Pyridinium dichromate

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2010

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:

Please refer to the QMRF and QPRF files provided under the section attached justification.

Qualifier:

according to guideline

Guideline:

other: ECHA Guidance on information requirements and chemical safety assessment Chapter R.6: QSARs and grouping of chemicals

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

other: Guidance on information requirements and chemical safety assessment, Chapter R.7a: Endpoint specific guidance, May 2008, ECHA.

Principles of method if other than guideline:

The vapour pressure of the test item was estimated by an atom/fragment contribution method using the software MPBPWIN Version v1.43, provided by the U.S. Environmental Protection Agency.
This program (MPBPWIN) estimates the boiling point (at 760 mm Hg), melting point and vapour pressure of substances. Structures are entered into MPBPWIN by SMILES (Simplified Molecular Input Line Entry System) notations.
The estimation method for the boiling point has been adapted from the Stein and Brown method ("Estimation of Normal Boiling Points from Group Contributions", J. Chem. Inf. Comput. Sci. 34: 581-87, 1994).
Melting point is estimated by two different methods; the first is the Joback Group contribution method, and the second is a Gold and Ogle method which simply uses the following formula: Tm = 0.5839 Tb, where Tm is the melting point in Kelvin and Tb is the boiling point in Kelvin. The Joback adaptation in MPBPWIN is an extension of the original method to include the same groups as in the adapted Stein and Brown boiling point method described above.
The vapour pressure is estimated in MPBPWIN 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). For solids, a melting point is required to adjust the vapour pressure from a super-cooled liquid to a solid. The Mackay method is not as applicable to as many chemical classes as the other methods, so it is generally not preferred.

GLP compliance:

no

Type of method:

other: calculation

Specific details on test material used for the study:

SMILES: O=[Cr](On1ccccc1)(O[Cr](=O)(On2ccccc2)=O)=O

Key result

Temp.:

25 °C

Vapour pressure:

0 Pa

Remarks on result:

other: QSAR Estimated value (Modified Grain method). The substance is within the applicability domain of the model.

Experimental Database Structure Match: no data

SMILES : O=[Cr](On1ccccc1)(O[Cr](=O)(On2ccccc2)=O)=O

CHEM  :

MOL FOR: C10 H10 N2 O7 Cr2

MOL WT : 374.19

------------------------ SUMMARY MPBPWIN v1.43 --------------------

 

Boiling Point: 440.12 deg C (Adapted Stein and Brown Method)

Melting Point: 349.84 deg C (Adapted Joback Method)

Melting Point: 143.32 deg C (Gold and Ogle Method)

Mean Melt Pt: 246.58 deg C (Joback; Gold,Ogle Methods)

Selected MP: 184.63 deg C (Weighted Value)

 

Vapour Pressure Estimations (25 deg C):

 (Using BP: 440.12 deg C (estimated))

 (Using MP: 153.00 deg C (user entered))

   VP: 3.79E-009 mm Hg (Antoine Method)

     : 5.06E-007 Pa (Antoine Method)

   VP: 4.27E-008 mm Hg (Modified Grain Method)

     : 5.7E-006 Pa (Modified Grain Method)

   VP: 9.79E-008 mm Hg (Mackay Method)

     : 1.3E-005 Pa (Mackay Method)

 Selected VP: 4.27E-008 mm Hg (Modified Grain Method)

            : 5.7E-006 Pa (Modified Grain Method)

 Subcooled liquid VP: 8.64E-007 mm Hg (25 deg C, Mod-Grain method)

                    : 0.000115 Pa (25 deg C, Mod-Grain method)  

Conclusions:

Using MPBPWIN v1.43 the vapour pressure of the test item was calculated to be 0.0000057 Pa at 25 °C. The substance is within the applicability domain of the model.

Executive summary:

The vapour pressure was calculated using MPBPWIN v1.43 as part of EPISuite v4.11 from US Environmental Protection Agency.

Using using MPBPWIN v1.43 the vapour pressure of the test item was calculated to be 0.0000057 Pa at 25 °C (EPI Suite, 2014).

 

The adequacy of a prediction depends on the following conditions:

a) the (Q)SAR model is scientifically valid: the scientific validity is established according to the OECD principles for (Q)SAR validation;

b) the (Q)SAR model is applicable to the query chemical: a (Q)SAR is applicable if the query chemical falls within the defined applicability domain of the model;

c) the (Q)SAR result is reliable: a valid (Q)SAR that is applied to a chemical falling within its applicability domain provides a reliable result;

d) the (Q)SAR model is relevant for the regulatory purpose.

 

For assessment and justification of these 4 requirements the QMRF and QPRF files were developed and attached to this study record.

 

Description of the prediction Model

The prediction model was descripted using the harmonised template for summarising and reporting key information on (Q)SAR models. For more details please refer to the attached QSAR Model Reporting Format (QMRF) file. 

 

Assessment of estimation domain

The assessment of the estimation domain was documented in the QSAR Prediction Reporting Format file (QPRF). Please refer to the attached document for the details of the prediction and the assessment of the estimation domain.

Description of key information

Using MPBPWIN v1.43 the vapour pressure of the test item was calculated to be 0.0000057 Pa at 25 °C. The substance is within the applicability domain of the model (reference 4.6-1).

Key value for chemical safety assessment

Vapour pressure:

0 Pa

at the temperature of:

25 °C

Additional information

The vapour pressure was calculated using MPBPWIN v1.43 as part of EPISuite v4.11 from US Environmental Protection Agency.

Using using MPBPWIN v1.43 the vapour pressure of the test item was calculated to be 0.0000057 Pa at 25 °C (EPI Suite, 2014).

 

The adequacy of a prediction depends on the following conditions:

a) the (Q)SAR model is scientifically valid: the scientific validity is established according to the OECD principles for (Q)SAR validation;

b) the (Q)SAR model is applicable to the query chemical: a (Q)SAR is applicable if the query chemical falls within the defined applicability domain of the model;

c) the (Q)SAR result is reliable: a valid (Q)SAR that is applied to a chemical falling within its applicability domain provides a reliable result;

d) the (Q)SAR model is relevant for the regulatory purpose.

 

For assessment and justification of these 4 requirements the QMRF and QPRF files were developed and attached to this study record.

 

Description of the prediction Model

The prediction model was descripted using the harmonised template for summarising and reporting key information on (Q)SAR models. For more details please refer to the attached QSAR Model Reporting Format (QMRF) file. 

 

Assessment of estimation domain

The assessment of the estimation domain was documented in the QSAR Prediction Reporting Format file (QPRF). Please refer to the attached document for the details of the prediction and the assessment of the estimation domain.