Disodium 2,5-dichloro-4-[4-[[5-[[(dodecyloxy)carbonyl]amino]-2-sulphonatophenyl]azo]-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulphonate

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:

From January 22nd to February 09th, 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)

Version / remarks:

Adopted on 27 July 1995

GLP compliance:

yes (incl. QA statement)

Type of method:

differential scanning calorimetry

Remarks:

and capillary method

Decomposition:

yes

Decomp. temp.:

ca. 350 - 380 °C

DSC analysis

During the heating up phase, endothermic signal was recorded in the temperature range of approx. 37 – 100 °C that can be associated with the water loss. Then, an exothermic reaction occurred between ca. 350 and 380 °C, which was associated to decomposition of the substance (energy release of ca. -150 J/g).

Reaction	Test item energy (J/g)	Onset Temperature (°C)	Mean Onset Temperature (°C)	RSD (%)	Peak (°C)	Endset Temperature (°C)
Endothermic (replication 1)	188.08	36.72	36.77	0.16	63.60	102.40
Endothermic (replication 2)	124.00	36.81			64.26	96.03
Exothermic (replication 1)	-156.58	354.76	355.35	0.23	363.23	381.88
Exothermic (replication 2)	-149.68	355.94			365.41	383.14

Based on the results of the DSC curves, it is concluded the test item undergoes decomposition starting from approximately 350 °C up to 380 °C. No reactions of melting/boiling reaction attributable to the test item were recorded.

At the start of the experiment, the substance appeared as a yellow brown powder; at the end of the experiment the substance appeared as dark brown powder.

Appearance of the test item

Replication No.	Appearance of the Test Item at the start	Initial Weight of the Test Item, (mg)	Residue (mg (%))	Appearance of the Test Item at the end
R1	Yellow brown granules	2.1	0.4 (19 %)	dark brown powder
R2	Yellow brown granules	2.1	0.4 (19 %)	dark brown powder

Capillary test

Test item did not melt up to 250 °C and no visual change was observed.

Conclusions:

Decomposition before melting/boiling at ca. 350 - 380 °C

Executive summary:

The thermal behaviour of the substance was investigated in accordance with the OECD guideline 102. For the differential scanning calorimetry experiment, the test item was weighed and placed into the crucible and the test was run with a closed crucible. The prepared capsule was inserted into the DSC apparatus and heated from room temperature up to 500 °C at a constant heating rate of 10 K/min. Before and after the test, the weight of the sample was determined. The measurements were performed under inert atmosphere. The experiment was performed in duplicate.

In order to confirm the DSC outcomes, an additional measurement with capillary method was performed in the temperature range of ca. 25 – 250 °C. The experiment was carried out in duplicates.

During the heating up phase, endothermic signal was recorded in the temperature range of approx. 37 – 100 °C that can be associated with the water loss.

Then, an exothermic reaction occurred between ca. 350 and 380 °C, which was associated to decomposition of the substance (energy release of ca. -150 J/g).

At the start of the experiment, the substance appeared as a yellow brown powder; at the end of the experiment the substance appeared as dark brown powder.

Conclusion

The test item undergoes decomposition starting from approximately 350 °C up to 380 °C. No reactions of melting/boiling reaction attributable to the test item were recorded.

Description of key information

Exothermic decomposition before melting/boiling at ca. 350 - 380 °C with an energy release of ca. 150 J/g.

Additional information

OECD 102 - differential scanning calorimetry