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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:
01 July 2011- 21 October 2011
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
Version / remarks:
(2008)
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
Version / remarks:
(1995)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
thermal analysis
Remarks:
(differential scanning calorimetry)
Decomposition:
yes
Decomp. temp.:
> 250 °C
Remarks on result:
other: Melting of the test substance was not observed below the temperature at which decomposition started
Decomposition:
yes
Decomp. temp.:
> 523 K
Remarks on result:
other: Melting of the test substance was not observed below the temperature at which decomposition started

Preliminary TGA

From 300°C upwards the weight of the sample decreased significantly. At 361°C, the sample weight had decreased by 25%. After the experiment, a small amount of charred residue remained in the sample container (original colour: white to off-white powder). The change of the colour indicated reaction and/or decomposition of the test substance. It was also observed that the majority of the test substance was evaporated from the sample container. TGA-curve: Figure 4 (see attachment).

 

DSC experiments

Experiment 1: An endothermic peak between 300°C and 400°C was observed. The extrapolated onset temperature of the peak was 354.75°C. The effect was most likely obtained due to reaction and/or decomposition of the test substance. After the experiment, a small amount of charred residue remained in the sample container. DSC curve: Figure 5 (see attachment).

 

Experiment 2: To investigate if the endothermic peak originated from reaction and/or decomposition of the test substance a lower heating rate of 5°C/minute was applied in this experiment. Figure 6 shows the DSC-curve obtained. An endothermic peak between 250°C and 400°C was observed. The extrapolated onset temperature of the endothermic peak was 340.65°C. As can be seen the endothermic peak shifted to lower temperatures. It demonstrated that reaction and/or decomposition of the test substance was the reason for the endothermic effect. After the experiment, a small amount of charred residue remained in the sample container. It was also observed that the majority of the test substance was evaporated from the sample container.

Conclusions:
FDCA has no melting temperature. The substance decomposes at > 250°C.

Description of key information

The substance has no melting temperature, it decomposes at > 250°C. 

Key value for chemical safety assessment

Additional information

A differential scanning calorimetry (DSC) test was performed in accordance with EC A.1 and OECD 102.