4-[[2-methoxy-4-[(4-nitrophenyl)azo]phenyl]azo]phenol

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 May 10, 2016 to May 24, 2016

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

Melting / freezing pt.:

225.7 °C

Atm. press.:

101 325 Pa

1. Melting point / melting range: DSC measurement

Two DSC measurements in aluminium crucibles with a hole with a heating rate of 10 K/min showed an endothermal effect (melting) in the temperature range of 160 – 240 °C for the 1st measurement and 200 – 240 °C for the 2nd measurement, respectively. At 240 °C, an exothermal decomposition started. The onset temperature was derived from the intersection of the tangent line with the highest slope of the endothermal peak with the baseline.

2. 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 were not as accurate as the DSC results. The filling height of the test item was approximately 5 mm.

Conclusions:

Under the study conditions, the melting temperature of the test substance was determined to be 225.7 °C (DSC measurements and the capillary method). Afterwards, decomposition started.

Executive summary:

A study was conducted to determine the melting /freezing point of the test substance according to OECD Guideline 102 and EU Method A.1. Two procedures were used: differential scanning calorimetry measurements and the capillary method. Two DSC measurements in aluminium crucibles with a hole with a heating rate of 10 K/min showed an endothermal effect (melting) in the temperature range of 160 – 240 °C for the 1st measurement and 200 – 240 °C for the 2nd measurement, respectively. At 240 °C, an exothermal decomposition started. The onset temperature was derived from the intersection of the tangent line with the highest slope of the endothermal peak with the baseline. The 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 were not as accurate as the DSC results. The filling height of the test item was approximately 5 mm. Under the study conditions, the melting temperature of the test substance was determined to be 225.7 °C. Afterwards, decomposition started (Dornhagen, 2016).

Description of key information

The melting point / freezing point was determined according to OECD Guideline 102 and EU Method A.1 (Dornhagen, 2016).

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:

225.7 °C