Registration Dossier

Diss Factsheets

Administrative data

Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
2,2'-dithiodi(benzoic acid)
EC Number:
204-352-8
EC Name:
2,2'-dithiodi(benzoic acid)
Cas Number:
119-80-2
Molecular formula:
C14H10O4S2
IUPAC Name:
2-[(2-carboxyphenyl)disulfanyl]benzoic acid
Test material form:
other: Solid
Details on test material:
The test material had a purity of 75.3%
Radiolabelling:
no

Study design

Analytical monitoring:
yes
Details on sampling:
-pH4: test substance insoluble
-pH7: 0.02g test substance made up to 100ml with pH7 buffer
-pH9: 0.02g test substance made up to 100ml with pH9 buffer
Buffers:
-pH4 buffer: 36ml 0.2M sodium acetate + 164ml 0.2M acetic acid, diluted to 1L with distilled water
-pH7 buffer: 500ml 0.1M monopotassium phosphate + 296ml 0.1M sodium hydroxide, diluted to 1L with distilled water
-pH9 buffer: 50mml 0.1M boric acid in 0.1M potassium chloride + 213ml 0.1M sodium hydroxide, diluted to 1L with distilled water
Duration of testopen allclose all
Duration:
5 d
pH:
9
Initial conc. measured:
ca. 0.2 g/L
Duration:
5 d
pH:
7
Initial conc. measured:
ca. 0.2 g/L
Number of replicates:
2

Results and discussion

Transformation products:
not specified
Total recovery of test substance (in %)open allclose all
% Recovery:
ca. 90
pH:
9
Temp.:
50 °C
Duration:
5 d
% Recovery:
85.9
pH:
7
Temp.:
50 °C
Duration:
5 d
Dissipation DT50 of parent compoundopen allclose all
pH:
7
Temp.:
25 °C
Hydrolysis rate constant:
0.004 d-1
DT50:
174.74 d
Remarks on result:
other: Extrapolated value
pH:
7
Temp.:
50 °C
Hydrolysis rate constant:
0.031 d-1
DT50:
22.76 d
pH:
7
Temp.:
60 °C
Hydrolysis rate constant:
0.083 d-1
DT50:
8.4 d
pH:
7
Temp.:
70 °C
Hydrolysis rate constant:
0.13 d-1
DT50:
5.35 d
Details on results:
-pH4: test substance was insoluble in pH4 buffer, so this part of the test was not carried out
-pH7: at 50degreesC hydrolysis was 14.1%, therefore further tests were carried out at 60 and 70 degC
-determination of rate constants: rate constants at 25 degrees C were calculation by extrapolation

Any other information on results incl. tables

Results:

Time (days)

pH7

pH9

Conc (g/l)

Log C

Conc (g/l)

Log C

0

0.2116

-0.6745

0.1987

-0.7018

0

0.1971

-0.7053

0.2044

-0.6895

1

-

-

0.2007

-0.6975

1

-

-

0.2095

-0.6788

2

-

-

0.1966

-0.7064

2

-

-

0.2038

-0.6908

3

0.1903

-0.7203

-

-

3

0.1796

-0.7457

-

-

5

0.1806

-0.7433

0.1866

-0.7291

5

0.1706

-0.7680

0.1985

-0.7022

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The t1/2 of DTBA at pH7 was calculated to be 174.74 days at 25 degC. At pH4 the test could not be carried out due to very poor solubililty. At pH9 and 50 degC, less than 10% hydrolysis was obtained so no further testing was conducted.