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Environmental fate & pathways

Hydrolysis

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Reference
Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1995
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Principles of method if other than guideline:
Method: other: US EPA Subdivision N Guideline 161-1
GLP compliance:
yes
Transformation products:
no
% Recovery:
100
Duration:
500 d
pH:
7
Temp.:
25 °C
DT50:
> 500 d
pH:
9
Temp.:
25 °C
DT50:
> 500 d
pH:
5
Temp.:
25 °C
DT50:
> 500 d
Details on results:
Degradation (in %): = 0 after 500day(s)
Conclusions:
The substance is hydrolytically stable in solution in the dark at 25°C at pH 5,7,9 and its half-life under these conditions is greater than 500 days.
Executive summary:

The hydrolytic stability of the synergist pyperonyl butoxide was studied in sterilised aqueous solution buffered to pH 5, 7, 9 incubated at 25°C under aseptic conditions in the dark. Pyperonyl butoxide was labelled with carbon14 in its phenyl ring.

The nominal initial concentration in the hydrolysis media was 1 mg/l, wich is below its reported water solubility of 14.3 mg/l.

At each pH, samples were analysed at zero time and at six additional time up to 30 days. Total recoveries of the applied radioactivities were in all cases in the range 95.1 - 105.9%.Icubated solution were analysed by reverse phase high performance liquid chromatography to determine the relative proportions of 14C piperonyl butoxide and any degradations products. Selected solutions were also analysed by high performance liquid chromatography operating in the normal phase mode to provide supporting qualitative and quantitative data.

At each pH, unchanges pyperonyl butoxide accounted for more than 96% of the recovered radioactivity at all times. No distinct degradation products were detected.

The substance is hydrolytically stable in solution in the dark at 25°C at pH 5,7,9 and its half-life under these conditions is greater than 500 days.

Description of key information

Key value for chemical safety assessment

Half-life for hydrolysis:
500 d
at the temperature of:
25 °C

Additional information