Reaction mass of 2-(cis-4-methylcyclohexyl)propan-2-ol and 2-(trans-4-methylcyclohexyl)propan-2-ol and cis-1-methyl-4-(propan-2-yl)cyclohexanol and trans-1-methyl-4-(propan-2-yl)cyclohexanol

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 June 2013 - 17 June 2013

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

This study was considered as reliable with restriction because it was not conducted under GLP and there are some lack of details in the study report.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 123 (Partition Coefficient (1-Octanol / Water), Slow-Stirring Method)

Deviations:

no

Principles of method if other than guideline:

In a stirring vessel maintained at 20°C, 1-octanol, water and the test item are equilibrated with each other at constant temperature and are slowly stirred. Then the concentrations of the test substance in the two phases are determined. The partition coefficient between water and 1-octanol (P) is defined as the ratio of the equilibrium concentrations of the test substance in 1-octanol saturated with water and water saturated with 1-octanol. Three independent slow-stirring experiments were carried out.

GLP compliance:

no

Type of method:

slow-stirring method

Partition coefficient type:

octanol-water

Analytical method:

gas chromatography

Key result

Type:

log Pow

Partition coefficient:

ca. 2.91

Temp.:

20 °C

pH:

ca. 5

Remarks on result:

other: +/-0.02

The concentrations obtained in both phases and the corresponding Log P are presented as a function of time during the three independent slow-stirring experiments in the following tables.

First experiment
Date		Water concentration (mg/L)	Octanol concentration (mg/L)	log P
13/06/2013 16:00		155.79	172.03	3.04
14/06/2013 08:00		171.67	196.31	3.06
14/06/2013 12:00		181.67	607.07	3.52
14/06/2013 16:00		210.96	183.10	2.94
17/06/2013 08:00		214.37	189.61	2.95
17/06/2013 13:00		239.22	176.58	2.87

Second experiment
Date	Water concentration (mg/L)	Octanol concentration (mg/L)	log P
13/06/2013 16:00	137.72	158.96	3.06
14/06/2013 08:00	170.67	182.27	3.03
14/06/2013 12:00	166.38	169.93	3.01
14/06/2013 16:00	236.74	167.64	2.85
17/06/2013 08:00	229.66	179.72	2.89
17/06/2013 13:00	230.71	174.87	2.88

Third experiment
Date	Water concentration (mg/L)	Octanol concentration (mg/L)	log P
13/06/2013 16:00	134.59	184.15	3.14
14/06/2013 08:00	162.30	162.44	3.00
14/06/2013 12:00	171.89	170.72	3.00
14/06/2013 16:00	221.27	176.61	2.90
17/06/2013 08:00	258.09	165.89	2.81
17/06/2013 13:00	229.76	192.85	2.92

A pH of 5 was obtained at the end of the three experiments.

Demonstration of attainment of equilibrium

Achievement of chemical equilibrium is demonstrated when a regression of the 1-octanol/water concentration ratio against time over a time span of four time points yields a slope that is not significantly different from zero at a p-level of 0.05.

The four first points of the first experiment are used in the following explanation and the slope (b1) was obtained : b1 = 0.107

Log P calculation

The previous procedure was conducted on the experimental data obtained for the three experiment to demonstrate the attainment of equilibrium. When the equilibrium was demonstrated, the value of log P of the experimental unit (Log Pi) was calculated as the average value of log P for the part of the curve of Log P vs. time curve, for which equilibrium has been demonstrated. The statistical weight assigned to the log P value of the experimental unit i (wi), corresponding to the inverse of the variance of the results at the equilibrium period, was calculated. These results are presented in the tables below.

 

FIRST EXPERIMENT
Date	log P	Equilibrium attained ?	Log Pi	wi
13/06/2013 16:00	3.04
14/06/2013 08:00	3.06
14/06/2013 12:00	3.52
14/06/2013 16:00	2.94	YES
17/06/2013 08:00	2.95	YES
17/06/2013 13:00	2.87	YES	3.07	10.74

SECOND EXPERIMENT
Date	log P	Equilibrium attained ?	Log Pi	wi
13/06/2013 16:00	3.06
14/06/2013 08:00	3,03
14/06/2013 12:00	3.01
14/06/2013 16:00	2.85	YES
17/06/2013 08:00	2.89	YES
17/06/2013 13:00	2.88	YES	2.91	205.45

THIRD EXPERIMENT
Date	log P	Equilibrium attained ?	Log Pi	wi
13/06/2013 16:00	3.14
14/06/2013 08:00	3.00
14/06/2013 12:00	3.00
14/06/2013 16:00	2.90	NO
17/06/2013 08:00	2.81	YES
17/06/2013 13:00	2.92	YES	2.91	164.82

For the three experiments, equilibrium has been reached for the fifth and sixth samples. All the calculation was made using the sixth samples data.

 

Average log P

The log P value (log Pav) was calculated as the average of the results of the three individual experimental units weighted with their respective variances.

The calculation is performed as follows:

 

Log Pav = (Σwi × log Pi) × (Σwi)^-1= 2.91 ± 0.02

Conclusions:

The following Partition Coefficient was determined for dihydroterpineol multiconstituent by slow-stirring method: log P = 2.91 ± 0.02.

Executive summary:

The partition coefficient of dihydroterpineol multiconstituent was determined at 20°C by slow-stirring method according to OECD guideline 123.

log Pow = 2.91 ± 0.02.

This value was the mean ± standard deviation of three independent determinations.

Description of key information

The partition coefficient of dihydroterpineol multiconstituent was determined at 20°C by slow-stirring method according to OECD guideline 123.

log Pow = 2.91 ± 0.02.

Key value for chemical safety assessment

Log Kow (Log Pow):

2.91

at the temperature of:

20 °C

Additional information

Key study conducted according to OECD guideline 123. The result is scientifically acceptable but not obtained under GLP.

Therefore a reliability of 2 (reliable with restrictions) was assigned.