2,4,6-tri-n-propyl-2,4,6-trioxo-1,3,5,2,4,6-trioxatriphosphorinane

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1995-03 till 1995-7

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

92/69/EWG

Principles of method if other than guideline:

The lowest feasible concentration fot the P-NMR analysis is about 0.03 mole/L. Thus the requirements of the guideline to test a concentration less than 0.01 mole/L could not quite be met.

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products:
Aliquots were taken after specific time intervals (2.4, 24, 96, 120 h), cooled, and immediately subjected to pH measurement and NMR analysis.

Buffers:

- pH: 4
- Type and final molarity of buffer: citric acid / sodium hydroxide solution; c = 1 mole/L

- pH: 7
- Type and final molarity of buffer: potassium dihydrogenphosphate / sodium hydroxide solution; c = 1 mole/L

- pH: 9
- Type and final molarity of buffer: glycine / sodium hydroxide solution; c = 2 mole/L

The buffers were prepared in D2O

Details on test conditions:

TEST SYSTEM
- Type of test flasks: glass flasks

Duration:

120 h

pH:

4

Temp.:

50 °C

Duration:

120 h

pH:

7

Temp.:

50 °C

Duration:

120 h

pH:

9

Temp.:

50 °C

Number of replicates:

nor specified

Positive controls:

not specified

Negative controls:

not specified

Preliminary study:

Due to peak superposition in the 31P-NMR spectra of the hydrolysis batches, an accurate quantification of the test substance (six-membered ring, cyclic trimer) is not possible. Nevertheless its 31P-NMR spectrum in organic solvents is well known and thus one can estimate that even at t = 0 only a low amount (<15 %) of a six-membered ring is present. The hydrolysis finally results in propane phosphonic acid. During the hydrolysis process a linear trimer and a dimer are generated, which can be identified by NMR spectroscopy. The identification of other intermediates was impossible.
Due to the results of the pre-test the test substance hydrolysis in 24 h at 50 °C and pH 4, 7 and 9 to more than 50 %. The half-life time at 25 °C could therefore be estimated to be < 1 day. According to the mentioned directive no further experimental test are necessary.

Transformation products:

yes

No.:

#1

No.:

#2

No.:

#3

% Recovery:

> 11 - < 13

pH:

4

Temp.:

50 °C

Duration:

24 h

% Recovery:

1

pH:

4

Temp.:

50 °C

Duration:

120 h

% Recovery:

> 9 - < 14

pH:

7

Temp.:

50 °C

Duration:

24 h

% Recovery:

1

pH:

7

Temp.:

50 °C

Duration:

120 h

% Recovery:

< 1

pH:

9

Temp.:

50 °C

Duration:

24 h

% Recovery:

< 1

pH:

9

Temp.:

50 °C

Duration:

120 h

Key result

pH:

4

Temp.:

50 °C

DT50:

< 1 d

Key result

pH:

7

Temp.:

50 °C

DT50:

< 1 d

Key result

pH:

9

Temp.:

50 °C

DT50:

< 1 d

Details on results:

TEST CONDITIONS
- pH and temperature maintained throughout the study: Yes

Validity criteria fulfilled:

yes

Conclusions:

Due to the results of this pre-test according to EU method C.7 (92/69/EWB), the test substance hydrolysis in 24 h at 50 °C and pH 4, 7 and 9 to more than 50 %. The half-life time at 25 °C could therefore be estimated to be < 1 day. According to the mentioned directive no further experimental test are necessary.

Executive summary:

In a hydrolysis pre-test according to EU method C.7 (92/69/EWB), the test item hydrolysis in 24h at 50°C and pH 4, 7 and 9 to more than 50%. In detail, the recovery of the test substance at pH 4 after 24 hours at 50°C was between 11 and 13 %, after 120 hours 1%. The recovery of the test substance at pH 7 after 24 hours at 50°C was between 9 and 14 %, after 120 hours 1%. And the recovery of the test substance at pH 9 after 24 and 120 hours at 50°C was below 1%. The half-life time at 25 °C could therefore be estimated to be < 1 day. Therefore, the substance will hydrolyses fast in contact with water under environmental conditions. Hydrolysis will contribute significantly to the degradation of the test item under environmental conditions. According to the mentioned directive no further experimental test are necessary.

Description of key information

The results of a pre-test according to EU method C.7 (92/69/EWB) show, that the test substance hydrolysis in 24 h at 50 °C and pH 4, 7 and 9 to more than 50 %. The half-life time at 25 °C could therefore be estimated to be < 1 day. According to the mentioned directive no further experimental test are necessary.

Additional information

In a hydrolysis pre-test according to EU method C.7 (92/69/EWB), the test item hydrolysis in 24h at 50°C and pH 4, 7 and 9 to more than 50%. In detail, the recovery of the test substance at pH 4 after 24 hours at 50°C was between 11 and 13 %, after 120 hours 1%. The recovery of the test substance at pH 7 after 24 hours at 50°C was between 9 and 14 %, after 120 hours 1%. And the recovery of the test substance at pH 9 after 24 and 120 hours at 50°C was below 1%. The half-life time at 25 °C could therefore be estimated to be < 1 day. Therefore, the substance will hydrolyses fast in contact with water under environmental conditions. Hydrolysis will contribute significantly to the degradation of the test item under environmental conditions. According to the mentioned directive no further experimental test are necessary.