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Physical & Chemical properties

Melting point / freezing point

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melting point/freezing point
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
melting point/freezing point
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Study period December 15, 2015
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
according to guideline
OECD Guideline 102 (Melting point / Melting Range)
according to guideline
EU Method A.1 (Melting / Freezing Temperature)
GLP compliance:
Other quality assurance:
other: ISO 9001
Type of method:
differential scanning calorimetry
glass tube method also used
Specific details on test material used for the study:
Trade name: Trigonox 125-C75
Batch number: 1511442890
Description: colourless clear liquid with a faint odour
Storage temperature: Avoid temperatures below -30 °C. If product freezes or separates, contact Akzo Nobel.For maximum quality store below: -20 °C.
For safety, store below 10 °C; based on REACH test substance information.
Expiration date: June 08, 2018
Key result
Melting / freezing pt.:
-33 °C
Atm. press.:
1 atm

Calibration check

Measured values for Indium:

- Onset temperature : 156.6 °C

- Enthalpy of melting : 28.8 J/g

The measured values are within the acceptance limits


Test method 1: Thermal analysis method:

The DSC curve of the measurement is shown below.

In the cooling to -80 °C and the isothermal stage at -80 °C, no crystallisation occurred (no exothermic signal in the blue curve), even not with the aid of glass splinters.

Since the material didn’t crystallize, no melting point can be determined with DSC.


Test method 2: The glass tube method

First the reaction mixture, seeded with glass splinters was cooled to -30 °C, to crystallize the reaction mixture.

Since no spontaneous crystallization occurred, the reaction mixture was cooled to -78 °C.

After spontaneous crystallization, the mixture was heated stepwise.

The temperature steps and appearance of the sample at each sample temperature is mentioned below.

  • 5 days at -30 °C, stirring 300 rpm; no crystallization occurred

  • 1 hour at -78 °C (in Dewar); solids formed

  • The Dewar was removed and the temperature was increased, with recording the reaction temperature inside the reaction mixture

  • At -33 °C the reaction mixture was completely dissolved

The melting point of tert-pentyl peroxypivalate, 75 % solution in isododecane is -33 °C.
Executive summary:

The melting point of tert-pentyl peroxypivalate, CAS 29240-17-3, 75 % solution in isododecane, was determined according to EC 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 using two methods, a thermal analysis method and a method a glass tube method, which is equivalent to the capillary method of the guidelines EC A.1 and OECD 102.

The melting point of the test substance is -33 °C.

Description of key information

The experimentally determined mp is -33 °C. The endpoint is waived as it is < -20 °C.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
-33 °C

Additional information