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Environmental fate & pathways

Henry's Law constant

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Endpoint:
Henry's law constant
Type of information:
calculation (if not (Q)SAR)
Remarks:
Migrated phrase: estimated by calculation
Adequacy of study:
disregarded due to major methodological deficiencies
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Scientifically acceptable method; the substance is not within the applicability domain of the estimation model.
Principles of method if other than guideline:
Calculation using SRC HENRYWIN v3.20: Bond estimation method
GLP compliance:
no
H:
0 Pa m³/mol
Temp.:
25 °C
Remarks on result:
other: 1.66E-11 Pa-m³/mol

Class

Bond contribution description

Comment

Value

Hydrogen

16 Hydrogen to Carbon (aliphatic) Bonds

 

-1.9148

Hydrogen

6 Hydrogen to Nitrogen Bonds

 

7.7011

Fragment

5 C-C

 

0.5815

Fragment

6 C-N

 

7.8060

Result

Bond estimation method for LWAPC value

total

14.174

Henrys Law Constant at 25 °C

1.64E-016 atm-m³/mol

6.70E-015 unitless

1.66E-011 Pa-m³/mol

Endpoint:
Henry's law constant
Type of information:
calculation (if not (Q)SAR)
Remarks:
Migrated phrase: estimated by calculation
Adequacy of study:
weight of evidence
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Scientifically acceptable method; but substance is not within the applicability domain of the estimation model.
Qualifier:
no guideline followed
Principles of method if other than guideline:
Calculation of Henry's Law Constant. Software used: SRC HENRYWIN v3.20: Bond estimation method
GLP compliance:
no
H:
0 Pa m³/mol
Temp.:
25 °C
Remarks on result:
other: 1.66E-11 Pa-m³/mol; The substance is not within the applicability domain of the model. (Maximum number of instances of bond in any of the training set compounds exceeded)

Class

Bond contribution description

Comment

Value

Hydrogen

16 Hydrogen to Carbon (aliphatic) Bonds

 

-1.9148

Hydrogen

6 Hydrogen to Nitrogen Bonds

 

7.7011

Fragment

5 C-C

 

0.5815

Fragment

6 C-N

 

7.8060

Result

Bond estimation method for LWAPC value

total

14.174

Henrys Law Constant at 25 °C

1.64E-016 atm-m³/mol

6.70E-015 unitless

1.66E-011 Pa-m³/mol

Executive summary:

QPRF: HENRYWIN v3.20: Bond contribution method

1.

Substance

See “Test material identity”

2.

General information

 

2.1

Date of QPRF

See “Data Source (Reference)”

2.2

QPRF author and contact details

See “Data Source (Reference)”

3.

Prediction

3.1

Endpoint
(OECD Principle 1)

Endpoint

Degree of volatilisation of substances from the aquatic environment

Dependent variable

Henry’s Law Constant

3.2

Algorithm
(OECD Principle 2)

Model or submodel name

HENRYWIN: Bond contribution method

Model version

v. 3.20

Reference to QMRF

Henry’s Law constant (HLC) using HENRYWIN v3.2: Estimation Accuracy (QMRF)

Predicted value (model result)

See “Results and discussion: Henry’s Law constant H”

Input for prediction

Chemical structure via CAS number or SMILES

Descriptor values

- Bond contribution values

- Correction factors

3.3

Applicability domain
(OECD principle 3)

Domains:

1) Molecular weight (range of test data set: 26.04 to 451.47 g/mol, mean: 144.64 g/mol) (On-Line HENRYWIN User’s Guide, Ch. 7.4 Estimation Domain and Appendix G)

Substance within range (174.29 g/mol)

2) Maximum number of instances of bond in any of the training set compounds (On-Line HENRYWIN User’s Guide, Appendix D)

Exceeded

3) Maximum number of instances of correction factor in any of the training set compounds (On-Line HENRYWIN User’s Guide, Appendix E)

Not exceeded

3.4

The uncertainty of the prediction
(OECD principle 4)

According to REACH Guidance Document R.7a, Appendix R.7.1-1 (Nov. 2012), measurement of HLC is not highly accurate, especially for very high or very low HLC values. The bond contribution method regarded by Altschuh et al. (1999) to produce the most reliable results with the exception of organochlorine pesticides. However, for some compounds, the method can yield a Henry's Law constant of 1.0x10-12atm*m3/mol or smaller. Numbers which are smaller than this value may be unrealistically low.

3.5

The chemical mechanisms according to the model underpinning the predicted result
(OECD principle 5)

The compound is split into a summation of individual bonds which comprise the compound. The summation of these bonds (= bond contribution values) is set equal to LWPAC. Correction factors were developed to correct for polar interactions and other deviations from the regression curve, which are applied to members of some chemical classes.

 

References:

Altschuh, J.R., Bruggemann, H. Santl, G. Eichinger, and O.G. Piringer.1999. Henry’s law constants for a diverse set of organic chemicals: experimental determination and comparison of estimation methods. Chemosphere 39: 1871-87.

On-Line HENRYWINUser's Guide:

-      Appendix D: Bond Method Contribution Values used by HENRYWIN.

-      Appendix E: Bond Method Correction Factors Used by HENRYWIN.

-      Appendix G. Chemicals Used to Derive Bond Contribution Values & Correction Factors.

Identified number of bonds and correction factors for the current substance:

HLC Appendix D, Table D-1: Bond Contribution Values Derived by Least-Square Regression Analysis

Bond

Coefficient
Value

No. Compounds
 in Training Set
containing
the Bond

Maximum No.
of instances of
each Bond
occurring in any
single compound

Comment

No. of instances
of each bond
found for the
current substance

C-H

-0.119677

284

27

Hydrogen bond

16

N-H

1.283513

16

4

Hydrogen bond

6

C-C

0.116304

200

9

5

C-N

1.300997

20

3

6

HLC Appendix D, Table D-2: Bond Contribution Values from a Subsequent Regression

Not applicable

HLC Appendix D, Table D-3: Additional Bond Contribution Values Used HENRYWIN

Not applicable

HLC Appendix E, Table E-1: Bond Correction Factors Derived from the Original Regression

Not applicable

HLC Appendix E, Table E-2: Bond Correction Factors Derived from the Second Regression

Not applicable

HLC Appendix E, Table E-3: Bond Correction Factors Derived Individually

Not applicable

Endpoint:
Henry's law constant
Type of information:
calculation (if not (Q)SAR)
Remarks:
Migrated phrase: estimated by calculation
Adequacy of study:
weight of evidence
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Scientifically acceptable method, but substance is not within the applicability domain of the estimation model.
Qualifier:
no guideline followed
Principles of method if other than guideline:
The Henry's Law constant is calculated using reliable and experimentally determined values for vapour pressure and water solubility.
GLP compliance:
no
H:
0.045 Pa m³/mol
Temp.:
25 °C
Remarks on result:
other: The substance is not within the model’s applicability domain.
Executive summary:

Applicability Domain for Estimation of Henry’s Law Constant using Vapour Pressure (VP) and Water Solubility (WS)

The applicability domain for this method is determined based on the substance’s water solubility.

-    The method is not suitable for the prediction of HLC due to high water solubility of the substance: >= 1 mol/L (EPI Suite, 2012) and > 30% (g/100 g; Lyman, 1985).

-    For miscible compounds the method is not valid (ECHA, 2012:Appendix R.7.1-1, p. 162).

 

References:

- ECHA, 2012. Guidance on information requirements and chemical safety assessment, Chapter R.7a: Endpoint specific guidance. 380 pp.

- EPI Suite, 2012. On-line Help for HENRYWIN v3.2

- Lyman, W.J.  1985.  Estimation of physical properties. In: Environmental Exposure from Chemicals. Volume I. Neely, W.B and Blau, G.E (editors). Boca Raton, FL: CRC Press, Inc., p.38-44.

Description of key information

From the water surface the substance will not evaporate into the atmosphere.

Key value for chemical safety assessment

Additional information

QSAR-disclaimer

 

In Article 13 of Regulation (EC) No 1907/2006, it is laid down that information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI (of the same Regulation) are met. Furthermore according to Article 25 of the same Regulation testing on vertebrate animals shall be undertaken only as a last resort.

 

According to Annex XI of Regulation (EC) No 1907/2006 (Q)SAR results can be used if (1) the scientific validity of the (Q)SAR model has been established, (2) the substance falls within the applicability domain of the (Q)SAR model, (3) the results are adequate for the purpose of classification and labeling and/or risk assessment and (4) adequate and reliable documentation of the applied method is provided.

 

For the assessment of N,N'-bis(3-aminopropyl)ethylenediamine (Q)SAR results were used for the estimation of the Henry’s Law constant. The criteria listed in Annex XI of Regulation (EC) No 1907/2006 are considered to be adequately fulfilled and therefore the endpoint(s) sufficiently covered and suitable for risk assessment.

 

Therefore, further experimental studies on the Henry’s Law Constant are not provided. Assessment of the Henry's Law constant:

A weight-of-evidence approach was used to assess the evaporation of the substance from the water surface to the atmosphere. The Henry's Law constant (HLC) was calculated based on measured data for water solubility (1000 g/L; GESTIS database, 2011) and vapour pressure (1.95 mmHg@ 25 °C; BASF SE, 2013). The HLC was 4.5E-02 Pa*m³/mol (BASF SE, 2013). As the substance has a high water solubility and is miscible with water, the method is not valid for the estimation of the Henry's Law constant. Nevertheless, the low evaporation potential is confirmed by other estimated data. The bond estimation method gives a value of 1.66 E-11 Pa*m³/mol (HENRYWIN Program, v3.20; EPI Suite v4.10; BASF SE, 2013), but the substance is not within the applicability domain of the estimation model as the maximum number of instances of two bonds in the training sets compounds was exceeded. As the method itself was valid for this compound, the latter value was used for the risk assessment.

Based on the presented data, the substance will not evaporate from the water surface into the atmosphere.