N'-[3-(dimethylamino)propyl]-N,N-dimethylpropane-1,3-diamine

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012-08-10 - 2012-08-21

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

GLP compliance:

yes (incl. QA statement)

Type of method:

shake-flask method to: flask method

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

- Name of test material (as cited in study report): bis-DMAPA
- Substance type: organic
- Appearance: clear colorless liquid
- Physical state: Liquid
- Composition of test material, percentage of components: 0.03% water, 16.02 meq/g total amine
- Lot/batch No.: PFW110019
- Storage condition of test material: Sample stored in cool, well-ventilated storage area prior to testing

Analytical method:

gas chromatography

Type:

Pow

Partition coefficient:

1.66

Temp.:

21.7 °C

pH:

11.5

Key result

Type:

log Pow

Partition coefficient:

0.214

Temp.:

21.7 °C

pH:

11.5

Details on results:

Duplicate log Pow values of 0.173/0.182, 0.216/0.123 and 0.328/0.262 were calculated for the octanol/water ratio 1:2, 1:1 and 2:1, respectively.

The test item contains three ionizable nitrogen atoms in the structure with computer estimated pKa values of 6.36, 8.39 and 10.17. Therefore the n-octanol saturated water was adjusted to pH 11.5 to ensure the test item was partitioned in its non-ionized form. As testing was carried out at pH 11.5 this does not truly reflect the properties of the test item at an environmentally relevant pH (pH 5-pH 9). In this pH range either some or all the ionizable groups would be charged which would increase the water solubility and lower the partition coefficient for the test item. For this reason the result can be taken as a worst-case and in most environmentally relevant situations the partition coefficient would be lower than the value reported.

Conclusions:

The partition coefficient of the test substance has been determined to be 1.66 at 21.7 ± 1.0°C, log Pow 0.214 at pH 11.5, using the shake-flask method.

Reference 2

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2012-02-22

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

shake-flask method to: flask method

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

- Name of test material (as cited in study report): bis-DMAPA
- Substance type: Amber liquid
- Physical state: Liquid
- Composition of test material, percentage of components: 0.03% water, 16.02 meq/g total amine
- Lot/batch No.: PFW110019
- Storage condition of test material: Sample stored in cool, well-ventilated storage area prior to testing

Analytical method:

other: not applicable, only preliminary estimation based on the structure

Key result

Type:

log Pow

Partition coefficient:

-0.07

Remarks on result:

other: The partition coefficient is estimated based on the structure of the substance. Therefore temperature and pH are not applicable.

Details on results:

From the molecular structure, the test substance contains 4 aliphatic -CH3 fragments; 6 aliphatic -C fragments, 12 -H fragments; one -NH-fragment; and 2 -N< fragments. Thus fragment constants of value 0.89 (-CH3 aliphatic); 0.20 (-C-fragment), 0.23 (-H aliphatic), -2.15 (-NH- fragment) and -2.18 (-N< fragment) were applied. The sum of the fragments in the molecule was therefore calculated as 1.01.

Also present in the molecule are 10 aliphatic bonds in the chain and therefore a bond factor of -1.08 was applied.

From the sum of fragments and factors the partition coefficient was estimated by calculation as -0.07 log units.
The calculation refers to the neutral structure. However as the pKa is 9.21, the chemical will be in its protonated form at environmentally and physiologically relevant pH values. The calculated value is therefore expected to represent an overestimation under those conditions.

Conclusions:

From the structure of the test substance, it was estimated by calculation that the partition coefficient is -0.07 log units. This calculation refers to the neutral structure. The chemical will be in its protonated form at environmentally and physiologically relevant pH values, with a predicted lower partitioning into octanol.

Description of key information

The partition coefficient of the test substance was determined in a GLP-compliant study according to OECD method 107, to be 0.214 (Log value), following the shake flask method (Tarran, 2012).

Key value for chemical safety assessment

Log Kow (Log Pow):

0.214

at the temperature of:

21.7 °C

Additional information

The log Pow of the test substance was determined in two studies. In one study, the log Pow of the test substance was determined following a scientifically accepted calculation method. In the other study, the log Pow of the test substance was experimentally determined according to OECD Guideline 107 and EC A.8 to be 0.214 at 21.7 °C and pH 12.8, following the shake flask method (Tarran, 2012). The latter study was selected as the key study.