Tris(pentane-2,4-dionato-O,O')vanadium

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-08-14 - 2018-02-07

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

not specified

GLP compliance:

no

Remarks:

study was performed not in compliance with GLP

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

not specified

Buffers:

- pH: 1.2, 4, 7 and 9
- Composition of buffer:
pH 1.2: Hydrochloric acid, 0.1 mol/L
pH 4: 90 mL of 0.1 mol/L NaOH were mixed with 500 mL 0.1 mol/L monopotassium citrate and diluted to 1000 mL with double distilled water.
pH 7: 296.3 mL of 0.1 mol/L NaOH were mixed with 500 mL 0.1 mol/L KH2P04 and diluted to 1000 mL with double distilled water.
pH 9: 213.0 mL of 0.1 mol/L NaOH were mixed with 500 mL 0.1 mol/L H3B03 in 0.1 mol/L KCl and diluted to 1000 mL with double distilled water.
Buffer systems were selected according to the guideline. The buffer systems were suitable for the required pH values

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: 100 mL glas beakers

TEST MEDIUM
- Volume used/treatment: 1000 mL
- Kind and purity of water: double destilled water

Number of replicates:

2

Positive controls:

no

Negative controls:

no

Preliminary study:

A preliminary test at 50°C for 120h has not been considered as necessary because it was known from literature that the test item decomposes in contact with water into Vanadylacetylacetonate and 2,4-Pentadione. In addition, in contact with water the test substance develops immediately the typical odor of 2,4-Pentadione.

Transformation products:

yes

No.:

#1

No.:

#2

Key result

pH:

1.2

DT50:

< 1 h

Type:

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

pH:

4

DT50:

< 1 h

Type:

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

pH:

7

DT50:

< 1 h

Type:

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

pH:

9

DT50:

< 1 h

Type:

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

Validity criteria fulfilled:

not specified

Conclusions:

The study was conducted scientifically reasonable according to OECD 111 and is sufficiently documented. Hence, it is sufficiently reliable to assess the hydrolysis behaviour of Vanadium-tris-acetylacetonate in unbuffered water. GC-FID measurement of the hydrolysis of Vanadium-tris-acetylacetonate showed complete hydrolysis at pH 1.2, 4 and 7 more than 80%. IR spectra of the treatment after one hour Vanadium(lll)acetylacetonate resulted in complete disappearance of the test item. Accordingly, the hydrolytic degradation can be described as a pseudo-first order kinetic and the half-life was determined to be < 1 h at pH 1.2, 4, 7 and 9. 2,4-Pentadione and Vanadyl acetylacetonate have been identified as only hydrolysis products via GC/FID measurement.
It can be concluded that the substance hydrolyses very rapidly in water (> 80% hydrolysis after 1h at pH 1.2, 4, 7 and 9). Hence, the half life is e.g. max. 1/48 of the test duration when put into aqueous test systems (e.g. daphnia (48 h test duration) or algae (72 h test duration) acute toxicity tests. Hence, the substance as such does not need to be tested in those systems, it is sufficient for hazard assesment to use data gained with the final reaction products 2,4-Pentadione (Cas no. 123-54-6) and Vanadyl acetylacetonate (3153-26-2) or comparable inorganic Vanadium compounds.

Executive summary:

The test was based on OECD 111 adapted to the specific properties of the test item Vanadium(lll)acetylacetonate. The test was performed at pH 1.2, 4 and 7. Determination at pH 9 has been omitted because hydrolysis was already complete at pH 7 and should be even faster at pH 9.

GC-FID measurement of the hydrolysis of Vanadium(lll)acetylacetonate showed complete hydrolysis at pH 1.2, 4 and 7 more than 80%.

IR spectra of the treatment after one hour Vanadium(lll)acetylacetonate resulted in complete disappearance of the test item.

2,4-Pentadione and Vanadyl acetylacetonate have been identified as only hydrolysis products via GC/FID measurement. It can be concluded that the substance hydrolyses very rapidly in water (> 80% hydrolysis after 1h at pH 1.2, 4, 7 and 9)

Description of key information

The test was based on OECD 111 adapted to the specific properties of the test item Vanadium(lll)acetylacetonate. The test was performed at pH 1.2, 4 and 7. Determination at pH 9 has been omitted because hydrolysis was already complete at pH 7 and should be even faster at pH 9.

GC-FID measurement of the hydrolysis of Vanadium(lll)acetylacetonate showed complete hydrolysis at pH 1.2, 4 and 7 more than 80%.

IR spectra of the treatment after one hour Vanadium(lll)acetylacetonate resulted in complete disappearance of the test item.

2,4-Pentadione and Vanadyl acetylacetonate have been identified as only hydrolysis products via GC/FID measurement. It can be concluded that the substance hydrolyses very rapidly in water (> 80% hydrolysis after 1h at pH 1.2, 4, 7 and 9)

Key value for chemical safety assessment

Half-life for hydrolysis:

1 h