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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:
May 15, 2000
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
The study was conducted according to an internationally recognised method, and under GLP. The substance is considered to be adequately characterised with its purity. Therefore full validation applies.
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
Principles of method if other than guideline:
Not applicable
GLP compliance:
yes (incl. certificate)
Remarks:
Swiss GLP compliance programme (inspected on October 22, 26-30 and November 5, 1998 / signed on March 1999)
Type of method:
capillary method
Specific details on test material used for the study:
Storage conditions of test material: At room temperature at about 20 °C, protected from light and under nitrogen atmosphere.
Key result
Melting / freezing pt.:
44.3 °C
Atm. press.:
1 atm
Decomposition:
no

Table 4.2/1: Determination of the melting point of ST 16 C 99 (summary)

 

Test

Starting

Temperature

[°C]

Heating rate in the

relevant

temperature range

[K/min]

Temperature

[°C]

Temperature

[K]

Preliminary test

25

10

47.8

321.0

25

10

48.0

321.2

25

10

47.2

320.4

1st main test

25

0.5

44.3

317.5

25

0.5

44.2

317.4

25

0.5

44.5

317.7

2nd main test

25

0.5

44.1

317.3

25

0.5

44.1

317.3

25

0.5

44.3

317.5

Mean melting point

44.3

317.5

Std. deviation

0.2

0.2

accuracy: ± 0.2 °C; 317.5 ± 0.2 K

Executive summary:

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

Two main runs were performed, and the mean final temperature was retained.

The melting temperature of test substance has been determined to be 44.3 ± 0.2 °C (317.5 ± 0.2 K).

Endpoint:
melting point/freezing point
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
Oct.2014
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
The study was not conducted according to internationally recognised methods, however testing was performed with scientific reasoning, and is useful to understand the phase changes. The substance is considered to be adequately characterised with its purity. Therefore validation applies with restrictions.
Qualifier:
no guideline followed
Principles of method if other than guideline:
Temperature recording during cooling in various conditions, without and with initiation.
GLP compliance:
no
Type of method:
method to determine freezing temperature
Specific details on test material used for the study:
The test substance was melted at 60°C.
Melting / freezing pt.:
37 - 37.8 °C
Remarks on result:
other: freezing obtained from supercooled liquid only with initiation

The following observations were made:

 Test  Observations  Comments
 1  beginning of freezing 20.9°C maximum temperature 25.4°C  cooling too fast, no plateau temperature observed
 2  beginning of freezing 25.9°C maximum temperature 37.0°C  cooling ca 4°C/min; plateau
 3  no freezing  cooling ca 4°C/min down to 17.5°C
 4  no freezing  cooling ca 4°C/min down to 2.7°C
 5  beginning of freezing 25.9°C maximum temperature 37.8°C  cooling ca 4°C/min; plateau
Executive summary:

The test substance was melted at 60°C, and then cooled down at a rate of ca 4°C/min. Adding a piece of solid test item led to a freezing temperature plateau observed around 37-38°C. Without initiation, no freezing was observed down to 3°C.

Description of key information

Melting Point (i.e. solid-to-liquid transition): ca. 44.3 °C

Freezing Point (i.e. liquid-to-solid transition): ca 37-38°C with initiation; no freezing observed down to 3°C without initiation.

The substance can be stable in supercooling conditions.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
44.3 °C

Additional information

A fully reliable experimental study, conducted according to a recognized OECD/EC method and under GLP, is available on the substance as solid, i.e. determination of melting. Therefore, it is considered as a key study, and the result is retained as key value.

A supporting study, conducted according to a reliable scientific procedure, was also provided for the determination of freezing on the melted substance.