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: 202-705-0 | CAS number: 98-83-9
Endpoint summary
Administrative data
Description of key information
Additional information
The rates of the reactions of OH radicals with styrene, alpha-methylstyrene, and beta-methylstyrene were measured by irradiating mixtures of these aromatic olefins and NO in an environmental chamber at 298K. Based on the experimentally determined reaction rate constant k(OH)=5.3 +/- 0.6 x 10E-11 cm³/molecule x sec (25°C) and assuming a tropospheric OH radical concentration of 5 x 10E5 radicals/cm³ (24 h day) a half-life of 7.27 h can be estimated for alpha-methylstyrene. Based on these results, for alpha-methylstyrene present in air rapid photodegradation by reaction with OH radicals is to be expected. Acetophenone and formaldehyde were observed as main breakdown products which underwent further decomposition. Similar results were obtained using the generally accepted calculation model EPIWIN v3.11, AOPWIN v1.91 (t1/2=7.2 h). The reaction of alpha-methylstyrene with ozone is a further elimination path (t1/2=2 h, calculated via EPIWIN). Due to the spectral properties of alpha-methylstyrene (absorption of light in the environmental UV spectrum) direct photolysis is to be expected. In a study conducted by CITI (Japan) according to OECD Guideline 111 (Hydrolysis as a Function of pH), alpha-methylstyrene proved to be stable at pH 4, 7, and 9 at 25°C.
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.
