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Vapour pressure

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Reference
Endpoint:
vapour pressure
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Study period:
from 17 to 18 of may 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:
REPORTING FORMAT FOR THE ANALOGUE APPROACH
The TARGET substance is a reaction from the octadecenyl-1,3-propanediamine and tridecyl hydrogen phosphate. The reaction leads to a reaction products of phosphoric acid, diisotridecyl ester and phosphoric acid, monoisotridecyl ester. Vapor pressure was estimated by QSAR for each of these analogues of the target substance.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The hypothesis is that properties are likely to be similar or follow a similar pattern as a result of the presence of a common organic part. This is a reasonable assumption (e.g. common functional group(s), common precursor(s))

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Analogue approach between :
- Phosphoric acid, C8-16-alkyl esters, reaction products with (Z)-N-9-octadecenyl-1,3-propanediamine (TARGET substance) and
- Phosphoric acid, diisotridecyl ester, reaction products with (Z)-N-9-octadecenyl-1,3-propanediamine (SOURCE substance 1)
- Phosphoric acid, monoisotridecyl ester, reaction products with (Z)-N-9-octadecenyl-1,3-propanediamine (SOURCE substance 2)

3. ANALOGUE APPROACH JUSTIFICATION
Thus, this endpoint study record is part of a Weight of Evidence approach comprising a read-across and a QSAR. QSAR may be used in estimating the Vapor pressure of the organic substance and allows to fulfil the information requirements as further explained in the provided endpoint summary.

QSAR for Vapor PRESSURE property
a. SOFTWARE AND MODEL
EPI Suite version 4.11
b. MODEL (incl. version number) : MPBPWIN v1.43

c. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL:
SMILES of the Read across substance.
d. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
According to the guidance R.7a - version 5 - December 2016, "For the determination of the vapour pressure, (Q)SAR approaches may be used if determination by experiment is not possible. ."

No formal QMRF assessment of the model is currently available, however, the user's guide describes all the information.
- Methodology
MPBPWIN estimates vapor 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
(1) 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.
(2) 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.
(2) 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.

e. APPLICABILITY DOMAIN
No formal QMRF assessment of the model is currently available, however, the user's guide describes all the information.
- Descriptor domain: there is no universally accepted definition of model domain. users may wish to consider :
1 - The possibility that property estimates are less accurate for compounds outside the Molecular Weight range of the training set compounds [16 – 943 g/mol]
2- And/or that have more instances of a given fragment than the maximum for all training set compounds.
3- 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.
- Similarity with analogues in the training set: the MPBPWIN training and validation datasets can be downloaded from the Internet at: http://esc.syrres.com/interkow/EpiSuiteData.htm

f. References
Lyman, W.J. 1985. In: Environmental Exposure From Chemicals. Volume I., Neely,W.B. and Blau,G.E. (eds), Boca Raton, FL: CRC Press, Inc., Chapter 2.
Lyman, W.J., Reehl, W.F. and Rosenblatt, D.H. 1990. Handbook of Chemical Property Estimation Methods. Washington, DC: American Chemical Society, Chapter 14.
Reason / purpose:
read-across source
Reason / purpose:
read-across source
GLP compliance:
no
Type of method:
other: calculation QSAR model
Test no.:
#1
Temp.:
25 °C
Vapour pressure:
0 Pa
Remarks on result:
other: Caculation QSAR with MPBPWIN model on Phosphoric acid, diisotridecyl ester, reaction products with (Z)-N-9-octadecenyl-1,3-propanediamine.
Test no.:
#2
Temp.:
25 °C
Vapour pressure:
0 Pa
Remarks on result:
other: Calculation QSAR with MPBPWIN model on Phosphoric acid, monoisotridecyl ester, reaction products with (Z)-N-9-octadecenyl-1,3-propanediamine
Conclusions:
An analogue approach between the target substance (Phosphoric acid, C8-16-alkyl esters, reaction products with (Z)-N-9-octadecenyl-1,3-propanediamine) and the isolated source substances (Phosphoric acid, diisotridecylamine ester and Phosphoric acid, monoisotridecylamine ester) has been conducted.
The hypothesis is that properties are likely to be similar or follow a similar pattern as a result of the presence of common organic part.
Indeed, the vapor pressure of the source substances are of the same order of magnitude, estimated by QSAR model MPBPWIN v1.43.

These data indicate that the reaction product of the target substance (Phosphoric acid, C8-16-alkyl esters, reaction products with (Z)-N-9-octadecenyl-1,3-propanediamine) has a very low Vapor Pressure ranged between 1.E-8 and 1.E-9 Pa.

Description of key information

An analogue approach between the target substance (Phosphoric acid, C8-16-alkyl esters, reaction products with (Z)-N-9-octadecenyl-1,3-propanediamine) and the isolated source substances (Phosphoric acid, diisotridecylamine ester and Phosphoric acid, monoisotridecylamine ester) has been conducted.

The hypothesis is that properties are likely to be similar or follow a similar pattern as a result of the presence of common organic part.

Indeed, the vapor pressure  of the source substances are of the same order of magnitude, estimated by QSAR model MPBPWIN v1.43.

These data indicate that the reaction product of the target substance (Phosphoric acid, C8-16-alkyl esters, reaction products with (Z)-N-9-octadecenyl-1,3-propanediamine) has a very low Vapor Pressure ranged between 1.E-8 and 1.E-9 Pa.

Key value for chemical safety assessment

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

Additional information