Dodecyl 5-oxo-L-prolinate

Vapour pressure

Administrative data

Endpoint:

vapour pressure

Type of information:

(Q)SAR

Adequacy of study:

key study

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
EPISuite

2. Model
MPBPWIN v1.43

3. Smiles or other identifiers used as input for the model
N1C(=O)CCC1C(=O)OCCCCCCCCCCCC

4. Scientific validity of the (Q)SAR model
- Defined endpoint: vapour pressure i.e. identical to OECD 104.
- Unambiguous algorithm: provided in MPBPWIN Help, including bibliographic references and all equations.
- Defined domain of applicability: vapour pressure estimation domains are detailed in MPBPWIN Help.
- Appropriate measures of goodness-of-fit and robustness and predictivity: vapour pressure estimation domains are detailed in MPBPWIN Help.
- Mechanistic interpretation: The vapour pressure of a substance is defined as the saturation pressure above a solid or liquid substance and is determined at various temperatures.

5. Applicability domain
Currently there is no universally accepted definition of model domain. However, users may wish to consider the possibility that property estimates are less accurate for compounds outside the Molecular Weight range of the training set compounds, and/or that have more instances of a given fragment than the maximum for all training set compounds. It is also possible that a compound may have a functional group(s) or other structural features not represented in the training set, and for which no fragment coefficient was developed. These points should be taken into consideration when interpreting model results.
The complete training sets for MPBPWIN's estimation methodology are not available. Therefore, describing a precise estimation domain for this methodology is not possible.
The current applicability of the MPBPWIN methodology is best described by its accuracy in predicting vapour pressure as described above in the Accuracy section.
- Descriptor domain:
The EPI Suite data files are files containing the experimental data sets used to derive and validate program methodologies or test program accuracy. In EPI Suite v4.00, the data files were available in either the appendices of the individual program help files or via Internet download from: http://esc.syrres.com/interkow/EpiSuiteData.htm
- Structural and mechanistic domains: Fragment number with and without correction is in accordance with Episuite appendices.
- Similarity with analogues in the training set: within the training set, 13 molecules can be considered close to the test item in terms of overall structure and MW values (MW playing a significant role in vapour pressure):
1 substance has a similar spatial structure, without ester and cyclic amide functions:
Dodecylbenzene CAS: 123-01-03; MW: 246.44, VP(exp): 5.11E-05 (mmHg); VP(est): 4.36E-0.4 (mmHg)
12 alkyl esters with a MW value close to Lauryl PCA, without cyclic amide function:
Isopropyl laurate CAS: 102233-13-3, MW: 242.41; VP(exp): 2.68E-03 mmHg; VP(est): 3.81E-03 (mmHg)
Methyl pentadecanoate CAS: 7132-64-1, MW: 256.43; VP(exp): 1.63E-04 mmHg; VP(est): 1.09E-03 (mmHg)
Isopropyl myristate CAS: 110-27-0, MW: 270.46; VP(exp): 9.35E-05 mmHg; VP(est): 8.12E-04 (mmHg)
Methyl hexadecanoate CAS: 112-39-0, MW: 270.46; VP(exp): 4.70E-05 mmHg; VP(est): 4.75E-04 (mmHg)
Ethyl palmitate CAS: 628-97-7, MW: 284.49; VP(exp): 2.34E-05 mmHg; VP(est): 2.66E-04 (mmHg)
Methyl linolenate CAS: 301-00-8, MW: 292.47; VP(exp): 5.07E-06 mmHg; VP(est): 3.10E-05 (mmHg)
Methyl linolenate CAS: 112-63-0, MW: 294.48; VP(exp): 3.67E-06 mmHg; VP(est): 9.44E-05 (mmHg)
Methyl oleate CAS: 112-62-9, MW: 296.50; VP(exp): 6.29E-06 mmHg; VP(est): 1.15E-04 (mmHg)
Methyl stereate CAS: 112-61-8, MW: 298.51; VP(exp): 1.36E-05 mmHg; VP(est): 3.28E-05 (mmHg)
Isopropyl palmitate CAS: 142-91-6, MW: 298.51; VP(exp): 5.59E-05 mmHg; VP(est): 2.05E-04 (mmHg)
Ethyl stearate CAS: 111-61-5, MW: 312.54; VP(exp): 2.59E-06 mmHg; VP(est): 6.27E-05 (mmHg)
Isopropyl stearate CAS: 112-10-7, MW: 326.57; VP(exp): 3.97E-05 mmHg; VP(est): 5.40E-05 (mmHg)

Comparison of estimated vs. experimental vapour pressure values among these 13 substances shows that estimates are overestimated by 36% (isopropyl stearate) to 26-fold (methyl linoleate). This strongly suggests that the estimation for Lauryl PCA is an overestimate, leading to a worst-case volatility.

6. Adequacy of the result
The prediction fits the purpose of classification/labelling, PBT/vPvB and risk assessments:
- Vapour pressure is used as a classification criterion in CLP Regulation to discriminate between gases and liquids, with an impact on some hazard classes. However, as the substance is a solid, vapour pressure is not used for classification.
- Vapour pressure is not used as a key criterion for PBT and vPvB assessments. Besides, the substance was proven to be readily biodegradable.
- Vapour pressure is used in exposure and risk assessment. However at this tonnage band no CSA is required, so a calculated vapour pressure value is sufficient. In addition, the very low estimated value, which is expected to be an overestimate, would be adequate to model a low inhalative exposure and volatility in environment.

Data source

Reference

Reference Type:

other: (Q)SAR report

Title:

Unnamed

Year:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: ECHA’s Practical guide : How to use and report (Q)SARs Version 3.1 – July 2016

Principles of method if other than guideline:

MPBPWIN estimates vapour pressure (VP) by three separate methods:
(1) the Antoine method,
(2) the modified Grain method,
and (3) the Mackay method.
All three use the normal boiling point to estimate VP. Unless the user enters a boiling point on the data entry screen, MPBPWIN uses the estimated boiling point from the adapted Stein and Brown method as described in the Boiling Point section of this help file. When a boiling point is entered on the data entry screen, MPBPWIN uses it. Each VP method is discussed below.
Antoine Method: Chapter 14 of Lyman et al (1990) includes the description of the Antoine method used by MPBPWIN. It was developed for gases and liquids.
The KF structural factors are available in chapter 14 of Lyman et al (1990); the variation of this parameter is related to chemical class and is small (roughly 0.99 to 1.2), so large errors in its selection are unlikely (Lyman, 1985). The value of R is 1.987 cal/mol-K.
MPBPWIN has extended the Antoine method to make it applicable to solids by using the same methodology as the modified Grain method to convert a super-cooled liquid VP to a solid-phase VP as shown below.
Modified Grain Method: Chapter 2 of Lyman (1985) describes the modified Grain method used by MPBPWIN. This method is a modification and significant improvement of the modified Watson method. It is applicable to solids, liquids and gases. The modified Grain method equations are:
The KF structural factors are available in chapter 14 of Lyman et al (1990); the variation of this parameter is related to chemical class and is small (roughly 0.99 to 1.2), so large errors in its selection are unlikely (Lyman, 1985). The modified Grain method may be the best all-around VP estimation method currently available.
Mackay Method: Mackay derived the following equation to estimate VP (Lyman, 1985):
ln P = -(4.4 + ln Tb)[1.803(Tb/T - 1) - 0.803 ln(Tb/T)] - 6.8(Tm/T - 1)
where Tb is the normal boiling pt (K), T is the VP temperature (K) and Tm is the melting pt (K). The melting point term is ignored for liquids. It was derived from two chemical classes: hydrocarbons (aliphatic and aromatic) and halogenated compounds (again aliphatic and aromatic).
MPBPWIN reports the VP estimate from all three methods. It then reports a "suggested" VP. For solids, the modified Grain estimate is the suggested VP. For liquids and gases, the suggested VP is the average of the Antoine and the modified Grain estimates. The Mackay method is not used in the suggested VP because its application is currently limited to its derivation classes.

GLP compliance:

no

Type of method:

other: calculation method

Test material

Test material information

Constituent 1

Reference substance name:

Dodecyl 5-oxo-L-prolinate

EC Number:

245-224-1

EC Name:

Dodecyl 5-oxo-L-prolinate

Cas Number:

22794-26-9

Molecular formula:

C17H31NO3

IUPAC Name:

dodecyl 5-oxo-L-prolinate

Specific details on test material used for the study:

TMI is not applicable, QSAR inputs are listed below:
- The CAS number has been captured into “CAS input” to retrieve any experimental data.
- The chemical name was captured.
- The Melting and Boiling points (determined experimentally) have been captured: 39 and 329.1C, respectively.
- SMILES: N1C(=O)CCC1C(=O)OCCCCCCCCCCCC

Results and discussion

Vapour pressure

Key result

Temp.:

25 °C

Vapour pressure:

0.041 Pa

Remarks on result:

other: selected VP among 3 methods: Modified Grain method

Any other information on results incl. tables

Results from CAS number input:

- no experimental vapour pressure data were found,

- the SMILES and structure were automatically generated, showing that this substance was recognized within the EPIsuite database.

The structure proposed by the tool based on the CAS corresponds indeed to the substance being investigated.

The VP estimate range among 3 methods was 0.0244-0.0775 Pa, showing a good consistence.

Applicant's summary and conclusion

Conclusions:

MPBPVP v1.43 enabled to estimate the vapour pressure of Lauryl PCA as 0.0409 Pa at 25°C. Based on similar substances in the model’s training set, this is expected to be an overestimate leading to a worst-case volatility. The estimate is fit for purpose of classification/labelling and PBT/vPvB/risk assessments at any tonnage band.