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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:
2009-07-30 to 2009-08-27
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
Deviations:
no
GLP compliance:
no
Type of method:
thermal analysis
Remarks:
differential scanning calorimetry (DSC)
Atm. press.:
1 016 hPa
Decomposition:
yes
Decomp. temp.:
ca. 400 °C

Thermal stability:

The DSC measurement (measured at 1016 hPa) in a closed glass crucible with the test item showed an endothermic effect in the temperature range 300 °C to 405 °C. Directly after the endothermic effect an exothermic effect in the temperature range 405 to 460 °C with energy of 217 J/g has been observed. An optical inspection showed a discoloration of the test item from purple to black. However the test item was still a powder after the measurement.

 

Melting point/Melting Range:

The first measurement in aluminium crucible (at 1016 hPa) with a hole showed multiple endothermic effects in the temperature range of 310 – 450 °C. No further effect was observed up to a temperature of 600 °C. An optical inspection of the test item showed a discolouration from purple to black. However the test item was still a powder.

An additional measurement with the capillary method was performed in order to clarify the results of the DSC measurements.

Due to the optical inspection and the result of the DSC measurement it can be concluded that the test item has no melting point at atmospheric condition up to the maximum temperature of measurements (600, 500 and 400 °C, respectively).

Due to the results of the capillary measurement (no changes up to 400 °C) and the DSC measurement in a closed glass crucible (changes at 405 °C resulting in a discoloration of the test item from purple to black) it can be concluded that the test item starts to decompose at approximately 400 °C.

Conclusions:
The test item, cobalt boron propionate, starts to decompose at approximately 400 °C.

Description of key information

No melting point can be stated. Cobalt, borate propionate complexes decomposes before melting. Temperature of decomposition: approx. 400 °C.

Key value for chemical safety assessment

Additional information

The melting point of the test substance was determined according to OECD guideline 102 with the differential scanning calorimetry method (DSC). The test item was heated up from ambient to the final temperature (600 °C) at a constant heating rate (10 K/min) in a defined atmosphere (nitrogen). The quantity of heat absorbed or released was measured and recorded. Aluminium crucibles with a small hole were used as containers for the test item and as empty reference crucible.

A measurement in a capillary tube in a metal block was used to clarify the results from the DSC-measurement. The maximum temperature of this equipment is limited to 400 °C. Set point and maximum temperature were chosen according to the results of the DSC measurements.

The results of the optical inspection of the DSC measurements and the result of the capillary measurement showed that cobalt, borate propionate complexes has no melting point at atmospheric condition up to the maximum temperature of the measurements. The results of the capillary measurement and the DSC measurement in a closed glass crucible showed that cobalt, borate propionate complexes starts to decompose at approx. 400 °C.