4-Ethoxy-2,3-difluorphenylboronic acid

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21.01. - 26.01.16

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)

GLP compliance:

no

Type of method:

flask method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

2.3

Temp.:

23 °C

pH:

9

A specified amount (see Table 1) of the test item was dissolved in 100 ml n-octanol (saturated with distilled water). 10 ml of this solution were added to six different flasks (experiment: 1A, 1B, 2A, 2B, 3A, 3B). Subsequently different amounts of n-octanol (saturated with distilled water) and 20 ml distilled water (saturated with n-octanol) were added to the flasks as described in Table 1. All mixtures were shaken for several minutes at ambient temperature (23 °C). After separation of the phases each phase was centrifuged (30 minutes at 23 °C and 15000 rpm) and the pH values of the aqueous phases were measured. For analytics the samples were prepared and the concentrations of the test item in the different phases were subsequently determined by HPLC.

Table 1: Test conditions and results of the shake flask method

Experiment	1A	1B	2A	2B	3A	3B
Amount of test item / mg	6.7
Concentration of the stock solution / mg/l	67
Volume of added stock solution / ml	10	10	10	10	10	10
Volume of added n-octanol / ml	0	0	20	20	30	30
Volume of added dist. water / ml	20	20	20	20	20	20
pH of the aqueous phase at 23 °C	5.2	5.3	5.5	5.5	5.4	5.5
Measured concentration in aqueous phase / mg/l	0.16/0.16	0.16/0.16	0.08/0.08	0.08/0.08	0.03/0.03	0.03/0.03
Mean concentration in aqueous phase / mg/l^1)	0.32	0.31	0.15	0.16	0.07	0.06
Measured concentration in n-octanol phase / mg/l	1.51/1.51	1.52/1.52	0.76/0.76	0.77/0.76	0.38/0.38	0.38/0.38
Mean concentration in n-octanol phase / mg/l^1)	60.31	60.68	30.32	30.54	15.05	15.20

¹⁾ For the mean concentration the sample preparation (dilution) is taken into account.

The given values of the concentrations in the aqueos and the n-octanol phases are mean values of two measurements. The following partition coefficients are calculated from the measured and unrounded concentration values and not from the rounded values given in Table 1.

Table 2: Partition coefficients of the shake flask method at pH 9

Experiment	Pow	log Pow	Average log Pow
1A	190.71	2.28	2.29
1B	194.61	2.29
2A	196.97	2.29	2.29
2B	189.52	2.28
3A	224.92	2.35	2.38
3B	256.11	2.41
Mean value (experiment 1A to 3B)			2.3
Standard deviation			0.05

The six determined log P_ow values are within a range of +/- 0.3 units as requested by the guideline.

Conclusions:

The parttion coefficient log Pow of the test item at room temperature (23 °C) was determined to be log Pow = 2.3.

Executive summary:

The partition coefficent (n-octanol/water) was determined according to the shake flask method described in the European Commission Regulation (EC) No. 440/2008, A.8 and in OECD guideline 107. The parttion coefficient log P_ow of the test item at room temperature (23 °C) was determined to be log P_ow = 2.3.

Description of key information

The partition coefficent (n-octanol/water) was determined according to the shake flask method described in the European Commission Regulation (EC) No. 440/2008, A.8 and in OECD guideline 107. The parttion coefficient log P_owof the test item at room temperature (23 °C) was determined to be log P_ow= 2.3.

Key value for chemical safety assessment

Log Kow (Log Pow):

2.3

at the temperature of:

23 °C