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Environmental fate & pathways

Henry's Law constant

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Reference
Endpoint:
Henry's law constant
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
key study
Study period:
2014
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Principles of method if other than guideline:
Estimation Program Interface EPI-Suite version 4.11: HENRYWIN (v3.20). The bond contribution method is used to calculate the volatility of the substance from the aqueous phase.
The Estimation Program Interface was developed by the US Environmental Agency's Office of Pollution Prevention and Toxics, and Syracuse Research Corporation (SRC). © 2000 - 2012 U.S. Environmental Protection Agency for EPI SuiteTM (Published online in November 2012).
GLP compliance:
no
H:
0 Pa m³/mol
Temp.:
25 °C
H:
< 0 atm m³/mol
Temp.:
25 °C
H:
< 0 dimensionless
Temp.:
25 °C

Validity of the model:

1. Defined Endpoint: Henry's Law Constant

2. Unambinguous algorithm: For 6.6`-Di-tert.-butyl-2.2`-methylenedi-p-cresol the following descriptors were applied:

bond estimation method

 class  bond contribution description  value
Hydrogen 26 Hydrogen to carbon (aliphatic) Bonds  -3.1116
Hydrogen  4 Hydrogen to carbon (aromatic) Bonds  -0.6172
Hydrogen  2 Hydrogen to oxygen Bonds  6.4635
Fragment  6 C-C  0.6978
Fragment  2 C-Car  0.9716
Fragment  12 Car-Car  3.1657
Fragment  2 Car-OH  1.1934

3. Applicability domain:

With a molecular weight of 340.51 g/mole the substance is within the range of the training set (26.04 - 451.47 g/mole). Regarding the structure, the fragment descriptors used by the program for the estimation are complete.

4a. Statistical characteristics (bond method):

number in dataset: 442

correlation coeff. (r²): 0.977

standard deviation: 0.4

average deviation: 0.249 [all statistical data related to the LWAPC value]

4b. Statistical characteristics (group method):

number in dataset: 318

correlation coeff. (r²): 0.956

standard deviation: 0.397

average deviation: 0.223 [all statistical data related to the LWAPC value]

5. Mechanistic interpretation:

The Henry's law constant is an important factor in determining the environmental fate of chemicals. Indeed, this constant is a fundamental input for fugacity models that estimate the multimedia partitioning of chemicals.

This model is based on the calculation of respective descriptor values, with the help of experimentally derived HLC's for defined groups that comprise a compound. For modelling each compound is then split into its subgroups and the respective values are summed up to yield the HLC.

Adequacy of prediction:

The result for 6.6`-Di-tert.-butyl-2.2`-methylenedi-p-cresol falls within the applicability domain described above and the estimation rules applied for the substance appears appropriate. Therefore the predicted value can be considered reliable yielding a useful result for further assessment.

Conclusions:
The QSAR determination of the Henry's Law Constant for 6.6`-Di-tert.-butyl-2.2`-methylenedi-p-cresol using the model HENRYWIN included in the Estimation Program Interface (EPI) Suite v4.11 revealed a value of 4.28E-006 Pa*m³/mol at 25 °C for the unaffected molecule of the substance as any decomposition (e.g. hydrolysis) of the substance is not taken into account by the program.
Executive summary:

The QSAR determination of the Henry's Law Constant for 6.6`-Di-tert.-butyl-2.2`-methylenedi-p-cresol using the model HENRYWIN included in the Estimation Program Interface (EPI) Suite v4.11 revealed a value of 4.28E-006 Pa*m³/mol at 25 °C for the unaffected molecule of the substance as any decomposition (e.g. hydrolysis) of the substance is not taken into account by the program.

Description of key information

The QSAR determination of the Henry's Law Constant for 6.6`-Di-tert.-butyl-2.2`-methylenedi-p-cresol using the model HENRYWIN included in the Estimation Program Interface (EPI) Suite v4.11 revealed a value of 4.28E-006 Pa*m³/mol at 25 °C for the unaffected molecule of the substance as any decomposition (e.g. hydrolysis) of the substance is not taken into account by the program.

Key value for chemical safety assessment

Henry's law constant (H) (in Pa m³/mol):
0
at the temperature of:
25 °C

Additional information