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Administrative data

Endpoint:
Henry's law constant
Type of information:
calculation (if not (Q)SAR)
Remarks:
Migrated phrase: estimated by calculation
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Accepted calculation method, substance within applicability domain

Data source

Referenceopen allclose all

Reference Type:
other: EPIWin calculation
Title:
Unnamed
Year:
2014
Report date:
2014
Reference Type:
other: Estimation software
Title:
Estimation Programs Interface Suite for Microsoft Windows, v4.11
Author:
US EPA
Year:
2012
Bibliographic source:
United States Environmental Protection Agency, Washington, DC, USA

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Calculation using HENRYWIN (v3.20) Bond Method
GLP compliance:
no

Test material

Constituent 1
Reference substance name:
162691-58-9
EC Number:
605-300-0
Cas Number:
162691-58-9
IUPAC Name:
162691-58-9
Constituent 2
Reference substance name:
CC2OC1CC(C)(C)C(=O)C(C)=C1O2
IUPAC Name:
CC2OC1CC(C)(C)C(=O)C(C)=C1O2
Details on test material:
- Name of test material: 1,3-Benzodioxol-5(6H)-one, 7,7a-dihydro-2,4,6,6-tetramethyl-

Results and discussion

Henry's Law constant H
H:
0.016 Pa m³/mol
Temp.:
25 °C

Any other information on results incl. tables

Result table for Bond Contribution Method from HENRYWIN v3.20

Class

Bond Contribution Description

Comment

Value

Hydrogen

16hydrogentocarbon(aliphatic)bonds

 

-1.9148

Fragment

5 C-C

 

0.5815

Fragment

2 C-Cd

 

0.1269

Fragment

1 C-CO

 

1.7057

Fragment

3 C-O

 

3.2564

Fragment

1 Cd-CO

 

1.9260

Fragment

1 Cd-O

 

0.2051

Fragment

1 Cd=Cd

 

0.0000

Factor

*adjacent aliphatic ether function(s)

 

-0.7000

Result

Bond estimation method for LWAPC value

Total

5.187

Henrys law constant at 25°C

1.59E-07 atm·m³/mole

6.50E-06 unitless

1.61E-02 Pa·m³/mole

Applicant's summary and conclusion

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 (196.25 g/mol)

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

Not 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.

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

Coeff.
Value

No.Compounds
inTrainingSet
containing
theBond

MaximumNo.
ofinstancesof
eachBond
occurringinany
singlecompound

Comment

No.ofinstances
ofeachbond
foundforthe
currentsubstance

C-H

-0.119677

284

27

Hydrogen bond

16

C-C

0.116304

200

9

 

5

C-Cd

0.063454

27

3

 

2

C-CO

1.70572

41

2

 

1

C-O

1.085473

83

4

 

3

Cd-CO

1.926035

9

1

 

1

Cd-O

0.20511

2

1

 

1

Cd=Cd

0

47

2

zero by definition

1

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

Bond Correction Factor

Coeff.
Value

No. Compounds
in Training Set
containing
the Factor

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

Comments

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

Adjacent aliphatic ether functions

(-C-O-C-O-C-)

-0.70

3

1

 

1

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