Propylidynetrimethanol, ethoxylated, esters with acrylic acid

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-05-26 to 2010-07-14

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

GLP compliance:

yes

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products: In the preliminary test, samples were taken at test start (0 h) and at test end (120 h).
For definitive testing, samples were taken at test start and at a minimum of 8 spaced points, normally between 10 and 90 % of hydrolysis, at each test temperature.
- Sampling intervals/times for pH measurements: Test start
- Sampling intervals/times for sterility check: The sterility of the definitive test solutions for pH 7 and 9 was checked by colony forming units (CFU)-determination with Water Plate Count agar. The CFU was determined by incubation at 25°C for 48 hours.
- Sample storage conditions before analysis: All test item containing samples were analysed immediately (max. 1 % of total incubation time until start of analyses) via LC-MS

Buffers:

- pH: pH 4, pH 7, pH 8
- Type and final molarity of buffer:
Buffer solution pH 4 45 mL of 0.1 mol/L NaOH were mixed with 250 mL 0.1 mol/L KH2-Citrate and diluted to 500 mL with double distilled water.

Buffer solution pH 7 148.15 mL of 0.1 mol/L NaOH were mixed with 250 mL 0.1 mol/L KH2PO4, diluted to 500 mL with double distilled water.

Buffer solution pH 9 106.5 mL of 0.1 mol/L NaOH were mixed with 250 mL 0.1 mol/L H3BO3 in 0.1 mol/L KCL, diluted to 500 mL with double distilled water.

- Composition of buffer: Buffers were freshly prepared from chemicals with analytical grade or better quality. If necessary, volumes were adapted. Buffers were purged with nitrogen for 5 min. Then the pH of the test solution was checked to a precision of at least 0.1 at the required temperature and adjusted if necessary.
Buffers were sterilised by filtration through 0.2 µm.

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: Sterile amber HPLC vials, volume 4 mL
- Sterilisation method: Autoclaving of double distlled water, sterilisation of buffer solutions by filtration through 0.20 µm.
- Measures taken to avoid photolytic effects: Photolytic effects were avoided by using amber vials.
- If no traps were used, is the test system closed
- Is there any indication of the test material adsorbing to the walls of the test apparatus? No
TEST MEDIUM
- Volume used/treatment: 2 mL
- Kind and purity of water: see above
- Preparation of test medium: Solutions of the test item with a concentration of 10 mg/L were prepared in buffer solution pH 4, 7 and 9.
An aliquot of the respective sterile buffer was spiked with a test item stock solution. Aliquots of the test solutions were filled into the vials, sealed and transferred into the thermostat. The time between test item application and transfer to thermostat/analysis did not exceed 30 min.
- Renewal of test solution: None

Duration:

12.5 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

other: < LOQ

Duration:

143 h

pH:

9

Temp.:

30 °C

Initial conc. measured:

0.33 mg/L

Duration:

379 h

pH:

9

Temp.:

20 °C

Initial conc. measured:

0.9 mg/L

Duration:

715 h

pH:

7

Temp.:

30 °C

Initial conc. measured:

8.03 mg/L

Duration:

716 h

pH:

7

Temp.:

20 °C

Initial conc. measured:

8.94 mg/L

Duration:

714 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

1.17 mg/L

Number of replicates:

Duplicates, single injection

Negative controls:

yes

Remarks:

Sterile buffer solutions (pH 4, 7 and 9)

Statistical methods:

The concentration of the test item was determined as a function of time. The log of the concentrations are plotted against time (log ct vs. t) and the slope of the resulting straight line from regression analysis gives the rate constant kobs [1/unit of time]

Preliminary study:

In a preliminary test more than 10 % of the test item at pH 7 and 9 has been hydrolysed after 120 hours. Due to stability of the test item at pH 4, 50 °C over a period of 120 hours, the definitive study for pH 4 was aborted. The study was reclassified as preliminary test.
The used analytical method was method A.

Test performance:

- Method validation
- Preliminary test (5 d)
- Preparation of the sterile test solutions
- Thermostatisation of the test solutions
- Analysis of samples
- Calculation of reaction rate constants and half lives for the test
item

Transformation products:

no

Key result

pH:

7

Temp.:

20 °C

DT50:

352 d

Type:

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

pH:

7

Temp.:

12 °C

DT50:

453 d

Type:

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

Remarks on result:

other: Extrapolated to environmental relevant temperature

Details on results:

TEST CONDITIONS
- pH, sterility, temperature, and other experimental conditions maintained throughout the study: Yes

Hydrolysis Results for the registered substance at pH 7 and 20 °C

                  

Hydrolysis Time [h]	Concentration [mg/L]	Log Concentration	Method
0.00	9.60	0.982	A
23.2	10.3	1.01	A
91.5	9.18	0.963	A
123	10.1	1.00	B
217	9.86	0.994	B
451	9.42	0.974	B
528	9.89	1.00	B
716	8.94	0.951	B

Hydrolysis Results for the registered substance at pH 7 and 30 °C

                  

Hydrolysis Time [h]	Concentration [mg/L]	Log Concentration	Method
0.00	9.60	0.982	A
22.6	10.3	1.01	A
91.5	9.02	0.955	A
123	9.76	0.989	B
217	9.40	0.973	B
450	8.68	0.939	B
528	8.84	0.946	B
715	8.03	0.905	B

Hydrolysis Results for the registered substance at pH7 and 50°C

Hydrolysis Time [h]	Concentration [mg/L]	Log Concentration	Method
0.00	9.60	0.982	A
22.0	9.06	0.957	A
41.4	12.8	1.11	A	1)
91.6	7.16	0.855	B
123	7.08	0.850	B
147	6.30	0.799	B
216	5.20	0.716	B
357	3.40	0.531	B
528	1.92	0.283	B
714	1.17	0.068	B

Hydrolysis Results for the registered substance at pH 9 and 20 °C

                  

Hydrolysis Time [h]	Concentration [mg/L]	Log Concentration	Method
0.00	10.1	1.00	A
22.0	9.10	0.959	A
39.8	7.20	0.857	A
90.4	4.96	0.695	B
121	3.98	0.600	B
146	3.96	0.598	B
193	3.12	0.494	B
259	1.71	0.233	B
379	0.900	-0.046	B

Hydrolysis Results for the registered substance at pH 9 and 30 °C

Hydrolysis Time [h]	Concentration [mg/L]	Log Concentration	Method
0.00	9.40	0.973	B
6.92	9.70	0.987	B
11.6	8.84	0.946	B
28.5	5.08	0.706	B
31.3	4.96	0.695	B
49.9	3.22	0.508	B
53.4	3.16	0.500	B
72.7	1.91	0.281	B
77.0	1.73	0.238	B
143.0	0.33	-0.481	B

Hydrolysis Results for the registered substance at pH 9 and 50 °C

Hydrolysis Time [h]	Concentration [mg/L]	Log Concentration	Method
0.00	9.40	0.973	B
1.98	6.50	0.813	B
4.23	5.14	0.711	B
6.27	3.54	0.549	B
8.02	2.36	0.373	B
9.52	1.80	0.255	B
10.6	1.55	0.190	B
11.9	1.25	0.0969	B
12.5	LOQ	LOQ	B

Validity criteria fulfilled:

yes

Conclusions:

Reaction rate constants and half lives with their corresponding confidence intervals are given above. The registered substance F is seen to be slightly hydrolytically instable at pH 7, 20 °C and 30 °C and hydrolytically instable at pH 7, 50°C and pH 9, with increasing instability to higher pH and temperature. At pH 4 and 50 °C no hydrolysis within 120 h was observed and, according to the guideline, a half life of > 1 year could be assumed for environmental relevant temperatures.

Executive summary:

Hydrolysis as a function of pH was determined according to OECD Guideline No. 111 and Council Regulation (EC) No. 440/2008, Method C.7 for the registered substance (batch number: S700040031) from 2010-05-26 to 2010-07-14 at Dr.U.Noack-Laboratorien, Sarstedt, Germany.

For pH 4, 7 and 9 a 5 day (preliminary) testing at 50 °C was performed. During this testing no hydrolysis was observed for the pH 4 samples. With respect to the guideline a half life of > 1 year could be assumed for the test item at pH 4 and environmental typical temperatures. For the other pH values the definitive testing was performed. The definitive testing was conducted with a test item concentration of 10 mg/L in buffer solutions of pH 7 and 9 at temperatures of 20, 30 and 50 °C, respectively. For pH 7 and 9 samples were taken at test start (0 h) and at least 8 spaced points until end. Buffer solutions were analysed at test start and test end and there was no analytical interference with the test item.

Analyses of the test item were performed via LC-MS on a reversed phase column for the for main components (2 EO, 3 EO, 4 EO and 5 EO). The method was validated with satisfactory results in regard to linearity, repeatability of injection, accuracy and specificity.

Reaction rate constants and half lives were calculated from the analysed concentrations and are presented in Table 1. The registered substance is seen to be slightly hydrolytically instable at pH 7, 20 °C and 30 °C and hydrolytically instable at pH 7, 50°C and pH 9, with increasing instability to higher pH and higher temperature. The slope of the regression graphs for the pH 7, 20 °C test conditions was not significantly different from zero, thus these results should be treated with respect to the high uncertainty of the evaluated data.

Reaction Rate Constants and Half Lives of the registered substance

	pH 4	pH 7			pH 9
	preliminary test  50 °C	20 °C	30 °C	50 °C	20 °C	30 °C	50 °C
Reaction rate constant kobs [1/s]	Stable, half life of > 1 year at environmental typical temperatures	2.28 x 10^-8	7.10 x 10^-8	8.25 x 10^-7	1.77 x 10^-6	6.65 x 10^-6	4.78 x 10^-5
Half life T½ [h]		8454	2711	233	109	28.9	4.03
Half life T½ [d]		352	113	9.72	4.54	1.20	0.17

Description of key information

In a study according to OECD test guideline 111 under GLP, the registered substance (TMPeoTA) was slightly hydrolytically instable with a half-life of 352 days at 20°C and pH 7. Adjusting to an average EU outdoor temperature of 12°C, the half-life was calculated to be 453 days at pH 7 (mean half-life from three temperatures).

Key value for chemical safety assessment

Half-life for hydrolysis:

453 d

at the temperature of:

12 °C

Additional information

Hydrolysis as a function of pH was determined according to OECD Guideline No. 111 and Council Regulation (EC) No. 440/2008, Method C.7 for the registered substance (batch number: S700040031) from 2010-05-26 to 2010-07-14 at Dr.U.Noack-Laboratorien, Sarstedt, Germany.

 

For pH 4, 7 and 9, a 5-day (preliminary) testing at 50 °C was performed. During this testing no hydrolysis was observed for the pH 4 samples. With respect to the guideline a half life of > 1 year could be assumed for the test item at pH 4 and environmental typical temperatures. For the other pH values the definitive testing was performed. The definitive testing was conducted with a test item concentration of 10 mg/L in buffer solutions of pH 7 and 9 at temperatures of 20, 30 and 50 °C, respectively. For pH 7 and 9 samples were taken at test start (0 h) and at least 8 spaced points until end. Buffer solutions were analysed at test start and test end and there was no analytical interference with the test item.

 

Analyses of the test item were performed via LC-MS on a reversed phase column for the main components (2 EO, 3 EO, 4 EO and 5 EO). The method was validated with satisfactory results in regard to linearity, repeatability of injection, accuracy and specificity.

 

Reaction rate constants and half-lives were calculated from the analysed concentrations and are presented in Table 1. The registered substance is seen to be slightly hydrolytically instable at pH 7, 20 °C and 30 °C and hydrolytically instable at pH 7, 50°C and pH 9, with increasing instability to higher pH and higher temperature. The slope of the regression graphs for the pH 7, 20 °C test conditions was not significantly different from zero, thus these results should be treated with respect to the high uncertainty of the evaluated data.

 

Reaction Rate Constants and Half Lives

pH4, pH 7, pH9

 

 

	preliminary test  50 °C	pH=7 20 °C	pH=7 30 °C	pH=7 50 °C	pH=9 20 °C	pH=9 30 °C	pH=9 50 °C
Reaction rate constant kobs [1/s]	Stable, half-life of > 1 year at environmental typical temperatures	2.28 x 10^-8	7.10 x 10^-8	8.25 x 10^-7	1.77 x 10^-6	6.65 x 10^-6	4.78 x 10^-5
Half-lifeT½[h]		8454	2711	233	109	28.9	4.03
Half-lifeT½[d]		352	113	9.72	4.54	1.20	0.17