Paraffin waxes (Fischer-Tropsch), isomerization

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

06/09/2022 – 13/09/2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

static method

Remarks:

method is suitable for multi-component systems; recommended range is 10e-2 to 10e5 Pa

Key result

Test no.:

#1

Temp.:

20.1 °C

Vapour pressure:

1.68 Pa

Test no.:

#2

Temp.:

19.8 °C

Vapour pressure:

55.44 Pa

Remarks on result:

other: excluded from the final result; it is suspected that test run 2 was not sufficiently degassed hence the higher readings

Key result

Test no.:

#3

Temp.:

20.1 °C

Vapour pressure:

1.65 Pa

Test results

Temp / °C	Temp / K	P / mbar	*P / Pa
Run 1
20.1	293.25	0.0168	1.68
33.6	306.75	0.2630	26.30
46.4	319.55	0.3307	33.07
57.4	330.55	0.9522	95.22
Run 2
19.8	292.95	0.5544	55.44
33.7	306.85	0.6851	68.51
46.5	319.65	1.2000	120.00
58.3	331.45	1.6000	160.00
Run 3
20.1	293.25	0.0165	1.65
35.5	308.65	0.0266	2.66
47.6	320.75	0.1938	19.38
62.3	335.45	0.5852	58.52

Conclusions:

1.7 Pa at 20°C (arithmetic mean of two determinations)

Executive summary:

The vapour pressure of the test material 'Paraffin waxes (Fischer-Tropsch), isomerization' was determined using a static method apparatus. Testing was conducted in accordance with the procedure described in EU Method A.4 and OECD Test Guideline 104.

The vapour pressure of the test material has been determined to be 1.7 Pa at 20°C.

Description of key information

vapour pressure of substance 'Paraffin waxes (Fischer-Tropsch), isomerization' (determined using EU Method A.4, static method): 1.7 Pa at 20°C (arithmetic mean of two determinations)

Key value for chemical safety assessment

Vapour pressure:

1.7 Pa

at the temperature of:

20 °C

Additional information

The negligible vapour pressure of the registration substance 'Paraffin waxes (Fischer-Tropsch), isomerization' is supported by test results for the closely related substances GTL waxy raffinate (C15-50; CAS 848301-87-1, EC 482-130-1) and GTL base oil (C18-50; CAS 848301-69-9, EC 482-220-0) consisting of linear and branched alkanes (paraffins) with a small amount of cycloalkanes (see supporting studies).

 

Predicted vapour pressure values, calculated using a validated QSAR method, are available for individual constituents of the substance GTL waxy raffinate (C15-50; CAS 848301-87-1, EC 482-130-1). Predictions are in the range 9.7E-19 to 2.4 Pa at 25°C. Based on the identical predicted results for individual constituents in the carbon range C30-50, a vapour pressure of <1.0E-09 Pa at 25°C can also be considered for the higher molecular weight constituents of the registration substance (>C50).

However, it should be noted that the predicted vapour pressures will differ when the substances are present in a mixture, as the registration substance:

• Vapour pressures of the components of a mixture will be lower than their individual vapour pressures due to Raoult’s Law (the total vapour pressure of an ideal mixture is proportional to the sum of the vapour pressures of the mole fractions of each individual component).


• Components that are normally solid under environmental conditions when part of a mixture may have lower melting points (and therefore be in a liquid state) and increased vapour pressure and water solubility (Banerjee 1984).

^{Source: Banerjee S. 1984. Solubility of organic mixtures in water. Environmental Science & Technology 18:587–591.}