α-chloro-o-xylene

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption

Remarks:

adsorption

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2017-02-20

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Accepted calculation method, substance within applicability domain (or: Accepted calculation method, but substance not within applicability domain of model)

Justification for type of information:

QSAR prediction

Principles of method if other than guideline:

KOCWIN (v2.00): estimation using estimated or experimental derived log Kow

GLP compliance:

no

Type of method:

other: QSAR estimation: KOCWIN v2.00: Koc estimate from log Kow

Test temperature:

25 °C

Computational methods:

- Other: log Kow used for estimation: 3.34 (estimated by KOCWIN)

Type:

Koc

Value:

791.4 L/kg

Temp.:

25 °C

Remarks on result:

other: The substance is within the applicability domain of the model.

Type:

log Koc

Value:

2.898 dimensionless

Temp.:

25 °C

Remarks on result:

other: The substance is within the applicability domain of the model.

Table: Koc Estimate from Log Kow

Log Kow (Kowwin estimate)	3.34
Non-Corrected Log Koc (0.8679 logKow - 0.0004)	2.8984
Fragment Correction(s)	none
Corrected Log Koc	2.8984
Estimated Koc	791.4 L/kg

Validity criteria fulfilled:

yes

Executive summary:

QPRF: KOCWIN v2.00

 

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	Adsorption to solid phase of soils etc.
		Dependent variable	Organic carbon normalised adsorption coefficient (Koc)
3.2	Algorithm (OECD Principle 2)	Model or submodel name	KOCWIN
		Model version	v. 2.00
		Reference to QMRF	QMRF: Estimation of Soil Adsorption Coefficient using KOCWIN v2.00 (EPI Suite v4.11): Estimation using log Kow
		Predicted value (model result)	See “Results and discussion”
		Input for prediction	- Chemical structure via CAS number or SMILES - log Kow (for log Kow method; optional)
		Descriptor values	- Chemical structure - Correction factors
3.3	Applicability domain (OECD principle 3)	Domains:
		1) Molecular weight (range of test data set: 32.04 to 665.02 g/mol; On-Line KOCWIN User’s Guide, Ch. 6.2.4 Domain)	Substance within range (140.61 g/mol)
		2) log Kow (range of test data set: -2.11 to 8.12; On-Line KOCWIN User’s Guide, Appendices E & F)	Substance within range (3.34)
		3) Correction factors: Number of instances of the identified correction factor does not exceed the maximum number as listed in Appendix D (On-Line KOCWIN User’s Guide)	Fulfilled.
3.4	The uncertainty of the prediction (OECD principle 4)	Nonpolar compounds: n = 68; r^2=0.478, average dev. = 0.371 Polar compounds: n = 447, r²=0.855, std. dev. = 0.396, average dev. = 0.307
3.5	The chemical mechanisms according to the model underpinning the predicted result (OECD principle 5)	Adsorption is caused by temporary (reversible) or permanent bonding between the substance and a surface (e.g. due to van der Waals interactions, hydrogen bonding to hydroxyl groups, ionic interactions, covalent bonding, etc.). The organic carbon normalized adsorption coefficient (Koc) is the ratio of a substance concentration sorbed in the organic matter component of soil or sediment to that in the aqueous phase at equilibrium. Estimation using log Kow: The model is based on the high correlation of log Kow and the adsorption potential.

 

References

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

- 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.

 

 

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

 

Model:	KOCWIN v2.00	MCI & Log Kow method
Substance:	Benzene, 1-(chloromethyl)-2-methyl-
CAS-#:	000552-45-4
SMILES:	c(c(ccc1)C)(c1)CCL
Molecular weight (g/mol):	140.61
Log Kow (experimental data):	3.34	Reference:
	Molecular weight (g/mol)				log Kow
	Minimum	Maximum	Average		Minimum	Maximum
Training set	32.04	665.02	224.4		-2.11	8.12
Validation set	73.14	504.12	277.8		-5.98	8.68
Assessment of molecular weight	Molecular weight within range of training and validation set.
Assessment of log Kow (only relevant for log Kow method)	Log Kow within range of training and validation set.
Appendix D. MCI & Log Kow Correction Factors for 447 Compound Training Set
Correction Factor Descriptor	Coefficient for Molecular Connectivity Index (MCI) Regression Methodology		Coefficient for log Kow Regression Methodology	Occurrence		No. of instances of each bond found for the current substance
	(new model)	Remark		(number of compounds	(max per structure)
						not applicable.

Reference 2

Endpoint:

adsorption / desorption

Remarks:

adsorption

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2017-02-20

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Accepted calculation method, substance within applicability domain (or: Accepted calculation method, but substance not within applicability domain of model)

Justification for type of information:

QSAR prediction

Principles of method if other than guideline:

KOCWIN (v2.00): estimation using first-order Molecular Connectivity Index (MCI)

GLP compliance:

no

Type of method:

other: QSAR estimation: KOCWIN v2.00: Koc estimate from MCI

Test temperature:

25 °C

Key result

Type:

Koc

Value:

730.4 L/kg

Temp.:

25 °C

Remarks on result:

other: The substance is within the applicability domain of the model.

Key result

Type:

log Koc

Value:

2.864 dimensionless

Temp.:

25 °C

Remarks on result:

other: The substance is within the applicability domain of the model.

Table: Koc Estimate from MCI

First Order Molecular Connectivity Index	4.343
Non-Corrected Log Koc (0.5213 MCI + 0.60)	2.8636
Fragment Correction(s)	none
Corrected Log Koc	2.8636
Estimated Koc	730.4 L/kg

Executive summary:

QPRF: KOCWIN v2.00 (18 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	Adsorption to solid phase of soils etc.
		Dependent variable	Organic carbon normalised adsorption coefficient (Koc)
3.2	Algorithm (OECD Principle 2)	Model or submodel name	KOCWIN
		Model version	v. 2.00
		Reference to QMRF	QMRF: Estimation of Soil Adsorption Coefficient using KOCWIN v2.00 (EPI Suite v4.11): MCI methodology
		Predicted value (model result)	See “Results and discussion”
		Input for prediction	- Chemical structure via CAS number or SMILES
		Descriptor values	- MCI (first order molecular connectivity index) - Correction factors
3.3	Applicability domain (OECD principle 3)	Domains:
		1) Molecular weight (range of test data set: 32.04 to 665.02 g/mol; On-Line KOCWIN User’s Guide, Ch. 6.2.4 Domain)	Substance within range (140.61 g/mol)
		2) Correction factors: Number of instances of the identified correction factor does not exceed the maximum number as listed in Appendix D (On-Line KOCWIN User’s Guide)	Fulfilled.
3.4	The uncertainty of the prediction (OECD principle 4)	Statistical accuracy for training dataset: n = 516, r² = 0.916, std. dev. = 0.330, average dev. = 0.263
3.5	The chemical mechanisms according to the model underpinning the predicted result (OECD principle 5)	Adsorption is caused by temporary (reversible) or permanent bonding between the substance and a surface (e.g. due to van der Waals interactions, hydrogen bonding to hydroxyl groups, ionic interactions, covalent bonding, etc.). The organic carbon normalized adsorption coefficient (Koc) is the ratio of a substance concentration sorbed in the organic matter component of soil or sediment to that in the aqueous phase at equilibrium. MCI methodology: The first-order molecular connectivity index is a measure to describe a variety of properties of chemicals. According to Sabljic (1984; cited in Meylan et al., 1992), the soil sorption potential is highly correlated with the first order MCI. Therefore, it has been used to derive the adsorption coefficient.

 

References

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

- 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.

 

 

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

 

Model:	KOCWIN v2.00	MCI & Log Kow method
Substance:	Benzene, 1-(chloromethyl)-2-methyl-
CAS-#:	000552-45-4
SMILES:	c(c(ccc1)C)(c1)CCL
Molecular weight (g/mol):	140.61
Log Kow (experimental data):	3.34	Reference:
	Molecular weight (g/mol)				log Kow
	Minimum	Maximum	Average		Minimum	Maximum
Training set	32.04	665.02	224.4		-2.11	8.12
Validation set	73.14	504.12	277.8		-5.98	8.68
Assessment of molecular weight	Molecular weight within range of training and validation set.
Assessment of log Kow (only relevant for log Kow method)	Log Kow within range of training and validation set.
Appendix D. MCI & Log Kow Correction Factors for 447 Compound Training Set
Correction Factor Descriptor	Coefficient for Molecular Connectivity Index (MCI) Regression Methodology		Coefficient for log Kow Regression Methodology	Occurrence		No. of instances of each bond found for the current substance
	(new model)	Remark		(number of compounds	(max per structure)
						not applicable.

 

Description of key information

The Koc of the test item is 730.4 L/kg at 20 °C. The Log Koc of the test item is 2.8636 at 20 °C.

Key value for chemical safety assessment

Koc at 20 °C:

730.4

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 2 -Methylbenzylchloride (Q)SAR results were used for Adsorption / Desorption.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 Adsorption / Desorption are not provided.

Discussion

The Koc and the Log Koc respectively were predicted with KOCWIN v.2.00 (EPI Suite v.4.11). The Koc estimated from MCI was 730.4 L/kg, the corrected Log Koc was 2.8636. These values are supported by a prediction derived from Log Kow: The Koc was 791.4 L/kg and the corrected Log Koc was 2.8984.

[LogKoc: 2.8636]