for Catalytic Oxidative Bromination
Organobromine compounds are important basic chemicals. Their synthesis involves the use of highly reactive, toxic, corrosive, and hazardous molecular bromine. Biological processes based on bromoperoxidases are the most effective and eco-friendly routes. H2O2 and molecular oxygen are the oxidant during the use of enzymes for halogenation. Many catalysts and reaction systems have been developed to improve the sustainability of catalytic oxidative bromination by using molecular oxygen and H2O2 as oxidants. The key feature of sustainable oxidative bromination is in-situ generation of active bromination agents from stable bromine precursors. The catalysts are developed to have two functions: selective activation of molecular oxygen or H2O2 and controlling the direction of bromination.
Organobromine compounds have a widespread use in life and society (1). Some organobromines serve as emulsifier, insecticide, or biologically active pharmaceuticals (2, 3). Bromosubstituents are able to improve flame retarding properties of materials (4-6). The carbon-bromine bond has unique chemical reactivity and is used as precursors of carbocations, carbanions, and free carbon radicals. Organobromines are essentially starting and intermediate compounds in organic synthesis and widely used as blocking molecules for materials science, industrial chemistry, and medical compounds (7-9). The typical methods for organobromine synthesis are summarized in Table 1. The reactions are generally performed with hazardous, toxic, and corrosive bromine in chlorinated solvents. Other synthesis processes involve modifying bromination reagents (NBS) or bromine carrying agents. Most process lead to heavy pollution.
The 12 principles of green chemistry are valuable benchmark guidelines in developing more eco-friendly, sustainable chemical products and process (10). The sustainability of chemical process, as promoted by the European Technology Platfor ...