1,2-dihydro-3H-1,2,4-triazol-3-one

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

dec 2017 - dec 2018

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)

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Identity: Triazolone
Appearance: Off-white powder
Storage conditions: Room temperature (15 to 25°C), dark
Batch number: 0727/16
Purity: 99%
Expiry date: 28 April 2019
Date received: 28 April 2017

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Preliminary test
The following procedure was carried out at each of pH 4, 7 and 9:

Aliquots (0.2 mL) of a stock solution of Triazolone in purified water (40 g/L) were added to separate Wheaton vials containing buffer solution (10 mL), which had been purged with nitrogen and pre-equilibrated at test temperature (50 ± 0.5°C).

The samples, of nominal concentration 800 mg/L, were placed in a 50°C oven in the dark until sampling was required (immediately, and then after 2.4, 24 and 163 hours).

At each sampling time, two samples were removed from the bath and an aliquot (1 mL) of each was diluted to volume (20 mL) with mobile phase for analysis by high performance liquid chromatography (HPLC).

Sample pH and incubation temperature were monitored over the period of the test.

Buffers:

Buffer solutions were prepared as follows:
pH 4: 0.2M aqueous potassium dihydrogen orthophosphate (550 mL) was mixed with
0.07M aqueous disodium hydrogen orthophosphate dodecahydrate (1250 mL) and purified water (3200 mL). The pH was adjusted to 4.0 ± 0.05 with orthophosphoric acid.
pH 7: 0.2M aqueous potassium dihydrogen orthophosphate (1250 mL) was mixed with
1M sodium hydroxide (150 mL) and purified water (3660 mL). The pH was adjusted to
7.0 ± 0.05 with 1M hydrochloric acid.
pH 9: 0.1M boric acid in 0.1M aqueous potassium chloride (2500 mL) was mixed with
1M sodium hydroxide (105 mL) and purified water (2395 mL). The pH was adjusted to
9.0 ± 0.05 with 1M hydrochloric acid or 1M sodium hydroxide, as required.

Duration:

120 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

99.05 mg/L

Duration:

120 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

99.05 mg/L

Duration:

120 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

99.05 mg/L

Number of replicates:

in accordance to guidelines

Preliminary study:

yes

Transformation products:

no

Key result

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Type:

not specified

Key result

pH:

7

Temp.:

25 °C

DT50:

> 1 yr

Type:

not specified

Key result

pH:

9

Temp.:

25 °C

DT50:

> 1 yr

Type:

not specified

Standard concentration (mg/L)	Peak area
99.05	2907.9
79.24	2368.4
59.43	1794.8
39.62	1222.3
19.81	616.79
9.905	310.17
4.952	155.67

	Ct (mg/L)
pH	t0h		t2.4h		t24h		t163h
	Measured	Mean	Measured	Mean	Measured	Mean	Measured	Mean
4	558*, 809	809	808, 809	808	808, 825	817	796, 811	804
7	798, 801	799	813, 754	784	819, 800	809	799, 817	808
9	799, 802	801	798, 799	799	795, 801	798	805, 797	801

Validity criteria fulfilled:

yes

Conclusions:

Triazolone was determined to be hydrolytically stable under acidic, neutral and basic conditions.

Executive summary:

A study was performed to determine the rate of hydrolysis of Triazolone as a function of pH. The test was conducted in accordance with the preliminary test as described in Council Regulation (EC) No. 440/2008 (Method C.7) and the OECD Guidelines for Testing of Chemicals (Method 111).

The preliminary study showed that at each of pH 4, 7 and 9 and 50±0.5ºC, less than 10% hydrolysis had occurred after 5 days, equivalent to a half-life of greater than 1 year under environmental conditions (25°C). No further testing was considered necessary. Triazolone was determined to be hydrolytically stable under acidic, neutral and basic conditions.

Description of key information

Triazolone was determined to be hydrolytically stable under acidic, neutral and basic conditions.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C