2-amino-2-ethylpropanediol

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption

Remarks:

adsorption

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

27 Feb 2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Validated QSAR model

Justification for type of information:

QSAR prediction: migrated from IUCLID 5.6

Principles of method if other than guideline:

Calculation based on QSAR model in Franco, A. and Trapp, S., Env Tox Chem 27, 10, pp. 1995-2004, 2008. The models are applicable for ionizable organic chemicals or organic electrolytes: acids, bases and amphoters.

GLP compliance:

no

Type of method:

other: calculation

Media:

soil

Type:

Koc

Value:

87 - 108

Remarks on result:

other: from eq. (3)

Type:

log Koc

Value:

1.94 - 2.03

Remarks on result:

other: from eq. (3)

Type:

Koc

Value:

491 - 922

Remarks on result:

other: from eq. (5)

Type:

log Koc

Value:

2.69 - 2.96

Remarks on result:

other: from eq. (5)

The log Koc was calculated at the optimal pH for each regression and additionally at pH values 4, 7 and 9, in order to see the variability at different potential environmental conditions. The Koc values obtained at different pH from both equations are listed in Table 1.

Table 1.

pH	logKoc based on eq. (3)	logKoc based on eq. (5)
6 (optimal for eq. (3))	1.94	-
4.5 (optimal for eq. (5))	-	2.96
4	1.94	2.94
7	1.94	2.96
9	2.03	2.69

AEPD is a primary amine and acts as a base in aqueous solution. At environmental conditions, it will be mainly present in protonated form, i.e. positively charged. Three structurally similar substances can be found in the training set for the model and one in the validation set. The experimental and calculated log Koc values for these substances, listed in Table 2, show that the model performs relatively well for these substances. The difference between experimental and calculated values remains below half a logarithmic unit in most cases and below one unit in all cases. Since, no trend can be observed on which of the equations gives better predictions, it is cautious to use both and select the highest value as worst case for assessment.

Table 2.

	pKa	logKow neutr.	Exp. log Koc	pH	log Koc calc Eq. 20 pHopt = 6	log Koc calc Eq. 24 pHopt = 4.5	Substance group	CAS	SMILES
Training set
anilin	4,61	0,94	2,58		2,44	2,49	Aromatic amine	62-53-3	c1(N)ccccc1
trimethylamin	9,75	0,06	1,99	5,5	2,22	1,89	Aliphatic amine	75-50-3	N(C)(C)C
dimethylamin	10,73	-0,43	2,04	5,5	2,01	1,41	Aliphatic amine	124-40-3	N(C)C
Validation set
n-butylamin	10,69	0,93	1,74	5,5	2,58	2,18	Aliphatic amine	109-73-9	NCCCC

 

Description of key information

logKoc = 2.96 (model by Franco and Trapp, 2008)

Key value for chemical safety assessment

Koc at 20 °C:

922

Additional information

There are no studies available investigating the adsoption/desorption behaviour of 2-amino-2-ethyl-1,3-propanediol (AEPD). The Koc was therefore estimated by calculation.

As primary amine, AEPD is partly present in its positively charged form under environmental pH. The regression used for calculation takes into account the adsorption of the charged and uncharged species. The predicted log Koc was 2.96, indicating low adsorption potential.