Sulfuric acid, mono-C12-14(even numbered)-alkyl esters, ammonium salts

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-07-05 to 2010-07-09

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 123 (Partition Coefficient (1-Octanol / Water), Slow-Stirring Method)

GLP compliance:

no

Type of method:

other: Slow-stirring method

Partition coefficient type:

octanol-water

Analytical method:

other: UPLC

Type:

log Pow

Partition coefficient:

0.8

Temp.:

22 °C

pH:

7.1 - 7.6

Remarks on result:

other: RSD 7.6%

Type:

Pow

Partition coefficient:

6.68

Temp.:

22 °C

pH:

7.1 - 7.6

Remarks on result:

other: RSD 15%

Annotation: According to the applied guideline the slow-stirring method is particularly suitable for the determination of substance with expected log P_ow value of 5 and higher, for which the shake-flask method (generally applicable from log P_ow= -2 to 4) is prone by yield erroneous results.

However, according to the REACH Guidance on information requirements and chemical safety assessment-Chapter R.7a: Endpoint specific guidance, the shake-flask method is not recommended for surfactants. Instead, the slow-stirring method is advised as the preferred test method in this case.

The concentration of the test item in the water and octanol phase of the three different test solutions was determined after 14, 16, 18 and 20 hours.

	Test solution 1		Test solution 2		Test solution 3
Time (h)	Co/Cw	log (Co/Cw)	Co/Cw	log (Co/Cw)	Co/Cw	log (Co/Cw)
14	7.56	0.88	6.20	0.79	5.13	0.71
16	9.24	0.97	7.72	0.89	4.94	0.69
18	5.77	0.76	6.41	0.81	5.58	0.75
20	7.72	0.88	7.14	0.85	6.72	0.83

 

The resulting mean values for the different test solutions are listed below:

Test solution	Mean value Co/Cw	Standard deviation	Mean value log (Co/Cw)	Standard deviation	Variance
1	7.57	1.42	0.87	0.09	0.007
2	6.87	0.70	0.84	0.04	0.002
3	5.59	0.80	0.75	0.06	0.04
Mean value of three test solutions
	6.68		0.82
RSD	15 %		7.6 %

Additional data:

pH-Value of water, saturated with 1-octanol: 5.8-5.9

 

pH-Value of test solution 1 after 20 h: 7.1-7.2

pH-Value of test solution 2 after 20 h: 7.5-7.6

pH-Value of test solution 3 after 20 h: 7.2-7.3

The substance is stable in n-octanol.

Description of key information

The partition coefficient: log Pow is 0.8 at 22°C

Key value for chemical safety assessment

Log Kow (Log Pow):

0.8

at the temperature of:

22 °C

Additional information

According to the REACH Guidance on information requirements and chemcial safety assessment - Chapter R.7a: Endpoint specific guidance, the shake-flask method is not recommended for surfactants. Instead, the slow-stirring method is advised as the preferred test method in this case (OECD Guideline 123). In the earlier version of the study report, the slightly erroneous value of log Pow = 0.91 was given.