Trimethoxyphenylsilane

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2008-08-05 to 2008-10-03

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

Principles of method if other than guideline:

The partition coefficient of the test material was determined over the environmentally relevant pH range of 4 to 10, using the shake-flask method, Method 107 of the OECD Guidelines for Testing of Chemicals, 27 July 1995.

GLP compliance:

yes

Type of method:

shake-flask method to: flask method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

0.015

Temp.:

22 °C

pH:

4.2 - 4.3

Type:

log Pow

Partition coefficient:

-0.021

Temp.:

22 °C

pH:

7 - 7.1

Type:

log Pow

Partition coefficient:

-0.419

Temp.:

22 °C

pH:

9.5 - 9.6

Table 1: pH 4, total weights (mg) and analysed concentration (mg/l) of the respective phases

Sample Number	Volume of water saturated n-octanol (ml)	Volume of stock solution (ml)	Total Weight (mg)*	Organic Phase		Aqueous Phase
				Analysed Concentration (mg/l)	Weight (mg)†	Analysed Concentration (mg/l)	Weight (mg)†	pH
1	50	50	9.92	93.0	4.65	85.6	4.28	4.3
2	60	60	11.9	89.4	5.36	86.3	5.18	4.2
3	45	90	17.9	122	5.48	113	10.2	4.3
4	45	90	17.9	121	5.45	112	10.1	4.2
5	100	50	9.92	59.0	5.90	59.7	2.98	4.3
6	110	55	10.9	55.6	6.12	58.9	3.24	4.2

*From analysis of the stock solution

†From analysis of the respective phase

Table 2: pH 4, partition coefficient determined for each sample

Sample Number	n-Octanol/Water Volume Ratio	Partition Coefficient	Log10Pow	Mean Partition Coefficient
1	1:1	1.09	3.62 x 10^-2	1.06
2		1.04	1.53 x 10^-2
3	1:2	1.08	3.20 x 10^-2	1.08
4		1.08	3.25 x 10^-2
5	2:1	0.989	-4.69 x 10^-3	0.967
6		0.945	-2.45 x 10^-2

pH 7, total weights (mg) and analysed concentration (mg/l) of the respective phases

Sample Number	Volume of water saturated n-octanol (ml)	Volume of stock solution (ml)	Total Weight (mg)*	Organic Phase		Aqueous Phase
				Analysed Concentration (mg/l)	Weight (mg)†	Analysed Concentration (mg/l)	Weight (mg)†	pH
1	50	50	9.80	95.3	4.77	90.4	4.52	7.0
2	60	60	11.8	88.1	5.29	92.0	5.52	7.0
3	45	90	17.6	126	5.69	122	11.0	7.0
4	45	90	17.6	118	5.32	123	11.0	7.0
5	100	50	9.80	58.6	5.86	66.8	3.34	7.1
6	110	55	10.8	57.2	6.29	68.7	3.78	7.0

*From analysis of the stock solution

†From analysis of the respective phase

pH 7, partition coefficient determined for each sample

Sample Number	n-Octanol/Water Volume Ratio	Partition Coefficient	Log10Pow	Mean Partition Coefficient
1	1:1	1.05	2.28 x 10^-2	1.01
2		0.958	-1.89 x 10^-2
3	1:2	1.04	1.50 x 10^-2	1.00
4		0.964	-1.59 x 10^-2
5	2:1	0.878	-5.67 x 10^-2	0.855
6		0.833	-7.95 x 10^-2

pH 10, total weights (mg) and analysed concentration (mg/l) of the respective phases

Sample Number	Volume of water saturated n-octanol (ml)	Volume of stock solution (ml)	Total Weight (mg)*	Organic Phase		Aqueous Phase
				Analysed Concentration (mg/l)	Weight (mg)†	Analysed Concentration (mg/l)	Weight (mg)†	pH
1	50	50	9.63	53.2	2.66	138	6.89	9.5
2	60	60	11.6	52.7	3.16	138	8.28	9.6
3	45	90	17.3	63.9	2.87	161	14.5	9.6
4	45	90	17.3	63.4	2.86	161	14.5	9.6
5	100	50	9.63	39.4	3.94	108	5.40	9.5
6	110	55	10.6	39.1	4.30	108	5.93	9.6

*From analysis of the stock solution

†From analysis of the respective phase

pH 10, partition coefficient determined for each sample

Sample Number	n-Octanol/Water Volume Ratio	Partition Coefficient	Log10Pow	Mean Partition Coefficient
1	1:1	0.386	-0.413	0.384
2		0.382	-0.418
3	1:2	0.396	-0.403	0.395
4		0.395	-0.404
5	2:1	0.365	-0.438	0.364
6		0.363	-0.440

Conclusions:

Log Kow values of 0.015, -0.021 and -0.419 at pH 4, 7 and 10 and 22 were determined for the hydrolysis product in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP.

Reference 2

Endpoint:

partition coefficient

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Study period:

2011

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:

The result was obtained using an appropriate QSAR method (see attached QMRF and QPRF for details).

Partition coefficient type:

octanol-water

Type:

log Pow

Partition coefficient:

-1.1

Estimated value, no data available for temperature and pH

Conclusions:

An octanol-water partition coefficient value of -1.1 was obtained for the hydrolysis product using an accepted calculation method. The result is considered to be reliable.

Description of key information

Log Kow (phenylsilanetriol): 0.015, -0.021 and -0.419 at pH 4, 7 and 10 and 22°C (measured)

Key value for chemical safety assessment

Log Kow (Log Pow):

-0.021

at the temperature of:

22 °C

Additional information

Measured Log Kow values of 0.015, -0.021 and -0.419 at pH 4, 7 and 10 respectively (at 22°C) were determined for the hydrolysis product (phenylsilanetriol) by the shake-flask method according OECD Guideline 107. A log Kow value of -1.1 was obtained using an appropriate calculation method.