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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:
october-november 2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well conducted study, performed under the Internal Management system. Certificate of analysis present in the report.
Qualifier:
according to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
Version / remarks:
1995
Deviations:
yes
Remarks:
see principles of method other than guideline
Qualifier:
according to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
Version / remarks:
2008
Deviations:
no
Qualifier:
according to
Guideline:
other: ASTM E537-07, Standard test method for the thermal stability of chemicals by Differential Scanning Calorimetry, 2007
Deviations:
no
Principles of method if other than guideline:
For glasstube method: Deviations from guideline (capillary method):
- The glass tube method uses a bigger glass tube than the capillary method (capillarymethod): 8 to 10 cm in length and 1.0 mm inner diameter)
- Heating in the glass tube method is done in small steps, whereas the capillary method uses a constant heating rate
- In the glass tube method liquid substances are first brought to the solid state, whereas the capillary method does not mention such procedure
GLP compliance:
no
Remarks:
Internal Management system.
Type of method:
capillary method
Remarks:
After DSC
Key result
Melting / freezing pt.:
> 9 - < 11 °C

Accuracy check DSC

The measured values for Indium are mentioned below.

- onset temperature : 156.48°C

- enthalpy of melting : 28.55 J/g

The measured values are within the acceptance limits.

Test method 1: Thermal analysis method

The DSC curve of the measurement is shown in the attachment. No heat peak was measured. This means that the substance did not solidify or crystallize during the cooling step to -50°C (due to super cooling), and consequently did neither melt during the heating step back to 20°C. This means that the melting point could not be determined with this method. For that reason test method 2 was carried out with the substance as well.

Test method 2: Glass tube method

 

The glass tube with solid sample was moved to the continuously stirred liquid bath with isopropyl alcohol to determine the melting point. The start temperature was -10°C. The appearance of the sample at each check is mentioned below.

- at -10°C: sample is completely in the solid state

- at 0°C   : sample is completely in the solid state

- at 4°C   : sample is completely in the solid state

- at 6°C   : sample is completely in the solid state

- at 7°C   : sample is completely in the solid state

- at 8°C   : sample is completely in the solid state

- at 9°C   : beginning of melting

- at 10°C : sample is for 70% in the liquid state

- at 11°C : sample is completely in the liquid state

 

The test was repeated with the same results.

Conclusions:
The melting range of tert-butyl peroxybenzoate is between 9°C and 11°C .
Executive summary:

The melting point of tert-butyl perbenzoate was determined according toEC Regulation No 440/2008, Guideline A.1 and according to OECD Guideline 102 ,and in accordance with European Chemicals Agency (ECHA), Guidance on information requirements and chemical safety assessment, Chapter R.7a, Endpoint specific guidance, May 2008. The melting point was determined by using two methods, a thermal analysis method and a glass tube method (equivalent to the capillary method of the guidelines EC A.1 and OECD 102).

 

The melting range of tert-butyl peroxybenzoate is between 9°C (initial melting temperature) and 11°C (final melting temperature).

 

Description of key information

The melting range of  tert-butyl peroxybenzoate is between 9°C and 11°C .

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
9 °C

Additional information

This is supported by handbooks and literature.