Sodium 2-(1-carboxylatoethoxy)-1-methyl-2-oxoethyl laurate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018-06-22 to 2018-09-19

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)

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient - Shake Flask Method)

GLP compliance:

no

Type of method:

flask method

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

- Test item: Esterlac SLL
- CAS No.: 13557-75-0
- Molecular weight: 294.37 g/mol
- Sum formula: C18H31NaO6
- Identity: 64.2% aicd value, 194 saponification number
- Physical state: Light yellow paste
- Storage: 10 °C - 30 °C

Analytical method:

other: Atomic absorption spectroscopy (AAS)

Key result

Type:

log Pow

Partition coefficient:

ca. 0.2

Temp.:

20 °C

Remarks on result:

other: pH not available; calculation method

Preliminary visual estimation of the n-octanol solubility

Defined amounts of the test item were stirred with increasing volumes of n-octanol at room temperature and visually checked for any undissolved parts (Table 1).

Table 1: Results of the preliminary visual estimation of the n-octanol solubility

Amount of test item / mg	Added volume of n-octanol / mL	Total volume of n-octanol / mL	Stirring time / h	Appearance of mixture
18.5	10	10	1	Dissolved
524.7	5	5	~2	Not dissolved (turbid solution)
	5	10	~4	Not dissolved (turbid solution with solid parts)

According to this preliminary test the solubility of the test item in n-octanol was between 2 and 52 g/L (without correction for the purity).

Calculation of the log Pow from the preliminary results

The Pow may be estimated from the saturation concentrations of n-octanol and water by the following equation:

Pow = c(n-octanol) / c(water) where c = saturation concentration in g/L

The estimated partition coefficient of the test item was calculated with the previously determined water solubility (c > 114 g/L) and the solubility in n-octanol obtained from the preliminary tests. The calculated log Pow was < -0.3.

Also the program KOWWIN was used for calculating the log Pow of the test item. The calculated log Pow was -0.1.

Due to the chemical nature of the test item (surface activity) the partition coefficient was estimated based on the ratio of the solubilities in water and n-octanol (solubility in n-octanol determined by flask method).

Determination of the solubility in n-octanol: Flask method

The individual saturation solubility of the test item in n-octanol was determined within this study. After that, the partition coefficient was estimated based on the ratio of test item solubility in n-octanol and water. The data for the evaluation are given in Table 2.

Table 2: n-octanol solubility experiments of the test item

Experiment	24 h	48 h	72 h	Blank ( 72 h)
Amount of test item / g	5.01	5.00	5.06	-
Amount of n-octanol / mL	20	20	20	20
Stirring time at 30 °C / h	24	48	72	72
Measured sodium concentration / %ww	2.7	2.4	2.5	0.9
n-octanol solubility* / g/L	194.4	162.7	173.3	-

*The test item contained approx.. 7.8% sodium (molecular mass 294.37 g/mol containing 1 sodium atom) without correction of the purity. The n-octanol solubility was calculated using the sodium content and the density of n-octanol (0.824 kg/L) and under consideration of the sodium content from the blank experiment.

The n-octanol solubility of the test item at 20 °C was determined to be 176.8 g/L.

Calculation of the partition coefficient log Pow from the individual solubilities

The water solubility of the test item was previously determined to be > 114 g/L at 20 °C. The n-octanol solubility of the test item was determined to be 176.8 g/L at 20 °C.

The partition coefficient log Pow was determined to be < 0.2.

The determination of the water solubility was associated with uncertainties. Nevertheless, the experimental results on solubility in both water and n-octanol constitute the best possible approximation to the behaviour of the test item in the respective test media and are thus considered suitable for estimating the partition coefficient. Moreover, the estimation by KOWWIN of the partition coefficient is similar to the value calculated from individual solubilities in water and n-octanol. Overall, the result for the log Pow < 0.2 is considered to be sufficiently reliable.

Conclusions:

The log Pow of the test item was estimated based on the ratio of the individual solubilities of the test item in water and n-octanol and found to be < 0.2.

Executive summary:

The log Pow of the test item was determined according to OECD 107 and estimated based on the ratio of the individual solubilities of the test item in water and n-octanol, which were determined according to the flask method. A log Pow < 0.2 was found.

Description of key information

The log Pow of the test item was determined according to OECD 107 and estimated based on the ratio of the individual solubilities of the test item in water and n-octanol, which were determined according to the flask method. The calculated log P_ow is 0.2.

Key value for chemical safety assessment

Log Kow (Log Pow):

0.2

at the temperature of:

20 °C