Reaction products of phosphoryl trichloride and 2-methyloxirane

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

EEC Directive 84/449/EEC (1984-09-19)

GLP compliance:

yes

Specific details on test material used for the study:

Product name: TCPP
Active ingredient content: 99.8% based on area of GC analyses

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Preliminary experiment:
Samples were taken at the beginning of the test and regularly afterwards to be able to estimate whether the half-life was lower than 2.4 hours or to estimate if less than 10% of the test substance was hydrolysed after 5 days.
At each sampling time a sample was taken, weighted and stored in refrigerator until analysis.

Buffers:

Buffer solutions were prepared as follows:
pH 4.0 - 100 ml 0.5 M potassium hydrogen phthalate and 0.8 ml 0.5 M NaOH diluted to 1000 ml with deionized water
pH 7.0 - 100 ml 0.5 M potassium dihydrogen phosphate and 5.92 ml 5 M NaOH diluted to 1000 ml with deionized water
pH 9.0 - 100 ml of 0.5 M boric acid and 100 ml 0.5 M potassium chloride and 4.32 ml 5 M NaOH diluted to 1000 ml with deionized water.
pH of buffer solutions were measured at 50 °C using a pH meter and adjusted with 0.5 M HCI or 0.5 M NaOH.

Duration:

5 d

pH:

4

Temp.:

50 °C

Duration:

5 d

pH:

7

Temp.:

50 °C

Duration:

5 d

pH:

9

Temp.:

50 °C

Preliminary study:

The analytical results show no decrease in initial concentration of > 10% at pH 4,7 and 9.

Transformation products:

no

pH:

4

Temp.:

50 °C

DT50:

1 yr

Type:

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

Remarks on result:

other: buffered solution

pH:

7

Temp.:

50 °C

DT50:

1 yr

Type:

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

Remarks on result:

other: buffered solution

pH:

9

Temp.:

50 °C

DT50:

1 yr

Type:

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

Remarks on result:

other: buffered solution

Details on results:

In preliminary test hydrolysis was below 1% after 5 days at all 3 pH values. In agreement with the guideline the test was considered complete and no
further testing has been performed.

The first peak out of three as found in the GC chromatogram of tris(2 -chloro-1 -methylethyl) phosphate containing about 78 - 79% of the total area was used for interpretation of the hydrolysis rate. The decrease of the area of the first peak was less than 1% after five days at all three testsed pH values indicating no hydrolysis. The stability of the two other isomers was checked by interpretation of the ratio of the peak areas of the three tris(2 -chloro-1 -methylethyl) phosphate isomers for a sample from the beginning and from the end of the hydrolyses test. The equivalence of these ratios indicate that non of the isomers is susceptible to hydrolyses.

The pH changes during the tests were small and always less than 0.05 pH units.

The measured temperature range during the test was 49.9 - 50.1°C.

Conclusions:

The test substance is hydrolytically stable, with an estimated half life of more than 1 year at 25 degree C.

Executive summary:

In a GLP-compliant report, preliminary hydrolysis testing was undertaken at 50ºC for five days. A decrease in concentration of less than 1% was observed at pH 4, 7 and 9. Based on this result, it is concluded with no need for further testing in accordance with the OECD guideline, that TCPP is stable in water at pH 4, 7 and 9 at 25ºC, with a half-life greater than or equal to one year.

(Geurts and van Veenendaal, 2001)

Description of key information

OECD 111 (Guerts & van Veenendaal, 2001): DT50 = >1yr (pH 4,7,9)

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C

Additional information

In a GLP-compliant report, preliminary hydrolysis testing was undertaken at 50ºC for five days (Geurts and van Veenendaal, 2001). A decrease in concentration of less than 1% was observed at pH 4, 7 and 9. Based on this result, it is concluded with no need for further testing in accordance with the OECD guideline, that TCPP is stable in water at pH 4, 7 and 9 at 25ºC, with a half-life greater than or equal to one year.