Ethoxytrimethylsilane

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Type of method:

flask method

Partition coefficient type:

octanol-water

Analytical method:

gas chromatography

Type:

Pow

Partition coefficient:

15.4

Temp.:

25 °C

pH:

7.1

Remarks on result:

other: mean Pow; temperature ± 0.5°C

Type:

log Pow

Partition coefficient:

1.19

Temp.:

25 °C

pH:

7.1

Remarks on result:

other: temperature ± 0.5°C

 

Sample Number	Volume of stock solution (ml)	Volume of n-octanol saturated water (ml)	Total Weight (mg)	Organic Phase		Aqueous Phase
				Analysed Concentration (mg/l)	Weight (mg)	Analysed Concentration (mg/l)	Weight (mg)	pH
1	50	25	48.3	952	47.6	63.0	1.58	6.8
2	50	25	48.3	935	46.7	62.6	1.57	6.8
3	40	40	38.7	879	35.2	57.3	2.29	6.9
4	40	40	38.7	891	35.7	54.6	2.18	7.0
5	25	50	24.2	838	21.0	52.4	2.62	7.0
6	25	50	24.2	807	20.2	55.2	2.76	7.0

 

Sample Number	n-Octanol/Water Volume Ratio	Partition Coefficient	Log10Pow	Mean Partition Coefficient
1 2	2:1	15.1 14.9	1.18 1.17	15.0
3 4	1:1	15.3 16.3	1.19 1.21	15.8
5 6	1:2	16.0 14.6	1.20 1.17	15.3

Mean P_ow: 15.4                                Log₁₀P_ow: 1.19                                P_owstandard deviation : 0.656

 

Conclusions:

An octanol-water partition coefficient value of 1.19 was determined in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP.

Reference 2

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The study was conducted according to a test protocol that is comparable to the appropriate OECD test guideline. It was not compliant with GLP.

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

yes

Remarks:

includes correction for silicon compounds

GLP compliance:

no

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

1.22

Remarks on result:

other: ± 0.13

Details on results:

Trimethylsilanol can react with 1-octanol to form octanoxytrimethylsilane (OTMS) once it partitions into the 1-octanol phase. The impact of this was investigated in the study and it was concluded that the effect on the measured log Kow was relatively small, with an average overestimation of log Kow by 0.05 log units. The RP HPLC/RAM method was therefore considered a valid method.

Conclusions:

An octanol-water partition coefficient value of 1.22 ± 0.13 was determined in a reliable study conducted according to an appropriate test protocol. The study was not conducted according to GLP.

Description of key information

Trimethylsilanol: 1.19 at 25 ± 0.5°C and pH 7.1 (shake flask method, OECD 107)

Key value for chemical safety assessment

Log Kow (Log Pow):

1.19

at the temperature of:

25 °C

Additional information

An octanol-water partition coefficient value of 1.19 at 25°C and pH 7.1 was determined for trimethylsilanol in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP. This is supported by a second reliable study that reports a log K_ow value of 1.22 at 25°C.