1-(5,5-dimethyl-1-cyclohexen-1-yl)pent-4-en-1-one

Hydrolysis

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

hydrolysis

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Reference 2

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.

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.