Reaction mass of 4-tert-butyl-2,5-xylenol and 6-tert-butyl-2,4-xylenol

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-01-25

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Meets the requirements of GLP. There are no deviations from the recommended guideline.

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)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

4.148

Temp.:

22 °C

pH:

5.5

Details on results:

The chromatogram of the test substance gave three peaks, two main peaks and another small peak. The corresponding log POW were determined with 2.348 (peak 1), 3.896 (peak 2), and 4.148 (peak 3). Although area is not necessarily correlated to absolute concentration if a UV detector is used, it is believed that the test substance consists mainly of the third peak, indicating that the log Pow should be regarded as 4.148.

Reference Items:

The values for log K and log Pow of the reference items were presented in the following table:

Compound	log K	log Pow
Acetophenone	-0.2958	1.70
Naphthalene	0.4222	3.60
Diphenylether	0.5889	4.20
Phenanthren	0.7727	4.50
Fluoranthene	0.9359	4.70
Triphenylamine	1.2083	5.70

 

Correlation Results

Dead time was 1.508 ± 0.004 minutes, with RSD 0.24%.

The RSD of the retention times of the reference items lay all below 0.5 %.

Equation of the regression:

log k = 0.383 * log Pow - 0.95228979 (r²= 0.9904)

 

Test substance:

 The validity criteria and results (mean ± sd) are presented in the following table:

 

Peak	Parameter	Criterion	Found	Assessment
1	Range (Max - Min. log Pow)	< 0.1	0.005	valid
	Value within Range of Ref. Items	1.70-5.70	2.348±0.003	valid
2	Range (Max - Min. log P0w)	<0.1	0.004	valid
	Value within Range of Ref. Items	1.70-5.70	3.896±0.002	valid
3	Range (Max - Min. log P0w)	<0.1	0.006	valid
	Value within Range of Ref. Items	1.70-5.70	4.148±0.004	valid

 

Conclusions:

The Partition Coefficient n-octanol/water calculated as log Pow for the test substance is 4.148.

Executive summary:

The Partition Coefficient (n-octanol/water), High Performance Liquid Chromatography (HPLC) method was carried out for the test substance. The calibration graph log Pow versus log k has been established with six references substances recommended in the OECD guideline 117. The dead time t_owas measured by using thio-urea as un-retained compound. Three injections were measured from the reference item mix, three injections from the test substance solution and again three injections from the reference item mix. The pH of the test substance solution was 5.5 and the assay temperature 22 ºC. The chromatogram of the test substance gave three peaks. The corresponding log Pow were determined with 2.348 (peak 1), 3.896 (peak 2), and 4.148 (peak 3). Although area is not necessarily correlated to absolute concentration if a UV detector is used, it is believed that the test substance consists mainly of the third peak, indicating that the log Pow should be regarded as 4.148.

Description of key information

Key study: Experimental result: Test according to OECD 117 and EU method A8. GLP study.

log Pow  4.148  at 22 °C and pH  5.5    

Key value for chemical safety assessment

Log Kow (Log Pow):

4.148

at the temperature of:

22 °C

Additional information

Key study: Experimental result: Test according to OECD 117 and EU method A8.

The Partition Coefficient n-octanol/water calculated as log Pow for the test substance is 4.148, at 22ºC and pH 5.5.