1,3,4-Thiadiazole-2(3H)-thione, 5-(tert-dodecyldithio)-

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

August/September 1990

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP guideline study on supporting substance; buffer details and recovery data for analytical method not reported as required by OECD Guideline 111. This result is read-across from ‘1,3,4-Thiadiazolidine-2,5-dithione, reaction products with hydrogen peroxide and tert-nonanethiol’. Read-across is justified as the two substances ‘1,3,4-Thiadiazolidine-2,5-dithione, reaction products with hydrogen peroxide and tert-dodecanethiol’ and ‘1,3,4-Thiadiazolidine-2,5-dithione, reaction products with hydrogen peroxide and tert-nonanethiol’ are virtually the same: the only difference between those two UVCB substances is that one of the used raw materials (alkanethiol) has a diversity in the C-range, i.e. on the one hand a tert. C12-alkanethiol is used in the manufacturing process, on the other hand a tert. C9. Hence, based on the (structural) similarity of both substances it is safe to say that the physicochemical, toxicological and ecotoxicological properties are likely to be similar.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1990

Report date:

1990

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

1,3,4-Thiadiazolidine-2,5-dithione, reaction products with hydrogen peroxide and tert-nonanethiol

EC Number:

293-927-7

EC Name:

1,3,4-Thiadiazolidine-2,5-dithione, reaction products with hydrogen peroxide and tert-nonanethiol

Cas Number:

91648-65-6

Molecular formula:

not applicable (UVCB substance)

IUPAC Name:

1,3,4-Thiadiazolidine-2,5-dithione, reaction products with hydrogen peroxide and tert-nonanethiol

Test material form:

liquid: viscous

Details on test material:

- Description: amber viscous liquid
- Storage condition of test material: ambient, dark

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not applicable.

Radiolabelling:

no

Study design

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products:
Preliminary study: Days 1, 2, 3, 4 and 5 (test performed at pH 4, 7 and 9 at 50 °C)
Definitive study: Days 1, 3, 5, 6 (day 7 for pH 7 at 30 °C) and 11 (test performed at pH 4, 7 and 9 at 6, 30 and 50 °C)
- Sampling method: 10 mL sub-samples were removed from the bulk incubation vessels at all timepoints
- Sampling intervals/times for pH measurements: pH measured immediately prior to study initiation
- Sampling intervals/times for sterility check: filter-sterilised immediately prior to study initiation
- Sample storage conditions before analysis: + 4 °C
- Other observation, if any (e.g.: precipitation, color change etc.): none

Buffers:

0.05 M sterile buffers at pH 4, 7 and 9 used

Estimation method (if used):

Not applicable.

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: not reported (large enough to hold 300 mL)
- Sterilisation method: filtration
- Lighting: flasks covered to exclude light

TEST MEDIUM
- Volume used/treatment: 200 mL for preliminary study and 300 mL for definitive study
- Kind and purity of water: distilled
- Preparation of test medium: A stock solution of test material at 63.4 mg/L was prepared in methanol (2 mL) and then diluted to 1L in distilled water
- Identity and concentration of co-solvent: methanol, 0.2 %

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Dissolved oxygen: not reported

Duration of test

Duration of test 1

Duration:

11 d

pH:

4

Initial conc. measured:

5.9 other: µg/mL

Duration of test 2

Duration:

11 d

pH:

7

Initial conc. measured:

1.4 other: µg/mL

Duration of test 3

Duration:

11 d

pH:

9

Initial conc. measured:

3.5 other: µg/mL

Number of replicates:

One at 6 °C and 50 °C and triplicate at 30°C

Positive controls:

no

Negative controls:

no

Statistical methods:

The data obtained for each temperature/pH treatment is plotted using:
log10 Ct versus t,
where:
Ct = concentration of test substance at time (t)
The reaction rate constant (Kobs) is calculated by regression analysis or from the equation below:
Kobs = 2.303 * slope

Results and discussion

Preliminary study:

The test compound degraded significantly (greater than 10 %) at all three pH levels, therefore the definitive study was performed.

Test performance:

Neither unusual observations during test, deviations from test procedure nor any other information affecting results are reported.

Transformation products:

not measured

Total recovery of test substance (in %)

Total recovery of test substance (in %) 1

% Recovery:

57

pH:

7

Temp.:

30 °C

Duration:

11 d

Total recovery of test substance (in %) 2

% Recovery:

57

pH:

7

Temp.:

50 °C

Duration:

11 d

Dissipation DT50 of parent compound

Dissipation DT50 of parent compound 1

pH:

7

Temp.:

30 °C

Hydrolysis rate constant:

0.27 d-1

Remarks on result:

other: slope = -0.133 Kobs = 0.270

Dissipation DT50 of parent compound 2

pH:

7

Temp.:

50 °C

Hydrolysis rate constant:

0.219 d-1

Remarks on result:

other: slope = -0.108, Kobs = 0.219

Other kinetic parameters:

No other kinetic parameters reported.

Details on results:

MAJOR TRANSFORMATION PRODUCTS
At pH 5: no degradation measured
At pH 7: degradation measured, major transformation products not measured
At pH 9: no degradation measured

Any other information on results incl. tables

Table 1: Preliminary Hydrolysis Determination

Treatment	Concentration of Test Material (µg/mL)						% remaining
	Day 0	Day 1	Day 2	Day 3	Day 4	Day 5
pH4	34.1	28.7	31.6	29.8	34.1	23.1	68
pH7	32.3	28.1	16.7	14.9	17.6	13.9	43
pH9	3.8	3.4	3.3	2.2	2.2	1.9	50

 

Table 2: Definitive Hydrolysis Determination

Treatment	Concentration of Test Material (µg/mL)
	Day 0	Day 1	Day 3	Day 5	Day 6	Day 7	Day 11
pH4: 6°C 30°C 30°C 30°C 50°C	5.9 5.9 5.9 5.9 5.9	5.7 5.7 5.9 6.5 6.0	5.5 5.8 5.6 6.0 5.9	6.3 6.1 6.4 6.1 6.2	6.6 6.5 6.6 6.4 6.4	- - - - -	6.1 6.2 6.3 6.4 6.1
pH7 6°C 30°C 30°C 30°C 50°C	1.4 1.4 1.4 1.4 1.4	1.2 1.3 1.2 1.2 0.8	1.4 1.1 1.2 0.9 0.5	1.4 1.0 0.6 0.5 0.6	1.3 0.8 <0.4 0.5 0.6	- 0.8 <0.8 <0.8 <0.8	1.2 <0.8 <0.8 <0.8 <0.8
pH9 6°C 30°C 30°C 30°C 50°C	3.5 3.5 3.5 3.5 3.5	3.8 3.7 3.6 3.8 3.4	3.7 3.1 3.6 2.3 3.4	3.6 3.5 3.6 3.6 3.4	3.6 3.4 3.3 3.5 3.5	- - - - -	3.5 3.1 3.4 3.4 2.9

 

Table 3: Linear Regression Calculations

Day	Concentration (µg/mL)
	pH7 30°C	pH7 50°C
0 1 3 5 6	1.40 1.23 1.07 0.70 0.65	1.40 0.80 0.50 0.60 0.60
Slope Kobs Kobs	-0.133 2.03 * slope 0.270	-0.108 2.03 * slope 0.209

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Validity criteria were fulfilled.

Conclusions:

The test report describes a valid guideline study, conducted with GLP compliance. Hydrolysis was only observed at pH 7 and not at pH 4 or pH 9.

Executive summary:

The hydrolysis reactions of the ‘1,3,4-Thiadiazolidine-2,5-dithione, reaction products with hydrogen peroxide and tert-nonanethiol’ (that should be also applicable for the structurally similar long-chain homologue ‘1,3,4-Thiadiazolidine-2,5-dithione, reaction products with hydrogen peroxide and tert-dodecanethiol') were determined in accordance with the OECD Guideline 111. A stock solution of test material (63.4 mg/L) was prepared in 2 mL of methanol and then diluted to 1L with distilled water (< 1 % co-solvent). Aliquots of the stock solution were adjusted to varying pH levels 4.0, 7.0, 9.0 (actual: 4.03, 6.94 and 8.90) using an appropriate 0.05 M buffer, filter-sterilized and incubated at the designated test temperatures (6 °C, 30 °C and 50 °C). The concentration of test material was then determined analytically on days 0, 1, 3, 5, 6, 7, and 11 of the study using high pressure liquid chromatography (HPLC). Significant hydrolysis was only observed for the pH7 treatment. The reaction rate constant (Kobs) was calculated for the 30 °C and 50 °C test temperatures, Kobs = 0.270 and 0.219/days, respectively.