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Administrative data

Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
not reported
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
Deviates from guideline by using pH 1 instead of pH 4.

Data source

Reference
Reference Type:
publication
Title:
Hydrolysis study of fluoroorganic and cyano-based ionic liquid anions – consequences for operational safety and environmental stability
Author:
Steudte S, Neumann J, Bottin-Weber U, Diedenhofen M, Arning J, Stepnowski P, Stolte S
Year:
2012
Bibliographic source:
Green Chem., 2012, 14, 2474-2483. DOI: 10.1039/c2gc35855g

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Version / remarks:
2004
Deviations:
yes
Remarks:
pH 1 instead of pH 4 was tested.
GLP compliance:
not specified
Remarks:
This study has been published in a scientific paper and is thus not subject to GLP.

Test material

Constituent 1
Chemical structure
Reference substance name:
Sodium dicyanoamide
EC Number:
217-703-5
EC Name:
Sodium dicyanoamide
Cas Number:
1934-75-4
Molecular formula:
C2HN3.Na
IUPAC Name:
sodium dicyanamide
Test material form:
solid
Details on test material:
Published data or data from handbook.
Specific details on test material used for the study:
- provided by Merck KGaA (Darmstadt, Germany)
Radiolabelling:
no

Study design

Analytical monitoring:
yes
Details on sampling:
- Sampling intervals for the parent/transformation products: at the start and at the end of the incubation
- Sampling method: not specified
Buffers:
- pH 1: 47.5 mL 0.2 M HCl and 25 mL 0.2 M KCl made up to 100 mL with distilled water
- pH 7: 29.63 mL 0.1 M NaOH and 50 mL 0.1 M KH2PO4 diluted with distilled water to 100 mL
- pH 9: distilled water was added to a mixture of 21.30 mL 0.1 M NaOH and 50 mL 0.1 M H3BO4 in 0.1 M KCl in a 100 mL flask.
Details on test conditions:
TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: headspace vials, material not specified
- Sterilisation method: not specified
- Measures taken to avoid photolytic effects: not specified; a water bath was employed
- Measures to exclude oxygen: argon atmosphere
- Is there any indication of the test material adsorbing to the walls of the test apparatus? Not reported
TEST MEDIUM
See section “buffers”
OTHER TEST CONDITIONS
- Adjustment of pH: pH values of the buffers were checked and adjusted using small amounts of conc. HCl or NaOH
Duration of testopen allclose all
Duration:
5 d
pH:
1
Temp.:
323 K
Remarks:
disregarded since not relevant under environmental conditions
Duration:
5 d
pH:
7
Temp.:
323 K
Duration:
5 d
pH:
9
Temp.:
323 °C
Number of replicates:
4
Positive controls:
no
Negative controls:
no

Results and discussion

Preliminary study:
Under environmental conditions (pH 7 and 9), the test substance was degraded by less than 10 %. Therefore, the test substance was considered hydrolytically stable with a half-life of >1 year at 298 K and no further tests were carried out.
Transformation products:
no
Remarks:
No transformation products were detected under environmental conditions (pH 7 and 9). Transformation products were detected only at pH 1.
Details on hydrolysis and appearance of transformation product(s):
not applicable
Total recovery of test substance (in %)open allclose all
% Recovery:
> 90
pH:
7
Temp.:
323 K
Duration:
5 d
Remarks on result:
hydrolytically stable based on preliminary test
% Recovery:
> 90
pH:
9
Temp.:
323 K
Duration:
5 d
Remarks on result:
hydrolytically stable based on preliminary test
Dissipation DT50 of parent compoundopen allclose all
Key result
pH:
7
Remarks on result:
hydrolytically stable based on preliminary test
Key result
pH:
9
Remarks on result:
hydrolytically stable based on preliminary test
Results with reference substance:
not examined

Any other information on results incl. tables

The test substance hydrolysed only at pH 1, which is not an environmentally relevant condition. The results were: at pH 1 and 283 K the half-life of N(CN)2is about 10.5 h, at 298 K it decreases to <2 h and at 310 K N(CN)2is rapidly hydrolysed to 50% within approximately 20 min.

A measurement at pH 4 is not described by the authors.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Under environmental conditions (pH 7 and 9), the test substance was degraded by <10 %. Therefore, the test substance was considered hydrolytically stable with a half-life of >1 year at 298 K.
Executive summary:

Hydrolysis of sodium dicyanoamide at about 50 °C was measured in aqueous buffered solutions at pH 1, pH 7 and pH 9 for 5 days. The experiment was conducted in accordance with the guideline OECD 111. Samples were taken and analysed at day 0 and day 5.

At test termination, the concentration of the dicyanoamide anion had decreased less than 10 % from of the initial at pH 7, and less than 10 % of the initial at pH 9. The test substance hydrolysed only at pH 1, which is not an environmentally relevant condition (pH1, 20 °C t1/2 <2h). At pH 7 and 9, no transformation products were detected. Therefore, the test substance was considered hydrolytically stable in the preliminary study with a half-life of >1 year at 298 K and no further tests were carried out.

This study is classified acceptable and satisfies the guideline requirement for hydrolysis study except for the lack of a measurement at pH 4.

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