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Physical & Chemical properties

Melting point / freezing point

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Administrative data

Endpoint:
melting point/freezing point
Type of information:
experimental study
Adequacy of study:
key study
Study period:
11 January 2012- 25 April 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study has been performed according to OECD and EC guidelines and according to the principles of GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report Date:
2012

Materials and methods

Test guidelineopen allclose all
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
Qualifier:
according to
Guideline:
EPA OPPTS 830.7200 (Melting Point / Melting Range)
Version / remarks:
(1998)
Deviations:
no
GLP compliance:
yes
Type of method:
thermal analysis
Remarks:
(differential scanning calorimetry)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Name of test material (as cited in study report): Paz-E
Substance type: mono-constituent
Physical state: white powder
Expiration date of the lot/batch: 25 November 2012
Storage condition of test material: At room temperature protected from light in desiccator (sample is hygroscopic)
Stability under test conditions: Stable

Results and discussion

Melting / freezing pointopen allclose all
Melting / freezing pt.:
119 °C
Decomposition:
yes
Decomp. temp.:
>= 375 °C
Melting / freezing pt.:
392 K
Decomposition:
yes
Decomp. temp.:
>= 648 K

Any other information on results incl. tables

Preliminary TGA

Starting at 400°C, the weight of the sample decreased significantly. At 421°C the sample weight had decreased by 25%. After the experiment, an expanded charred residue remained in the sample container (original colour: white). The change of the colour indicated reaction and/or decomposition of the test substance. TGA-curve: Figure 4 (see attachment).

DSC experiments

Experiment 1: An endothermic peak between 100°C and 150°C was observed. The extrapolated onset temperature of the peak was 119.51°C. The effect was most likely obtained due to melting of the test substance. After the experiment, an expanded charred residue remained in the sample container. The change of the colour indicated reaction and/or decomposition of the test substance. DSC curve: Figure 5 (see attachment).

Experiment 2: To investigate the melting peak between 100°C and 150°C a repeated heating cycle was applied in the second experiment. With the first heating the extrapolated onset temperature of the melting peak was 118.52°C. During cooling no exothermic peak was observed which indicates that the test substance had not recrystallized. With the second heating therefore only an exothermic effect was observed between 375°C and 450°C. After the experiment, an expanded charred residue remained in the sample container. Figures 6 and 7 shows the DSC-curves obtained.

Experiment 3: A third experiment was performed with a lower end temperature. DSC curve: see Figure 8. The extrapolated onset temperature of the melting peak was 119.36°C. After the experiment, the sample pan was opened. It was visually observed that the test

substance had molten.

Experiment 4: The fourth experiment was performed as a duplicate of the first experiment. DSC curve: see Figure 9. Similar results as with the first experiment were obtained. The extrapolated onset of the melting peak was 118.60°C. After the experiment, an expanded charred residue remained in the sample container.

Applicant's summary and conclusion

Conclusions:
The melting temperature of Paz-E is 119°C. Decomposition starts at 375°C.