Rhodium tris(2-ethylhexanoate)

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

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 104 (Vapour Pressure Curve)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

static method

Test no.:

#1

Temp.:

20 °C

Vapour pressure:

21.7 hPa

Test no.:

#2

Temp.:

25 °C

Vapour pressure:

28.8 hPa

Test no.:

#3

Temp.:

50 °C

Vapour pressure:

102.8 hPa

The vapour pressure was measured in the temperature range of 46 °C to 87 °C. The measured vapour pressures at the corresponding temperatures are listed in Table 1. At 86.6 °C no constant vapour pressure could be measured. Even after >7 hours the vapour pressure continued to rise slowly and it was concluded that the vapour pressure should only be measured at lower temperatures due to an apparent gas formation of the test item at temperatures above 76.5 °C.

Table1: Measured vapour pressures and corresponding temperatures

Temperature / °C	Vapour pressure / hPa
46.1	85.6
56.2	136.5
66.4	214.1
76.5	324.9
86.6	p not constant, rises continuously

The regression curve with slope B and intercept A was calculated. The calculated Antoine constants A, B, and C are shown in Table 2. From these parameters, the values of vapour pressure at 20, 25, and 50 °C were calculated using the following equation:

log (p/hPa) = B/(C+T[°C]) + A

Table2: Antoine parameters and extrapolated vapour pressures

T / °C	p / hPa	log (p/hPa) = A + B/(C+T[°C])
20	21.7	A = 8.61111
25	28.8	B = -2132.49
50	102.8	C = 273.15

The following vapour pressure values for the test item were extrapolated from the experimental data:

T / °C	p / hPa	p / Pa
20	21.7	2171
25	28.8	2875
50	102.8	10281

Conclusions:

The vapour pressure was determined to be 21.7 hPa at 20°C, 28.8 hPa at 25°C and 102.8 hPa at 50°C.

Executive summary:

Nau (2018) is a GLP-compliant study following OECD guideline 104 and EU method A4, using the static method. The study is considered to be reliable without restrictions (Klimisch 1). The vapour pressure was determined to be 21.7 hPa at 20°C, 28.8 hPa at 25°C and 102.8 hPa at 50°C.

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, the vapour pressure was determined to be 21.7 hPa at 20°C, 28.8 hPa at 25°C and 102.8 hPa at 50°C.

For rhodium tris(2-ethylhexanoate), solvent 2-ethylhexanoic acid the vapour pressure was determined to be 24.8 hPa at 20°C, 31.9 hPa at 25°C and 100.5 hPa at 50°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 104 and EU method A4, using the static method. The study is considered to be reliable without restrictions (Klimisch 1). The vapour pressure for rhodium tris(2-ethylhexanoate), solvent 2-ethylhexan-1-ol was determined to be 21.7 hPa at 20°C, 28.8 hPa at 25°C and 102.8 hPa at 50°C.

Nau (2018b) is a GLP-compliant study following OECD guideline 104 and EU method A4, using the static method. The study is considered to be reliable without restrictions (Klimisch 1). The vapour pressure for rhodium tris(2-ethylhexanoate), solvent 2-ethylhexanoic acid was determined to be 24.8 hPa at 20°C, 31.9 hPa at 25°C and 100.5 hPa at 50°C.