N'-(1,3-dimethylbutylidene)-3-hydroxy-2-naphthohydrazide

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 November 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: Directive 92/69/EEC, A.8 (HPLC method) (EEC publ.no L383, Dec 1992)

Qualifier:

according to guideline

Guideline:

OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)

Version / remarks:

(1989)

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:

1.7

Temp.:

20 °C

pH:

6

Remarks on result:

other: major component

Type:

log Pow

Partition coefficient:

0.6

Temp.:

20 °C

pH:

6

Remarks on result:

other: minor component

Details on results:

estimated log Pow based on Rekker Calculation method: 3.76
estimated pKa based on Perrin's Calculation method: acidic groups (phenol) 8.38, basic groups (ARCONHR) -1.92

Two peaks were observed in the chromatogram and it was assumed that the large peak derives from the major component of BMH whereas the small peak derives from a minor component in BMH. All test substance related peaks eluted well within 10 minutes.

The results of the Calculation method and the HPLC method are not in agreement. Since the HPLC method is a more accurate method than the Calculation method, the result of the HPLC method is reported as the partition coefficient (n-octanol/water), Pow, of BMH.

The t₀ (the retention time of the unretarded component) was determined to be 0.866 minutes as a mean value of both measurements (i.e. 0.866 and 0.866 minutes).

Substance	tr^1	k’	log k’	log Pow	Pow
Reference substance
Ethylmethylketone	1.307	0.509	-0.293	0.3
Nitrobenzene	2.074	1.395	0.145	1.9
Toluene	3.453	2.987	0.475	2.7
Bromobenzene	3.792	3.378	0.529	3.0
1,4-dichlorobenzene	4.934	4.697	0.672	3.4
Biphenyl	5.781	5.676	0.754	4.0
Test substance
minor component	1.410	0.628	-0.202	0.6^2	3.9
major component	2.010	1.320	0.121	1.7^2	48

¹      Mean value of the retention times of two chromatograms.

²      Interpolated from the regression line: log k’ = 0.297*log P_ow- 0.378 (r=0.994, n = 6)

Conclusions:

The HPLC method (with UV-detection) was used to determine the n-octanol/water partition coefficient of BMH. At 20.0 +/- 0.5°C , the Pow value for the major component in BMH is 48 (log Pow = 1.7) and for the minor component in BMH the Pow is 3.9 (log Pow = 0.6).

Description of key information

log Kow of BMH is 1.7 (EC A.8, OECD 117: HPLC-UV).

Key value for chemical safety assessment

Log Kow (Log Pow):

1.7

at the temperature of:

20 °C

Additional information

K_ow of BMH is 48.

In water, BMH hydrolyses into two compounds, being 3-Hydroxy-2 -naphthoic acid, hydrazine (HNH; CAS no. 5341-58-2) and Methyl isobutyl ketone (MIBK; CAS no. 108-10-1), with a DT50 of 28 hours under environmentally relevant conditions. The K_ow of these compounds have been calculated with the KOWWIN program (version 1.67). The Log K_ow is calculated to be 1.85 and 1.16, respectively.