Fatty acids, C18 unsatd., mono- and diesters with triethanolamine, di-Me sulfate quaternized

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

13.01.2005-15.03.2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Fatty acids, C16-18(even numbered) and C18 unsatd., reaction products with triethanolamine, di-Me sulfate-quaternized

Cas Number:

91995-81-2 / 157905-74-3 / 93334-15-7

Molecular formula:

n.a. (UVCB)

IUPAC Name:

Fatty acids, C16-18(even numbered) and C18 unsatd., reaction products with triethanolamine, di-Me sulfate-quaternized

Test material form:

solid

Study design

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products: samples were taken at the beginning of the test and after 24, 48, 72, 120, 144, and 168 h at pH 4, 7, and 9 at 50°
- Sampling method: sampling was performed by adding the same volume acetonitrile (5 mL) with 2% glacial acetic acid directly to the incubation vessels and direct injection of the sample
- Sampling intervals/times for pH measurements: pH of test solution was determined at the beginning of the test and after 24, 48, 72, 120, 144, and 168 h at pH 4, 7, and 9 at 50°

Buffers:

- pH: 4, 7, and 9
- Type and final molarity of buffer: 0.05 M citrate buffer (pH 4), 0.05 M phosphate buffer (pH 7), and 0.05 M borate buffer (pH 9) according to EC method C.7 (92/69/EC), OECD guideline 111 and/or BBA Merkblatt Nr. 55, Teil I
- Composition of buffer: not reported, but buffer systems selected according to EC method C.7 (92/69/EC), OECD guideline 111 and/or BBA Merkblatt Nr. 55, Teil I

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: amber glass vials (volume: 20 mL) closed with PTFE sealed screw caps
- Sterilisation method: not reported
- Measures taken to avoid photolytic effects: photolytic interference was avoided (amber glass vials)
- Measures to exclude oxygen: all suitable precautions were taken to exclude dissolved oxygen: bubbling the solution with helium for five minutes before preparing the test solution
- Details of traps for volatile, if any: no traps used
- If no traps were used, is the test system closed/open: the system was closed with PTFE sealed screw caps
- Is there any indication of the test material adsorbing to the walls of the test apparatus? no
TEST MEDIUM
- Volume used/treatment: 5 mL
- Kind and purity of water: bi-distilled grade
- Preparation of test medium: The test item was dissolved in acetone (100 mg/L). 0.5 mL of this stock solution were transferred to a series of 20 mL glass vials. The solvent was evaporated under a fume hood at ambient temperature overnight. Afterwards, 5 mL of the selected buffer was added to each vial. The vials were closed with PTFE sealed screw caps. The concentration did not exceed 0.01 M at the test temperature. The nominal concentrations were 10 mg/L at pH 4, 7, and 9.
- Renewal of test solution: no
- Identity and concentration of co-solvent: acetone was used to prepare the stock solution (100 mg test item/L); after transferring 0.5 ml of this stock solution to the test vials the solvent was evaporated (no further solvents used in the test)
OTHER TEST CONDITIONS
- Adjustment of pH: no
- Dissolved oxygen: all suitable precautions were taken to exclude dissolved oxygen: bubbling the solution with helium for five minutes before preparing the test solution

Duration of test

Duration of test 1

Duration:

7 d

pH:

4

Temp.:

50 °C

Initial conc. measured:

7.37 mg/L

Duration of test 2

Duration:

7 d

pH:

7

Temp.:

50 °C

Initial conc. measured:

7.45 mg/L

Duration of test 3

Duration:

7 d

pH:

9

Temp.:

50 °C

Initial conc. measured:

8.17 mg/L

Number of replicates:

All measurements were carried out in duplicate (no further informations)

Results and discussion

Preliminary study:

Only the preliminary test was carried out.

Test performance:

In a preliminary test conducted according to OECD Guideline 111 and EU-Method C.7 the hydrolysis of the test item as a function of pH was investigated.

Transformation products:

yes

Identity of transformation products

Identity of transformation products 1

No.:

#1

Reference

Reference substance name:

Unnamed

Identity of transformation products 2

No.:

#2

Reference

Reference substance name:

Unnamed

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

- Formation and decline of each transformation product during test: mono-, di-, and triester were detected; the tri-esters were rapidly degraded to di-esters, which sequentially degrade to the mono-esters
- Pathways for transformation: ester cleavage

Dissipation DT50 of parent compound

Dissipation DT50 of parent compound 1

pH:

4

Temp.:

50 °C

Hydrolysis rate constant:

0.01 h-1

DT50:

27.3 d

Type:

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

Dissipation DT50 of parent compound 2

pH:

7

Temp.:

50 °C

Hydrolysis rate constant:

0.01 h-1

DT50:

72.3 h

Type:

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

Dissipation DT50 of parent compound 3

pH:

9

Temp.:

50 °C

Hydrolysis rate constant:

0.01 h-1

DT50:

47.8 h

Type:

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

Dissipation DT50 of parent compound 4

pH:

4

Temp.:

25 °C

Hydrolysis rate constant:

0.69 a-1

DT50:

> 1 yr

Type:

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

Dissipation DT50 of parent compound 5

pH:

7

Temp.:

25 °C

Hydrolysis rate constant:

0.01 h-1

DT50:

17 d

Type:

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

Dissipation DT50 of parent compound 6

pH:

9

Temp.:

25 °C

Hydrolysis rate constant:

0.01 h-1

DT50:

11.3 d

Type:

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

Any other information on results incl. tables

1. Time course of partially unsaturated TEA-EQ at pH 4, 7, and 9 and 50°C

a. Time course of partially unsaturated TEA-EQ at pH 4 and 50°C

Time (h)	pH	Actual concentration (mg/L)	Actual concentration in (%) of initial conc.
0 24 48 72 120 144 168	4.02 4.00 4.02 4.00 4.00 4.00 4.00	7.37 7.24 6.85 7.09 3.58* 7.03 5.69	100 98.3 92.9 96.2 48.7* 95.5 77.2
Mean Std. Deviation RSD	4.01 0.01 0.25

*discarded as an outliner

b. Time course of partially unsaturated TEA-EQ at pH 7 and 50°C

Time (h)	pH	Actual concentration (mg/L)	Actual concentration in (%) of initial conc.
0 24 48 72 120 144 168	7.06 7.03 7.00 7.00 6.99 6.99 6.98	7.45 4.37 3.12 3.38 0.887* 1.59 1.25	100 58.7 41.9 45.3 11.9* 21.3 16.7
Mean Std. Deviation RSD	7.01 0.03 0.43

*discarded as an outliner

c. Time course of partially unsaturated TEA-EQ at pH 9 and 50°C

Time (h)	pH	Actual concentration (mg/L)	Actual concentration in (%) of initial conc.
0 24 48 72 120 144 168	9.03 9.01 9.04 9.04 9.03 9.01 9.03	8.17 3.54 2.89 1.84 0.486* 0.767 0.590	100 43.3 35.4 22.5 5.9* 9.4 7.2
Mean Std. Deviation RSD	9.03 0.01 0.11

*discarded as an outliner

The temperature during the entire period of the test was measured to be 50.0 to 50.2°C

The results from the 120 h sampling were regarded as artefact, and therefore excluded from the analysis. As a consequence, the measurement was extended to 168 h test duration.

2. Rate constants and half-lives at 50 and 25°C

	pH 4	pH 7	pH 9
50°C
Kobs (h)	0.00106	0.00958	0.01449
t1/2 (h)	654	72.3	47.8
t1/2 (d)	27.3	3.01	1.99
25°C
Kobs (h)	0.000187	0.00169	0.00256
t1/2 (h)	3700	409	271
t1/2 (d)	154.2	17.0	11.3

The degradation rate was calculated according to the assumption of Arrhenius.

At pH 4 and 50°C, the degradation of the main component of partially unsaturated TEA-EQ was less than 10% over a period of 120 h. The corresponding half-life at 25°C is therefore assumed to be above one year (default assumption acc. to guidelines). In contrast, at pH 7 and 9 and 50°C, more than 10% of the test item were hydrolysed within 120 h. Based on the results half-lives of 17 (pH 7) and 11.3 d (pH 9) were deduced from the reaction rate constants at 25°C.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The hydrolysis of partially unsaturated TEA-EQ as a function of pH was investigated in a study conducted according to OECD Guideline 111 and EU-method C.7. (Preliminary test; main test not conducted due to the pronounced biodegradability of the test substance). At pH 4 and 50°C, the degradation of the main component of partially unsaturated TEA-EQ was less than 10% over a period of 120 h. The corresponding half-life at 25°C is therefore assumed to be above one year (default assumption acc. to guidelines). In contrast, at pH 7 and 9 and 50°C, more than 10% of the test item were hydrolysed within 120 h. Based on the results half-lives of 17 (pH 7) and 11.3 d (pH 9) were deduced from the reaction rate constants at 25°C. Di- and mono-ester were detected as degradation products.

Executive summary:

The hydrolysis of partially unsaturated TEA-EQ as a function of pH was investigated in a study conducted according to OECD Guideline 111 and EU-method C.7. (Preliminary test; main test not conducted due to the pronounced biodegradability of the test substance).

The following results were obtained:

Hydrolysis of partially unsaturated TEA-EQ at 50°C

pH	Temperature (°C)	Rate constant	t1/2
4	50	0.00106 1/h	27.3 d
7	50	0.00958 1/h	72.3 h
9	50	0.01449 1/h	47.8 h

Hydrolysis of partially unsaturated TEA-EQ at 25°C

pH	Temperature (°C)	Rate constant	t1/2
4	25*	0.693 1/a	>1 a*
7	25	0.00169 1/h	17.0 d
9	25	0.00256 1/h	11.3 d

* default assumption acc. to guideline

At pH 4 and 50°C, the degradation of the main component of partially unsaturated TEA-EQ was less than 10% over a period of 120 h. The corresponding half-life at 25°C is therefore assumed to be above one year (default assumption acc. to guidelines). In contrast, at pH 7 and 9 and 50°C, more than 10% of the test item were hydrolysed within 120 h. Based on the results half-lives of 17 (pH 7) and 11.3 d (pH 9) were deduced from the reaction rate constants at 25°C. Di- and mono-ester were detected as degradation products.