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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:
8 days
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study
Qualifier:
according to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
Qualifier:
according to
Guideline:
EPA OPPTS 830.7200 (Melting Point / Melting Range)
Qualifier:
according to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
Deviations:
no
GLP compliance:
yes
Type of method:
differential scanning calorimetry
Specific details on test material used for the study:
Batch 135214 of Disperse Blue 359 was a dark blue powder with a purity of 99%.
Key result
Melting / freezing pt.:
>= 236.7 °C
Atm. press.:
ca. 1 013.25 hPa
Decomposition:
yes
Decomp. temp.:
> 236.7 °C

The TGA-curve of the test item showed a significant decrease of the sample from 275 ˚C onwards, at 549 ˚C the sample weight had decreased by 24%. After the experiment, a black molten residue remained in the sample container (c.f. original colour dark blue). The change of the colour indicated reaction and/or decomposition of the test item.

The DSC-curve obtained in experiment 1 shows a small exothermic peak between 150 ˚C and 175 ˚C. The reason for this effect was most likely due to an artefact. An endothermic peak between 200 ˚C and 250 ˚C was observed, the extrapolated onset temperature of the peak was 237.680 ˚C. The effect was most likely obtained due to melting of the test item. An exothermic peak between 275 ˚C and 400 ˚C was observed, most likely due to reaction and/or decomposition of the test item. After the experiment a black molten residue remained in the sample container.

To investigate reaction and/or decomposition a lower heating rate of 5 ˚C/minute was applied in experiment 2. An endothermic peak followed by an exothermic peak between 200 ˚C and 275 ˚C was observed. The extrapolated onset temperature of the endothermic peak was 234.043 ˚C. The effect was most likely obtained due to melting of the test item. After the experiment, a black molten residue remained in the sample container.

To investigate the melting peak experiment 3 was stopped directly after the melting peak for the visual observation of the residue. The extrapolated onset temperature of the melting peak was 238.506 ˚C. After the experiment, a dark purple molten residue remained in the sample container. It demonstrated that melting and/or decomposition of the test item was the reason for the endothermic effect.

The melting temperature was determined as the average melting temperature obtained from experiment 1 (237.680 ˚C), experiment 2 (234.043 ˚C), experiment 3 (238.506 ˚C).

Conclusions:
The melting temperature of Disperse Blue 359 was determined at 236.7 (509.9K) by using DSC.
Reaction and/or decomposition of Disperse Blue 359 was observed during DSC experiments during and after melting. Boiling of the test item was not observed below the temperature at which the reaction and/or decomposition started. Based on this, the test item has no boiling point.
Executive summary:

The melting temperature of Disperse Blue 359 was determined at 236.7 (509.9K) by using DSC.

Reaction and/or decomposition of Disperse Blue 359 was observed during DSC experiments during and after melting. Boiling of the test item was not observed below the temperature at which the reaction and/or decomposition started. Based on this, the test item has no boiling point.

Description of key information

The melting temperature of Disperse Blue 359 was determined at 236.7 (509.9K) by using DSC.

Reaction and/or decomposition of Disperse Blue 359 was observed during DSC experiments during and after melting. Boiling of the test item was not observed below the temperature at which the reaction and/or decomposition started. Based on this, the test item has no boiling point.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
236.7 °C

Additional information

The melting temperature of Disperse Blue 359 was determined at 236.7 (509.9K) by using DSC.

Reaction and/or decomposition of Disperse Blue 359 was observed during DSC experiments during and after melting. Boiling of the test item was not observed below the temperature at which the reaction and/or decomposition started. Based on this, the test item has no boiling point.