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Boiling point

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Reference
Endpoint:
boiling point
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
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 limited documentation / justification
Justification for type of information:
1. SOFTWARE:
The Estimation Programs Interface (EPI) SuiteTM

2. MODEL (incl. version number)
MPBPWIN v1.43 (September 2010)

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL:
Oc1c(C(=O)Nc2ccc(O)cc2)cccc1
CAS no. 526-18-1

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- Defined endpoint: Boiling point

- Unambiguous algorithm: MPBPWIN estimates the normal boiling point using an adaptation of the Stein and Brown (1994) method which is an extension and refinement of the Joback method (Joback, 1982; Reid et al, 1987).  The Stein and Brown (1994) method is a group contribution QSAR (quantitative structure activity relationship) method that calculates boiling point (Tb) of a compound by adding group increment values according to the relationship:
Tb  =  198.2  + Σ( ni * gi )
where  gi  is a group increment value and  ni  is the number of times the group occurs in the compound.  The resulting  Tb  (deg K) is then corrected by one of the following equations:
Tb (corr)  =  Tb  -  94.84  +  0.5577 Tb  -  0.0007705 (Tb)2   [Tb <= 700 K]
Tb (corr)  =  Tb  + 282.7  -  0.5209 Tb     [Tb > 700 K]
The Stein and Brown (1994) method was developed using a training dataset of boiling points for 4426 diverse organic compounds collected from the Aldrich Handbook (Aldrich, 1990).
MPBPWIN incorporates additional extensions to Stein and Brown Method such as (1) new group contributions missing from Brown and Stein (e.g. thiophosphorus [P=S], quaternary ammonium) and (2) correction factors for specific types of compounds (e.g. amino acids, various aromatic nitrogen rings, and phosphates).
Substructure searchable data set of melting point test is available at: http://esc.syrres.com/interkow/EpiSuiteData_ISIS_SDF.htm

- Appropriate measures of goodness-of-fit and robustness and predictivity: r^2 = 0.935; std deviation =22; avg deviation= 14.5
- Mechanistic interpretation: mean value

5. APPLICABILITY DOMAIN
- Descriptor 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.

6. ADEQUACY OF THE RESULT
The estimation is considered acceptable. The Stein and Brown method was derived from a training set of 4426 diverse organic compounds with following reported statistical accuracy (Stein and Brown, 1994):
 Average absolute error = 15.5 deg Kelvin
 Standard deviation = 24.6 deg Kelvin
 Average error = 3.2%

It was then validated on a dataset of 6584 compounds collected from HODOC (1990) (compounds not used in the training set) with the following statistical accuracy (Stein and Brown, 1994):
 Average absolute error = 20.4 deg Kelvin
 Standard deviation = 38.1 deg Kelvin
 Average error = 4.3%
Reason / purpose for cross-reference:
(Q)SAR model reporting (QMRF)
Guideline:
other: REACH Guidance on QSARs R.6
Principles of method if other than guideline:
Stein, S.E. and Brown, R.L.   1994.   Estimation of normal boiling points from group contributions. J. Chem. Inf. Comput. Sci. 34: 581-7.
Joback, K.G.   1982.   A Unified Approach to Physical Property Estimation Using Multivariate Statistical Techniques.  Stevens Institute of Technology, submitted to the Dept. of Chem. Eng. for M.S. Degree at the Massachusetts Institute of Technology in June 1984. (see  also: Reid et al., 1987).
Reid, R.C., Prausnitz, J.M. and Poling, B.E.  1987.   The Properties of Gases and Liquids. Fourth edition.  NY: McGraw-Hill, Inc., Chapter 2.
Specific details on test material used for the study:
SMILES: Oc1c(C(=O)Nc2ccc(O)cc2)cccc1
Boiling pt.:
448.16 °C
Remarks on result:
other: QSAR predicted value

MPBPVP predicted that 2-Hydroxy-N-(4-hydroxyphenyl)benzamide (also called osalmid) has a boiling point Bp= 448.16ºC

Description of key information

1. SOFTWARE:              

      The Estimation Programs Interface (EPI) SuiteTM

2. MODEL (incl. version number)

      MPBPWIN  v1.43 (September 2010)

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL:

      Oc1c(C(=O)Nc2ccc(O)cc2)cccc1

      CAS no. 526-18-1

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL

- Defined endpoint: Boiling point

- Unambiguous algorithm: MPBPWIN estimates the normal boiling point using an adaptation of the Stein and Brown (1994) method which is an extension and refinement of the Joback method (Joback, 1982; Reid et al, 1987).  The Stein and Brown (1994) method is a group contribution QSAR (quantitative structure activity relationship) method that calculates boiling point (Tb) of a compound by adding group increment values according to the relationship:

Tb  =  198.2  + Σ( ni * gi )

where  gi  is a group increment value and  ni  is the number of times the group occurs in the compound.  The resulting  Tb  (deg K) is then corrected by one of the following equations:

Tb (corr)  =  Tb  -  94.84  +  0.5577 Tb  -  0.0007705 (Tb)2   [Tb <= 700 K]

Tb (corr)  =  Tb  + 282.7  -  0.5209 Tb     [Tb > 700 K]

The Stein and Brown (1994) method was developed using a training dataset of boiling points for 4426 diverse organic compounds collected from the Aldrich Handbook (Aldrich, 1990).

MPBPWIN incorporates additional extensions to Stein and Brown Method such as (1) new group contributions missing from Brown and Stein (e.g. thiophosphorus [P=S], quaternary ammonium) and (2) correction factors for specific types of compounds (e.g. amino acids, various aromatic nitrogen rings, and phosphates).

Substructure searchable data set of melting point test is available at: http://esc.syrres.com/interkow/EpiSuiteData_ISIS_SDF.htm

- Appropriate measures of goodness-of-fit and robustness and predictivity:  r^2 = 0.935; std deviation =22; avg deviation= 14.5

- Mechanistic interpretation: mean value

5. APPLICABILITY DOMAIN

- Descriptor 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.       

6. ADEQUACY OF THE RESULT

The estimation is considered acceptable. The Stein and Brown method was derived from a training set of 4426 diverse organic compounds with following reported statistical accuracy (Stein and Brown, 1994):

 Average absolute error = 15.5 deg Kelvin

 Standard deviation = 24.6 deg Kelvin

 Average error = 3.2%

It was then validated on a dataset of 6584 compounds collected from HODOC (1990) (compounds not used in the training set) with the following statistical accuracy (Stein and Brown, 1994):

 Average absolute error = 20.4 deg Kelvin

Key value for chemical safety assessment

Boiling point at 101 325 Pa:
448.16 °C

Additional information

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