Sodium dicyanoamide

Hydrolysis

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

Test material information

Constituent 1

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 test

Duration of test 1

Duration:

5 d

pH:

1

Temp.:

323 K

Remarks:

disregarded since not relevant under environmental conditions

Duration of test 2

Duration:

5 d

pH:

7

Temp.:

323 K

Duration of test 3

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 %)

Total recovery of test substance (in %) 1

% Recovery:

> 90

pH:

7

Temp.:

323 K

Duration:

5 d

Remarks on result:

hydrolytically stable based on preliminary test

Total recovery of test substance (in %) 2

% Recovery:

> 90

pH:

9

Temp.:

323 K

Duration:

5 d

Remarks on result:

hydrolytically stable based on preliminary test

Dissipation DT50 of parent compound

Dissipation DT50 of parent compound 1

Key result

pH:

7

Remarks on result:

hydrolytically stable based on preliminary test

Dissipation DT50 of parent compound 2

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)₂⁻is about 10.5 h, at 298 K it decreases to <2 h and at 310 K N(CN)₂⁻is 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.