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Hydrolysis

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Endpoint:
hydrolysis
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:
Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
August 4th, 2003
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
This study was not performed according to GLP. However, this study is well documented and is considered reliable with restrictions.
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Deviations:
not applicable
Principles of method if other than guideline:
The aim of the study is to assess the stability of the substance in a series of simple media simulating perfumery applications. The test media are standard aqueous buffers at pH 2, pH 5, pH 7, pH 8.5 and pH 12 containing 1% of non ionic surfactant. The tests are done in accelerated conditions at 40 °C during ca. one month.
GLP compliance:
no
Specific details on test material used for the study:
No additional information
Radiolabelling:
no
Analytical monitoring:
yes
Details on sampling:
200 – 300 ppm of raw material are dissolved in the pH buffer containing the surfactant (Arkopal N 150) and put into storage in an oven at 40°C. Small aliquots of the test solution are extracted with an organic solvent (typically cyclohexane or ethyl acetate) containing a hydrocarbon standard (typically C12, C17 or C20) on a regular basis throughout the test (typically at time = 0, 0.25, 1, 2, 4, 7, 15, 21 and 28 days). The extracts are analyzed by GC-FID and the results are plotted as (Area/Area Std) expressed in [%]. The measurement at time = 0 is set at 100% and the succeeding measurements are calculated relatively to the time = 0 measurement. Therefore the curves represent the percentage of product remaining in the test solution at the time of analysis.
Buffers:
Buffer solutions:
pH 2 (± 0.1) buffer: Reference Handbook of Chemistry and Physics buffer type A
pH 5 (± 0.1) buffer: Reference Handbook of Chemistry and Physics buffer type C
pH 7 (± 0.1) buffer: Reference Handbook of Chemistry and Physics buffer type D
pH 8.5 (± 0.1) buffer: Reference Handbook of Chemistry and Physics buffer type F
pH 12 (± 0.1) buffer: Reference Handbook of Chemistry and Physics buffer type I
Estimation method (if used):
Not applicable
Details on test conditions:
No data
Duration:
28 d
pH:
2
Temp.:
40 °C
Initial conc. measured:
> 200 - < 300 other: ppm
Duration:
28 d
pH:
5
Temp.:
40 °C
Initial conc. measured:
> 200 - < 300 other: ppm
Duration:
28 d
pH:
7
Temp.:
40 °C
Initial conc. measured:
> 200 - < 300 other: ppm
Duration:
28 d
pH:
8.5
Temp.:
40 °C
Initial conc. measured:
> 200 - < 300 other: ppm
Duration:
28 d
pH:
12
Temp.:
40 °C
Initial conc. measured:
> 200 - < 300 other: ppm
Number of replicates:
1
Positive controls:
no
Negative controls:
no
Statistical methods:
None
Preliminary study:
No data
Test performance:
No data
Transformation products:
no
Details on hydrolysis and appearance of transformation product(s):
Results showed that the major constituent of the parent compound is stable (less than 10% disappearance) up to 28 days in the range of pH from 5 to 8.5 at 40°C. At higher pH (pH of 12), the parent compound is unstable (ca. 40% disappearance after 28 days at 40°C).
% Recovery:
> 90
pH:
2
Temp.:
40 °C
Duration:
28 d
Remarks on result:
other: Hydrolytically stable
% Recovery:
> 90
pH:
5
Temp.:
40 °C
Duration:
28 d
Remarks on result:
other: Hydrolytically stable
% Recovery:
> 90
pH:
7
Temp.:
40 °C
Duration:
28 d
Remarks on result:
other: Hydrolytically stable
% Recovery:
> 90
pH:
8.5
Temp.:
40 °C
Duration:
28 d
Remarks on result:
other: Hydrolytically stable
% Recovery:
> 60
pH:
12
Temp.:
40 °C
Duration:
28 d
Other kinetic parameters:
None
Details on results:
No additional information
Results with reference substance:
None
Validity criteria fulfilled:
not applicable
Conclusions:
The disappearance of the major constituent in the parent compound after 28 days at 40 °C and at environmentally relevant pH is less than 10 %. It can be concluded that under the conditions of the present test, test substance is hydrolytically stable at environmentally relevant pHs (as defined in the OECD TG 111 for hydrolysis as a function of pH).
Executive summary:

Hydrolysis study was performed similar to OECD Guideline No. 111. The aim of the study is to assess the stability of the substance in a series of simple media simulating perfumery applications. The test media are standard aqueous buffers at pH 2, pH 5, pH 7, pH 8.5 and pH 12 containing 1% of non ionic surfactant (Arkopal N 150). The tests are done in accelerated conditions at 40 °C during ca. one month. The test substance is a mixture of two isomers: 1-((5,5)-Dimethyl-1-cyclohexen-1-yl)pent-4-en-1-one (present at ca. ~70% in the mixture) and 1-((3,3)-Dimethyl-1-cyclohexen-1-yl)pent-4-en-1-one (present at ca. ~20% in the mixture). The first isomer (which is the major constituent in the parent compound) is used as a tracer in this stability test.

200 – 300 ppm of raw material are dissolved in the pH buffer containing the surfactant (Arkopal N 150) and put into storage in an oven at 40°C. Small aliquots of the test solution are extracted with an organic solvent (typically cyclohexane or ethyl acetate) containing a hydrocarbon standard (typically C12, C17 or C20) on a regular basis throughout the test (typically at time = 0, 0.25, 1, 2, 4, 7, 15, 21 and 28 days). The extracts are analyzed by GC-FID and the results are plotted as (Area/Area Std) expressed in [%]. The measurement at time = 0 is set at 100% and the succeeding measurements are calculated relatively to the time = 0 measurement. Therefore the curves represent the percentage of product remaining in the test solution at the time of analysis.

 

The disappearance of the major constituent in the parent compound after 28 days at 40 °C and at environmentally relevant pH is less than 10 %. It can be concluded that under the conditions of the present test, test substance is hydrolytically stable at environmentally relevant pHs (as defined in the OECD TG 111 for hydrolysis as a function of pH).

Description of key information

A GLP study is scientifically unjustified.

Key value for chemical safety assessment

Additional information

The registered substance contains no organic functional groups that may hydrolyze under environmental conditions. The substance consists only of organic functional groups that are relatively or completely inert with respect to hydrolysis, notably a ketone. Based on the chemical structure an estimation of the hydrolysis rate is not possible. To support this statement, one stability test was performed according to a method similar to OECD Guideline 111 but without GLP statement on a mixture of two isomers: 1-(5,5-Dimethyl-1-cyclohexen-1-yl)-4-penten-1-one, present as the major constituent at ca. 70% in the mixture, and corresponding to the registered/target substance (mono-constituent), and 1-(3,3-Dimethyl-1-cyclohexen-1-yl)-4-penten-1-one, present at ca. 20% as second constituent. In this study, the major constituent/registered substance (used as a tracer in this study) is hydrolytically stable at environmentally relevant pH. In conclusion, a GLP study is scientifically unjustified.