2-{3-[(4-amino-2-methylpyrimidin-5-yl)methyl]-4-methyl-1,3-thiazol-3-ium-5-yl}ethyl hydrogen phosphate

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19 Jul - 14 Sep 2016

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:

no

Type of method:

effusion method: Knudsen cell

Specific details on test material used for the study:

Storage conditions: Ambient temperature (10 to 30 °C)

Temp.:

20 °C

Vapour pressure:

0 hPa

Remarks on result:

other: Extrapolated from experimental data

Temp.:

25 °C

Vapour pressure:

0 hPa

Remarks on result:

other: Extrapolated from experimental data

Temp.:

50 °C

Vapour pressure:

0 hPa

Remarks on result:

other: Extrapolated from experimental data

Results
Vapour pressure was measured in the overall temperature range of 50 to 120 °C. The 1^st measurement was done in the range of 70 to 120 °C, but due to the unusual course of the measurement it was repeated. The 2^nd measurement was done in the range of 50 to 120 °C. At the beginning of this measurement the test item was kept for 6 h at 50 °C under vacuum so as to reduce the content of possibly present volatile components of test item.

Table 1 – Measured vapour pressures and corresponding temperatures

Temperature [°C]	Vapour pressure [hPa]
70	1.8E-04
80	3.2E-04
90	4.2E-04
100	5.0E-04
110	4.2E-04
120	1.6E-04
50**	5.8E-05
60**	1.3E-04
70**	2.4E-04
80**	3.7E-04
90**	4.9E-04
100**	3.0E-04
110**	1.2E-04
120**	1.3E-04

** 2^nd measurement

Both measurements showed a comparable vapour pressure course. Both showed decreasing vapour pressures above 90 °C, the mass loss after the measurement was ca. 7%. The test item could have partially lost phosphate or it could be that the increasing vapour pressures up to 90°C were mainly due to impurities (even though at the beginning of the 2^nd measurement the test item was kept under vacuum). The mass loss was in the same order of magnitude as the impurities of the test item (i.e. 5%). For a conservative approach, the observed vapour pressures up to 90 °C were used for the evaluation.

Table 2 – Antoine parameters and extrapolated vapour pressures from experimental data

T [°C]	p [hPa]	p [Pa]	Log p = A + B/(C + T)
20	1.1E-05	1.1E-03	A = 3.63690
25	1.5E-05	1.5E-03	B = -2521.61
50	6.8E-05	6.8E-03	C = 273.15

 

 

Description of key information

1.1E-05 hPa at 20 °C
1.5E-05 hPa at 25 °C
6.8E-05 hPa at 50 °C

(OECD 104, vapour pressure curve)

Key value for chemical safety assessment

Vapour pressure:

0 hPa

at the temperature of:

20 °C

Additional information

Extrapolated vapour pressures from experimental data.