2,2'-(cyclohexylimino)bisethanol

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

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:

no

GLP compliance:

no

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Sample solutions:
pH 4,0 (1): 115,1 mg in 50 ml buffer = 2302 mg/l
pH 4,0 (2): 106,1 mg in 50 ml buffer = 2122 mg/l
pH 7,0 (1): 120,5 mg in 50 ml buffer = 2410 mg/l
pH 7,0 (2): 132,3 mg in 50 ml buffer = 2646 mg/l
pH 9,0 (1): 119,8 mg in 50 ml buffer = 2396 mg/l
pH 9,0 (2): 110,4 mg in 50 ml buffer = 2208 mg/l
After dissolution of the test substance the pH was re-adjusted with c = 1 mol/l hydrochloric acid.

Buffers:

Buffer solutions:
pH 4,0: 11,76 g citric acid monohydrate, 2,57 g sodium chloride, 68 ml sodium hydroxide solution c = 1 mol/l in 1000 ml water
pH 7,0: Supelco No. 1.09407 (potassium dihydrogenphosphate/di-sodium hydrogenphosphate)
pH 9,0: Supelco No. 1.09408 (boric acid/potassium chloride/sodium hydroxide)

Details on test conditions:

Preliminary Test:
In a preliminary test solutions of the test substance at pH 4, pH 7 and pH 9 are thermostated at 50 °C. As less than 10 per cent of the reaction was observed after 5 days (t1/2 > 1 year) the chemical was considered hydrolytically stable and no additional test was required.

The sample solutions (2) were incubated in closed flasks at 50 ± 0,5 °C for 5 days. To check the suitability of the analytical method, the sample solutions (1) were stirred for 30 min at room temperature and afterwards immediately analysed. (recovery test).

Duration:

5 d

pH:

9

Temp.:

50 °C

Initial conc. measured:

> 2 208 - < 2 396 mg/L

Duration:

5 d

pH:

7

Temp.:

50 °C

Initial conc. measured:

> 2 410 - < 2 646 mg/L

Duration:

5 d

pH:

4

Temp.:

50 °C

Initial conc. measured:

> 2 122 - < 2 302 mg/L

Number of replicates:

2

Positive controls:

no

Negative controls:

no

Preliminary study:

Result of hydrolysis test

pH 4,0
Hydrolysis test
sample weight (mg) 106,1
pH at start 3,99
pH at end 4,00
recovered substance (mg) 88,6
recovery rate (%) 83,5
GC area-% of recovered substance:
Peak 1 (area-%) 77,8
Peak 2 (area-%) 19,8
Peak 3 (area-%) 2,4

Recovery test
sample weight (mg) 115,1
pH at start 4,00
pH at end ---
recovered substance (mg) 100,0
recovery rate (%) 86,9
GC area-% of recovered substance:
Peak 1 (area-%) 77,4
Peak 2 (area-%) 20,0
Peak 3 (area-%) 2,6

pH 7,0
Hydrolysis test
sample weight (mg) 132,3
pH at start 6,99
pH at end 6,95
recovered substance (mg) 129,5
recovery rate (%) 97,9
GC area-% of recovered substance:
Peak 1 (area-%) 81,0
Peak 2 (area-%) 17,0
Peak 3 (area-%) 2,0

Recovery test
sample weight (mg) 120,5
pH at start 7,00
pH at end ---
recovered substance (mg) 121,9
recovery rate (%) 101,2
GC area-% of recovered substance:
Peak 1 (area-%) 80,7
Peak 2 (area-%) 17,1
Peak 3 (area-%) 2,2

pH 9,0
Hydrolysis test
sample weight (mg) 110,4
pH at start 8,99
pH at end 8,90
recovered substance (mg) 109,8
recovery rate (%) 99,5
GC area-% of recovered substance:
Peak 1 (area-%) 81,3
Peak 2 (area-%) 16,8
Peak 3 (area-%) 1,9

Recovery test
sample weight (mg) 119,8
pH at start 9,01
pH at end ---
recovered substance (mg) 120,2
recovery rate (%) 100,3
GC area-% of recovered substance:
Peak 1 (area-%) 80,9
Peak 2 (area-%) 17,0
Peak 3 (area-%) 2,2

Transformation products:

no

pH:

9

Temp.:

50 °C

DT50:

> 1 yr

pH:

7

Temp.:

50 °C

DT50:

> 1 yr

pH:

4

Temp.:

50 °C

DT50:

> 1 yr

Conclusions:

In a preliminary OECD111 test solutions of the test substance at pH 4, pH 7 and pH 9 are thermostated at 50 °C.
The gas chromatograms of the test substance after hydrolysis test and after immediate analysis (recovery test) show no significant differences at the respective pH values. Also, the recovery rates of the test substance are comparable at respective pH values.
Therefore, it can be concluded that the test substance is hydrolytically stable at pH 4, pH 7 and pH 9 (t0.5 25 °C > 1 year).

Description of key information

In a preliminary OECD111 test solutions of the test substance at pH 4, pH 7 and pH 9 are thermostated at 50 °C.
The gas chromatograms of the test substance after hydrolysis test and after immediate analysis (recovery test) show no significant differences at the respective pH values. Also, the recovery rates of the test substance are comparable at respective pH values.
Therefore, it can be concluded that the test substance is hydrolytically stable at pH 4, pH 7 and pH 9 (t0.5 25 °C > 1 year).

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C