Rhodium tris(2-ethylhexanoate)

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

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:

yes (incl. QA statement)

Type of method:

differential scanning calorimetry

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Expiration date of the lot/batch: March 31, 2018
- Purity test date: Inspection certificate dated September 22, 2017

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Ambient temperature (10 °C to 30 °C), dry

FORM OF THE TEST ITEM
- Purity: 2.07% rhodium
- Form: Liquid
- Appearance: Brownish liquid
- Solvent: 2-ethylhexan-1-ol

Remarks on result:

other: No melting point was measured above -100 °C. However, since melting may be hindered at low temperatures due to supercooling it should only be assumed that no melting point exists above -50 °C.

Two DSC measurements in aluminium crucibles with a hole were performed. The mass loss after the DSC measurements amounted to 96 %.

In the first test the test item was cooled down to -50 °C with a cooling rate of 1 K/min, -50 °C were kept for 60 min and afterwards the test item was heated up with a heating rate of 10 K/min. The measurement was stopped at 300 °C. The measurement showed an endothermal effect in the temperature range of 155 to 220 °C.No further endothermic or exothermic effects were observed up to the final temperature (300 °C).The onset temperature was derived from the intersection of the tangent line with the highest slope of the endothermal peak with the baseline.

In the second test the test item was cooled down to -100 °C with a cooling rate of 1 K/min, -100 °C were kept for 360 min and afterwards the test item was heated up to 300 °C with a heating rate of 10 K/min. The measurement showed an endothermal effect in the temperature range of 150 to 225 °C. No further endothermic or exothermic effects were observed up to the final temperature (300 °C).The onset temperature was derived from the intersection of the tangent line with the highest slope of the endothermal peak with the baseline.

No melting point was measured above -100 °C. However, since melting may be hindered at low temperatures due to supercooling it should only be assumed that no melting point exists above
-50 °C.

Table 1: DSC measurements

Ident No.	Test item / mg	Starting temperature / °C	Final test temperature / °C	Temperature range (endo-thermal) / °C	Onset / °C	Crucible	Observations after the measurement
36644	11.34	-50	300	155 to 220	183.71	Aluminium with a hole	Black residue; mass loss: 96 %
36650	11.13	-100	300	150 to 225	184.37	Aluminium with a hole	Black residue; mass loss: 96 %

Conclusions:

No melting point was measured above -100 °C. However, since melting may be hindered at low temperatures due to supercooling it should only be assumed that no melting point exists above -50 °C.

Executive summary:

Nau (2018) is a GLP-compliant study following OECD guideline 102 and EU method A1. It is reliable without restrictions and is suitable for use for this endpoint. Melting point was measured using differential scanning calorimetry. No melting point was measured above -100 °C. However, since melting may be hindered at low temperatures due to supercooling it should only be assumed that no melting point exists above -50 °C.

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Description of key information

Rhodium tris(2-ethylhexanoate) is placed on the market with two different solvents, 2-ethylhexan-1-ol and 2-ethylhexanoic acid. Information on both compositions is therefore included.

For rhodium tris(2-ethylhexanoate), solvent 2-ethylhexan-1-ol, no melting point was measured above -100 °C. However, since melting may be hindered at low temperatures due to supercooling it should only be assumed that no melting point exists above -50 °C.

For rhodium tris(2-ethylhexanoate), solvent 2-ethylhexanoic acid, no melting point was measured above -50 °C. However, since melting may be hindered at low temperatures due to supercooling it should only be assumed that no melting point exists above -20 °C.

Additional information

Rhodium tris(2-ethylhexanoate) is placed on the market with two different solvents, 2-ethylhexan-1-ol and 2-ethylhexanoic acid. Information on both compositions is therefore included.

Nau (2018a) is a GLP-compliant study following OECD guideline 102 and EU method A1, and assessed the melting point of rhodium tris(2-ethylhexanoate), solvent 2-ethylhexan-1-ol. The study is reliable without restrictions and is suitable for use for this endpoint. Melting point was measured using differential scanning calorimetry. No melting point was measured above -100 °C. However, since melting may be hindered at low temperatures due to supercooling it should only be assumed that no melting point exists above -50 °C.

Nau (2018b) is a GLP-compliant study following OECD guideline 102 and EU method A1, and assessed the melting point of rhodium tris(2-ethylhexanoate), solvent 2-ethylhexanoic acid. The study is reliable without restrictions and is suitable for use for this endpoint. Melting point was measured using differential scanning calorimetry. No melting point was measured above -50 °C. However, since melting may be hindered at low temperatures due to supercooling it should only be assumed that no melting point exists above -20 °C.