Reaction product of propylidynetrimethanol, propoxylated, reaction products with ammonia and 2,2-Dimethyl-3-(4-morpholinyl)propanal

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2014-06-13 to 2014-07-03

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The study is regarded as reliable without restrictions. The study was conducted under GLP equivalent conditions. The study was conducted under supervision of a quality assurance unit which had ensured e.g instrumentation validation, reagent/materials certification, analyst certification and providing standard operating procedures. The study was conducted according to OECD guideline but have deviation to the guideline requirements. Deviations: The study was conducted only at the temperature of 10 °C. It was assumed that the slowest rate of hydrolysis will be observed at 10 °C. Thus, this deviation was not regarded to have an influence of the outcome of the study.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

yes

Remarks:

The study was conducted only at the temperature of 10 °C. It was assumed that the slowest rate of hydrolysis will be observed at 10 °C. Thus, this deviation was not regarded to have an influence of the outcome of the study.

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

yes

Remarks:

The study was conducted only at the temperature of 10 °C. It was assumed that the slowest rate of hydrolysis will be observed at 10 °C. Thus, this deviation was not regarded to have an influence of the outcome of the study.

GLP compliance:

yes

Remarks:

The study was conducted under supervision of a quality assurance unit which had ensured e.g instrumentation validation, reagent/materials certification, analyst certification and providing standard operating procedures.

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products: The stability measurement of the test item was performed initially after sample preparation and again after one and eight days.
- Sampling method: A microliter pipette was used.
- Sampling intervals/times for pH measurements: The pH value was once measured immediately after sample preparation and again after one and eight days.
- Sample storage conditions before analysis: The samples are kept at 10 °C and at room temperature.
- Other observation: No alteration of the test solution was observed.

The substance was dissolved in dry acetonitrile (approx. 100 mg in 5 mL ACN). The organic solutions (26 - 27 μL) was added to 5 mL of the tempered buffer solutions (10 °C). Immediately after vortexing, the sample solution (100 μg test item/mL water) was injected by a 500 μL syringe at a constant flow rate (10 μL/min) into the mass spectrometer.

Buffers:

- pH 4: 5.7 g ammonium formate and 1.885 mL (0.1 M) of formic acid were dissolved and diluted to 500 mL with ultra-pure water. The pH value was adjusted with formic acid to pH 4.03 (degassed with argon).
- pH 7: ultra-pure water, measured after degassing with argon pH: 6.8.
- pH 9: 3.2 g ammonium formate (0.1 M) and 2.0 mL ammonia solution (25 %) were dissolved and diluted to 500 mL with ultra-pure water. The pH value was adjusted with formic acid to pH 9.04 (degassed with argon).
The pH of each buffer solution was checked with a calibrated pH meter.

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: 5 mL volumetric flask.
- Measures taken to avoid photolytic effects: The samples were stored in the dark.
- Measures to exclude oxygen: The solvents used were degassed with argon and the samples were stored under argon.
- If no traps were used, is the closed / open. A closed test system was used.
- Is there any indication of the test material adsorbing to the walls of the test apparatus? There was no evidence that the test matrial had a affinity for adsorption on the walls of the test apparatus.

TEST MEDIUM
- Volume used/treatment: 5 mL Buffer solution containing not more than 1 % (v/v) of acetonitrile
- Kind and purity of water: degassed ultra-pure water

Number of replicates:

3 replicates

Positive controls:

no

Negative controls:

no

Preliminary study:

The substance was known to be hydrolytically unstable at environmentally relevant temperature. Thus, no preliminary test was conducted.

Transformation products:

yes

No.:

#1

No.:

#2

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

The substance contains two imine groups which are known to be hydrolytically unstable. After getting into contact with the water (buffer solution) the hydrolysis reaction forms the respective aldehyde and amine compound.

#1 degradation product:
- CAS no.: 23588-51-4
- CAS name: 4-Morpholinepropanal, a,a-dimethyl-
- IUPAC name: 2,2-dimethyl-3-(morpholin-4-yl)propanal
- Common name: Aldehyde M

#2 degradation product:
- CAS: 9046-10-0
- IUPAC name: Reaction products of propane-1,2-diol, propoxylated by amination of the terminal hydroxyl groups
-Common name: Jeffamin D 230

% Recovery:

0

pH:

4.03

Temp.:

10 °C

Duration:

1.25 min

% Recovery:

0

pH:

6.8

Temp.:

10 °C

Duration:

1.25 min

% Recovery:

0

pH:

9.04

Temp.:

10 °C

Duration:

1.25 min

pH:

4

Temp.:

25 °C

DT50:

< 1 min

Type:

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

Key result

pH:

7

Temp.:

25 °C

DT50:

< 1 min

Type:

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

pH:

9

Temp.:

25 °C

DT50:

< 1 min

Type:

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

Other kinetic parameters:

Due to the fast hydrolysis it was technically not possible to determine the kinetic parameters of the hydrolysis. The first measurement was immediately after mixing of the stock solution of the substance with the respective buffer solution. This procedure took 1 min 15 sec. No parent compound could be detected in the test solution. Thus it was concluded that the substance was fully hydrolysed after 1.25 min at 10 °C. Thus, further test at different temperature were omitted as it was predicted that at higher temperature the same results would be achieved.

Details on results:

The test item was completely hydrolysed after 1 min 15 sec. Neither the substance nor its partly hydrolysed form was observed, independently of the pH value (pH 4.03, 6.8 and 9.04). The first measurement was taken 1 min 15 sec after mixing and a stable MS signal was observed. The second and the third measurements after 4 and 7 min do not indicate a significant increase of the signal intensities. Consequently the substance was dissolved in water due to the hydrolysis reaction after 1 min 15 sec.
It was technically not possible to achieve six spaced data points showing hydrolysis of the test substance between 10 % and 90 % hydrolysis as requested by the guideline. The first data point was taken after 1 min 15 sec which was the time from mixing the stock solution of the test item with the respective buffer solution. This was confirmed in all replicate measurements. Thus, it was not possible to prepare a log-transformed presentation of the date nor to calcualte the DT50 values.
As the substance was fully hydrolysed the respective degradation products were identified. The degradation products were identified at any time point and pH values.

Validity criteria fulfilled:

not applicable

Conclusions:

The hydrolysis was investigated using a flow-injection mass spectrometer. The test item was fully hydrolysed after 1 min and 15 sec at pH 4, 7 and 9 at temperature of 10 °C. It was concluded that the substance will undergoes fast hydrolysis when getting into contact with water under all conditions.

Executive summary:

A study was conducted in accordance with OECD guideline 111 to determine the kinetics of the hydrolysis at different pH values (4,7 and 9). The substance consists of two imine groups which are known to be hydrolytically unstable. It was assumed that when getting into contact with water the substance will undergo hydrolysis forming the respective aldehyde and amine compounds. Thus no preliminary test was conducted. A stock solution of the test item in acetonitrile was prepared. 26-27 µL of the stock solution was mixed with 5 mL of the tempered buffer solution. Thus, the test solution did not contain more than 1 % organic solvent. The test solution as measured immediately after mixing. This took 1 min 15 sec. No parent compound was detected at any pH values (4,7 and 9) in the first measurements after 1.25 min. This was confirmed in all replicate measurements. It was therefore technically not possible to provide a minimum of six spaced data points showing hydrolysis between 10 and 90 %. Furthermore it was not possible to calculate the accurate DT50 values of the test item. It was concluded that the DT50 (pseudo first order) will be less than 1 min. As no parent compound was observed the two hydrolysis products were identified. The initial assumption was confirmed. The respective aldehyde 2,2-dimethyl-3-(morpholin-4-yl)propanal (Aldehyde M) and amine Reaction products of propane-1,2-diol, propoxylated by amination of the terminal hydroxyl groups (Jeffamin D230) were detected using the APCI-MS method and identified using the mass spectra in combination with the exact mass. In deviation to the guideline requirements the test was only conducted at 10 °C. This temperature was the lowest value requested by the guideline. As the hydrolysis depends on the temperature it was assumed that the slowest hydrolysis rate will be at 10 °C. As the parent compound could not be detected at all three pH values immediately after mixing of the test solution, it was concluded that the same results will be achieved at higher temperatures. Thus, test at other temperatures were omitted. In conclusion it was stated that the substance will undergo fast hydrolysis when getting into contact with water under all conditions.

Description of key information

The hydrolysis was investigated using a flow-injection mass spectrometer. The test item was fully hydrolysed after 1 min and 15 sec at pH 4, 7 and 9 at temperature of 10 °C. It was concluded that the substance will undergo fast hydrolysis when getting into contact with water under all conditions.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 min

at the temperature of:

25 °C

Additional information

A study was conducted in accordance with OECD guideline 111 to determine the kinetics of the hydrolysis at different pH values (4,7 and 9). The substance consists of two imine groups which are known to be hydrolytically unstable. It was assumed that when getting into contact with water the substance will undergo hydrolysis forming the respective aldehyde and amine compounds. Thus no preliminary test was conducted. A stock solution of the test item in acetonitrile was prepared. 26-27 µL of the stock solution was mixed with 5 mL of the tempered buffer solution. Thus, the test solution did not contain more than 1 % organic solvent. The test solution as measured immediately after mixing. This took 1 min 15 sec. No parent compound was detected at any pH values (4,7 and 9) in the first measurements after 1.25 min. This was confirmed in all replicate measurements. It was therefore technically not possible to provide a minimum of six spaced data points showing hydrolysis between 10 and 90 %. Furthermore it was not possible to calculate the accurate DT50 values of the test item. It was concluded that the DT50 (pseudo first order) will be less than 1 min. As no parent compound was observed the two hydrolysis products were identified. The initial assumption was confirmed. The respective aldehyde 2,2-dimethyl-3-(morpholin-4-yl)propanal (Aldehyde M) and amine Reaction products of propane-1,2-diol, propoxylated by amination of the terminal hydroxyl groups (Jeffamin D230) were detected using the APCI-MS method and identified using the mass spectra in combination with the exact mass. In deviation to the guideline requirements the test was only conducted at 10 °C. This temperature was the lowest value requested by the guideline. As the hydrolysis depends on the temperature it was assumed that the slowest hydrolysis rate will be at 10 °C. As the parent compound could not be detected at all three pH values immediately after mixing of the test solution, it was concluded that the same results will be achieved at higher temperatures. Thus, test at other temperatures were omitted. In conclusion it was stated that the substance will undergo fast hydrolysis when getting into contact with water under all conditions.

As key value for chemical safety assessment a half-life at 25 °C was estimated to be less than 1 min.

 

Furthermore in a supplemental study the hydrolysis of the test substance in contact with water was investigated by HPLC-UV method. The test item rapidly decomposes in contact with water. Decomposition is indicated by the difference of the chromatograms prepared in acetonitrile and in aqueous phases. The chromatogram of the test substance, that was dissolved in ultra-pure water, shows a peak located at ca. 4.5 min (retention time), whereas the chromatogram of the test substance, that was dissolved in acetonitrile, shows a peak located at ca. 3 minutes (retention times).