4-phenoxyphenol

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

(Q)SAR

Adequacy of study:

key study

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 adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE and MODEL
EPI Suite version 4.11
Kocwin v2.00 (september 2010)

2. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
SMILES : O(c(ccc(O)c1)c1)c(cccc2)c2
NAME : Phenol, 4-phenoxy-
CAS Number : 831-82-3

3. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
No formal QMRF assessment of the model is currently available, however, the user's guide describes all the information.
- Defined endpoint: Koc
- Methodology : KOCWIN estimates Koc with two separate estimation methodologies: (1) estimation using first-order Molecular Connectivity Index (MCI) and (2) estimation using log Kow (octanol-water partition coefficient)

(1) Molecular Connectivity Index (MCI).  This QSAR estimation methodology is described completely in Meylan, W., P.H. Howard and R.S. Boethling. 1992.  Molecular topology/fragment contribution method for predicting soil sorption coefficients. Environ. Sci. Technol. 26: 1560-1567. And the QSAR has been re-regressed using a larger database of experimental Koc values that includes many new chemicals and structure types.
(2) Log Kow : this traditional method of estimating soil adsorption Koc involves correlations developed with log octanol-water partition coefficient.

The MCI methodology is somewhat more accurate than the Log Kow methodology, although both methods yield good results.  If the Training datasets are combined in to one dataset of 516 compounds (69 having no corrections plus 447 with corrections), the MCI methodology has an r2, standard deviation and average deviation of 0.916, 0.330 and 0.263, respectively, versus 0.86, 0.429 and 0.321 for the Log Kow methodology.

4. APPLICABILITY DOMAIN
No formal QMRF assessment of the model is currently available, however, the user's guide describes all the information.
- Descriptor domain: organic chemical
- Structural and mechanistic domains:
Training Set Molecular Weights: Training Set Molecular Weights: Minimum MW: 73.14 Maximum MW: 504.12 Average MW: 277.8
Appendix D of the KOCWIN Help gives the maximum number of fragments that occur in any individual compound of the training set.

Similarity with analogues in the training set: the MCI methodology uses 516 compounds in the training sets

5. REFERENCES
Meylan, W., P.H. Howard and R.S. Boethling.  1992.  Molecular topology/fragment contribution method for predicting soil sorption coefficients. Environ. Sci. Technol. 26: 1560-1567.

Guideline:

other: REACH guidance on QSARs R.6 Principles

Principles of method if other than guideline:

- Software tool(s) used including version: OPERA-model for Organic carbon-sorption coefficient
- Model(s) used: v1.5 (2016)
- Model description: see field 'Justification for type of information"
- Justification of QSAR prediction: see field 'Attached justification'

GLP compliance:

no

Specific details on test material used for the study:

SMILES : O(c(ccc(O)c1)c1)c(cccc2)c2

Type:

Koc

Value:

ca. 2 463 L/kg

Remarks on result:

other: QSAR predicted value (MCI method)

Type:

Koc

Value:

ca. 1 002 L/kg

Remarks on result:

other: QSAR predicted (LogKoW)

KOCWIN predicted that 4 -Phenoxyphenol has a Koc of 2463 L/kg (MC method) or 1002 L/kg (LogKow Method).

Validity criteria fulfilled:

yes

Conclusions:

KOCWIN predicted that 4 -Phenoxyphenol has a Koc of 2463 L/kg (MC method) or 1002 L/kg (LogKow Method).

Executive summary:

KOCWIN predicted that 4 -Phenoxyphenol has a Koc of 2463 L/kg (MC method) or 1002 L/kg (LogKow Method).

Description of key information

QSAR predicted that 4 -PhenoxyPhenol has a Koc :

• 2 463 L/kg with KOCWIN (MCI Method)
• 1 002 L/kg with KOCWIN (LogKow Method)

The MCI methodology is somewhat more accurate than the Log Kow methodology, although both methods yield good results. In this case, the mean of the both values are used : 1 733 L/kg (it is also the solution taken over by OPERA QSAR using both methods and the result is of the same order of magnitude - 1 780 L/kg).

The final predicted Koc is 1 733 L/kg.

Key value for chemical safety assessment

Koc at 20 °C:

1 733