3-[3-(1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)propoxy]- 2-hydroxypropyl methacrylate and 1-[3-(1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)propoxy]-3-hydroxypropan-2-yl methacrylate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Testing conducted between 16 May 2008 and 02 Sepetember 2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to GLP and in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not effect the quality of the relevant results.

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Type:

log Pow

Partition coefficient:

> 6.5

Temp.:

30 °C

pH:

7.7

Details on results:

Results:
Preliminary estimate:
Approximate solubility in n-octanol: >1.00 x 103 g/l
Aproximate solubility in water: <1.50 x 10E-3 g/l
Approximate Pow: >6.69 x 10E5
Log10 Pow: >5.83

results from definitive test:
Mean Log Pow: >6.50
Partition coefficient:>3.16 x 10E6.

Definitive test:

The retention times (RT) in minutes of the deadtime and the retention times, capacity factors (k) and log₁₀ Pow values for the reference standards are shown in the following tables below:

Dead time	RT (Injection 1)	RT (Injection 2)	Mean RT (mins)
Thiourea	2.640	2.638	2.639

Stanadard	RT injection1	RT injection 2	Mean RT (mins)	Capacity factor (k)	Log10 K	Log10 Pow
Benzene	5.169	5.175	5.172	0.960	-1.78 x 10 -2	2.1
Toluene	6.391	6.400	6.396	1.42	0.153	2.7
Naphthalene	7.532	7.543	7.538	1.86	0.269	3.6
Phenanthrene	12.084	12.105	12.095	3.58	0.554	4.5
Triphenylamine	23.295	23.322	23.309	7.83	0.894	5.7
DDT	31.921	31.951	31.936	11.1	1.05	6.5

Partition coefficient of sample: The retention times, capacity factors and log10 Pow values determined for the sample are shown in the table below:

Peak No.	Injection	RT (mins)	Capacity factor (k)	Log10 K	Log10 Pow
1	1	47.219	16.9	1.23	>6.50
1	2	47.302	16.9	1.23	>6.50
2	1	50.828	18.3	1.26	>6.50
2	2	50.919	18.3	1.26	>6.50

Discussion:

Substances having a log10 Pow greater than 3 are regarded as having the potential to biaccumulate in the environment. The test material was considered to contain one (alcoholic) dissociating group, with an estimated pKa of 13.07 +/- 0.20 (using ACD/I-lab web Service (ACD/pKa 8.03)). Therefore, testing was carried out at approximately neutral pH, with the test material present in its unionised form.

The two peaks observed in the sample injections has been considered to be due to the test material having a chiral centre, leading to two different structural isomeric forms.

To conclude, the partition coefficient of the test material has been determined to be greater than 3.16 x 10⁶, log10 Pow >6.50.

Dead time	RT (Injection 1)	RT (Injection 2)	Mean RT (mins)
Thiourea	2.640	2.638	2.639

Conclusions:

The partition coefficient of the test material has been determined to be > 3.16 x 10E6, log Pow >6.50.

Executive summary:

The partition coefficient of SiMAA2 conducted in study number 2551/0013 was determinated using the HPLC Method, Method A8 of Commission Directive 92/69/EEC (which constitutes Annex V of council directive 67/548/EEC).

Under the conditions of the test, the test material was determined to have a partition coefficient of > 3.16 x 10⁶, and a log Pow >6.50.

Description of key information

The partition coefficient of SiMAA2 was determinated using the HPLC Method, Method A8 of Commission Directive 92/69/EEC.

Under the conditions of the test, the test material was determined to have a partition coefficient of > 3.16 x 10⁶, and a log Pow >6.50.

Key value for chemical safety assessment

Log Kow (Log Pow):

6.5

at the temperature of:

30 °C