4'-Butyl-4-ethoxy-2,3-difluoro-1,1'-biphenyl

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 2012-07-13 to 2012-10-08

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)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

no

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

6.9

Temp.:

20 °C

pH:

7

Details on results:

The log Pow was determined to >6.5. It was extrapolated to be 6.9.

Preliminary Visual Estimation of the Water Solubility

Different amounts of the test item and water were stirred at room temperature until the mixture appeared dissolved or the water solubility could be estimated to be below 10 mg/L.

Table 1. Appearance of the test mixture

Amount of the test item in mg	Total volume in mL	Appearance of mixture
10.4	100	undissolved
12.4	250	undissolved
3.9	500	undissolved

The solubility of the test item in water was below 7.8 mg/L.

 

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 2. 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
0.020	0.020	2	30	undissolved
--	0.020	10	30	undissolved
--	0.020	50	60	dissolved

The solubility of the test item in n-octanol is higher than 0.40 g/L.

With the data obtained the partition coefficient was calculated as: log Pow > 1.7. Therefore, the partition coefficient n-octanol/water of the test item at room temperature was determined by the HPLC-method.

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 6.8 for the test item.

HPLC-Method

Table 3. Determination of the Dead Time t0

Dead time marker	tR in min 1. measurement	tR in min 2. measurement	tR in min mean
Formamide	2.50	2.50	2.50

 

Table 4. Calibration data (*from OECD guideline 117, adopted 2004)

Calibration substance	1. lnj. tR in min	2. Inj. tR in min	mean tR in min	k	log k	log Pow
2-Butanone	2.99	2.98	2.98	0.19	-0.71	0.3
Acetanilide	3.16	3.16	3.16	0.26	-0.58	1.0
Cinnamyl alcohol	3.81	3.80	3.81	0.52	-0.28	1.9
2,6-Dicholoro- benzonitrile	4.86	4.86	4.86	0.94	-0.03	2.6
Allyl phenyl ether	7.04	7.04	7.04	1.82	0.26	2.9
Benzophenone	6.35	6.35	6.35	1.54	0.19	3.2
Cumene	13.0	13.1	13.1	4.22	0.63	3.7
Diphenyl ether	11.9	12.0	12.0	3.79	0.58	4.2
l-Fluoranthene	24.4	24.5	24.4	8.77	0.94	5.1
4,4' DDT	61.1	61.3	61.2	23.5	1.37	6.5

 

Regression: logPow = a + b * logk

Parameters: a = 2.48, b = 2.78, r2 = 0.9811

Table 5. log Pow of the test item

	1. Inj. tR in min	2. Inj. tR in min	mean tR in min	k	logk	log Pow
Test Item	103.7	103.4	103.5	40.4	1.61	>6.5* (6.9)**

* above the highest log Pow value of calibration substances (DDT)
** via extrapolation

Conclusions:

The partition coefficient of the test item was estimated to be 6.9 at 20 °C.

Executive summary:

A study was conducted in accordance with OECD TG 117 and Regulation (EC) No 440/2008 method A.8 to determine the partition coefficient of the test substance using the HPLC method. 10.9 mg of the test item were dissolved in 50 mL methanol and diluted from 0.1 mL to 1.75 mL with methanol / distilled water 40:60 % (v/v) and injected as single solutions twice. The solubility of the test item in water and n-octanol was preliminary determined and a partition coefficient log Pow > 1.7 was calculated. Using the HPLC method for the main test, the value found for the partition coefficients n-octanol/water was above the highest log Pow values of the calibration curve, therefore, it was determined to be >6.5. After extrapolation the log Pow for the test item was estimated to be 6.9.

Description of key information

The partition coefficient of the test item was estimated to be 6.9 at 20 °C.

Key value for chemical safety assessment

Log Kow (Log Pow):

6.9

at the temperature of:

20 °C

Additional information

A study was conducted in accordance with OECD TG 117 and Regulation (EC) No 440/2008 method A.8 to determine the partition coefficient of the test substance using the HPLC method (reference 4.7-1). 10.9 mg of the test item were dissolved in 50 mL methanol and diluted from 0.1 mL to 1.75 mL with methanol / distilled water 40:60 % (v/v) and injected as single solutions twice. The solubility of the test item in water and n-octanol was preliminary determined and a partition coefficient log Pow > 1.7 was calculated. Using the HPLC method for the main test, the value found for the partition coefficients n-octanol/water was above the highest log Pow values of the calibration curve, therefore, it was determined to be >6.5. After extrapolation the log Pow for the test item was estimated to be 6.9.