Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Hydrolysis

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2001
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study without detailed documentation
Qualifier:
equivalent or similar to guideline
Guideline:
EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
Deviations:
no
GLP compliance:
no
Radiolabelling:
no
Analytical monitoring:
yes
Buffers:
Buffer solutions:
- 0.05 M acetate buffer solution pH 4
- 0.05 M phosphate buffer solution pH 7
- 0.05 M borate buffer pH 9

Buffer solutions for calibration of pH meter and electrode:
- standard buffer solutions pH 4 (Art. 33543), pH 7 (Art. 33546), pH 9 (Art. 33548)

Details on test conditions:
Preparation of the test solutions:
- Two sets of test solutions, buffered to pH values of 4, 7 and 9, each with a test substance concentration of approx. 20 mg/l, were prepared by adding a stock solution of the test substance in acetonitrile to the corresponding buffer solution

lncubation and sampling:
- aliquots of the test solutions were filled into autosampler vials which had been pre-rinsed with the test solutions and which were tightly closed with crimp caps
- incubated at 25 °C in an autosampler at room temperature (approx. 25 °C)
- the concentration of the sample analyzed immediately after preparation was taken as initial concentration
- the test solutions were analyzed after time intervals
- one vessel at each pH value was used exclusively for pH measurements
- the pH values of the test solutions were measured at the start of incubation and at several sampling times
Duration:
6 h
pH:
4
Temp.:
25
Initial conc. measured:
17 mg/L
Duration:
4 h
pH:
7
Temp.:
25
Initial conc. measured:
17 mg/L
Duration:
1 h
pH:
9
Temp.:
25
Initial conc. measured:
9.5 mg/L
Number of replicates:
two replicates; In the above-cited initial concentration is an average value of two measurements
Transformation products:
yes
No.:
#1
Details on hydrolysis and appearance of transformation product(s):
Hexanoic acid (CAS 111-14-8) is the hydrolysis product. A material balance was established for heptanoic anhydride and heptanoic acid using the corresponding reference solutions.
% Recovery:
4.9
pH:
4
Temp.:
25 °C
Duration:
5.2 h
% Recovery:
10
pH:
4
Temp.:
25 °C
Duration:
4.7 h
% Recovery:
26.6
pH:
7
Temp.:
25 °C
Duration:
2.4 h
% Recovery:
9.9
pH:
7
Temp.:
25 °C
Duration:
3.8 h
% Recovery:
0
pH:
9
Temp.:
25 °C
Duration:
56 min
% Recovery:
2.4
pH:
9
Temp.:
25 °C
Duration:
56 min
pH:
4
Temp.:
25 °C
Hydrolysis rate constant:
0.374 h-1
DT50:
1.9 h
Remarks on result:
other: 95% confidence intervals for half-life: 1.6 - 2.2 h
pH:
7
Temp.:
25 °C
Hydrolysis rate constant:
0.451 h-1
DT50:
1.5 h
Remarks on result:
other: 95% confidence intervals for half-life: 1.4 - 1.8 h
pH:
9
Temp.:
25 °C
Hydrolysis rate constant:
3.656 h-1
DT50:
11 min
Remarks on result:
other: no confidence interval can be given because of low number of data points
Validity criteria fulfilled:
yes
Conclusions:
Heptanoic anhydride is hydrolytically instable with half-lives at 25 °C of 1.9 h at pH 4, 1.5 h at pH 7 and 11 minutes at pH 9.
Executive summary:

The rate of hydrolysis of heptanoic anhydride in aqueous solution buffered to pH values of 4, 7 and 9 was studied according to EU testing guideline C.7. The substance is hydrolytically instable with half-lives at 25 °C of 1.9 h at pH 4, 1.5 h at pH 7 and 11 minutes at pH 9. Therefore the hydrolysis is base-catalyzed. Heptanoic anhydride can be considered as hydrolytically instable in the pH range 2 -10, which is of relevance for biological systems.

Description of key information

Heptanoic anhydride is hydrolytically instable with half-lives at 25 °C of 1.9 h at pH 4, 1.5 h at pH 7 and 11 minutes at pH 9.

Key value for chemical safety assessment

Half-life for hydrolysis:
1.5 h
at the temperature of:
25 °C

Additional information

The half-life of 1.5 h was measured at pH 7.

Heptanoic anhydride can be considered as hydrolytically instable in the pH range 2-10, which is of relevance for biological systems.