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Physical & Chemical properties

Partition coefficient

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Administrative data

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Scientifically accepted calculation method
Justification for type of information:
QSAR prediction: migrated from IUCLID 5.6

Data source

Referenceopen allclose all

Reference Type:
other: EPIWIN calculation
Title:
Unnamed
Year:
2013
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; November 2012

Materials and methods

Principles of method if other than guideline:
Estimation of log Kow using KOWWIN v1.68
GLP compliance:
no
Type of method:
other: estimation method
Partition coefficient type:
octanol-water

Test material

Constituent 1
Chemical structure
Reference substance name:
L-2-hydroxy-2-phenylacetic acid
EC Number:
210-276-6
EC Name:
L-2-hydroxy-2-phenylacetic acid
Cas Number:
611-71-2
Molecular formula:
C8H8O3
IUPAC Name:
hydroxy(phenyl)acetic acid
Constituent 2
Reference substance name:
O=C(O)C(O)c(cccc1)c1
IUPAC Name:
O=C(O)C(O)c(cccc1)c1
Details on test material:
Name of test material (as cited in study report): BENZENEACETIC ACID, .alpha.-HYDROXY-, (R)-

Results and discussion

Partition coefficient
Type:
log Pow
Partition coefficient:
0.568
Temp.:
25 °C
Remarks on result:
other: The substance is within the applicability domain of the model.

Any other information on results incl. tables

TYPE | NUM | LOGKOW FRAGMENT DESCRIPTION | COEFF | VALUE

--------+-------+------------------------------------------------+------- ---+--------

Frag | 1 | -CH [aliphatic carbon] | 0.3614 | 0.3614

Frag | 1 | -OH [hydroxy, aliphatic attach] |-1.4086 | -1.4086

Frag | 6 | -COOH [acid, aliphatic attach] |-0.6895 | -0.6895

Factor| 1 | HO-C-COOH (alcohol-acid carbon) | 0.3114 | 0.3114

Const | | Equation Constant | | 0.2290

-------+-----+--------------------------------------------+---------+--------

Log Kow = 0.5677

Applicant's summary and conclusion

Executive summary:

QPRF: KOWWIN v1.68 (01 Nov. 2013)

 

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

Octanol-water partition coefficient (log Kow)

Dependent variable

Octanol-water partition coefficient (log Kow)

3.2

Algorithm
(OECD Principle 2)

Model or submodel name

KOWWIN

Model version

v. 1.68

Reference to QMRF

QMRF: Estimation of Octanol-Water Partition Coefficient using KOWWIN v1.68 (EPI Suite v4.11)

Predicted value (model result)

See “Results and discussion”

Input for prediction

Chemical structure via CAS number or SMILES

Descriptor values

- Chemical structure

- Fragments

- Correction factors

3.3

Applicability domain
(OECD principle 3)

Domains:

1) Molecular weight
(range of test data set: 18.02 to 719.92 g/mol; On-Line KOWWIN User’s Guide, Ch. 6.2.3 Estimation Domain)

Substance (not) within range (152.15 g/mol)

2) Fragments: Number of instances of the identified fragments does not exceed the maximum number as listed in Appendix D (On-Line KOWWIN User’s Guide)

fulfilled.

3) Fragments: Substance has a functional group(s) or other structural features not represented in the training set, and for which no fragment coefficient was developed (Appendix D, On-Line KOWWIN User’s Guide)

applicable.

4) Correction factors: Number of instances of the identified correction factor does not exceed the maximum number as listed in Appendix D (On-Line KOWWIN User’s Guide)

fulfilled.

 

3.4

The uncertainty of the prediction
(OECD principle 4)

According to REACH Guidance Document R.7a, (Nov. 2012), solubility in water is difficult to model accurately. For this reason, as well as the fact that the experimental error on solubility measurements can be quite high (generally reckoned to be about 0.5 log unit), the prediction of aqueous solubility is not as accurate as is the prediction of octanol/water partitioning.

3.5

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

The water solubility of a substance depends on its affinity for water as well as its affinity for its own crystal structure. In general, substances with high melting points have poor solubility in any solvent.

 

References

- US EPA (2012). On-Line KOWWIN User’s Guide.

 

 

Assessment of estimation domain (molecular weight, fragments, correction factors):

 

Copy from 611 -71 -2_Epiwin.pdf