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EC number: 206-016-6 | CAS number: 287-92-3
Phototransformation in air
Administrative data
Link to relevant study record(s)
- Endpoint:
- phototransformation in air
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Remarks:
- estimated by calculation
- Adequacy of study:
- key study
- Study period:
- Up to 1985
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Non-GLP, non guideline study. Data calculated in accordance with TGD guideline. Study published in peer review literature.
- Justification for type of information:
- A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.
- Reason / purpose for cross-reference:
- read-across: supporting information
- Principles of method if other than guideline:
- The author applied a least squares analysis of degradation rate constants for organic chemicals by hydroxyl radicals developed by other investigators.
- GLP compliance:
- not specified
- Remarks:
- No data reported
- Specific details on test material used for the study:
- Details on properties of test surrogate or analogue material (migrated information):
No data reported - Estimation method (if used):
- Calculated half life based on -OH radical concentration of 5 E5 molecules/cm3 as specified in the TGD
- Light source:
- not specified
- Details on light source:
- No data reported
- Details on test conditions:
- No data reported
- Preliminary study:
- No data reported
- Test performance:
- No data reported
- Key result
- DT50:
- 3.95 d
- Test condition:
- No data reported
- Results with reference substance:
- No data reported
- Conclusions:
- The atmospheric half-life of n-pentane is estimated to be 3.95 days.
- Executive summary:
Measured data from 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 n-pentane based on all valid studies at the time of publication. The half life of n-pentane is 3.95 days.
- Endpoint:
- phototransformation in air
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Remarks:
- estimated by calculation
- Adequacy of study:
- key study
- Study period:
- Up to 1985
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Non-GLP, non guideline study. Calculated data, published in peer review paper and was calculated in accordance with the TGD.
- Justification for type of information:
- A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.
- Reason / purpose for cross-reference:
- read-across: supporting information
- Principles of method if other than guideline:
- The author used data from other investigators. This data was 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. This calculation was in accordance with the TGD
- GLP compliance:
- not specified
- Remarks:
- Not reported
- Specific details on test material used for the study:
- Details on properties of test surrogate or analogue material (migrated information):
No data reported - Estimation method (if used):
- Endpoint was calculated based on a rate constant of 3.5 E -12 and-OH radical concentration of 5 E5 molecules/cm3
- Details on light source:
- No data reported
- Details on test conditions:
- No data reported
- Preliminary study:
- No data reported
- Test performance:
- No data reported
- Key result
- DT50:
- 2.3 d
- Results with reference substance:
- No data reported
- Conclusions:
- The dissipation half-life of 2-methylbutane was calculated as 2.3 days
- Executive summary:
Measured data from 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 2 -methylbutane based on all valid studies at the time of publication. The half life of 2 -methylbutane is 2.3 days.
Referenceopen allclose all
The rate constant of the reaction between n-pentane and OH-radicals has been measured by several researchers. The result of the experiments have been reported and reviewed by Atkinson (1985). The reported values are between 3.5 and 5.3.10-12 cm3/(molecule.sec) at 300K (27C). On the basis of the review of available data Atkinson recommends a rate of 4.06.10-12 cm3/ (molecule.sec). The latter value has been used in the risk assessment. Taking into account the OH-radical concentration as given in the TGD of 5.105 molecules/cm3, atmospheric half-life of n-pentane is estimated to 3.95 days.
Based on a calculated rate constant of 7.38E-12 cm3 molecule-1sec-1, and a hydroxyl radical concentration of 5E5 molecule.cm-3
Description of key information
There is no data available for this substance. However, key data is available for the structural analogues Pentane and 2 -methylbutane and is presented in the dossier. The data is read across to this substance based on analogue read across and a discussion and report on the read across strategy is provided as an attachment inIUCLID Section 13.
The dissipation half-life of 2-methylbutane was calculated as 2.3 days. Based on a calculated rate constant of 7.38E-12 cm3 molecule-1sec-1, and a hydroxyl radical concentration of 5E5 molecule.cm-3.
The atmospheric half-life of n-pentane is estimated to be 3.95 days. The rate constant of the reaction between n-pentane and OH-radicals has been measured by several researchers. The result of the experiments have been reported and reviewed by Atkinson (1985). The reported values are between 3.5 and 5.3.10-12 cm3/(molecule.sec) at 300K (27C). On the basis of the review of available data Atkinson recommends a rate of 4.06.10-12 cm3/ (molecule.sec). The latter value has been used in the risk assessment. Taking into account the OH-radical concentration as given in the TGD of 5.105 molecules/cm3
Key value for chemical safety assessment
- Half-life in air:
- 3.95 d
- Degradation rate constant with OH radicals:
- 0 cm³ molecule-1 s-1
Additional information
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