(4-tert-butyl-2,6-dimethylphenyl)acetonitrile

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption

Remarks:

adsorption

Type of information:

(Q)SAR

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Accepted calculation method, substance within applicability domain

Justification for type of information:

QSAR prediction: migrated from IUCLID 5.6

Data source

Reference

Reference 1

Reference Type:

other: EPIWin calculation

Title:

Unnamed

Year:

2014

Report date:

2014

Reference 2

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

Principles of method if other than guideline:

Calculation using KOCWIN (v2.00) Molecular Connectivity Index (MCI)

GLP compliance:

no

Type of method:

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

Test material

Test material information

Constituent 1

Reference substance name:

(4-tert-butyl-2,6-dimethylphenyl)acetonitrile

EC Number:

284-183-4

EC Name:

(4-tert-butyl-2,6-dimethylphenyl)acetonitrile

Cas Number:

84803-57-6

Molecular formula:

C14H19N

IUPAC Name:

2-(4-tert-butyl-2,6-dimethylphenyl)acetonitrile

Constituent 2

Reference substance name:

Cc1cc(C(C)(C)C)cc(C)c1CC(#N)

IUPAC Name:

Cc1cc(C(C)(C)C)cc(C)c1CC(#N)

Details on test material:

- Name of test material: Benzeneacetonitrile, 4-(1,1-dimethylethyl)-2,6-dimethyl-

Study design

Test temperature:

25 °C

Results and discussion

Adsorption coefficient

Adsorption coefficient 1

Type:

Koc

Value:

3 216

Temp.:

25 °C

Remarks on result:

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

Adsorption coefficient 2

Type:

log Koc

Value:

3.51

Temp.:

25 °C

Remarks on result:

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

Any other information on results incl. tables

Koc Estimate from MCI:

First Order Molecular Connectivity Index	6.858
Non-Corrected Log Koc (0.5213 MCI + 0.60)	4.1751
Fragment Correction(s)
1 Nitrile/Cyanide (-C#N)	-0.6677
Corrected Log Koc	3.5074
Estimated Koc	3216 L/kg

Applicant's summary and conclusion

Executive summary:

QPRF: KOCWIN v2.00 (MCI methodology) (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 (201.31 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):

Training set: Molecular weights	Training set	Validation set
Minimum	32.04	73.14
Maximum	665.02	504.12
Average	224.4	277.8
Assessment of molecular weight	Molecular weight within range of training set
Training set: Log Kow	Training set	Validation set
Minimum	-2.11	-5.98
Maximum	8.12	8.68
Assessment of log Kow	Log Kow within range of training set

Appendix D. MCI Correction Factors

Correction Factor Descriptor	Coefficient for Molecular Connectivity Index (MCI) Regression Methodology		Occurrence		No. of instances of each bond found for the current substance
	(new model)	Remark	(number of compounds)	(max per structure)
Nitrile/Cyanide (-C#N)	-0,667701	(a)	11	2	1

(a) Counted up to twice per structure, regardless of number of occurrences.