[trans(trans)]- 4-Methyl-4'-propyl-1,1'-bicyclohexyl

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

28 May - 12 Jun 2015

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:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: EU Method A.8 Partitition coefficient n-octanol/water

Deviations:

no

GLP compliance:

no

Type of method:

flask method

Partition coefficient type:

octanol-water

Analytical method:

gas chromatography

Key result

Type:

log Pow

Partition coefficient:

> 7.2

Temp.:

20 °C

Remarks on result:

other: no information on pH provided

Preliminary Visual Estimation of the n-Octanol Solubility

Different amounts of the test item were stirred with increasing amounts of n-octanol at room temperature and visually checked for any undissolved parts.

Table 1. Appearance of the test mixture

Amount of the test item in g	Total amount of the test item in g	Volume n-octanol (total volume) in mL	Stirring time in min	Appearance of mixture
0.011	0.011	2	40	dissolved
0.079	0.090	2	35	dissolved
0.758	0.848	2	0	dissolved

The solubility of the test item in n-octanol is at least 424 g/L (without correction for the purity).

The estimated partition coefficient was calculated with the water solubility data (cs = 31.1 μg/L) and the data indicated in table 1. lt was calculated to be: log Pow > 7.1.

In addition the program kowwinnt (part of Episuite from SRC) was used to calculate the log Pow of the test item. The calculated value was 7.7 for the test item.

Determination of the solubility in n-octanol according to the flask method

Due to the very high solubility of the test item in n-octanol observed in the preliminary test (see above) it was not practicable to use the fivefold quantity determined in the preliminary test in the main test. Therefore about the 2.5 fold quantity of the preliminary test was weighed into each of three glass vessels for the performance of the main test.

As after the performance of the main test all test item was dissolved in n-octanol only a range of the n-octanol solubility can be given as result of the n-octanol solubility of the test item.

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)	5.28	5.67	5.55	--
Amount of octanol (mL)	5	5	5	5
Stirring time at 30°C (h)	24	48	72	72
Aliquot of the flasks (mL)	0.25	0.25	0.25	0.25
First dilution to (mL)	10	10	10	10
Aliquot of the flasks (mL)	0.25	0.25	0.25	0.25
Second dilution to (mL)	10	10	10	10
Final dilution factor	1600	1600	1600	1600
Measured concentration (mg/L)	> 259.1/ > 266.2	> 271.2/ > 256.9	> 296.0 > 304.4	-- / --
Mean concentration (mg/L)	> 262.7	> 264.0	> 300.2	--
n-octanol solubility (g/L)	> 420	> 422	> 480	--

The n-octanol solubility of the test item at 20°C was determined to be > 480 g/L.

Hence, the partition coefficient Pow was estimated from the individual solubility in n-ocatanol and water by the following equation: Pow = Cs (octanol)/ Cs (water). The partition coefficient Pow of the test item was determined to be log Pow > 7.2.

Conclusions:

The partition coefficient n-octanol/water of the test item was determined to be: log Pow > 7.2.

Executive summary:

The partition coefficient (n-octanol/water) was estimated based on the ration of the individual solubilities of the test item in water and n-octanol. The solubilities of the test item in water and in n-octanol were determined according to the European Commission Regulation (EC) No. 440/2008, A.6. and to the OECD Guideline 105. The partition coefficient log Pow of the test item at 20 °C was determined to be: log Pow > 7.2.

Description of key information

log Pow > 7.2 at 20 °C

Additional information

The partition coefficient (n-octanol/water) was estimated based on the ration of the individual solubilities of the test item in water and n-octanol. The solubilities of the test item in water and in n-octanol were determined according to the European Commission Regulation (EC) No. 440/2008, A.6. and to the OECD Guideline 105. The partition coefficient log Pow of the test item at 20 °C was determined to be: log Pow > 7.2.