2,4-dioxo-1,3-diazetidine-1,3-bis(methyl-m-phenylene) diisocyanate

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Remarks:

adsorption

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:

There is no experimental data available for the determination of carbon partition coefficient log Koc of 2,4-dioxo-1,3-diazetidine-1,3-bis(methyl-m-phenylene) diisocyanate).If no experimental data are available, the estimated value of the Estimation Program Interface EPI-Suite version 4.11 (KOCWIN) may be used to fill data gaps needed for hazard and risk assessment, classification and labelling and PBT / vPvB assessment. The structure of the substance not highly complexand are covered by fragment descriptors of the programme. Therefore, the rules applied for the substance appears appropriate.

Guideline:

other: REACH guidance QSARs R6, May/July 2008

Principles of method if other than guideline:

Estimation Program Interface EPI-Suite version 4.11: KOCWIN (v2.00) for the estimation of the organic carbon-normalized sorption coefficient for soil and sediment (Koc).
The Estimation Program Interface was developed by the US Environmental Agency's Office of Pollution Prevention and Toxics, and Syracuse Research Corporation (SRC). © 2000 - 2012 U.S. Environmental Protection Agency for EPI SuiteTM (Published online in November 2012).

GLP compliance:

no

Type of method:

other: Estimation

Media:

soil

Type:

log Koc

Value:

4.01

Remarks on result:

other: calculation (logKow method)

Type:

log Koc

Value:

4.05

Remarks on result:

other: calculation (MCI method)

Phase system:

other: Koc

Type:

other: Koc

Value:

10 200 L/kg

Remarks on result:

other: calculation (logKow method)

Phase system:

other: Koc

Type:

other: Koc

Value:

11 200 L/kg

Remarks on result:

other: calculation (MCI method)

Validity of the model:

1. Defined Endpoint: Organic carbon partition coefficient, given as logarithmic Koc and Koc

2. Unambigous algorithm: The molecule is first classified as a polar substance.

Based on structure of the molecule, the following fragments were applied: -CH3 [aliphatic carbon], -C [aromatic carbon], -N [aliphatic attach, one aromatic attach], -NC(=O)N- [urea] and -N=C=O [isocyanate, aromatic attach].

The number of times of the fragments that occurs in the structure of the substance applied by the program is verified. For estimation of logKoc according to the logKow method the estimated logKow of 6.62 as calculated by the program was used.

3. Applicable domain: With a molecular weight of 348.39 g/mole the substance is within the range of the training set (32 - 665 g/mole) as well as in the validation set (27 - 991 g/mole). Regarding the structure of 2,4-dioxo-1,3-diazetidine-1,3-bis(methyl-m-phenylene) diisocyanate, the fragment descriptors found by the program are complete.

4a. Statistical characteristics (MCI method): N training set without corrections = 69; N training set with correction = 447; N validation set = 158; Correction coefficient of the total training set without corrections r² = 0.967; Correlation coefficient of the total training set with corrections r² = 0.900; Correlation coefficient of the total validation set r² = 0.850.

4b.Statistical characteristics (Kow method): N training set without corrections = 68; N training set with correction = 447; N validation set = 150; Correction coefficient of the total training set without corrections r² = 0.877; Correlation coefficient of the total training set with corrections r² = 0.855; Correlation coefficient of the total validation set r² = 0.778.

5. Mechanistic interpretation: Log Koc is estimated based on the likeliness of a substance for sorption to surfaces of soil/sediment particles. The log Koc is a physical inherent property used extensively to describe a chemical's likeliness to adsorb to organic carbon.

Adequacy of prediction:

The result for 2,4-dioxo-1,3-diazetidine-1,3-bis(methyl-m-phenylene) diisocyanate falls within the applicability domain described above and the estimation rules applied for the substance appear appropriate.

Validity criteria fulfilled:

not applicable

Conclusions:

The QSAR determination of the carbon partition coefficient using the model KOCWIN included in the Estimation Program Interface (EPI) Suite v4.11 revealed values of 10200 L/kg (logKow method) and 11200 L/kg (MCI method) for the unaffected molecule of the substance as any decomposition (e.g. hydrolysis) of the substance is not taken into account by the program.

Executive summary:

The organic carbon partition coefficient (Koc) was predicted using the QSAR calculation of the Estimation Program Interface (EPI) Suite v 4.11. The Koc was estimated to be 10200 L/kg (logKow method), and 11200 L/kg (MCI method). The results relate to the unaffected molecule of the substance as any decomposition (e.g. hydrolysis) of the substance is not taken into account by the program.

Description of key information

The QSAR determination of the carbon partition coefficient using the model KOCWIN included in the Estimation Program Interface (EPI) Suite v4.11 revealed values of 10200 L/kg (logKow method) and 11200 L/kg (MCI method) for the unaffected molecule of the substance as any decomposition (e.g. hydrolysis) of the substance is not taken into account by the program (Engemann, 2015).

Key value for chemical safety assessment

Koc at 20 °C:

10 200

Additional information

KOWWIN program, v. 1.68 © 2000 (U.S. Environmental Protection Agency)

[LogKoc: 4.01]