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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:
September 2009 – March 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well conducted study, according to EU guideline, under the Internal Management system. Certificate of analys is present in the report.
Qualifier:
according to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
Version / remarks:
2008
Deviations:
yes
Remarks:
See principles of method if other than guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
Version / remarks:
1995
Deviations:
yes
Remarks:
See principles of method if other than guideline
Qualifier:
according to
Guideline:
other: ASTM E537-07, Standard test method for the thermal stability of chemicals by Differential Scanning Calorimetry, 2007
Deviations:
no
Qualifier:
according to
Guideline:
other: ISO 1392, Determination of crystallizing point – General method, 1977
Deviations:
no
Principles of method if other than guideline:
- The crystallizing tube is not put into an outer protection tube.
- A 20 mm magnetic driven Teflon coated steel bar is used as stirrer instead of a mechanically driven stirrer with a loop of 20 mm.
- The temperature in the substance and in the cooling bath is measured with thermocouples instead of thermometers.
- A 500 ml insulating cooling bath made of glass and containing ethanol as cooling liquid is used for cooling the substance instead of a Dewar vessel-The bath is continuously stirred with a magnetic stirrer and its temperature is controlled via an external thermostatted bath.
- The substance is cooled down in steps of 5°C to below -25°C or until crystallization occurs, instead of a one-step cooling to a temperature of 3 to 5°C below the expected crystallizing point.
It is not expected that these deviations will have affected the outcome of the study.
GLP compliance:
no
Remarks:
Internal Management system
Type of method:
capillary method
Remarks:
after DSC
Melting / freezing pt.:
< 29 °C
Atm. press.:
101 325 Pa

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 freeze or crystallize during the cooling step to -50°C, and consequently did neither melt during the heating step back to 20°C. This means that the melting/freezing point could not be determined with this method.

Test method 2: Method for determination of the freezing temperature

Cooling was done in seven steps from 0°C to -29°C. The appearance of the sample at each temperature level is mentioned below.

- at 0°C : liquid, clear, viscous

- at -5°C : liquid, a little hazy, viscous

- at -10°C : liquid, a little hazy, viscous

- at -15°C : liquid, a little hazy, viscous

- at -20°C : liquid, a little hazy, very viscous

- at -25°C : liquid, a little hazy, very viscous

- at -29°C : liquid, a little hazy, very viscous

No crystallization or freezing was observed. Also the temperature profile did not show any indication of crystallization or freezing. The hazy appearance was most probably due to some water in the sample. Since the substance remained liquid in the temperature range from 0°C to -29°C, it can be concluded that the melting/freezing point of Di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide is below -29°C.

Conclusions:
The freezing point of di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide is below -29°C.
Executive summary:

The melting/freezing point of Di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide 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/freezing point was determined by using two methods, a thermal analysis method and a method for determination of the freezing temperature.

According to ASTM E537-07, Standard test method for the thermal stability of chemicals by Differential Scanning Calorimetry, 2007:

The freezing point of di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide is below -29°C.

Description of key information

The freezing  point of di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide  is below -29°C.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
-29 °C

Additional information