3-mercaptopropionic acid

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008.05.25-2008.12.26

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Deviations:

yes

Remarks:

measured value lies slightly outside the recommended range

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesamt fuer Umwelt, Wasserwirtschaft und Gewerbeaufsicht, Rheinland-Pfalz, Germany

Type of method:

effusion method: by loss of weight or by trapping vaporisate

Temp.:

ca. 20 °C

Vapour pressure:

ca. 0.022 hPa

Temp.:

ca. 25 °C

Vapour pressure:

ca. 0.041 hPa

Transition / decomposition:

no

The following vapour pressures were determined experimentally and considered as valid:

Experiment	T	T	p	Standard deviation p	RSD p
No	°C	K	Pa	Pa	%
2-1	9.9	283.0	0.59	0.05	7.8
2-2	14.7	287.8	0.88	0.01	1.0
2-3	18.8	291.9	1.55	0.29	18.7
2-4	26.9	300.0	8.17	0.42	5.2
1-1	27.5	300.6	7.17	0.19	2.6
1-2	37.2	310.3	11.5	1.65	14.3

1/T was plotted against log(p). The graph 1/T vs. log(p) shows a straight line with a coefficient of determination r² of 0.9349. For 3-mercaptopropanoic acid, the pressures at 20 °C and at 25 °C were calculated from the regression equation (2.17 Pa at 20 °C and 4.05 Pa at 25 °C).

Conclusions:

The vapour pressure of the test substance 3-mercaptopropanoic acid has been determined to be 0.0217 hPa at 20 °C and 0.0405 hPa at 25 °C.

Executive summary:

The test material 3 -mercaptopropanoic acid has been determined to have vapour pressure: 0.0217 hPa at 20 °C and 0.0405 hPa at 25 °C by using the effusion method (weight loss) according to OECD 104 resp. EU A.4.

Description of key information

Vapour pressure: 0.0217 hPa at 20 °C,
                                0.0405 hPa at 25 °C.

Key value for chemical safety assessment

Vapour pressure:

2.17 Pa

at the temperature of:

20 °C

Additional information

The study performed in experimental laboratory with GLP standards (Paulus, 2009, LAUS) dedicated to estimate the vapour pressure of the test material 3 -mercaptopropionic acid has been chosen as a key study. The vapour pressure has been determined (0.0217 hPa at 20 °C and 0.0405 hPa at 25 °C) by using of the effusion method (weight loss) according to current guidelines: method OECD 104 resp. EU A.4.

The study (Rampy, 1973, Dow) was not performed according to current standards, vapour pressure was calculated by extrapolation of data from temperature range 130 -140°C to 25 °C , while in the key study the vapour pressure is determined by interpolation. Therefore the later study presents more reliable result. Two studies (Rampy, 1973, Dow) and (Daubert and Danner, 1989) support the key study.