1-ethoxy-2,3-difluorobenzene

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2000-10-13

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:

OECD Guideline No. 117, adopted on 30th March 1989.

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Commission Directive No. 92/69/EEC, A.8, 31 July 1992 (HPLC method)

Deviations:

no

GLP compliance:

yes

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

2.82

Temp.:

23 °C

Remarks on result:

other: pH value not reported

Evaluation of k’ and P_ow

The capacity factor k' was calculated from the dead time to and retention times according to the

equation:

 

k' = (t_r-t₀) / t₀

t_o: HPLC dead time (min)

t_r: HPLC retention time of test and reference substances (min)

 

The log k’ data of the reference substances were then plotted against their log P_ow values from

batch equilibrium given in table 2. Using this plot, the P_ow values determined for the reference

substances were within ± 0.5 log units of the values determined by the batch equilibrium method

in the OECD guideline and the log k’ value of the test substance was then used to determine its

log P_ow value. The values of the P_ow taken from the duplicate analyses were within the range of

0.1  log units.

 

Determination of dead time (t₀)

Formamide, t₀ = 1.19 min

Determination of the retention time (t_r)

Nitrobenzene, t_r = 5.50 min

Methyl benzoate, t_r = 7.50 min

Ethyl benzoate , t_r = 14.0 min

Toluene, t_r = 17.8 min

1,4 Dichlorobenzene, t_r = 38.8 min

Test item, t_r = 18.7 min

Evaluation of k’ and log k'

Nitrobenzene, k’ = 3.61 log k' = 0.558

Methyl benzoate, k’ = 5.29 log k' = 0.724

Ethyl benzoate, k’ = 10.7 log k' = 1.03

Toluene, k’ = 13.9 log k'- 1.14

1,4 Dichlorobenzene, k’ = 31.5 log k'- 1.50

Test item, k’ = 14.7 log k'- 1.17

 

Evaluation of P_ow: log P_ow = 2.82 ± 0.01

Linear least squares regression: a = 1.58, b = 0.971, r² = 0.99.

Conclusions:

The partition coefficient of the test item was determined to be 2.82 at 23 °C.

Executive summary:

The partition coefficient (P_ow) of the test item was estimated according to the test guidelines described in Commission Directive 92/69/EEC, A.8, 31 July 1992 and OECD Guideline for Testing of Chemicals No. 117 "Partition Coefficient (n-octanol/water), High Performance Liquid Chromatography (HPLC) Method". Therefore, HPLC was performed on a Symmetry Cl8 column packed with solid phase containing long hydrocarbon chains chemically bound onto silica. The test substance was eluted along the column by partitioning between the mobile solvent phase and the hydrocarbon stationary phase. The test substance was retained in proportion to its hydrocarbon-water partition coefficient. Using reference substances a relationship between the retention time on a reverse-phase column and the n-octanol/water partition coefficient was established. The value of the partition coefficient was determined to be 2.82 at 23 °C.

Description of key information

The partition coefficient of the test item was determined to be 2.82 at 23 °C (reference 4.7-1).

Key value for chemical safety assessment

Log Kow (Log Pow):

2.82

at the temperature of:

23 °C

Additional information

The partition coefficient (P_ow) of the test item was estimated according to the test guidelines described in Commission Directive 92/69/EEC, A.8, 31 July 1992 and OECD Guideline for Testing of Chemicals No. 117 "Partition Coefficient (n-octanol/water), High Performance Liquid Chromatography (HPLC) Method". Therefore, HPLC was performed on a Symmetry Cl8 column packed with solid phase containing long hydrocarbon chains chemically bound onto silica. The test substance was eluted along the column by partitioning between the mobile solvent phase and the hydrocarbon stationary phase. The test substance was retained in proportion to its hydrocarbon-water partition coefficient. Using reference substances a relationship between the retention time on a reverse-phase column and the n-octanol/water partition coefficient was established. The value of the partition coefficient was determined to be 2.82 at 23 °C (reference 4.7-1).