α-[2-(methylamino)ethyl]benzyl alcohol

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
EPI v.4.11 (MPBPWIN v1.43), US EPA

2. MODEL (incl. version number)
MPBPWIN v1.43 (The modified Grain method)

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
OC(c1ccccc1)CCNC

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
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. 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.
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 may be the best all-around VP estimation method currently available.
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.
Estimation Accuracy
The accuracy of MPBPWIN's "suggested" VP estimate was tested on a dataset of 3037 compounds with known, experimental VP values between 15 and 30 deg C (the vast majority at 25 or 20 deg C).
The experimental values were taken from the PHYSPROP Database that is part of the EPI Suite. For this test, the CAS numbers were run through MPBPWIN as a standard batch-mode run (using the default VP estimation temperature of 25 deg C) and the batch estimates were compared to PHYSPROP's experimental VP.
The estimation error increases as the vapor pressure (both experimental and estimated) decreases, especially when the vapor pressure decreases below 1x10-6 mm Hg.
The estimation methodology uses the normal boilinig point to estimate the liquid-phase vapor pressure.
For solids, the melting point is required to convert the liquid-phase vapor pressure to the solid-phase vapor pressure. VP estimation error can be introduced by:
(1) poor Boiling Point estimates or values
(2) poor Melting Point estimates or values (for solids)
The 3037 compound test set contains 1642 compounds with available experimental Boiling points and
Melting points. For this subset of compounds, the estimation accuracy statistics are (based on log VP):
number = 1642
r2 = 0.949
std deviation = 0.59
avg deviation = 0.32
These statistics clearly indicate that VP estimates are more accurate with experimental BP and MP data.

5. APPLICABILITY DOMAIN
Currently there is no universally accepted definition of model domain. Property estimates are less accurate for compounds outside the Molecular Weight range of the training set compounds (Molecular Weight range: 16.04 – 959.17), and/or that have more instances of a given fragment than the maximum for all training set compounds.
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 vapor pressure as described above in the Accuracy section.
6. ADEQUACY OF THE RESULT
The estimate value has been generated by a valid model. The model is applicable to α-[2-(methylamino)ethyl]benzyl alcohol with the necessary level of reliability and is sufficiently relevant for the regulatory purpose.

Data source

Reference

Reference Type:

other: QSAR

Title:

EPI Suite Version 4.11

Year:

2012

Bibliographic source:

MPBPWINv1.43 (US EPA) (2015)

Materials and methods

Principles of method if other than guideline:

- Software tool(s) used including version: MPBPWINv1.43 (US EPA)
- Model(s) used: Modified Grain method
- Model description: see field 'Justification for non-standard information'

GLP compliance:

no

Type of method:

other: Qsar

Test material

Test material information

1

Reference substance name:

α-[2-(methylamino)ethyl]benzyl alcohol

EC Number:

255-679-8

EC Name:

α-[2-(methylamino)ethyl]benzyl alcohol

Cas Number:

42142-52-9

Molecular formula:

C10H15NO

IUPAC Name:

3-(methylamino)-1-phenylpropan-1-ol

Results and discussion

Vapour pressure

Test no.:

#1

Temp.:

25 °C

Vapour pressure:

0.037 Pa

Applicant's summary and conclusion

Conclusions:

MPBPWINv1.43 (US EPA) predicted that the vapour pressure of the substance is 0.0371 Pa at 25°C.