Oct-2-ene

Phototransformation in air

Administrative data

Endpoint:

phototransformation in air

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP status not known, guideline not known, published in peer reviewed literature, acceptable with restrictions

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in Section 13.

Cross-reference

Reason / purpose for cross-reference:

read-across: supporting information

Reference

Endpoint:

phototransformation in air

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP status not known, guideline not known, published in peer reviewed literature, acceptable with restrictions

Justification for type of information:

Read-across between the target substance Oct-2-ene (EC 203-894-2 / CAS 111-67-1) and source substances from the Higher Olefins category is based upon the similarity of the chemical structures and their respective physico-chemical properties. The ECHA Read-Across Assessment Framework (RAAF) states that substances with qualitatively similar properties can form the basis of read-across in circumstances where the source and target substances share such similar characteristics.
Target substance Oct-2-ene is a mono-constituent linear internal olefin. The members of the Higher Olefins category include linear and branched alpha olefins with the carbon-carbon double bond at terminal (alpha-olefin) or non-terminal (internal olefin) carbons. Structurally, the differences between the target substance and the various source substances include: 1) the length of the carbon chain (eight for the target substance, and six to 30 for the category members); and 2) the location of the carbon-carbon double bond (uniformly at the C2 position for the target substance, but variable for category members).
The target and source substances both fit within the boundaries of chemical category of higher olefins. Studies conducted by the HOPA consortium on a large range of higher olefin category members demonstrated sufficiently similar physico-chemical, environmental fate and toxicological properties to substantiate the basis for read-across, or if these properties differ, they do so in a predictable manner based upon one or more structural components (e.g., reduced water solubility with increasing higher carbon number of the category member). Category members in the C6-C10 range may be moderately toxic to highly toxic to aquatic organisms. Although category members of a carbon chain length C10 or greater may exhibit a reduced acute aquatic toxicity attributable to reduced water solubility, the environmental toxicity of all category members is expected to be manifested as non-polar narcosis. Justification for inclusion of Oct-2-ene within the boundaries of the higher olefins category, and the relevance of each category member as an analogue substance to Oct-2-ene, is provided in Section 13 (Document name: “HOPA Higher Olefins CJD with Category Matrix Report [rev 1 Sept 2016]”; Document name: "ACC Product Stewardship Summary for Higher Olefins Category (2008-12-03)”).

Reason / purpose for cross-reference:

read-across source

Principles of method if other than guideline:

The author used data from other investigators. These data were generated using two methods: absolute and relative constant techniques. The author then applied a least squares analysis of degradation rate constants for organic chemicals by hydroxyl radicals developed by other investigators.

GLP compliance:

not specified

Estimation method (if used):

The rate constants were taken from experiments using relative constant techniques.

DT50:

10.2 h

Test condition:

Author reports a recommended rate constant of 3.75E-11 cm3 molecule-1sec-1. Half life is calculated based on this rate constant and a hydroxyl radical concentration of 5E5 molecule.cm-3.

Validity criteria fulfilled:

not applicable

Conclusions:

The estimated half life of 1-hexene is 10.2 hours based on a recommended reaction rate with hydroxyl radicals and the concentration of hydroxyl radicals recommended in the Technical Guidance Document (2003).

Executive summary:

Measured data from the author and other investigators were quality assessed and then used to develop rate constants for different chemicals. Therefore, this value represents a valid rate constant for 1 -hexene based on all valid studies at the time of publication.

Data source

Reference

Reference Type:

publication

Title:

Kinetics and mechanisms of the gas phase reactions of the hydroxyl radical with organic compounds under atmospheric conditions

Author:

Atkinson, R.

Year:

1985

Bibliographic source:

Chem. Rev. 85, (1985) 69 - 201

Materials and methods

Principles of method if other than guideline:

The author used data from other investigators. These data were generated using two methods: absolute and relative constant techniques. The author then applied a least squares analysis of degradation rate constants for organic chemicals by hydroxyl radicals developed by other investigators.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Hex-1-ene

EC Number:

209-753-1

EC Name:

Hex-1-ene

Cas Number:

592-41-6

Molecular formula:

C6H12

IUPAC Name:

hex-1-ene

Details on test material:

data not reported

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
not applicable

Study design

Estimation method (if used):

The rate constants were taken from experiments using relative constant techniques

Details on light source:

data not reported

Details on test conditions:

data not reported

Results and discussion

Preliminary study:

data not reported

Test performance:

data not reported

Dissipation half-life of parent compound

DT50:

10.2 h

Test condition:

Author reports a recommended rate constant of 3.75E-11 cm3 molecule-1sec-1. Half life is calculated based on this rate constant and a hydroxyl radical concentration of 5E5 molecule.cm-3

Results with reference substance:

data not reported

Applicant's summary and conclusion

Validity criteria fulfilled:

not applicable

Conclusions:

The estimated half life of 1-hexene is 10.2 hours based on a recommended reaction rate with hydroxyl radicals and the concentration of hydroxyl radicals recommended in the Technical Guidance Document (2003).

Executive summary:

Measured data from the author and other investigators were quality assessed and then used to develop rate constants for different chemicals. Therefore, this value represents a valid rate constant for 1 -hexene based on all valid studies at the time of publication.