Sodium O,O-diisopropyl dithiophosphate

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21-11-2012 - 31-05-2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Sodium O,O-diisobutyl dithiophosphate

EC Number:

258-508-5

EC Name:

Sodium O,O-diisobutyl dithiophosphate

Cas Number:

53378-51-1

Molecular formula:

C8H18NaO2PS2

IUPAC Name:

Sodium O,O-diisobutyl phosphorodithioate

Test material form:

other: 51 % w/w solution in water, stabilized with X % NaOH

Details on test material:

- Substance type: Liquid
- Physical state: Light brown liquid

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material:
PHYSICO-CHEMICAL PROPERTIES
- Boiling point: 107 °C
- Water solubility (under test conditions): > 1000 g/L
- pH 12-14
The production method yields the substance in an approximately 50% aqueous solution with a content of sodium hydroxide.

Study design

Analytical monitoring:

yes

Buffers:

- pH: 4, 7, 9
- Composition of buffer: (Concentration in mmol dm-3)
4: Citric acid 0.6; Sodium chloride 0.4; Sodium hydroxide 0.7
7: Disodium hydrogen orthophosphate (anhydrous) 0.3; Potassium dihydrogen orthophosphate 0.2; Sodium chloride 0.2
9: Disodium tetraborate 0.1; sodium chloride 0.2

Duration of test

Duration of test 1

Duration:

120 h

pH:

4

Initial conc. measured:

> 0.001 - < 0.001 g/L

Duration of test 2

Duration:

120 h

pH:

7

Initial conc. measured:

> 0.001 - < 0.001 g/L

Duration of test 3

Duration:

120 h

pH:

9

Initial conc. measured:

> 0.001 - < 0.001 g/L

Number of replicates:

2 replicates pr pH value

Positive controls:

not specified

Negative controls:

not specified

Results and discussion

Transformation products:

not specified

Total recovery of test substance (in %)

Total recovery of test substance (in %) 1

% Recovery:

> 96.4 - < 101

pH:

4

Temp.:

50 °C

Duration:

120 h

Total recovery of test substance (in %) 2

% Recovery:

> 94 - < 98.6

pH:

7

Temp.:

50 °C

Duration:

120 h

Total recovery of test substance (in %) 3

% Recovery:

> 103 - <= 104

pH:

9

Temp.:

50 °C

Duration:

120 h

Dissipation DT50 of parent compound

Dissipation DT50 of parent compound 1

Key result

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Type:

not specified

Remarks on result:

other: Estimated from results at 50°C

Dissipation DT50 of parent compound 2

Key result

pH:

7

Temp.:

25 °C

DT50:

> 1 yr

Type:

not specified

Remarks on result:

other: Estimated from results at 50°C

Dissipation DT50 of parent compound 3

Key result

pH:

9

Temp.:

25 °C

DT50:

> 1 yr

Type:

not specified

Remarks on result:

other: Estimated from results at 50°C

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

For all: Linearity of detector response/concentration in the range of 0.10-1.0 mg/L. For pH: second-order behavier. At pH 7 & 9: First-order behavior with correlation coefficents (r2) ≥ 0.998

Conclusions:

The test item was found not to hydrolyse neither at pH 4; 7 nor 9. The half-life is expected to be greater than 1 year at 25 ºC.
Remark: the test solution contains NaOH due to the production method.