2-nitro-4-(trifluoromethyl)benzonitrile

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 – 22 May 2019

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

2000

GLP compliance:

yes

Remarks:

The test was performed in compliance with the requirements of the Principles of Good Laboratory Practices (GB/T 22278-2008).

Test material

Test material information

Constituent 1

Reference substance name:

2-nitro-4-(trifluoromethyl)benzonitrile

EC Number:

212-298-1

EC Name:

2-nitro-4-(trifluoromethyl)benzonitrile

Cas Number:

778-94-9

Molecular formula:

C8H3F3N2O2

IUPAC Name:

2-nitro-4-(trifluoromethyl)benzonitrile

Radiolabelling:

no

Study design

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products: Samples were taken at day 0, 1, 2, 3, 4 and 5.
- Sampling method: At each sampling date 10 mL water sample was taken.

Buffers:

- pH 4: 0.400 mL 0.1 mol/L sodium hydroxide solution and 50.0 mL 0.1 mol/L potassium hydrogen phthalate solution were placed in a 100 mL volumetric flask. Deionised water (without CO2) was used to dilute to 100 mL.
- pH 7: 41.3 mL 0.0667 mol/L potassium dihydrogen phosphate solution was placed in a 100 mL volumetric flask. 0.0667 mol/L disodium hydrogen phosphate solution was used to dilute to 100 mL.
- pH 9: 21.3 mL 0.1 mol/L sodium hydroxide solution and 50 mL 0.1 mol/L boric acid were placed in a 100 mL volumetric flask. 0.1 mol/L potassium chloride was used to dilute to 100 mL.

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: Test substance solutions at different pH values were each separately loaded into a series of six 10 mL test tubes and placed in a biochemical culture box.
- Sterilisation method: Prior to testing, all buffer solutions and test utensils were sterilised for 20 minutes at 120 °C under 10^5 Pa conditions.
- Lighting: Continuous darkness
- Measures to exclude oxygen: Prior to adding the test substance, nitrogen gas was used to aerate the buffer solution for 5 minutes. Test tubes were sealed.

TEST MEDIUM
- Volume used/treatment: The test solutions (100 mL) of different pH values were each separately loaded into six 10 mL test tubes
- Kind and purity of water: Deionised water (Watsons, China)
- Preparation of test medium:
Test solution I (369 mg/L): 0.0372 g test substance was precisely weighed, and pH = 4 buffer solution was used to dissolve this and dilute it to 100 mL, yielding a test substance concentration 369 mg/L.
Test solution II (367 mg/L): 0.0370 g test substance was precisely weighed, and pH = 7 buffer solution was used to dissolve this and to dilute it to 100 mL, yielding a test substance concentration 367 mg/L.
Test solution III (372 mg/L): 0.0375 g test substance was precisely weighed, and pH = 9 buffer solution was used to dissolve this and dilute it to 100 mL, yielding a test substance concentration 372 mg/L.

Duration of test

Duration of test 1

Duration:

5 d

pH:

4

Temp.:

50 °C

Initial conc. measured:

369 mg/L

Duration of test 2

Duration:

5 d

pH:

7

Temp.:

50 °C

Initial conc. measured:

363 mg/L

Duration of test 3

Duration:

5 d

pH:

9

Temp.:

50 °C

Initial conc. measured:

370 mg/L

Number of replicates:

6

Positive controls:

no

Negative controls:

no

Results and discussion

Preliminary study:

The results revealed that at day 0 the concentrations of the test substance in buffer solutions with a pH of 4.00, 7.00, and 9.00 were 369, 363, and 370 mg/L respectively; at day 5 the concentrations were 344, 343, and 350 mg/L respectively; hydrolysis rates were all less than 10%.

Transformation products:

not measured

Dissipation DT50 of parent compound

Dissipation DT50 of parent compound 1

pH:

4

Temp.:

50 °C

Hydrolysis rate constant:

0.014 d-1

DT50:

49.4 d

Type:

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

Dissipation DT50 of parent compound 2

pH:

7

Temp.:

50 °C

Hydrolysis rate constant:

0.011 d-1

DT50:

61.1 d

Type:

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

Dissipation DT50 of parent compound 3

pH:

9

Temp.:

50 °C

Hydrolysis rate constant:

0.011 d-1

DT50:

62.3 d

Type:

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

Any other information on results incl. tables

Table 1: Test Substance Hydrolysis Test Results (50 ± 0.5) °C

Time (d)	Measured concentration (mg/L)
	pH 4.00	pH 7.00	pH 9.00
0	369	363	370
1	350	339	361
2	362	355	342
3	347	339	349
4	350	346	341
5	344	343	350
Hydrolysis rate H5 (%)	6.78	5.51	5.41
Hydrolysis rate constant k	0.0140	0.0113	0.0111
Half-life (t1/2, d)	49.4	61.1	62.3
Hydrolysis rate Ht (%)	Hydrolysis rate Ht (%) = ((c0 – ct)/c0) * 100% C0: initial concentration at 0 d (mg/L) Ct: concentration at t d (mg/L)
Reaction rate constant k	Reaction rate constant k was calculated based on the following formula: k = 2.303/t lg(C0/Ct) In which: Ct: measured concentration at t d, mg/L; C0: measured concentration at 0 d, mg/L; t: number of days, d.
Half-life (t1/2, d)	t1/2 = 0.693/k

 

Applicant's summary and conclusion

Validity criteria fulfilled:

not applicable