Dibutyl hydrogen phosphate

Henry's Law constant

Link to relevant study record(s)

Reference

Endpoint:

Henry's law constant

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2013

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:

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).

Guideline:

other: REACH guidance on QSARs R.6, May 2008

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

Specific details on test material used for the study:

SMILES: O=P(OCCCC)(OCCCC)O
Molecular weight: 210.21g/mole
(value relate to the pure substance)

Key result

H:

0 Pa m³/mol

Temp.:

25 °C

Remarks on result:

other: Bond estimation method

Validity of the model:

1. Defined Endpoint: Henry's Law Constant

2. Unambinguous algorithm: For dibutyl hydrogen phosphate the following descriptors were applied:

bond estimation method

class	bond contribution description	value
Hydrogen	18 Hydrogen to Carbon (aliphatic) Bonds	-2.1542
Hydrogen	1 Hydrogen to Oxygen Bonds	3.2318
Fragment	6 C-C	0.6978
Fragment	2 C-O	2.1709
Fragment	3 O-P	1.1791
Fragment	1 O=P	1.6334

3. Applicability domain: With a molecular weight of 210.21 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 dibutyl hydrogen phosphate 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 dibutyl hydrogen phosphate using the model HENRYWIN included in the Estimation Program Interface (EPI) Suite v4.11 revealed a value of 0.000432 Pa*m³/mol at 25°C.

Executive summary:

The Henry's Law Constant (HLC) of dibutyl hydrogen phosphate was predicted using the QSAR calculation of the Estimation Program Interface (EPI) Suite v4.11. The HLC was estimated to be 0.000432 Pa*m³/mol at 25°C. This value indicates that dibutyl hydrogen phosphate is essentially non-volatile from water, and a long-range transport via the atmosphere is not expected.

The result relates to the unaffected molecule of dibutyl hydrogen phosphate as any decomposition (e.g. hydrolysis) of a substance is not taken into account by the program.

Description of key information

The QSAR determination of the Henry's Law Constant for dibutyl hydrogen phosphate using the model HENRYWIN included in the Estimation Program Interface (EPI) Suite v4.11 revealed a value of 0.000432 Pa*m³/mol at 25°C.

Key value for chemical safety assessment

Henry's law constant (H) (in Pa m³/mol):

0

at the temperature of:

25 °C

Additional information

The Henry's Law Constant (HLC) of dibutyl hydrogen phosphate was predicted using the QSAR calculation of the Estimation Program Interface (EPI) Suite v 4.11. The HLC was estimated to be 0.000432 Pa*m³/mol at 25°C. This value indicates that dibutyl hydrogen phosphate is essentially non-volatile from water, and a long-range transport via the atmosphere is not expected.

The result relates to the unaffected molecule of dibutyl hydrogen phosphate as any decomposition (e.g. hydrolysis) of a substance is not taken into account by the program.