Marjoram, sweet, ext.

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

16 January - 2 February 2018

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
iSafeRat® HA-QSAR toolbox v1.1

2. MODEL (incl. version number)
iSafeRat® HA-QSAR v 1.3 to predict Vapour Pressure

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
SMILES code (see attached QPRF)

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF

5. APPLICABILITY DOMAIN
See attached QPRF

6. ADEQUACY OF THE RESULT
See attached QPRF

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Deviations:

yes

Remarks:

QSAR model

Principles of method if other than guideline:

A Quantitative Structure-Property Relationship (QSPR) model was used to calculate the vapour pressure of the constituents of the test item. This QSPR model has been validated as a QSAR model to be compliant with the OECD recommendations for QSAR modeling (OECD, 2004) and predicts the endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following Guideline for Testing of Chemicals No. 104, "Vapour Pressure". The criterion predicted was the vapour pressure at 25°C in Pascals.

The determination was performed using a regression method in which validated boiling point values are plotted against the log of vapour pressure values, where the pressure is in Pascals. The comparison was made with other members of the same chemical group. The results are considered to be as accurate as those from a good quality OECD guideline 104 study.

GLP compliance:

no

Type of method:

other: QSAR

Key result

Test no.:

#1

Temp.:

25 °C

Vapour pressure:

181 Pa

Remarks on result:

other: constituent 1

Key result

Test no.:

#2

Temp.:

25 °C

Vapour pressure:

12.7 Pa

Remarks on result:

other: constituent 2

Key result

Test no.:

#3

Temp.:

25 °C

Vapour pressure:

28.1 Pa

Remarks on result:

other: constituent 3

Key result

Test no.:

#4

Temp.:

25 °C

Vapour pressure:

9.7 Pa

Remarks on result:

other: constituent 4

Key result

Test no.:

#5

Temp.:

25 °C

Vapour pressure:

249 Pa

Remarks on result:

other: constituent 5

Key result

Test no.:

#6

Temp.:

25 °C

Vapour pressure:

372 Pa

Remarks on result:

other: constituent 6

Key result

Test no.:

#7

Temp.:

25 °C

Vapour pressure:

28.1 Pa

Remarks on result:

other: constituent 7

Key result

Test no.:

#8

Temp.:

25 °C

Vapour pressure:

160 Pa

Remarks on result:

other: constituent 8

Key result

Test no.:

#9

Temp.:

25 °C

Vapour pressure:

7.58 Pa

Remarks on result:

other: constituent 9

Key result

Test no.:

#10

Temp.:

25 °C

Vapour pressure:

343 Pa

Remarks on result:

other: constituent 10

Key result

Temp.:

25 °C

Vapour pressure:

286 Pa

Remarks on result:

other: constituent 11

Key result

Temp.:

25 °C

Vapour pressure:

239 Pa

Remarks on result:

other: constituent 12

Key result

Temp.:

25 °C

Vapour pressure:

13.4 Pa

Remarks on result:

other: constituent 13

Key result

Temp.:

25 °C

Vapour pressure:

15.4 Pa

Remarks on result:

other: constituent 14

Key result

Temp.:

25 °C

Vapour pressure:

24 Pa

Remarks on result:

other: constituent 15

Key result

Temp.:

25 °C

Vapour pressure:

13.4 Pa

Remarks on result:

other: constituent 16

The results below are the vapour pressure values of 16 constituents of the substance (covering more than 89% of the composition), which can be anticipated during a study following the OECD Guideline No. 104. The vapour pressure values are calculated as follows:

Constituents	vapour pressure (Pa) at 25 °C	95% confidence limits (Pa)
constituent 1	181	171 - 190
constituent 2	12.7	10.1 - 15.8
constituent 3	28.1	22.5 - 35.0
constituent 4	9.70	9.20 - 10.2
constituent 5	249	236 - 262
constituent 6	372	352 - 392
constituent 7	28.1	22.5 - 35.0
constituent 8	160	152 - 169
constituent 9	7.58	6.08 - 9.45
constituent 10	343	325 - 361
constituent 11	286	272 - 302
constituent 12	239	227 - 252
constituent 13	13.4	10.7 - 16.7
constituent 14	15.4	14.7 - 16.3
constituent 15	24.0	22.1 - 25.9
constituent 16	13.4	10.7 - 16.7

Conclusions:

The vapour pressures of 16 constituents of the test item were estimated based on a valid QSAR as follows:

Constituents : vapour pressure (Pa) at 25 °C (95% confidence limits (Pa))
Constituent 1 : 181 Pa (171-190 Pa)
Constituent 2 : 12.7 Pa (10.1-15.8 Pa)
Constituent 3 : 28.1 Pa (22.5-35.0 Pa)
Constituent 4 : 9.7 Pa (9.20-10.2 Pa)
Constituent 5 : 249 Pa (236-262 Pa)
Constituent 6 : 372 Pa (352-392 Pa)
Constituent 7 : 28.1 Pa (22.5-35.0 Pa)
Constituent 8 : 160 Pa (152-169 Pa)
Constituent 9 : 7.58 Pa (6.08-9.45 Pa)
Constituent 10 : 343 Pa (325-361 Pa)
Constituent 11 : 286 Pa (272-302 Pa)
Constituent 12 : 239 Pa (227-252 Pa)
Constituent 13 : 13.4 Pa (10.7-16.7 Pa)
Constituent 14 : 15.4 Pa (14.7-16.3 Pa)
Constituent 15 : 24.0 Pa (22.1-25.9 Pa)
Constituent 16 : 13.4 Pa (10.7-16.7 Pa)

Executive summary:

A calculation method prediction was performed to assess the vapour pressure of 16 constituents of the substance. This calculation method predicts the endpoint value which would be expected when testing a pure substance under experimental conditions in a laboratory following Guideline for Testing of Chemicals No. 104.

The estimation method is based on a linear regression equations for a series of common structures (for example alkanes) generated using high quality vapour pressure data. In the majority of cases data for vapour pressure were obtained from the following methods described in the OECD Guideline No. 104: isoteniscope, dynamic, static, effusion (vapour pressure balance or loss of weight) and gas saturation methods. Likewise, data for boiling points were obtained from the following methods described in the OECD Guideline No. 103: DSC (Differential Scanning Calorimetry), DTA (Differential Thermal Analysis), dynamic method, capillary (Siwoloboff) method, ebulliometer, distillation and photocell detection.

Finally the vapour pressures of 16 constituents of the test item (covering more than 89% of the composition) were estimated in a range between 7.58 and 372 Pa at 25°C.

Description of key information

The vapour pressure of the constituents of the substance (16 components of the substance covering more than 89% of the composition) are in the range between 7.58 and 372 Pa at 25°C (valid QSAR estimations).

Additional information

No study was conducted on the test item itself.

The test item is a natural complex substance (NCS). It is a mixture of several constituents, but 16 of them represent more than 89% of that mixture.

This calculation method predicts the endpoint value which would be expected when testing a pure substance under experimental conditions in a laboratory following Guideline for Testing of Chemicals No. 104. The criterion predicted was the vapour pressure in Pa at 25°C.

The vapour pressures of the constituents of the substance were estimated at 25°C as follows:

onstituents	vapour pressure (Pa) at 25 °C	95% confidence limits (Pa)
constituent 1	181	171 - 190
constituent 2	12.7	10.1 - 15.8
constituent 3	28.1	22.5 - 35.0
constituent 4	9.70	9.20 - 10.2
constituent 5	249	236 - 262
constituent 6	372	352 - 392
constituent 7	28.1	22.5 - 35.0
constituent 8	160	152 - 169
constituent 9	7.58	6.08 - 9.45
constituent 10	343	325 - 361
constituent 11	286	272 - 302
constituent 12	239	227 - 252
constituent 13	13.4	10.7 - 16.7
constituent 14	15.4	14.7 - 16.3
constituent 15	24.0	22.1 - 25.9
constituent 16	13.4	10.7 - 16.7

The substance is an UVCB with constituents having different vapour pressures. In addition we can not anticipate the impact of the interactions between the constituents and the influence of the physical state of the substance on the whole substance vapour pressure.

Therefore we considered the vapour pressure of the 16 constituents of the substance and no single key value was retained (nor calculated weighted Vapour pressure nor worst-case).