Disodium 2,2'-[(9,10-dihydro-5,8-dihydroxy-9,10-dioxo-1,4-anthrylene)diimino]bis[5-tert-butylbenzenesulphonate]

Melting point / freezing point

Link to relevant study record(s)

Reference

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 13, 2017 - February 28, 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Deviations:

no

GLP compliance:

no

Type of method:

differential scanning calorimetry

Key result

Decomposition:

yes

Decomp. temp.:

> 280 °C

Melting point / melting range // boiling point / boiling range: Differential scanning calorimetry

The DSC measurement in an aluminium crucible with a hole showed an ambiguous course of the baseline. After the measurement a black residue was found in the crucible. The mass loss after the DSC measurement amounted to 31 %. The result of the DSC measurement is summarized in Table1.

Table1: DSC measurements

Ident No.	Test item / mg	Starting temperature / °C	Final test temperature / °C	Temperature range / °C	Crucible	Observations after the measurement
36678	10.11	25	500	-	Aluminium with a hole	Black residue after the measurement; mass loss:  31 %

Due to the ambiguous course of the baseline of the DSC measurement a measurement with the capillary method was performed to clarify the behaviour of the test item.

Melting point / melting range: capillary tube in a metal block

A measurement with the capillary method was performed to clarify the results of the DSC measurements. Since this measurement was performed only as a verifying screening a high heating rate of 10 K/min was chosen and therefore the absolute temperature values derived with the capillary method are not as accurate as the DSC results. The filling height of the test item was approximately 5 mm. The results are summarized in Table 2.

Table2: Results of the capillary method

No.	Set point / °C	Heating rate / K/min	End point / °C	Remarks
1	220	10	400	220 °C:Test item unchanged (green solid) 250 °C: Condensate in the upper end of the capillary tube              (outside of the heated part of the apparatus) 280 °C:Test item changes colour to black in upper part of the capillary 297 °C:Test item black in the upper part of the capillary and liquid 350 °C:The whole content of the capillary is black and liquid (melted) 400 °C:End of measurement, no further effects observable

Under consideration of the results from the DSC measurement (ambiguous course of the baseline) and the capillary method it was concluded that decomposition started at approximately 280 °C[1].

The test item had no melting point and no boiling point at atmospheric conditions.

[1]Not valid as thermal stability

Executive summary:

The test itemhad no melting point and no boiling point at atmospheric conditions. Under consideration of the results from the DSC measurement and the capillary method it was concluded that decomposition started at approximately 280 °C.

Description of key information

The test itemhad no melting point and no boiling point at atmospheric conditions. Under consideration of the results from the DSC measurement and the capillary method it was concluded that decomposition started at approximately 280 °C.