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Diss Factsheets

Administrative data

Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
21 May 1996 to 19 August 1996.
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study conducted according to OECD Guideline with GLP certificate.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1996
Report date:
1996

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
N1-(5-methylhexan-2-yl)benzene-1,4-diamine
Cas Number:
63302-43-2
Molecular formula:
C13H22N2
IUPAC Name:
N1-(5-methylhexan-2-yl)benzene-1,4-diamine
Details on test material:
Sponsor's identification: TRAE
Description: Very dark purple solid block
Label: Distilled TRAE Y-775 Jan30, 96 Naugatuck Rhyang
Date received: 22 April 1996
Storage conditions: Room temperature



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:
The concentration of the sample solution was determined by (HPLC).
Samples:
Duplicate aliquots (A and B) of sample solutions were diluted to contain acetonitrile:buffer solution (50:50).

pH 1.2: dilution factor of 5 (pH 9 buffer solution was included in the dilution)
pH 4: dilution factor of 2
pH 7: dilution factor of 2
pH 10: dilution factor of 2

Standards
Duplicate standard solutions (A and B) were prepared in acetonitrile:buffer solution (50:50) at nominal concentrations of 2.5 and 1 mg/l.
Buffers:
Buffer solution 1.2: Potassium chloride 0.05 mol dm-3, Hydrochloric acid 0.06 mol dm-3
Buffer solution 4: Sodium hydroxide 0.10 mol dm-3, Hydrochloric acid 0.05 mol dm-3
Buffer solution 7: Disodium hydrogen orthophosphate 0.04 mol dm-3, Potassium dihydrogen orthophosphate 0.03 mol dm-3
Buffer solution 9: Disodium tetraborate 0.05 mol dm-3, Hydrochloric acid 0.02 mol dm-3

The buffer solutions were filtered through a 0.2 um membrane filter to ensure they were sterile before commencement of the test. Also these solutions were subjected to ultrasonication and degassing with nitrogen to minimise dissolved oxygen content.
Estimation method (if used):
Not applicable
Details on test conditions:
Preparation of samples
Sample solutions were prepared in stoppered glass flasks at nominal concentrations of 5 x 10-3 g/l in the pH 4, 7 and 9 buffer solutions.
The solutions were shielded from light.

Preliminary Test
The sample solutions were maintained at 50.0 + 0.5'C and the concentrations monitored by high performance liquid chromatography (HPLC).

Test 3
Results from the Preliminary Test showed it necessary to undertake further testing
at pH 4 at 25'C and pH 1.2 at 37'C.
Duration of testopen allclose all
Duration:
72 h
pH:
1.2
Initial conc. measured:
0.005 g/L
Duration:
22 h
pH:
4
Initial conc. measured:
0.005 g/L
Duration:
169 h
pH:
4
Initial conc. measured:
0.005 g/L
Duration:
2.4
pH:
7
Initial conc. measured:
0.005 g/L
Duration:
2.4 h
pH:
9
Initial conc. measured:
0.005 g/L
Number of replicates:
2
Positive controls:
no
Negative controls:
no
Statistical methods:
A graph of the common logarithm of the concentration (g/l) versus time (hours) was plotted for pH 4 and pH 1.2 and the rate constant and half life calculated.

Results and discussion

Preliminary study:
pH: 4 Temperature: 50.0 ± 0.5 degrees C:
Time = 0 h: concentration = 0.00476 g/L (100% of initial)
Time = 2.4 h: concentration = 0.00448 g/L (94% of initial)
The extent of hydrolysis indicated that further tests (Test 3), conducted at 25 degrees C at pH 4 and 37 degrees C at pH 1.2, were required.

pH 7 Temperature: 50.0 ± 0.5 degrees C:
Time = 0 h: concentration = 0.00475 g/L (100% of initial)
Time = 2.4 h: concentration = <0.0000798 g/L (<2% of initial)
Greater than 50% hydrolysis after 2.4 hours at 50 degrees C, equivalent to a half life of less than 1 day at 25'C.

pH: 9 Temperature: 50.0 ± 0.5 degrees C:
Time = 0 h: concentration = 0.00491 g/L (100% of initial)
Time = 2.4 h: concentration = 0.0000722 g/L (<2% of initial)
Greater than 50% hydrolysis after 2.4 hours at 50 *C, equivalent to a half life of less than 1 day at 25'C.

Test performance:
No data
Transformation products:
not measured
Details on hydrolysis and appearance of transformation product(s):
Transformation products were not measured.
See below for details of hydrolysis.
Dissipation DT50 of parent compoundopen allclose all
pH:
1.2
Temp.:
37 °C
Hydrolysis rate constant:
0.025 h-1
DT50:
27.9 h
Type:
(pseudo-)first order (= half-life)
pH:
4
Temp.:
25 °C
Hydrolysis rate constant:
0.006 h-1
DT50:
112 h
Type:
(pseudo-)first order (= half-life)
pH:
7
Temp.:
25 °C
DT50:
< 1 d
pH:
9
Temp.:
25 °C
DT50:
< 1 d
Other kinetic parameters:
None measured
Details on results:
See tables below and document attached under background information.

Any other information on results incl. tables

pH: 1.2, Temperature: 37.0 ± 0.5 degrees C

Time (hours)

0

4.5

29 1/4

72

Concentration (g/l)

0.00496

0.00487

0.00251

0.000866

Log10 [concentration (g/l)]

-2.31

-2.31

-2.6

-3.06

% of initial

100

98

51

17

pH: 4 Temperature: 25.0 ± 0.5 degrees C

 

Time (hours)

0

3

73

121

169

Concentration (g/l)

0.00453

0.00442

0.003

0.00229

0.00154

Log10 [concentration (g/l)]

-2.34

-2.36

-2.52

-2.64

-2.81

% of initial

100

99.7

66.4

50.7

34.1

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Conclusions:
The hydrolysis rate constants and half-lives of TRAE are as follows:
pH 1.2, temp 37 degrees C: rate constant = 0.0248 h-1, half-life = 27.9 hours
pH 4, temp 25 degrees C: rate constant = 0.00616 h-1, half-life = 112 hours
pH 7, temp 25 degrees C: half-life < 1 day
pH 9, temp 25 degrees C, half-life < 1 day
Executive summary:

The hydrolysis of the test substance was evaluated in accordance with OECD Guideline 111.

The hydrolysis rate constants and half-lives of TRAE are as follows:

pH 1.2, temp 37 degrees C: rate constant = 0.0248 h-1, half-life = 27.9 hours

pH 4, temp 25 degrees C: rate constant = 0.00616 h-1, half-life = 112 hours

pH 7, temp 25 degrees C: half-life

pH 9, temp 25 degrees C, half-life