6,6'-diphenylfulvene

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
EPIWIN software by US-EPA

2. MODEL (incl. version number)
MPBPWIN v1.43

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
c(ccc1C(c(ccc2)cc2)=C(C=C3)C=C3)cc1

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- The complete test sets of experimental data for (melting point, boiling point and) vapor pressure can be downloaded via the Internet at: http://esc.syrres.com/interkow/EpiSuiteData.htm

5. APPLICABILITY DOMAIN
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 plot clearly indicates that the estimation error increases as the vapor pressure (both experimental and estimated) decreases, especially when the vapor pressure decreases below 1x10-6 mm Hg (0.0001333 Pa).
The estimation methodology uses the normal boil 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. Further, the plot clearly indicates that the estimation error increases as the vapor pressure (both experimental and estimated) decreases, especially when the vapor pressure decreases below 1x10-6 mm Hg (0.0001333 Pascals).

Estimation domain: The intended application domain is organic chemicals. Inorganic and organometallic chemicals generally are outside the 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 ca. (ca. 16-943) 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 vapor pressure as described above in the accuracy section.

6. ADEQUACY OF THE RESULT
The result calculated for the organic substance is reasonable and can be used without any further testing:
- Experimental results from literature (melting point of 82°C and boiling point of 309 °C) have been used for calculation, which reduces the VP estimation error.
- The result is in the magnitude with a relatively low estimation error (estimation error increases as the vapor pressure decreases, especially when the vapor pressure decreases below 0.0001333 Pa).
- With a molecular weight of 230.3 the substance lies within the weight range of the training set compounds, does not have more instances of a given fragment than the maximum for all training set compounds and the functional groups are represented in the training sets (fragment coefficients were developed).

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to other study

Reference

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Qualifier:

no guideline available

Principles of method if other than guideline:

not specified, handbook data

GLP compliance:

not specified

Type of method:

other: No data

Melting / freezing pt.:

82.25 °C

Decomposition:

no

Remarks on result:

other: no further information available

Conclusions:

melting point = 82.25 °C (reliable peer reviewed handbook data)

Executive summary:

There is no available information on the methods used to determine the value for this endpoint. However, this information is taken from The Yaws Handbook of Physical Properties for Hydrocarbons and Chemicals, which is considered to be a reliable peer reviewed handbook. The substance melts at 82.25 °C.

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Reference

Endpoint:

boiling point

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Authoritative secondary source

Principles of method if other than guideline:

no information is given on test method

GLP compliance:

not specified

Type of method:

other: not specified

Key result

Boiling pt.:

309 °C

Remarks on result:

other: no further details available

Conclusions:

boiling point = 309 °C (publication)

Executive summary:

The boiling point of the substance is reported as 309 °C (Reference: Aracil, Ignacio; Environmental Science & Technology 2010, V44(11), P4169-4175 CAPLUS). There is no available information on the methods used to determine the value for this endpoint.

Data source

Reference

Title:

EPI Suite Version 4.10

Year:

2012

Bibliographic source:

MPBPWIN - three separate methods for VP: Antoine method (1990), modified Grain method (1985) and Mackay method (1985)

Materials and methods

Test guideline

Guideline:

other: REACH guidance on QSARs Chapter R.6

Version / remarks:

May 2008

Principles of method if other than guideline:

Vapor Pressure is estimated by three methods; all three methods use the boiling point.  The first is the Antoine method (see Chapter 14 of W.J. Lyman's book "Handbook of Chemical Property Estimation Methods", Washington, DC: American Chemical Society, 1990).  The second is the modified Grain method (see page 31 of Neely and Blau's Environmental Exposure from Chemicals, Volume I, CRC Press, 1985).  The third is the Mackay method (see page 31-2 of Neely and Blau's Environmental Exposure from Chemicals, Volume I, CRC Press, 1985).

GLP compliance:

no

Type of method:

other: QSAR calculation

Test material

Test material information

Constituent 1

Reference substance name:

6,6'-diphenylfulvene

EC Number:

218-533-4

EC Name:

6,6'-diphenylfulvene

Cas Number:

2175-90-8

Molecular formula:

C18H14

IUPAC Name:

1,1'-(cyclopenta-2,4-dien-1-ylidenemethylene)dibenzene

Results and discussion

Vapour pressure

Vapour pressure 1

Key result

Temp.:

25 °C

Vapour pressure:

0.046 Pa

Remarks on result:

other: Modified Grain Method (MPBPWIN v1.43) - most relevant for solids

Vapour pressure 2

Temp.:

25 °C

Vapour pressure:

0.033 Pa

Remarks on result:

other: Antoine Method (MPBPWIN v1.43)

Vapour pressure 3

Temp.:

25 °C

Vapour pressure:

0.084 Pa

Remarks on result:

other: Mackay Method (MPBPWIN v1.43)

Any other information on results incl. tables

MPBPWIN predicted that the substance has a vapour pressure = 0.046 Pa (modified grain method)

Applicant's summary and conclusion

Conclusions:

The study report describes a scientifically accepted calculation method for the vapour pressure using the US-EPA software MPBPWIN v1.43.No GLP criteria are applicable for the usage of this tool and the QSAR estimation is easily repeatable. The result (0.046 Pa at 25°C) is adequate for the regulatory purpose.

Executive summary:

The vapour pressure of the substance was determined by the computer program MPBPWIN v1.43 (EPIWIN software) by US-EPA (2012). The program calculates the vapour pressure according to three different methods: Antoine, Modified Grain and Mackay. For solids, the value of the Modified Grain method is the most relevant.

An experimental melting point of 82 °C and boiling point of 309 °C from literature have been used for calculation of the vapour pressure at 25 °C.

The Antoine Method gives a result of 0.0333 Pa, the Mackay Method results in a vapour pressure of 0.0838 Pa and according to the Modified Grain Method the substance has a vapour pressure of 0.046 Pa (selected VP for solids).

The substance lies in the domain of the estimation model and the estimation errors are decreased by different factors (experimental melting & boiling pointfrom literature, magnitude of result). The result is adequate for the regulatory purpose and no further testing is required.