Brominated benzylpolystyrene (BrBPS) are used as flame retardants. Since BrBPS are used in so many different applications, their environmental fate is of great interest. In particular, relevant properties for a risk assessment are the bioaccumulation rate, toxicity potential and decomposition pathways are of interest.
COSMO-RS and QSAR logKow predictions
Persistent molecules with an octanol:water partition coefficients (logKow) between 4.5 and 10 may accumulate strongly. Researchers calculated logKow to serve as first screening parameter to estimate bioaccumulation. Furthermore, COSMO-RS predictions were compared with quantitative structure-activity relationship models (QSAR).
Being a quantum-mechanical based method, the COSMO-RS method ultimately includes 3-dimensional molecular structure information in the thermodynamic predictions, which the QSAR models do not. Based on the specific model, the QSAR predictions either show a wide spread or no dependence at all on the polymer chain length. In contrast, the COSMO-RS predictions show a moderate increase in logKow, leveling off above 7 monomer units, which can be rationalized by the polymer rolling up like a ball.
J. N. Louwen and T. Stedeford, Computational assessment of the environmental fate, bioaccumulation, and toxicity potential of brominated benzylpolystyrene, Toxicol. Mech. Meth. 21, 183–192 (2011)Key conceptsCOSMO-RS logP