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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:
04.-07.07.2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
GLP compliance:
no
Type of method:
differential scanning calorimetry
Key result
Melting / freezing pt.:
>= 52 - <= 163 °C
Atm. press.:
1 013 hPa
Decomposition:
no

Two DSC measurements with a heating rate of 10 K/min showed four endothermal effects (melting) in the temperature range of 50 - 60 °C, 60 - 75 °C, 120 - 140 °C and 155 - 175 °C. The onset temperatures were derived from the intersection of the tangent line with the highest slope of the endothermal peak with the baseline.

 

Melting point (DSC measurements)

Ident
No.

Test
item /
mg

Starting
temperature /

°C

Final test
temperature /

°C

Temperature
range (endo-
thermal) /
°C

Onset
(melting) /
°C

Crucible

Observations

after the
measurement

36351

7.34

25

500

50-60
60-75
120-140
155-175

52.5
64.2
130.0
162.5

Aluminium
with a hole

-

36355

7.64

25

500

50-60
60-75
125-140
155-170

52.2
64.0
130.0
163.2

Aluminium
with a hole

 

 

An additional measurement with the capillary method was performed in order to clarify the melting point.

 

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.

Results of the capillary method

No.

Set
point /
°C

Heating
rate /
K/min

End
point /

°C

Remarks

1

25

10

200

Approx. 65 °C: test item started to melt

Approx. 68 °C: test item baked together

Approx. 131 °C: test item nearly clear slightly cloudy

Approx. 164 °C: test item totally molten, no further change

observed up to 200 °C

 

The test item showed four endothermal effects. The first was observed with an onset temperature of 52 °C in the DSC-measurement (optical observation: no effect was observed). At the second endothermal effect with an onset temperature of 64 °C (DSC-measurement) the optical observation showed the test item started to melt. At the third endothermal effect at 130 °C onset temperature (DSC-measurement) the test item was slightly cloudy. At the fourth endothermal effect at 163 °C onset temperature (DSC measurement) the test item was observed to be completely molten by optical inspection. Thus, it was concluded that the test item has a melting range from 52 to 163 °C.

Conclusions:
The melting point of the test item was determined to be in the range 52 -163°C.
Executive summary:

A study was conducted according to OECD test guideline 102 and Regulation (EC) No 440/2008 method A.1 to determine the melting point of the test item using differential scanning calorimetry. The test item and the reference are heated up from the starting temperature to the final temperature at a constant heating rate in a defined atmosphere (nitrogen). Open crucibles were used as containers for the test item and as empty reference crucible. The quantity of heat absorbed or released was measured and recorded. 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 test item showed four endothermal effects. The first was observed with an onset temperature of 52 °C in the DSC-measurement (optical observation: no effect was observed). At the second endothermal effect with an onset temperature of 64 °C (DSC-measurement) the optical observation showed the test item started to melt. At the third endothermal effect at 130 °C onset temperature (DSC-measurement) the test item was slightly cloudy. At the fourth endothermal effect at 163 °C onset temperature (DSC measurement) the test item was observed to be completely molten by optical inspection. Thus, it was concluded that the test item melts in the range from 52 to 163 °C.

Description of key information

The melting point of the test item was determined to be in the range 52 -163°C (reference 4.2 -1).

Key value for chemical safety assessment

Additional information

A study was conducted according to OECD test guideline 102 and Regulation (EC) No 440/2008 method A.1 to determine the melting point of the test item using differential scanning calorimetry. The test item and the reference are heated up from the starting temperature to the final temperature at a constant heating rate in a defined atmosphere (nitrogen). Open crucibles were used as containers for the test item and as empty reference crucible. The quantity of heat absorbed or released was measured and recorded. 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 test item showed four endothermal effects. The first was observed with an onset temperature of 52 °C in the DSC-measurement (optical observation: no effect was observed). At the second endothermal effect with an onset temperature of 64 °C (DSC-measurement) the optical observation showed the test item started to melt. At the third endothermal effect at 130 °C onset temperature (DSC-measurement) the test item was slightly cloudy. At the fourth endothermal effect at 163 °C onset temperature (DSC measurement) the test item was observed to be completely molten by optical inspection. Thus, it was concluded that the test item melts in the range from 52 to 163 °C.