On the thermally induced isomerisation of hexabromocyclododecane stereoisomers.
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 alpha-, beta-, and gamma-HBCD enabled the unambiguous elucidation of the individual isomerisation reactions as well as the quantification of all respective rate constants. At 160 degrees C the rate constants range over two orders of magnitude from 1.50x10(-3) to 1.88x10(-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.
Köppen
Robert
R
Department of Analytical Chemistry, Reference Materials, Federal Institute for Materials Research and Testing (BAM), Richard-Willstätter-Strasse 11, D-12489 Berlin, Germany.
Becker
Roland
R
Jung
Christian
C
Nehls
Irene
I
D002851:Chromatography, High Pressure Liquid; D006358:Hot Temperature; D006842:Hydrocarbons, Brominated / Q000737:chemistry* / Q000302:isolation & purification; D007536:Isomerism; D007700:Kinetics; D013237:Stereoisomerism; D013997:Time Factors
D006842:Hydrocarbons, Brominated; C089796:hexabromocyclododecane