Registration Dossier

Diss Factsheets

Physical & Chemical properties

Partition coefficient

Currently viewing:

Administrative data

Link to relevant study record(s)

Referenceopen allclose all

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Guideline:
other: no data
Principles of method if other than guideline:
no data
GLP compliance:
not specified
Type of method:
other: measured
Partition coefficient type:
octanol-water
Analytical method:
not specified
Type:
log Pow
Partition coefficient:
-0.77
Remarks on result:
other: value from secondary literature source
Details on results:
The log Pow value has been obtained from a secondary literature source which did not list the temperature or pH of the test system.

Value from generally accepted authoritative secondary source. No data available for temperature and pH value.

Conclusions:
The value for the log Pow of Methanol is reported to be -0.77 from a reliable peer-reviewed handbook source.
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
No data
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study
Qualifier:
according to guideline
Guideline:
EU Method A.8 (Partition Coefficient)
Deviations:
not specified
GLP compliance:
yes
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Analytical method:
high-performance liquid chromatography
Type:
log Pow
Partition coefficient:
-1.09
Temp.:
22 °C
pH:
7.5
Details on results:
Preliminary estimate: The estimated n-octanol solubility was approximately 18.08 g/L. The water solubility of the substance in water was 49.23 g/L. Therefore the Pow, estimate = 18.08/49.23 = 0.37 or log Pow,estimated = -0.43.
The log Pow of the test substance was -1.09 ± 0.16 (22 ± 1 ºC).

All concentrations of the n-octanol phases are corrected with the recovery of the extraction, as shown in the tables below.

Results of the partition test:

Serie

Conc. n-octanol phase (g/L)

Conc. aqueous phase (g/L)

Pow

Log Pow

Mean log Pow

1

0.030

0.513 (pH 7.5)

0.06

-1.23

-127

0.025

0.519 (pH 7.5)

0.05

-1.32

2

0.016

0.304 (pH 7.5)

0.05

-1.27

-1.09

0.033

0.302 (pH 7.5)

0.11

-0.97

3

0.063

0.579 (pH 7.5)

0.11

-0.96

-0.97

0.059

0.548 (pH 7.5)

0.11

-0.97

Mean value of all determinations: Series 1, 2 and 3:

Pow= 0.081 ± 0.030

Log Pow= -1.09 ± 0.16 (22 ± 1ºC)

The recovery of the partition test is calculated with the concentrations of the stock solution which was analysed by means of HPLC.

Determination of the recovery:

est

n-octanol phase

(mg/L)

Aqueous phase

(mg)

Total

(mg)

Recovery

(%)

1

0.829

15.477

16.306

93

2

0.743

9.089

9.823

112

3

1.832

33.820

35.651

102

Results of the recovery test after extraction with 0.01 N H2SO4:

Original

concentration

(g/L)

Concentration

after extraction

(g/L)

Recovery

%

0.069

0.054

78

0.069

0.046

66

The mean value of the recovery of the two solutions is 72 ± 8 %.

Conclusions:
The log partition coefficient n-octanol/water (Log Pow) of boric acid appeared to be -1.09 ± 0.16 (22 ± 1 ºC).

Description of key information

TMBX is hydrolytically unstable and experimental derivation of a octanol water partition coefficient is technically not possible. A value of -5.67 is predicted by KOWWIN v1.68 however given the hydrolytic instability of the substance this cannot be considered reliable. TMBX hydrolyses to form methanol and boric acid, both of which are toxicologically significant species and the partition coefficients for these breakdown products should be considered instead. The log partition coefficient n-octanol/water (Log Pow) of boric acid was measured to be -1.09 ± 0.16 (22 ± 1 ºC).   The value for the log Pow of Methanol is reported to be -0.77 from a reliable peer-reviewed handbook source.

Based upon the most sensitive environmental toxicity studies available, the partition coefficient for Boric acid was selected as the most appropriate value for the Chemical Safety Assessment.

Key value for chemical safety assessment

Log Kow (Log Pow):
-1.09
at the temperature of:
22 °C

Additional information