Pages 383-391 Commercial Linear Alkylbenzene Sulfonates

Abstract

Abstract Motivation. Biodegradation (metabolism by microorganisms) is one of the most important processes determining the fate of organic chemicals in the environment. Structure-biodegradation relationships for linear alkylbenzene sulfonates (LAS) can be used to interpret the mechanism of LAS biodegradation and predict biodegradation rates by using theoretical descriptors computed from the chemical structure. Method. Relationships between the electronic structure and biodegradability of commercial LAS are investigated by using semiempirical quantum chemistry method with the PM3 Hamiltonian. Results. Electronic and stereo effects are the main factors affecting the course of LAS biodegradation, and oxygen atoms may be the real donors. Conclusions. The different biodegradation rates of these compounds can be modeled by using some structural and electronic parameters such as the energy of frontier molecular orbitals, the dipole moment, the bonding orbital parameters, the charge density and the net charges at the active site