Fatty acids, C16-18 and C18-unsatd., esters with propylene glycol

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Study period:

June 2014

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

QSAR prediction

Principles of method if other than guideline:

Calculation based on KOWWIN v1.68, Estimation Programs Interface Suite™ for Microsoft® Windows v4.10. US EPA, United States Environmental Protection Agency, Washington, DC, USA.

GLP compliance:

no

Partition coefficient type:

octanol-water

Key result

Type:

log Pow

Partition coefficient:

16.11

QSAR result; pH and temperature are not reported. For detailed description of the model and its applicability, see "Any other information on materials and methods incl. tables".

Reference 2

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 Feb - 21 Apr 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Guideline study with acceptable restrictions (no temperature and pH given for log Pow measurements)

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

no

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Key result

Type:

log Pow

Partition coefficient:

8.474

Temp.:

20 °C

Remarks on result:

other: no pH value was given.

Details on results:

The log Kow is determined to be 8.474 at 20 °C.

Calibration:

By analysis of six different reference items via HPLC the corresponding retention times can be determined. By relating the logarithm of the determined capacity factors (log k) to the corresponding log Pow values (known from literature), the calibration curve with the following parameters was set up:

y = 2.6966x + 5.4104 (with x 0 log k and y = log Pow)

R² = 0.6651

Table of reference items and their retention times (as mean of a duplicate determination), the respective capacity factors are also given (k = (t_r -t₀)/t₀):

Reference Item	Log Pow	Retention time tR[min]	Capacity factor k	Log k
Urea	--	2.338 (t0)	--	--
4-Chlorophenol	2.4	2.448	0.047	-1.327
Ethyl benzoate	2.6	2.823	0.207	-0.683
Ethyl benzene	3.2	3.082	0.319	-0.497
n-Butyl benzene	4.6	3.486	0.491	-0.309
Dibenzyl	4.8	3.407	0.458	-0.340
Triphenylamine	5.7	3.675	0.572	-0.242

Partition Coefficient of the Test Item:

The table below summarises the measured and calculated values of the mean signals of the test item:

Area [%]	Average Area [%]	Retention time tR[min]	Average tR[min]	Capacity factor	Log k	Log Pow
6.75 6.90 7.16 6.87	6.92	4.560 4.560 4.560 4.570	4.563	0.952	-0.021	5.353
8.60 8.74 8.85 8.93	8.78	24.777 24.731 24.737 24.774	24.755	9.590	0.982	8.058
17.50 18.26 18.50 17.69	17.99	26.324 26.252 26.276 26.313	26.291	10.248	1.011	8.136
48.84 49.97 51.45 49.73	50.00	34.334 34.253 34.272 34.377	34.309	13.678	1.136	8.474

The mean components of the test item elute in a range from 4.563 minutes to 34.309 minutes. By applying the calibration equation given above, the following partition coefficient can be reported for the mean component (amount of 50%):

log Pow = 8.474

The retention times of the reference items ranging from 2.4 to 3.7 minutes and the mean component of the test item elute at 34.3 minutes. The partition coefficient was calculated by extrapolation of the regression line.

Conclusions:

The log Kow is determined to be 8.474 at 20 °C.

Description of key information

log Pow = 8.474 (OECD 117)
log Pow > 10 (KOWWIN v1.68)

Key value for chemical safety assessment

Log Kow (Log Pow):

8.474

at the temperature of:

20 °C

Additional information

The log Pow of the test substance was determined according to OECD 117 by HPLC method.

Due to the use of reference substances with lower log Pow (max. log Pow = 5.7, triphenylamine) the final result had to be extrapolated from the calibration equation with R² = 0.6651. This result is therefore supported by QSAR calculation with KOWWIN v1.68.

The log Pow =16.11 of the test substance was determined by QSAR calculation for the main component 2-[(Z)-octadec-9-enoyl]oxypropyl (Z)-octadec-9-enoate. Due to the fact that this substance is long chain fatty acid ester which exceeds the applicability domain of KOWWIN the value for log Pow is reported with restrictions.Therefore the partition coefficient of the substance is deduced to be > 10.