2-benzyl-4-methyl-4a,5,6,7,8,8a-hexahydro-4H-benzo[d][1,3]dioxine

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

21 September 2021

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification

Remarks:

The test item falls within the applicability domain of the model except for descriptor/response domain and was therefore predicted by extrapolation for its VAPOUR PRESSURE. The predicted extrapolated value is considered valid within the reported 95% confidence interval range. Therefore, this endpoint value can be considered reliable and fit for purpose, with some restrictions due to descriptor/response domain.

Justification for type of information:

1. SOFTWARE
iSafeRat® – in Silico Algorithms For Environmental Risk And Toxicity

2. MODEL (incl. version number)
iSafeRat® VP v1.5

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
C(C1=CC=CC=C1)C1OC(C2C(O1)CCCC2)C

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

5. APPLICABILITY DOMAIN
See attached Study Report with QPRF in annex

6. ADEQUACY OF THE RESULT
See attached Study Report with QPRF in annex

Reason / purpose for cross-reference:

reference to other study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Deviations:

not applicable

Remarks:

QSAR model

Principles of method if other than guideline:

The VAPOUR PRESSURE was determined using the iSafeRat® VP model which predicts the endpoint value which would be expected when testing the substance under experimental conditions in a laboratory following the Guideline for Testing of Chemicals No. 104. This model is based on a serie of linear relationships in which validated boiling point values are plotted against the log of vapour pressure values, where the pressure is in Pascals. Several regressions have been determined depending on the capability of the substance to participate in intermolecular interactions, such as hydrogen bonding. They form different local models.

GLP compliance:

no

Type of method:

other: QSAR model

Remarks:

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.

Key result

Temp.:

25 °C

Vapour pressure:

0.295 Pa

95% confidence interval (α = 0.05): 0.231 – 0.378 Pa.

 

Applicability domain

 

Descriptor domain

The BP (324.2°C) given as the input to the iSafeRat® VP model does not fall within the descriptor domain of the model between a BP of 30.7°C and 256°C. Therefore, the prediction is considered as an extrapolation.

 

Response domain

The predicted log VP (-0.5297) does not fall within the response domain of the model between a log VP of 0.661 and 4.938. Therefore, the prediction is considered as an extrapolation.

 

Structural fragment domain

All chemical groups within the molecular structure are represented within the datasets of the model.

 

Mechanism domain

The model is based on different Simple Linear Regression equations (i.e. local models), selected on the basis of an initial classification about the capability of the substance to participate in intermolecular interactions, such as hydrogen bonding. iSafeRat® VP includes the following local models, ranked by increasing intermolecular attractive interactions:

• Vapour pressure local model for NonPolar Organic compounds, which can only participate in weak Van der Waals attractive forces (e.g. alkanes, halides, alkenes, thiols… etc.).


• Vapour pressure local model for Oxygenated, NonHydroxylated compounds, which can participate in strong Van der Waals attractive forces (e.g. ethers, mono-esters, ketones, aldehydes, epoxides, lactones, carbonates, (meth)acrylates).


• Vapour pressure local model for Nitrogenated compounds, which can participate in hydrogen bonds and/or strong Van der Waals attractive forces (e.g. amines, anilines, pyridines, pyrroles, nitriles, lactames, azoles, etc.).


• Vapour pressure local model for Oxygenated, Hydroxylated compounds (Secondary and Tertiary Alcohols and phenols), which can participate in hydrogen bonds.


• Vapour pressure local model for Oxygenated, Hydroxylated compounds (Primary Alcohols), which can participate in hydrogen bonds.


• Vapour pressure local model for Carboxylic Acids, which can participate in hydrogen bonds.

Given the molecular structure of the substance (ether), the local model used to predict its vapour pressure is the one dedicated to Oxygenated, NonHydroxylated compounds, which can participate in strong Van der Waals attractive forces.

Conclusions:

Low volatility (based on volatility bands criteria for occupational exposure (Chesar / ECETOC TRA), << 500 Pa).

Executive summary:

A validated Quantitative Structure-Property Relationship (QSPR) model was used to calculate the VAPOUR PRESSURE pressure of the test item.

 

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 test item falls within the applicability domain of the model except for descriptor/response domain and was therefore predicted by extrapolation for its VAPOUR PRESSURE. The predicted extrapolated value is considered valid within the reported 95% confidence interval range. Therefore, this endpoint value can be considered reliable and fit for purpose, with some restrictions.

 

The VAPOUR PRESSURE of the test item was predicted as 0.295 Pa at 25°C.

95% confidence interval (α = 0.05): 0.231 – 0.378 Pa.

Description of key information

The vapour pressure of the substance was determined to be 0.295 Pa at 25°C (low volatility)

Key value for chemical safety assessment

Vapour pressure:

0.295 Pa

at the temperature of:

25 °C

Additional information

No experimental study was available on the substance.

Therefore, the Vapour Pressure was reliably estimated by a validated QSAR. An experimental boiling point was used as input.