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Partition coefficient

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Reference
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
from January to February 1996
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-compliant guideline study - The study is considered as reliable without critical missing information : pH and quality criteria not reported.
Qualifier:
according to guideline
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
Version / remarks:
(1989)
Qualifier:
according to guideline
Guideline:
EU Method A.8 (Partition Coefficient)
Version / remarks:
(HPLC method)
Principles of method if other than guideline:
Reverse phase High Performance Liquid Chromatography on octadecyl-modified silica stationary phase is used.
Partitioning on the column occurs in order of hydrophobicity when a suitable mobile phase is used. From relationships between the measured retention times and the known octanol/water partition coefficients of reference substances, the partition coefficient of the test substance is calculated.
GLP compliance:
yes (incl. QA statement)
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
Commercial name : DIMETOL (as reported in the report):
Chemical nature : 2,6-dimethylheptan-2-ol
Empirical formula : C9H20O
Molecular weight : 144.2 g/mol
CAS number : 13254-34-7
Stability: stable in acetonitrile and in the mobile phase
batch : 003046
purity: 99,1 % (GC)
Density : 0,813 g/mL at 20°C
Analytical method:
high-performance liquid chromatography
Type:
log Pow
Partition coefficient:
3
Temp.:
45 °C
Remarks on result:
other: pH not reported

Table 1: Standards used for determination of log Kow of DIMETOL

 

Reference substances

Log Pow

tR1

tR2

tRm

k

log k

Thiourea

 

1,83

1,83

1,83

 

 

Aniline

0,9

2,63

2,62

2,62

0,435

-0,361

Methyl benzoate

2,1

3,64

3,64

3,64

0,992

-0,004

Benzophenone

3,2

5,12

5,12

5,12

1,798

0,255

Naphtalene

3,6

6,01

6,01

6,01

2,287

0,359

1,2,4-Trichlorobenzene

4,2

9,24

9,23

9,24

4,052

0,608

n-Butylbenzene

4,6

11,61

11,61

11,61

5,349

0,728

Triphenylamine

5,7

19,36

19,35

19,36

9,586

0,982

 

 

Calculation:

 

k = (tR /t0) - 1 capacity factor,

where,

tR1, tR2, tRm : retention times (1rst calibration, 2ndcalibration, average)

t: « dead time », i.e. retention time of thiourea

 

Linear regression parameters: log Pow = a x log k + b

where;

Correlation coefficient : r2= 0,995

Slope : a = 3,500

Y-axis intercept : b = 2,188

 

Results obatined for the peak of  DIMETOL:

tR1 4,998
tR2 4,999
tRm 4,9985
k 1,734
log k 0,239
log Kow 3
Conclusions:
Dimetol has a partition coefficient n-octanol/water of log Pow = 3.0 at 45°C
Executive summary:

A study was conducted to determine the partition coefficient of Dimetol by Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline 117.

 

Under the test conditions, the partition coefficient, log Kow, of Dimetol was determined to be 3.0 at 45 °C.

Description of key information

A study was conducted to determine the partition coefficient of Dimetol by Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline 117.

Key value for chemical safety assessment

Log Kow (Log Pow):
3

Additional information