Benzyl 4-[(1-butyl-5-cyano-1,6-dihydro-2-hydroxy-4-methyl-6-oxopyridin-3-yl)azo]benzoate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 May to 21 May, 2019

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:

2004

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Regulation EC No. 440/2008

Qualifier:

according to guideline

Guideline:

other: Method A.24

Version / remarks:

Regulation EC No. 2016/266

Principles of method if other than guideline:

The suitable method will be decided on the basis of the preliminary test results.

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

5.87

Temp.:

20 °C

pH:

7.1

Details on results:

PRELIMINARY TESTS
The preliminary test at room temperature showed, that the water solubility of the test item was below 7.86 mg/l. The observations of the preliminary test are:
Amount of test item [mg] Volume of water [ml] Stirring time [d] Remark
9.05 100 7 not dissolved
4.68 250 7 not dissolved
3.93 500 7 not dissolved
The preliminary test at room temperature showed, that the octanol solubility of the test item was below 1.73 g/l. The observations of the preliminary test are:
Amount of test item [mg] Added volume of octanol [ml] Stirring time at RT [min] Remark
130 5 40 not dissolved
20 45 not dissolved
50 985 not dissolved
With a water solubility of less than 7.86 mg/l and the solubility in octanol of less than 1.73 g/l, determined from these preliminary tests, the partition coefficient can be estimated to be ca. 2.3.
For the determination of the log Pow value at this value, the HPLC method is recommended and carried out.

MAIN TEST
After the measurements of the retention times, tR, the log k values of the reference items were plotted as a function of their log Pow values. The partition coefficient of the test item was obtained by interpolation of the calculated capacity factor on the calibration graph of the reference items.

1st run 2nd run mean value
t0 (min) 1.639 1.639 1.639

reference item (1st meas.) tR k log k log Pow[1]
Acetanilide 2.027 0.237 -0.626 1.0
4-Methyl benzyl alcohol 2.167 0.322 -0.492 1.6
Cinnamyl alcohol 2.197 0.340 -0.468 1.9
Allyl phenyl ether 3.177 0.938 -0.028 2.9
Diphenyl ether 4.131 1.520 0.182 4.2
Fluoranthene 6.945 3.237 0.510 5.1
4,4’ DDT 9.397 4.733 0.675 6.5
The first measurement and the linear regression of the calibration graph leads to an equation for the log Pow of log Pow = 3.882 × log k + 3.451 (correlation coefficient, r, = 0.9884).

reference item (2nd meas.) tR k log k log Pow1
Acetanilide 2.029 0.238 -0.624 1.0
4-Methyl benzyl alcohol 2.168 0.323 -0.491 1.6
Cinnamyl alcohol 2.197 0.340 -0.468 1.9
Allyl phenyl ether 3.181 0.941 -0.026 2.9
Diphenyl ether 4.132 1.521 0.182 4.2
Fluoranthene 6.936 3.232 0.509 5.1
4,4’ DDT 9.386 4.727 0.675 6.5
The second measurement and the linear regression of the calibration graph leads to an equation for the log Pow value of log Pow = 3.888 × log k + 3.449 (correlation coefficient, r, = 0.9883).
With the determined regression coefficients a and b, the log Pow of the test item can be calculated for both measurements.
Test item tR k log k log Pow Pow (1st meas.)
1st meas. 8.525 4.201 0.623 5.87 742623
2nd meas. 8.509 4.192 0.622 5.87 739524
mean value 5.87 741074
standard deviation < 0.01 1550
The test item has a partition coefficient of log Pow = 5.87 ± < 0.01 at 20 °C and pH 7.1.

Conclusions:

The partition coefficient of the test item is: log Pow = 5.87 ± < 0.01 at 20 °C and pH 7.1.

Executive summary:

The partition coefficient of the test item was determined by HPLC method, according to the EU method A.8 (2008), EU method A.24 (2016) and OECD guideline 117 (2004).

The partition coefficient of the test item was found to be: log Pow = 5.87 ± < 0.01 at 20 °C and pH 7.1.

Description of key information

log Pow = 5.87 ± < 0.01 at 20 °C and pH 7.1

Key value for chemical safety assessment

Log Kow (Log Pow):

5.87

at the temperature of:

20 °C

Additional information

EU method A.8 (2008), EU method A.24 (2016) and OECD guideline 117 (2004).