Resin acids and Rosin acids, cobalt salts

Melting point / freezing point

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Deviations:

no

GLP compliance:

no

Type of method:

thermal analysis

Decomposition:

yes

Decomp. temp.:

180 °C

Reference 2

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Remarks:

Michelin analysis proved that these results are not correct (see endpoint study record "melting point / freezing point Michelin Report").

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

thermal analysis

Melting / freezing pt.:

180.5 °C

Decomposition:

no

Sublimation:

no

Description of key information

The report edited by Defitrace indicates melting point and boiling point for this substance, whereas product Y is a cobalt organometallic compound with high molecular weight (662 g/mol) that decomposes thermally without change of state. We contest also the conclusions of this study.

We remind too that cobalt is not particularly volatile (melting point = 1495 °C, boiling point = 2927 °C).

We conducted TGA measurements to follow weight losses of the product as function of temperature. DSC measurements were then performed to characterise potential thermal phenomena’s.

Melting point: endothermic peak without weight variation

Boiling point:  endothermic peak without degradation of the product. At the end of the transition, % losses = 100 %.

Additional information

Discussion:

- Phenomenon considered as melting point by Defitrace: weak endothermic peak at 180.5 °C under argon (DSC).

The phenomenon observed by Defitrace near 170 °C is excessively weak and expanded: could not be characteristic of a melting point. We did not observe this phenomenon under nitrogen or helium in our DSC curves. We observed losses (≈ 4 %) between 150 °C and 200 °C that mainly relate to volatile organic impurities vaporisation.

 

Under air, only exothermic peaks are observed. Near 180 °C, visual observations show a significant browning of product Y, which becomes partially liquid: sign of chemical modification (oxidation) of the product. The substance decomposes before melting occurs.

 

- Phenomenon considered as boiling point by Defitrace: endothermic peak near 379 °C under argon (DSC).

 

We observed this phenomenon by Michelin between 400 and 470 °C (E = 100 to 200 J/g). Under nitrogen, the residue at 750 °C is about 9.2 % (black residue) corresponding to cobalt as metal. It means that there was no vaporisation of the compound, rather a degradation and loss of organic matter.

 

Under air, only exothermic peaks are observed.

 

Conclusions:

 

No obvious melting or boiling phenomenon could be seen on DSC thermograms. The endothermic phenomenon near 380 °C does not correspond to product Y boiling but product degradation with matter loss, confirmed by the presence of an inorganic residue at 750 °C (TGA). There is also neither melting nor boiling of the product.