Registration Dossier
Registration Dossier
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 201-944-8 | CAS number: 89-83-8
Phototransformation in air
Administrative data
Link to relevant study record(s)
- Endpoint:
- phototransformation in air
- Type of information:
- calculation (if not (Q)SAR)
- Remarks:
- estimated by calculation
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Accepted calculation method.
- Principles of method if other than guideline:
- Calculated with AOP Program v1.92 of EPI-Suite Software. The Atmospheric Oxidation Program (AOPWIN) estimates the rate constant for the atmospheric, gas-phase reaction between photochemically produced hydroxyl radicals and organic chemicals. The rate constants are then used to calculate atmospheric half-lives for organic compounds based upon average atmospheric concentrations of hydroxyl radicals and ozone.
- GLP compliance:
- no
- Estimation method (if used):
- PHOTOCHEMICAL REACTION WITH OH RADICALS
- sensitiser for indirect photolysis: OH radicals
- Concentration of OH radicals: 0.5 E6 OH/cm³, 24 h/d - % Degr.:
- 50
- Sampling time:
- 3.6 h
- Executive summary:
In the atmosphere a half-life of 3.6 h for thymol is estimated due to reaction with photochemically produced hydroxyl radicals, considering an OH-concentration of 500,000 radicals/cm³ as a 24-h average (Currenta, 2010).
Reference
A 24-hour day and an OH radical concentration of 0.5 E06 OH/cm³ are assumed for the calculation.
Rate constant (for indirect photolysis): 0.000000000107 cm³/(molecule*sec)
Description of key information
In the atmosphere a half-life of 3.6 h for thymol is estimated due to reaction with photochemically produced hydroxyl radicals, considering an OH-concentration of 500,000 radicals/cm³ as a 24-h average (Currenta, 2010).
Key value for chemical safety assessment
Additional information
As no data on phototransfromation in air are available, the rate constant for the atmospheric gas-phase reaction between photochemically produced hydroxyl radicals and organic chemicals is estimated with the Atmospheric Oxidation Program (AOPWIN) of US Environmental Protection Agency. Since the estimated half-life of thymol in air is much shorter than 48 h, no potential of long-range transport of thymol is expected.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
