Bis(triethoxysilylpropyl)amine

Hydrolysis

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

02 Nov 2016 - 13 Jun 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

- The hydrolysis test was conducted as a preliminary test within the purposes of an adsorption study according to OECD 106 (see cross reference). Soil samples from 5 different soil types (neutral pH) were weighed into test vessels with 0.01 M CaCl2-solution. After agitation overnight the aqueous phase was filtrated and fortified with the test item. Samples were shaken and at defined sampling points, samples were analyzed to determine hydrolysis of the test item.

GLP compliance:

yes (incl. QA statement)

Remarks:

Staatliches Gewerbeaufsichtsamt Hildesheim, Germany

Radiolabelling:

no

Analytical monitoring:

yes

Remarks:

LC-MS/MS

Details on sampling:

- Determination timepoints of hydrolysis in aqueous phase: 0, 0.25, 0.5, 1, 2, 4, 6, 24 h (except of LUFA soil 2.4 the 24 h measurement did not take place)
- Sampling method: soil samples from 5 different soil types were weighed into the test vessels and an appropriate volume of 0.01 M CaCl2-solution was added. After agitation overnight (12 h minimum) the aqueous phase was filtrated and fortified with the test item. Samples were shaken on an overhead shaker. At defined sampling points, samples were stabilized with acetonitrile (factor 1.1). Samples were analyzed to determine hydrolysis of the test item.
- Sample storage conditions before analysis: no storage

Buffers:

- Type and final molarity of buffer: 0.01 M CaCl2-solution

Estimation method (if used):

The response of the test item was determined as a function of time. The ln responses were plotted against time and the slope of the resulting regression graph gives the rate constant k [1/unit of time]:
K = - slope

The half-life (T½) [unit of time] of the reaction is given by:
T1/2= (0.693/kobs)

Details on test conditions:

TEST SYSTEM
- Type of test flasks: 20 mL headspace vials
- Sterilisation method: none
- Lighting: not specified
- Details on test procedure for unstable compounds: see details on sampling
- If no traps were used, is the test system closed/open: closed
- Is there any indication of the test material adsorbing to the walls of the test apparatus: no
- other: soil samples from 5 different soil types were weighed into the test vessels and an appropriate volume of 0.01 M CaCl2-solution was added

OTHER TEST CONDITIONS
- Adjustment of pH: no

Duration:

24 h

Temp.:

20 °C

Initial conc. measured:

1 mg/L

Remarks:

Hydrolysis was measured in 5 different soils with pH between 5.5 and 7.2

Number of replicates:

two per soil

Transformation products:

not measured

pH:

7.1

Temp.:

20 °C

Hydrolysis rate constant:

0 s-1

DT50:

1.8 h

Remarks on result:

other: Eurosoil 2

pH:

5.5

Temp.:

20 °C

Hydrolysis rate constant:

0 s-1

DT50:

5.6 h

Remarks on result:

other: Eurosoil 3

pH:

6.7

Temp.:

20 °C

Hydrolysis rate constant:

0 s-1

DT50:

1.9 h

Remarks on result:

other: Eurosoil 4

pH:

7.1

Temp.:

20 °C

Hydrolysis rate constant:

0 s-1

DT50:

1 h

Remarks on result:

other: LUFA 2.4

pH:

7.2

Temp.:

20 °C

Hydrolysis rate constant:

0 s-1

DT50:

1.9 h

Remarks on result:

other: LUFA 5M

Table 1: Characteristics of soils used.

	Soils
	Eurosoil 2	Eurosoil 3	Eurosoil 4	LUFA soil 2.4	LUFA soil 5M
FAO soil unit (Eurosoils) Soil Type (LUFA Soils)	Rendzina	Dystric Cambisol	Orthic Luvizol	loam	sandy loam
pH (0.01 M CaCl2)	7.1	5.5	6.7	7.1	7.2
Organic Carbon [%]	3.72	3.01	1.31	1.74	0.92
Clay (<0.002 mm) [%]	22.6	17.0	20.3	25.2	10.2
Silt (0.002-0.063 mm) [%]	64.1	36.8	75.7	42.3	31.1
Sand (0.063-2 mm) [%]	13.4	46.4	4.1	32.6	58.7
Cation Exchange Capacity [mval/100g]	28.9	16.6	17.3	22	10

Table 2: Analytical determination of Hydrolysis in Aqueous Phase (initial nominal concentration of parent substance 1 mg/L)

Time [h]	Eurosoil 2		Eurosoil 3		Eurosoil 4		LUFA 2.4		LUFA 5M
	Mean c [mg/L]	%	Mean c [mg/L]	%	Mean c [mg/L]	%	Mean c [mg/L]	%	Mean c [mg/L]	%
0	0.99	-	0.99	-	0.983	-	0.99	-	0.99	-
0.25	0.893	90	0.944	95	0.891	91	0.887	90	0.873	88
0.5	0.797	81	0.901	91	0.838	85	0.722	73	0.78	79
1	0.695	70	0.856	86	0.746	76	0.573	58	0.666	67
2	0.508	51	0.76	77	0.562	57	0.318	32	0.501	51
4	0.31	31	0.675	68	0.384	39	0.0904	9	0.288	29
6	0.153	15	0.535	54	0.208	21	0.0144	1	0.135	14
24	0.000111	0.011	0.0501	5	0.000147	0.015	-	-	0.000125	0.013

Mean c = mean concentration of two test item replicates, internal standard taken into account

Validity criteria fulfilled:

not applicable

Conclusions:

The test item is prone to fast hydrolysis therefore a Tier 1 test (preliminary study) in order to determine the hydrolysis half-lives of the substance in soil eluates was performed within the purposes of an adsorption study according to OECD guidance 106. The hydrolysis rate and a hydrolytic half-life were determined in soil-conditioned 0.01 M CaCl2 solution for each soil and spiked with the test item. Half-lives between 1 - 5.6 h were determined for the substance depending on the soil.

Reference 2

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

08 Aug - 05 Sep 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

- The test item is prone to hydrolysis. Therefore in the frame of the biodegradation test (see cross reference) according to OECD guideline 301, a preliminary test on the hydrolysis of the substance was performed. The hydrolysis test was performed in purified water for 2 h duration. The test item hydrolyses to ethanol and a silanol hydrolysis product. Ethanol was analytically monitored at several timepoints in order to gather information on the hydrolysis rate of the test item.

GLP compliance:

yes

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products: right after preparation of the test solution and after 0.5, 1 and 2 h
- Sampling method: 1 mL of test solution was taken out of the vessel at sampling points
- Sample storage conditions before analysis: no storage

Details on test conditions:

TEST MEDIUM
- Test solution: water + test item (31 µL (corresp. to 30 mg) test item in 300 mL purified water)
- Kind and purity of water: purified water

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Temperature: RT
- Other: each test solution was stirred by a stirrer

Duration:

2 h

pH:

9.5

Initial conc. measured:

100 mg/L

Remarks:

Temperature: room temperature mentioned in report

Number of replicates:

2

Positive controls:

no

Negative controls:

no

Transformation products:

yes

No.:

#1

Details on hydrolysis and appearance of transformation product(s):

- Formation of transformation product during test: the produced amount of ethanol reached to the theoretical amount after 0.5 h from preparation of the test solutions, showing that the test item was completely hydrolyzed after 0.5 h.

Remarks on result:

other: see field "details on results"

Details on results:

Half of the test material was hydrolyzed right after the preparation of the solution at timepoint 0. 97-99% of the test material was hydrolyzed after 0.5 h.

Table 5: Produced amount of ethanol over 2 h.

Sampling point			Production of ethanol (GC)
			Right after preparation	0.5 h	1 h	2 h
Water + test item	1	mg	10	19.3	19.2	19.7
		%	51	99	98	101
	2	mg	12	18.9	19.1	19.2
		%	62	97	98	99
Theoretical amount (mg)			19.5

Validity criteria fulfilled:

not applicable

Conclusions:

The test item is prone to hydrolysis. Therefore in the frame of the biodegradation test according to OECD guideline 301, a preliminary test on the hydrolysis of the substance was performed. Since the test item hydrolyses to ethanol and a silanol hydrolysis product, ethanol was analytically monitored at several timepoints in order to gather information on the hydrolysis rate of the test item. Half of the test material was hydrolzed right after the preparation of the solution at timepoint 0. 97-99% of the test material was hydrolyzed after 0.5 h.

Reference 3

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 Aug - 02 Sep 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Version / remarks:

2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Staatliches Gewerbeaufsichtsamt Hildesheim, Hildesheim, Germany (2020-08-27)

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products: Samples were taken at test start (0 h) and at a minimum of 12 spaced points, normally between 10 and 90% of hydrolysis, if possible. If, after an incubation time of 10 min, hydrolysis of at least 75% was determined, the number of spaced points was reduced. For the transformation product ethanol the remaining 10 mL of the sample were prepared.
- Temperature check: every 10 minutes automatically (pH 4 and pH 9), once per hour (pH 7), and at least once per day manually
- Sample storage conditions before analysis: The time between test item application and transfer to thermostat / analysis did not exceed 10 min if possible, but at least not more than 2.5% of the total study time.

Buffers:

- pH: 4, 7, 9
- Type and composition of buffer pH 4: 0.36 g of sodium hydroxide and 11.511 g of mono potassium citrate were dissolved in 1000 mL purified water.
- Type and composition of buffer pH 7: 7.708 g of ammonium acetate were dissolved in 1000 mL purified water.
- Type and composition of buffer pH 9: 0.852 g sodium hydroxide, 3.7276 g potassium chloride and 3.0916 g boric acid were dissolved in 1000 mL purified water.
- other: Buffers were purged with nitrogen for 5 min and then the pH was checked to a precision of at least 0.1 at the test temperatures. Buffers were sterilized by filtration through 0.2 µm.

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: 15 mL Centrifuge tubes (pH 4 and pH 9), 15 mL sterile centrifuge tubes (pH 7)
- Test concentration: 30 mg/L in buffer solution at pH 4, 7, 9 with 10% acetonitrile dried as co-solvent
- Sterilisation method: buffers were sterilized by filtration (see section "Buffers"), due to the fast hydrolysis at pH 4 and 9, no sterility is deemed necessary at these test conditions. At pH 7, the study was performed under sterile test conditions.
- Temperature: 10, 20, 30 ± 0.5 °C.
- Measures taken to avoid photolytic effects: Photolytic effects were avoided by using an opaque water bath. The study was conducted protected from direct sunlight.
- If no traps were used, is the test system closed/open: closed

TEST MEDIUM
- Volume used/treatment: 10.33 mL
- Kind and purity of water: Purified water, MERCK, In-house device Milli-Q Advantage A10, ≥ 18.2 MΩ/cm ≤ 50 ppb TOC
- Preparation of test medium: 9.297 mL of the respective buffer solution pH 4, 7 or 9 were given into the test vessels. 1.033 mL of the test item solution (300 mg/L in acetonitrile, dried) was spiked into the vessels and the vessels were closed. For control samples, 9 mL of the respective buffer solution was spiked with 1 mL acetonitrile, dried without test item. Prior to application the buffers pH 4 and 9 were tempered to test temperature.
- Identity and concentration of co-solvent: Acetonitrile, 10% (v/v)

Remarks:

The test was conducted until 90% decomposition was reached.

Number of replicates:

One replicate per sampling date, single injected

Negative controls:

yes

Remarks:

buffer solution at the respective pH value with 10% acetonitrile, dried as co-solvent

Preliminary study:

Due to the fast hydrolysis of the test item, no preliminary test was deemed to be necessary.

Transformation products:

yes

Remarks:

Ethanol was identified as major transformation product and quantified. Additional transformation products were postulated on basis of the expected de-ethoxylation processes and monitored on their masses traces of m/z 258, 286, 314, 342, 370, and 398 Da.

No.:

#1

Details on hydrolysis and appearance of transformation product(s):

- Formation and decline of each transformation product during test: Ethanol was identified as major transformation product and quantified. In sum nine possible transformation products, originated from de-ethoxylation, could be postulated. These nine possible structures were analysed based on their six possible molecular masses and additionally by their retention time differences based on the molecule symmetry. The monitored masses traces are m/z 258 Da, 286 Da, 314 Da, 342 Da, 370 Da and 398 Da. For all test conditions the ln concentration vs. time plots have regression graphs with slopes significantly non zero.
- Pathways for transformation: A confirmation of pseudo first order reaction kinetics with coefficients of determination > 0.8 was achieved for all test conditions.
- Other: First order reaction kinetics were applied for data computation.

pH:

4

Temp.:

10 °C

Hydrolysis rate constant:

0.001 s-1

DT50:

14.3 min

Type:

(pseudo-)first order (= half-life)

pH:

4

Temp.:

20 °C

Hydrolysis rate constant:

0.002 s-1

DT50:

7.7 min

Type:

(pseudo-)first order (= half-life)

pH:

4

Temp.:

30 °C

Hydrolysis rate constant:

0.002 s-1

DT50:

4.73 min

Type:

(pseudo-)first order (= half-life)

pH:

7

Temp.:

10 °C

Hydrolysis rate constant:

0 s-1

DT50:

25.8 h

Type:

(pseudo-)first order (= half-life)

pH:

7

Temp.:

20 °C

Hydrolysis rate constant:

0 s-1

DT50:

11.9 h

Type:

(pseudo-)first order (= half-life)

pH:

7

Temp.:

30 °C

Hydrolysis rate constant:

0 s-1

DT50:

3.69 h

Type:

(pseudo-)first order (= half-life)

pH:

9

Temp.:

10 °C

Hydrolysis rate constant:

0.001 s-1

DT50:

12.5 min

Type:

(pseudo-)first order (= half-life)

pH:

9

Temp.:

20 °C

Hydrolysis rate constant:

0.002 s-1

DT50:

5.62 min

Type:

(pseudo-)first order (= half-life)

pH:

9

Temp.:

30 °C

Hydrolysis rate constant:

0.004 s-1

DT50:

2.7 min

Type:

(pseudo-)first order (= half-life)

Details on results:

TEST CONDITIONS
- pH, temperature, and other experimental conditions maintained throughout the study: Yes, for details see section "any other information on results incl. tables".

MAJOR TRANSFORMATION PRODUCTS
At pH4:
- Range of maximum concentrations in % of the applied amount and day(s) of incubation when observed: for details see section "any other information on results incl. tables"
- Range of maximum concentrations in % of the applied amount at end of study period: for details see section "any other information on results incl. tables"

At pH7:
- Range of maximum concentrations in % of the applied amount and day(s) of incubation when observed: for details see section "any other information on results incl. tables"
- Range of maximum concentrations in % of the applied amount at end of study period:for details see section "any other information on results incl. tables"

At pH9:
- Range of maximum concentrations in % of the applied amount and day(s) of incubation when observed: for details see section "any other information on results incl. tables"
- Range of maximum concentrations in % of the applied amount at end of study period: for details see section "any other information on results incl. tables"

Table 1: pH – value of the test system.

Intended pH-value	Measured pH‑value
	at 10 °C	at 20 °C	at 30 °C
4.0 ± 0.1	4.027	4.041	4.019
7.0 ± 0.1	6.914	6.879	6.870
9.0 ± 0.1	9.098	9.039	9.045

Table 2: Temperature monitoring for the test system.

Test	Intended Temperature	Measured Temperature
		Mean ± SD	Min. / Max.
pH 4	10.0 ± 0.5	10.1 ± 0.1	9.90 / 10.3
	20.0 ± 0.5	20.0 ± 0.02	19.9 / 20.0
	30.0 ± 0.5	30.01 ± 0.005	30.00 / 30.02
pH 7	10.0 ± 0.5	10.1 ± 0.1	9.84 / 10.4
	20.0 ± 0.5	20.1 ± 0.03	20.1 / 20.2
	30.0 ± 0.5	30.0 ± 0.01	30.0 / 30.0
pH 9	10.0 ± 0.5	10.1 ± 0.06	9.98 / 10.2
	20.0 ± 0.5	20.0 ± 0.02	20.0 / 20.0
	30.0 ± 0.5	29.9 ± 0.005	29.91 / 29.92

Table 3: Mass Balance for major transformation product ethanol at pH 4 and 10 °C.

Hydrolysis Time [min]	Ethanol   [mmol/L]	As Test Item^1   [mmol/L]	MB   [%]
0.00	0.0751	0.0811	125
1.00	0.0830	0.0800	125
2.00	0.0943	0.0770	124
4.00	0.123	0.0717	123
7.25	0.158	0.0513	103
10.0	0.179	0.0552	113
14.0	0.225	0.0477	114
18.0	0.253	0.0397	109
22.0	0.287	0.0315	106
26.0	0.299	0.0260	101
34.0	0.336	0.0171	97
42.0	0.354	0.0115	94
50.0	0.385	0.00672	94

1 = molecular factor taken into account

MB = Mass balance

Table 4: Mass Balance for major transformation product ethanol at pH 4 and 20 °C.

Hydrolysis Time [min]	Ethanol   [mmol/L]	As Test Item^1   [mmol/L]	MB   [%]
0.00	0.0736	0.0740	115
0.50	0.0913	0.0710	114
1.00	0.106	0.0707	117
2.00	0.122	0.0629	110
3.00	0.146	0.0548	105
5.00	0.183	0.0415	95
7.00	0.219	0.0414	103
9.00	0.258	0.0344	102
11.0	0.279	0.0246	93
13.0	0.309	0.0193	93
17.0	0.330	0.0150	92
21.0	0.361	0.0105	92
25.0	0.375	0.00891	93

1= molecular factor taken into account

MB= Mass balance

Table 5: Mass Balance for major transformation product ethanol at pH 4 and 30 °C.

Hydrolysis Time [min]	Ethanol   [mmol/L]	As Test Item^1   [mmol/L]	MB   [%]
0.00	0.0632	0.0672	113
0.50	0.0783	0.0654	114
1.00	0.0911	0.0619	112
1.50	0.123	0.0598	117
2.00	0.128	0.0426	93
2.50	0.141	0.0441	98
3.00	0.169	0.0474	110
3.50	0.179	0.0429	106
4.50	0.209	0.0388	107
6.00	0.239	0.0305	102
9.00	0.294	0.0174	97
12.5	0.332	0.0116	97
15.0	0.352	0.00737	96

1= molecular factor taken into account

MB= Mass balance

Table 6: Mass Balance for major transformation product ethanol at pH 7 and 10 °C.

Hydrolysis Time [min]	Ethanol   [mmol/L]	As Test Item^1   [mmol/L]	MB   [%]
0	0.0570	0.0602	100
120	0.0845	0.0679	115
240	0.0984	0.0575	103
360	0.111	0.0633	115
480	0.171	0.0520	113
899	0.216	0.0500	120
1077	0.216	0.0348	99
1257	0.232	0.0383	108
1440	0.270	0.0351	112
1680	0.232	0.0328	100
1906	0.242	0.0312	100
2884	0.308	0.0220	103
3346	0.334	0.0127	96

1= molecular factor taken into account

MB= Mass balance

Table 7: Mass Balance for major transformation product ethanol at pH 7 and 20 °C.

Hydrolysis Time [min]	Ethanol   [mmol/L]	As Test Item^1   [mmol/L]	MB   [%]
0	0.0570	0.0619	103
60	0.0886	0.0497	90
120	0.108	0.0503	96
180	0.187	0.0534	118
240	0.157	0.0467	102
420	0.193	0.0378	98
480	0.204	0.0371	100
899	0.340	0.0312	126
1077	0.374	0.0187	117
1257	0.387	0.0164	116
1443	0.326	0.0188	105
1661	0.355	0.00903	98

1= molecular factor taken into account

MB= Mass balance

Table 8: Mass Balance for major transformation product ethanol at pH 7 and 30 °C.

Hydrolysis Time [min]	Ethanol   [mmol/L]	As Test Item^1   [mmol/L]	MB   [%]
0.00	0.0570	0.0619	103
30.0	0.0823	0.0516	91
62.0	0.0994	0.0543	99
90.0	0.146	0.0523	107
118	0.147	0.0459	99
150	0.185	0.0468	109
178	0.180	0.0345	90
238	0.226	0.0315	97
298	0.245	0.0267	97
357	0.260	0.0214	93
478	0.317	0.0161	97
902	0.400	0.00353	101

1= molecular factor taken into account MB= Mass balance

Table 9: Mass Balance for major transformation product ethanol at pH 9 and 10 °C.

Hydrolysis Time [min]	Ethanol   [mmol/L]	As Test Item^1   [mmol/L]	MB   [%]
0.00	0.0645	0.0682	113
0.50	0.0917	0.0687	120
1.00	0.0916	0.0697	122
3.00	0.118	0.0620	117
5.00	0.138	0.0560	113
6.42	0.172	0.0539	118
10.0	0.171	0.0475	109
13.0	0.210	0.0272	89
16.2	0.238	0.0257	94
20.1	0.252	0.0249	96
26.7	0.287	0.0217	100
33.0	0.313	0.0161	98
40.0	0.328	0.00559	86

  1= molecular factor taken into account

MB= Mass balance

Table 10: Mass Balance for major transformation product ethanol at pH 9 and 20 °C.

Hydrolysis Time [min]	Ethanol   [mmol/L]	As Test Item^1   [mmol/L]	MB   [%]
0.00	0.0649	0.0860	126
0.50	0.0910	0.0836	129
1.00	0.1122	0.0803	129
2.00	0.137	0.0680	119
3.00	0.161	0.0621	116
4.00	0.194	0.0567	116
5.00	0.210	0.0498	111
6.00	0.254	0.0415	109
8.00	0.278	0.0297	99
10.0	0.298	0.0296	103
13.2	0.346	0.0164	97
16.0	0.366	0.0130	96
20.0	0.406	0.00703	97

1= molecular factor taken into account

MB= Mass balance

Table 11: Mass Balance for major transformation product ethanol at pH 9 and 30 °C.

Hydrolysis Time [min]	Ethanol   [mmol/L]	As Test Item^1   [mmol/L]	MB   [%]
0.00	0.0929	0.0651	116
0.50	0.111	0.0653	120
1.00	0.137	0.0534	109
1.50	0.165	0.0522	114
2.00	0.186	0.0468	111
2.50	0.217	0.0404	110
3.00	0.232	0.0392	112
3.50	0.254	0.0315	106
4.00	0.265	0.0289	105
5.00	0.292	0.0219	101
6.50	0.321	0.0145	97
8.00	0.348	0.0099	97
11.0	0.374	0.00397	95

1= molecular factor taken into account

MB= Mass balance

Table 12: Validity criteria.

Validity criterion	Required	This study
First order kinetic	To confirm first order behavior, the regression graph should have a correlation factor of ≥ 0.8.	pH 4 10 °C: 0.990 20 °C: 0.987 30 °C: 0.987 pH 7 10 °C: 0.920 20 °C: 0.937 30 °C: 0.990 pH 9 10 °C: 0.940 20 °C: 0.992 30 °C: 0.992
Temperature	The test temperature should be within± 0.5 °C of the nominal temperature.	Fulfilled
Test systems	The pH values of the buffer solutions should be in the range of ± 0.1 pH at test temperature.	Fulfilled
Sensitivity	Sensitivity of the analytical method should be sufficient to quantify test item concentrations at least down to a 90% reduction of the initial concentration.	Fulfilled

Validity criteria fulfilled:

yes

Conclusions:

The study according to the OECD guideline 111 showed that the test item hydrolyses fast at pH 4 and 9 (t1/2 ≤ 1 h) and all tested temperatures. At pH 7 the test item showed a hydrolysis rate of t1/2 = 11.9 h at 20 °C.
Ethanol was identified as major transformation product and quantified. Additional transformation products were postulated on basis of the expected de-ethoxylation processes with the masses (m/z) 258, 286, 314, 342, 370, and 398 Da and qualitatively determined.

Description of key information

DT50 = 11.9 h at pH 7 and 20 °C (OECD 111)

Key value for chemical safety assessment

Half-life for hydrolysis:

11.9 h

at the temperature of:

20 °C

Additional information

A reliable hydrolysis study according to OECD guideline 111 and GLP criteria is available for the registered substance. The study showed that the test item hydrolyses fast at pH 4 and 9 (t1/2 ≤ 1 h at 20 °C) and at pH 7 the test item showed a hydrolysis rate of t1/2 = 11.9 h at 20 °C. Ethanol was identified as major transformation product and quantified. Additional transformation products were postulated on basis of the expected de-ethoxylation processes with the masses (m/z) 258, 286, 314, 342, 370, and 398 Da and qualitatively determined.

The following additional information is available on the registered substance:

A preliminary test on the hydrolysis of 3-(triethoxysilyl)-N-[3-(triethoxysilyl)propyl]-1-propanamine (CAS No. 13497-18-2) was performed in the frame of the biodegradation test according to OECD guideline 301 and GLP. The hydrolysis test was performed in purified water with duration of 2 h. The test item hydrolyses to ethanol and the respective silanol hydrolysis product. Ethanol was analytically monitored at time points 0, 0.5, 1 and 2 h in order to gather information on the hydrolysis rate of the test item. More than half of the test material (51 – 62%) was hydrolyzed right after the preparation of the solution at time point 0. 97-99% of the test material was hydrolyzed after 0.5 h, showing that the substance hydrolyses rapidly in water at alkaline pH (9.5) and room temperature.

Furthermore, a hydrolysis study was conducted as a preliminary test within the purposes of an adsorption study according to OECD 106. The half-life of the substance was determined in soil eluates of 5 different soil types having neutral pH values (5.5 - 7.2). The parent substance was analytically monitored via LC-MS at time points 0, 0.25, 0.5, 1, 2, 4, 6 and 24 h. The hydrolysis half-lives were between 1 - 5.6 h, indicating rapid hydrolysis of the substance in soils of neutral pH.