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Description of key information

The organic carbon partition coefficient (log Koc) of 'Reaction mass of benzyl 2-ethylhexyl adipate and bis(2-ethylhexyl) adipate and dibenzyl adipate' was predicted using the Estimation Program Interface (EPI) Suite version 4.1. 
'Reaction mass of benzyl 2-ethylhexyl adipate and bis(2-ethylhexyl) adipate and dibenzyl adipate' is a "multi constituent substance" consisting of benzyl 2-ethylhexyl adipate [CAS 58394-64-2], bis(2-ethylhexyl) adipate [CAS 103-23-1] and dibenzyl adipate [CAS 2451-84-5].
The estimation revealed values of 23290 L/kg (log Kow method) and 21900 L/kg (MCI method) for benzyl 2-ethylhexyl adipate, 2811 L/kg (log Kow method) and 13320 L/kg (MCI method) for dibenzyl adipate and 192900 L/kg (log Kow method) and 36000 L/kg (MCI method) for bis(2-ethylhexyl) adipate. All values indicate a potential for adsorption.

Key value for chemical safety assessment

Additional information

The organic carbon partition coefficient (log Koc) of 'Reaction mass of benzyl 2-ethylhexyl adipate and bis(2-ethylhexyl) adipate and dibenzyl adipate' was predicted using the Estimation Program Interface (EPI) Suite version 4.1.

'Reaction mass of benzyl 2-ethylhexyl adipate and bis(2-ethylhexyl) adipate and dibenzyl adipate' is a "multi constituent substance" consisting of benzyl 2-ethylhexyl adipate [CAS 58394-64-2], bis(2-ethylhexyl) adipate [CAS 103-23-1] and dibenzyl adipate [CAS 2451-84-5].

For each constituent of the substance the program estimated the Koc with two separate estimation methodologies. The estimations are based on the first-order Molecular Connectivity Index (MCI) and the log Kow, which is internally calculated by the program, respectively.

For estimating Koc, based on the method on statistical relationships between Koc and the octanol/water partition coefficient (Kow) the following log Kow values were used:

constituent A [benzyl 2-ethylhexyl adipate]: log Kow 6.46

constituent B [bis(2-ethylhexyl) adipate]: log Kow 8.12

constituent C [dibenzyl adipate]: log Kow 4.80

Koc values in the range of 2811 to 192900 L/kg were obtained.

Moreover, calculations performed based upon the molecule structure using the molecular connectivity method (MCI method) yielded Koc values in the range of 13320 to 36000 L/kg.

The results for all constituents of 'Reaction mass of benzyl 2-ethylhexyl adipate and bis(2-ethylhexyl) adipate and dibenzyl adipate' falls within the applicability domain of the model and the applied estimating rules appear appropriate. Concerning uncertainties of estimation for the investigated substances, bis(2-ethylhexyl) adipate is located in the training dataset. Thus, the probability is high, that the structural fragments applied by the program for the substance of interest were appropriate.

For bis(2-ethylhexyl) adipate the residual, defined as the difference between the experimental log Koc value and the log Koc values predicted by the MCI- and log Kow-method, expressed as absolute value, is +0.37 for the MCI method, and +1.10 for the log Kow method.

The uncertainty can be stated due to the lack of information of the experimental study design, as bis(2-ethylhexyl) adipatee is poorly soluble in water.

Therefore, the experimentally determined log Koc for bis(2-ethylhexyl) adipate reported in the database of the program, cannot be used for hazard and risk assessment and the value is scored to be not assignable.

Further, the predicted log Kow for bis(2-ethylhexyl) adipate is 8.12. It is assumed that log Koc results predicted by the log Kow method are less accurate with increasing log Kow values, due to low level presence of compounds with higher log Kow values in the training set.

Regarding the predicted values for benzyl 2-ethylhexyl adipate and dibenzyl adipate it is considered that their uncertainty is in the same range as bis(2-ethylhexyl) adipate. Nevertheless, the predictions of the organic carbon partition coefficients yield useful results for further evaluation, indicating a potential for adsorption.