On the thermally induced isomerisation of hexabromocyclododecane stereoisomers

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• 作者：Robert Kö ; ppen ; Rol ; Becker ; Christian Jung ; Irene Nehls
• 关键词：Flame retardant ; Diastereomers ; Enantiomers ; Rearrangement ; Kinetics ; HBCD
• 刊名：Chemosphere
• 出版年：2008
• 期刊代码：15_00456535
• 类别：env
• 出版时间：March 2008
• 卷：71
• 期：4
• 页码：656-662
• 文件大小：398 K

摘要

The interconversion of the stereoisomers contained in technical 1,2,5,6,9,10-hexabromocyclododecane, a major brominated flame retardant increasingly found in the environment and in biota, was investigated at elevated temperatures. The application of pure enantiomers of the three constituents α-, β-, and γ-HBCD enabled the unambiguous elucidation of the individual isomerisation reactions as well as the quantification of all respective rate constants. At 160 °C the rate constants range over two orders of magnitude from 1.50 × 10⁻³ to 1.88 × 10⁻⁵ mol(%) s⁻¹. A preliminary mechanistic explanation for the differences of the rate constants which govern the composition of HBCD diastereomers at equilibrium is given.