

The means between both determinations give the following values for the melting range:

Melting range: - 25.5 °C to - 14.7 °C (247.8 to 258.6 K)

Standard deviation: 0.2 (begin); 0.4 (end)

Estimated accuracy: ± 0.5 °C

Validity

All validity criteria were met, as can be taken from the following table.

 

Table 4.2/3: Validity

Parameter

Criterion

Found

Assessment

Difference between duplicate determinations

≤ 0.5 K

0.5 K

valid

Difference between begin and end of melting

process

≤ 0.5 K

10.8 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 is a mixture, this can be considered as normal.

No observations were made which might cause doubts on the validity of the study outcome.

Therefore, the result of the study is considered valid.

Conclusions:
The melting range of test substance was determined as (- 25.5 to - 14.7 °C) (247.8 to 258.6 K).
Executive summary:

The melting range of the test substance was determined under GLP according to EU Method A.1 and OECD 102, by using capillary method.

The substance being viscous, a sharp transition from liquid to solid was not anticipated. Therefore, a short piece of thin wire was used to detect melting.

The temperature, at which the wire started to sink in the liquefying test item was recorded as begin of melting process. The end of melting process was recorded when the wire had fully moved into the test item.

Two main runs were performed and the mean final temperatures were retained to define the melting range of the test item.

The melting range of the test substance was determined under GLP according to EU Method A.1 and OECD 102, using the capillary method.

A preliminary test indicated that the substance is solid liquid at 5°C and solid at -20°C and -80°C.

Then the main test was carried out. The substance being viscous, a sharp transition from liquid to solid was not anticipated. Therefore, a short piece of thin wire was used to detect melting. Thetemperature, at which the wire started to sink in the liquefying test item was recorded as begin of melting process. The end of melting process was recorded when the wire had fully moved into the test item.

The results of two determinations were within accuracy limits of the method but a difference was observed between beginning and ending of melting process. Finally mean values of both independant valid determinations were used to determine the melting range of this natural complex substance. No indication of decomposition was recorded

Description of key information

The melting range of the test item was determined to be (-25.5 to -14.7 °C) (247.8 to 258.6 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 and is considered as a key study.

Note that considering the complex nature of the substance,no sharp melting point could be determined experimentally. Therefore, the result is expressed as a melting range and no single key value can be retained for purpose of CSA.