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Physical & Chemical properties

Vapour pressure

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Reference
Endpoint:
vapour pressure
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2016-07-27 to 2016-07-28
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. SOFTWAREiSafeRat® toolbox – in Silico Algorithms For Environmental Risk And Toxicity version 2.32. MODEL (incl. version number)iSafeRat® vapour pressure HA-QSAR v1.33. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODELC1C(CCC)COC(=O)C14. SCIENTIFIC VALIDITY OF THE (Q)SAR MODELSee attached QMRF5. APPLICABILITY DOMAINSee attached QPRF6. ADEQUACY OF THE RESULTSee attached QPRF
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 104 (Vapour Pressure Curve)
Deviations:
not applicable
Remarks:
QSAR model
Principles of method if other than guideline:
The purpose of the in silico study was to determine the vapour pressure of 5-propyl-tetrahydropyran-2-one. 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 104 study.
GLP compliance:
no
Type of method:
other: QSAR model
Key result
Test no.:
#1
Temp.:
25 °C
Vapour pressure:
6.48 Pa
Remarks on result:
other: [5.50-7.63]
Remarks:
CI95%

The test item falls within the applicability domains of the iSafeRat® HA-QSAR module for vapour pressure.

- descriptor domain: The test item falls within the descriptor domain of the model as described in the relevant QMRF report, the applicability domain was based on k-Nearest Neighbours approach taking into account 5 closest training neighbours (k=5).

Moreover, the boiling point falls within the descriptor domain of the model between 30.7°C and 256°C. The test item falls within the response domain of the training set between log vapour pressure (in log (Pa)) of 0.67 to 4.91.

- structural fragment domain: Currently, iSafeRat® HA-QSAR VP module can reliably predict the vapour pressure solubility for chemicals generally classified as MOA 1 substances (non-polar narcotics) and ethers, esters, ketones, aldehydes, alcohols, acids and phenols. The test item as an ester can be taken into account for vapour pressure prediction. All chemical group within the molecular structure is taken into account by the model.

- mechanism domain: Vapour pressure of the substance is determined using boiling point as the descriptor. The local models used is depending of the capability of the substance to participate in hydrogen bonding with water. The test item falls within the following local model : Vapour pressure local model for Oxygenated, NonHydroxylated compounds (for hydrogen bond acceptor compounds which are not donors, e.g. ethers, mono-esters, ketones, aldehydes, epoxides, lactones, carbonates, (meth)acrylates).

- metabolic domain, if relevant: Not relevant.

- considerations on structural analogues: HA-QSAR module for vapour pressure is mainly based on the thermodynamic relationship between boiling point and vapour pressure. This model was constructed using high quality data for boiling point and vapour pressure for 77 compounds.

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

The prediction 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 domains of the model and was therefore reliably predicted for its vapour pressure. Therefore, this endpoint value can be considered valid and fit for purpose.

The vapour pressure of the test item was predicted as 6.48 Pa at 25°C.

95% confidence interval (α = 0.05): 5.50 – 7.63 Pa.

Description of key information

Low volatility (calculated value).

Key value for chemical safety assessment

Vapour pressure:
6.48 Pa
at the temperature of:
25 °C

Additional information

No experimental study was available on the substance. A calculated result from a validated QSAR is proposed, and retained as key data.