1,3-Propanediol, 2,2-bis(hydroxymethyl)-, allyl ether

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

28 March 2018 - 11 April 2018

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)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

NA

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Samples in buffer solutions were prepared by mixing 10 mL of a solution in medium with 2 g NaCl, then the solution was extracted two times with the solvent dichloromethane (2 x 4 mL) and the organic phase was collected into a 10 mL flask, after drying with Na2SO4. The flask was filled up to 10 mL with dichloromethane after addition of 1000 µL ISTD stock solution (1000 mg/L in dichloromethane). 400 µL of this solution and 100 µL of SiL-mix were given into a GC vial and the mixture was heated at approx. 70 °C for 1 h. After cooling down the solution was measured via GC.

Buffers:

Buffer solution, pH 4:
CH3COOH, 2 M 80.0 mL
CH3COONa 40 mL
Demineralised water ad 1000 mL
pH 4.00
pH was adjusted using acetic acid solution.

Buffer solution, pH 7:
KH2PO4 8.7086 g
Demineralised water 2500 mL
NaOH, 2 M 14.9 mL
Demineralised water ad 1000 mL
pH 7.00
pH was adjusted using NaOH solution.

Buffer solution, pH 9:
H3BO3 3.0934 g
KCl 3.7290 g
Demineralised water 500 mL
NaOH, 2 M 10.76 mL
Demineralised water ad 1000 mL
pH 9.04
No adjustment of pH was necessary.

Estimation method (if used):

NA

Details on test conditions:

Test Item Solutions:
For the preparation of the test item solution in demineralised water, 5 mL of the test item solution in methanol (concentration 100 g/L) were filled up to 1000 mL with demineralised water in order to reach the test item concentration of 500 mg/L and ≤ 1 % solvent in the hydrolysis assay. The 100 g/L stock solu-tion in methanol was prepared by dissolution of 2.5009 g test item in 25.009 mL methanol in a 25 mL measuring flask. 250 mL of this test item solution in demineralised water were mixed with 250 mL of each buffer solution and the resulting mixtures were sterile filtrated via 0.2 µm PTFE filters.

For the preparation of blank solutions, 100 mL of demineralised water were mixed with 100 mL of each buffer solution and the resulting mixtures were also sterile filtrated via 0.2 µm PTFE filters.

Experimental Conditions:
The temperature during the Tier 1 was held constant at 49.6 – 50.2 °C. The test was conducted protected from light and air. All test vessels were autoclaved and purged with argon before the test. All buffer solutions and demineralised water were purged with argon to remove oxygen for 5 minutes before usage. Furthermore, sterile membrane filters (0.2 µm, PTFE) were used in order to exclude bacterial contaminations of the buffer or test solutions.

Pre-Test, Tier 1:
For the Tier 1 assessment, 12 sterilised flasks were used, one for each blank and three for each test item in buffer solution. Three replicates were extracted per test item buffer solution at the beginning of the test as a start value. The test vessels were filled up with the test solutions; then purged with argon to remove oxygen in the little head space, tightly closed and incubated at a set temperature of 49.6 – 50.2 °C over a period of approximately 119 h. All flasks were extracted and analysed at the end of the test.

Duration:

5 d

pH:

4

Temp.:

50 °C

Initial conc. measured:

500 mg/L

Duration:

5 d

pH:

7

Temp.:

50 °C

Initial conc. measured:

500 mg/L

Duration:

5 d

pH:

9

Temp.:

50 °C

Initial conc. measured:

500 mg/L

Number of replicates:

Three replicates were extracted per test item buffer solution at the beginning of the test as a start value.

Positive controls:

not specified

Negative controls:

not specified

Statistical methods:

Recovery rate after hydrolysis in % was calculated from the following equation:
H = (Ct / Co) x 100%
with
ct = concentration at time t
c0 = concentration at time 0

Preliminary study:

No signs of hydrolysis were observed in all buffer solutions (pH 4, 7 and 9) in the tier 1 assessment. The amount of 1,3-Propanediol, 2,2-bis(hydroxymethyl)-, allyl ether after five days was more than 90% of the amount at the start of the test, thus the test item was concluded to be hydrolytically stable and no further examination was made.

Test performance:

No observations arousing doubts concerning the accuracy of the results and the validity of the study were made.

Transformation products:

no

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

NA

% Recovery:

94.7

St. dev.:

12.02

pH:

4

Temp.:

50 °C

Duration:

5 d

% Recovery:

101.9

St. dev.:

1.27

pH:

7

Temp.:

50 °C

Duration:

5 d

% Recovery:

96.7

St. dev.:

5.68

pH:

9

Temp.:

50 °C

Duration:

5 d

Key result

Remarks on result:

hydrolytically stable based on preliminary test

Other kinetic parameters:

NA

Details on results:

The amount of test item after five days in all three buffer solutions at 50°C was more than 90% of the amount at the start of the test, therefore the test item was considered to be hydrolytically stable (following OECD Guidelines, t(0.5) at 25°C is considered to be greater than 1 year) and no further examination was made beyond the tier 1 assessment.

Results with reference substance:

NA

Hydrolysis Results

pH	Time	Conc. Mean [mg/L]	Standard Deviation [mg/L]	RSD [%]	[%] of Start Concentration after 5 Days
4.0	0 d	241.19	12.02	5.0	-
	5 d	228.50	12.02	5.3	94.7
7.0	0 d	279.50	11.10	4.0	-
	5 d	284.77	1.27	0.4	101.9
9.0	0 d	273.30	8.31	3.0	-
	5 d^1	229.57	27.21	11.9	84.0
	5 d^2	264.18	5.68	2.2	96.7

¹values were not used in the evaluation (see table 9.1-b)

²repetition of determination

Validity criteria fulfilled:

yes

Conclusions:

In all buffer solutions (pH 4, 7 and 9), no signs of hydrolysis of the test item were observed in the tier 1 assessment. The amount of test item after five days was more than 90% of the amount at the start of the test. Therefore, the test item was considered to be hydrolytically stable and no further examination was made.

Executive summary:

The hydrolysis behaviour of 1,3-Propanediol, 2,2-bis(hydroxymethyl)-, allyl ether in dependence of pH was assessed according to the OECD Guideline 111 (‘Hydrolysis as a function of pH’) and EU method C.7 (‘Degradation: Abiotic degradation: Hydrolysis as a function of pH’). Sterile aqueous buffer solutions of different pH values (pH 4, 7 and 9) were treated with the test item solution and incubated in the dark under controlled laboratory conditions (at constant temperatures). Samples were taken at the beginning and after five days for analysis for the test item.

The amount of test item after five days in all three buffer solutions at 50°C was more than 90% of the amount at the start of the test, therefore the test item was considered to be hydrolytically stable (following OECD Guidelines, t(0.5) at 25°C is considered to be greater than 1 year) and no further examination was made beyond the tier 1 assessment. There were no observations which aroused doubts concerning the accuracy of the results and the validity of the study.

Description of key information

The hydrolysis behaviour of 1,3-Propanediol, 2,2-bis(hydroxymethyl)-, allyl ether in dependence of pH was assessed according to the OECD Guideline 111 (‘Hydrolysis as a function of pH’) and EU method C.7 (‘Degradation: Abiotic degradation: Hydrolysis as a function of pH’). Sterile aqueous buffer solutions of different pH values (pH 4, 7 and 9) were treated with the test item solution and incubated in the dark under controlled laboratory conditions (at constant temperatures). Samples were taken at the beginning and after five days for analysis for the test item.

The amount of test item after five days in all three buffer solutions at 50°C was more than 90% of the amount at the start of the test, therefore the test item was considered to be hydrolytically stable (following OECD Guidelines, t(0.5) at 25°C is considered to be greater than 1 year) and no further examination was made beyond the tier 1 assessment. There were no observations which aroused doubts concerning the accuracy of the results and the validity of the study.