N-[3-(trimethoxysilyl)propylcyclohexylamine]

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 - 13 Mar 2015

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

guideline study but not GLP

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

no

Remarks:

study according to ISO 9001:2008

Radiolabelling:

no

Analytical monitoring:

yes

Remarks:

1H NMR Spectroscopy

Details on sampling:

- Sampling method: 1H-NMR measurements were started immediately after mixing the sample and transferring the sample tube into the spectrometer. This takes about 2 minutes. Then every 10 to 40 sec a 1H NMR spectrum was acquired. Experiments were performed at 298 K (25 °C).
- Sample storage conditions before analysis: no storage before analysis

Buffers:

- pH: 4
- Composition of buffer: CertiPur, Citric acid + hydrochloric acid + sodium hydroxide, company Merck

- pH: 7
- Composition of buffer: Baker Analyzed, Potassium dihydrogen phosphate + disodiumhydrogen phosphate, company J. T. Baker

- pH: 9
- Composition of buffer: CertiPur, Boronic acid + potassium chloride + sodium hydroxide, company Merck

Estimation method (if used):

Half-life time and reaction rate could be calculated from a (ln c[MeOSi] vs. time) plot assuming first-order kinetics and using the Na-TSP-d4 as internal standard.

Details on test conditions:

TEST MEDIUM
- Preparation of test medium: deuterated water / 3-trimethylsilylpropionic acid, sodium salt, 2,2,3,3-tetradeuterated (Na-TSP-d4) (pH 4.0, pH 9.0: 5006.46 mg D2O + 21.53 mg Na-TSP-d4; pH 7.0: 5028.41 mg D2O + 23.08 mg Na-TSP-d4)

Positive controls:

no

Negative controls:

no

Transformation products:

yes

No.:

#1

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

- Formation and decline of each transformation product during test: at pH 4 and 7 decreasing signals of methoxysilyl groups and increasing signals of MeOH could be observed. At pH 9 only signals of methanol could be observed after the first measurement. There were no signals of methoxysilyl groups detectable. Therefore it can be concluded that hydrolysis was already completed when the first spectrum was measured. Since hydrolysis was finished after the first 1H NMR measurement (about 2 minutes after mixing the test sample) no exact half-life time or reaction rate could be calculated.

pH:

4

Temp.:

25 °C

Hydrolysis rate constant:

0.268 min-1

DT50:

2.6 min

Type:

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

pH:

7

Temp.:

25 °C

Hydrolysis rate constant:

0.17 min-1

DT50:

4.1 min

Type:

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

pH:

9

Temp.:

25 °C

DT50:

< 2 min

Type:

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

Validity criteria fulfilled:

not applicable

Remarks:

No validity criteria mentioned in the guideline

Conclusions:

A study investigating the hydrolysis rate of the substance according to the EC test guideline C.7 resulted in half lives of 2.6, 4.1 and << 2 min at pH 4, 7 and 9, respectively.

Description of key information

N-[3-(trimethoxysilyl)propylcyclohexylamine] (CAS 3068-78-8): half-life = 4.1 min at pH 7 and 25 °C

Key value for chemical safety assessment

Half-life for hydrolysis:

4.1 min

at the temperature of:

25 °C

Additional information

One study (2015) is available investigating the hydrolysis rate of N-[3-(trimethoxysilyl)propylcyclohexylamine] (CAS 3068-78-8) as a function of pH according to EC test guideline C.7. The hydrolysis of the substance at pH 4, 7 and 9 was identified using ¹H NMR Spectroscopy. Half-lives of 2.6, 4.1 and << 2 min at pH 4, 7 and 9, respectively were determined in the study showing the rapid hydrolysis of the substance.