Cyclooctane

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2021-05-31 - 2021-06-14

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)

Version / remarks:

1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient - HPLC Method)

Version / remarks:

European Commission Regulation (EC) No. 440/2008

Deviations:

no

GLP compliance:

no

Type of method:

flask method

Partition coefficient type:

octanol-water

Analytical method:

analysis (not specified)

Key result

Type:

log Pow

Partition coefficient:

4.2

Temp.:

25 °C

Remarks on result:

other: pH not determined

Increasing amounts of the test item were stirred with a defined volume of n-octanol at room temperature and visually checked for any undissolved particles.

 

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

Added amount of test item / g	Total amount of n-octanol / g	Total volume of n-octanol / mL	Stirring time / h	Appearance of Mixture
0.1148	0.1148	2		Immediately dissolved
0.9176	1.0324	2	-	Immediately dissolved
1.0228	2.0552	2	-	Immediately dissolved
1.0070	3.0622	2	-	Immediately dissolved
1.0146	4.0768	2	-	Immediately dissolved

 

According to this preliminary test the solubility of the test item in n-octanol was above 2038 g/L (without correction for the purity).

 

Calculation of the partition coefficient log POW

The partition coefficient POW may be estimated from the saturation concentrations in n-octanol and water by the following equation:

 

Pow= Csn-octanol/Cswater

cS = saturation concentration in g/L

 

The estimated partition coefficient was calculated with the water solubility data (cS < 1.44 mg/L) and the preliminary visual estimation of the n-octanol solubility. It was calculated to be: log POW > 6.2.

Also, the program KOWWIN (part of EPI Suite) was used for calculating the log POW of the test item. The calculated value was 4.2. Due to the calculations the partition coefficient should be estimated with the HPLC method. The HPLC method was not applicable due to the chemical properties (not UV/VIS active) of the test item and the shake flask method was not applicable due to the low water solubility. Therefore, the octanol solubility was determined using the flask method.

 

Determination of the solubility in n-octanol: Flask method

The individual saturation solubility of the test item in n-octanol was performed within this study. After that, the partition coefficient was estimated based on the ratio of the test item solubility in n-octanol and water according to equation (1). The flask method was performed. The data for the evaluation are given in the following Table 2.

 

 

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

Experiment	24 h experiment	48 h experiment	72 h experiment	Blank experiment (72 h)
Amount of test item / g	10.07	10.13	10.04	-
Amount of octanol / mL	10	10	10	10
Stirring time at 30 °C / h	24	48	72	72
Optical observation after the stirring time	Completely dissolved	Completely dissolved	Completely dissolved	-
n-Octanol solubility / g/L	>1007	>1013	>1004	-

 

The n-octanol solubility of the test item at 20 °C was determined to be >1013 g/L, the partition coefficient Pow of the test item was determined to be: log Pow >6.5.

 

Calculation of the partition coefficient log POW from the individual solubilities

The water solubility of the test item at 20 °C was determined to be below 1.44 mg/L in the respective study. The n-octanol solubility of the test item at 20 °C was determined to be above 1013 g/L. As only limit values could be termined for the solubility in water and in n-octanol, those values were not useful to calculate a partition coefficient.

 

The program KOWWIN (part of EPI Suite) was used for calculating the log POW of the test item. The calculated value was 4.2.

Conclusions:

The program KOWWIN (part of EPI Suite) was used for calculating the log POW of the test item. The calculated value was 4.2.

Executive summary:

A study was conducted in accordance with OECD TG 107 and Regulation (EC) No 440/2008 method A.8 to determine the partition coefficient of the test substance using the flask method. The water solubility of the test item at 20 °C was determined to be below 1.44 mg/L. Within this project the n-octanol solubility of the test item at 20 °C was determined to be above 1013 g/L. As only limit values could be determined for the solubility in water and in n-octanol, those values were not used to calculate a partition coefficient. Instead, the program KOWWIN (part of EPI Suite) was used for calculating the log POW of the test item. The calculated value was 4.2.

Description of key information

The program KOWWIN (part of EPI Suite) was used for calculating the log POW of the test item. The calculated value was 4.2 (reference 4.7-1).

Key value for chemical safety assessment

Log Kow (Log Pow):

4.2

at the temperature of:

20 °C

Additional information

A study was conducted in accordance with OECD TG 107 and Regulation (EC) No 440/2008 method A.8 to determine the partition coefficient of the test substance using the flask method. The water solubility of the test item at 20 °C was determined to be below 1.44 mg/L. Within this project the n-octanol solubility of the test item at 20 °C was determined to be above 1013 g/L. As only limit values could be determined for the solubility in water and in n-octanol, those values were not used to calculate a partition coefficient. Instead, the program KOWWIN (part of EPI Suite) was used for calculating the log POW of the test item. The calculated value was 4.2.