2-Methoxy-4-methylphenyl methyl carbonate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11-08-2011 to 01-12-2011

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study performed under GLP. The test item Log Kow was extrapolated from the calibration range. The information is acceptable as a measured value with provided supporting information as part of a weight of evidence approach.

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

The test item Log Kow was extrapolated from the calibration range. The information is acceptable as a measured value as part of a weight of evidence approach with provided supporting information.

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

See above.

GLP compliance:

yes (incl. QA statement)

Remarks:

inspected: May 2009; signature: September 2009

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

photometric method

Type:

log Pow

Partition coefficient:

2.27

Temp.:

30 °C

pH:

7

Remarks on result:

other: mean of five replicates (n=5)

Preliminary estimate:

Approximate K_ow : 120

Log10 K_ow estimate: 2.08

Definitive test:

Calibration:

The retention times, capacity factors (k) and log₁₀ K_ow values for the reference standards are shown in Table 2

Table 2: Calibration

	RT 1	RT 2	RT 3	RT 4	RT 5	Mean RT	STD	CV (%)	K	Log10K	Log10Kow
	(min)	(min)	(min)	(min)	(min)	(min)
(To) Dead Time	3.23	3.22	3.22	3.22	3.22	3.22	0.00	0.14	0	-	-
2-Butanone	5.06	5.06	5.05	5.05	5.04	5.05	0.01	0.17	0.57	-0.246	0.30
4-Acetylpyridine	5.92	5.91	5.91	5.90	5.91	5.91	0.01	0.14	0.83	-0.079	0.50
Aniline	6.41	6.41	6.41	6.39	6.39	6.40	0.01	0.17	0.99	-0.006	0.90
Benzonitrile	9.47	9.45	9.44	9.44	9.43	9.45	0.02	0.16	1.93	0.286	1.60
Nitrobenzene	13.39	13.37	13.36	13.35	13.34	13.36	0.02	0.14	3.15	0.498	1.90
Methylbenzoate	18.99	18.96	18.94	18.93	18.92	18.95	0.03	0.15	4.88	0.688	2.10

 

Partition coefficient calculation:

The partition coefficient was calculated using the equation:

Log₁₀ K_ow = slope x Log₁₀K + intercept

Log₁₀ K_ow = 2.27

Partition coefficient of sample:

The retention times, capacity factors (k) and and log₁₀K_ow values determined for the sample are shown in Table 3.

 

Table 3: Partition coefficient of sample

	RT 1	RT 2	RT 3	RT 4	RT 5	Mean RT	STD	CV (%)	K	Log10K	Log10Kow
	(min)	(min)	(min)	(min)	(min)	(min)
(To) Dead Time	3.22	3.22	3.22	3.22	3.22	3.22	0.00	0.00	0.00	-	-
test item	19.47	19.46	19.46	19.45	19.45	19.46	0.01	0.04	5.043	0.703	2.27

 

RT = Retention time

Mean RT = Mean retention time

STD = standard deviation

CV = coefficient of variation

Mean log₁₀ K_ow: 2.27

Partition coefficient: 1.86 x 10²

Conclusions:

The partition coefficient of the test substance was determined to be log Pow = 2.27 at 30 °C and ca. pH 7.0

Executive summary:

The n-octanol/water partition coefficient was determined using the HPLC method within EU Method A.8 and OECD TG 117 under GLP. The test was performed with a concentration of 0.1 g test item/L injected at 10 μl into 50% methanol : 50% HPLC water. Samples of the test item were analysed via HPLC on a C18 column with RI detection. Calibration was performed using six reference items with known log Kow values (given by the guidelines). The void time of the HPLC system was determined from the injection peak. Five individual log Kow values for the chromatographic resolved test item signal were derived under consideration of the calibration and the analytically resolved chromatographic peak. Finally, a mean value was calculated from these individual log Kow values. The mean log Kow was 2.27 where n=5. The partition coefficient of the test substance was determined to be log Kow = 2.27 at a temperature 30 °C and approximately neutral pH.

Description of key information

Weight of evidence: Log Kow limit-value: < 2.44 and measured-log Kow = 2.27 at 25 °C and pH 7, 2017

Key value for chemical safety assessment

Log Kow (Log Pow):

2.27

at the temperature of:

25 °C

Additional information

Weight of evidence: Log Kow limit-value: < 2.44 and measured-log Kow = 2.27 at 25 °C and pH 7, 2017

 

The substance is by expert judgement expected to have a Log Kow value < 2.44 based on the following information:

 

1. measured-log Kow = 2.27 (extrapolated) at 30 °C and ca. pH 7.0, EU Method A.9, 2011

The n-octanol/water partition coefficient was determined using the HPLC method within EU Method A.8 and OECD TG 117 under GLP. The test was performed with a concentration of 0.1 g test item/L injected at 10 μl into 50% methanol : 50% HPLC water. Samples of the test item were analysed via HPLC on a C18 column with RI detection. Calibration was performed using six reference items with known log Kow values (given by the guidelines). The void time of the HPLC system was determined from the injection peak. Five individual log Kow values for the chromatographic resolved test item signal were derived under consideration of the calibration and the analytically resolved chromatographic peak. Finally, a mean value was calculated from these individual log Kow values. The mean log Kow was 2.27 where n=5. The partition coefficient of the test substance was determined to be log Kow = 2.27 at a temperature 30 °C and approximately neutral pH. Applicant assessment indicates: the test item Log Kow was extrapolated from the calibration range. The information is acceptable as a measured value with provided supporting information as part of a weight of evidence approach.

 

Supporting information: 

2. calculated-log Kow = 2.08 at 25 °C and ca. pH 7.0, KOWWIN v1.68, US EPA, 2017

Expert judgement would indicate based on KOWWIN v1.68 model performance: a measured value of log Kow = 2.28 would not be unexpected.

 

3. Measured water solubility (376 mg/L, anon., OECD TG 105, 2011) would indicate in WSKOW v1.42 model a log Kow = 2.44, is an appropriate limit-value based on the totality of data.

 

Conclusion: The substance has a log Kow << 4.0

Range: 2.08 > Log Kow < 2.44 and measured Log Kow = 2.27

 

Under REACH Regulation No. (EC) 1907/2006: Annex XI: section 1.2 - weight of evidence, adequate information is available for environmental hazard and risk assessment and therefore further testing is omitted.

 

References for further information:

1. Experimental Study: Anon., Log Kow, OECD TG 117, 2011

2. Experimental Study: Anon., Water Solubility, OECD TG 105, 2011

3. QMRF Title: KOWWIN v1.68 : n-Octanol/Water Partition Coefficient (Log Kow) : version 1.01, 01 September 2015

4. QPRF Title: 2 -methoxy-4-methylphenyl methyl carbonate using the model KOWWIN v1.68 for the endpoint: Partition Coefficient (Log Kow): version 1.0, 11 July 2017

5. Related model: WSKOW v1.42, US EPA, 2010