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Chlorinated alkanes were heavily used in a wide range of industrial applications including as degreasers, paint strippers, chemical intermediates, and soil fumigants. These compounds are an environmental concern due to the adverse health effects associated with them and have been detected in environmental matrices including soils and groundwater. Chlorinated alkanes are recalcitrant, and current remediation methods that employ zero-valent iron (ZVI) are unable to directly dehalogenate these compounds, limiting the available approaches forin situremediation of these widely utilized chemicals. This study employed a novel approach for the remediation of 1,2,3-trichloropropane (TCP), 1,2-dichloropropane (1,2-DCP), 1,3-dichloropropane (1,3-DCP), 1-chloropropane (1-CP), and 1,2-dichloroethane (1,2-DCA) in the presence of ZVI and vitamin B12, a naturally occurring electron mediator. Batch reactions were performed in order to determine a kinetic model for the associated degradation mechanisms. Dechlorination byproducts were confirmed through gas chromatography-mass spectrometry (GC-MS) coupled to a purge and trap. Free chloride was quantified by ion chromatography (IC) utilizing suppressed conductivity detection. In the absence of vitamin B12, reductive dechlorination of chlorinated alkanes was observed to not occur when exposed to only reactive ZVI particles (μm). However, in the presence of ZVI combined with vitamin B12, complete reductive dechlorination was observed and followed a pseudo-first-order reaction.

Polychlorinated biphenyls (PCBs) are banned in the U.S. but are persistent in the environment; current regulations provide an urgent need to remediate PCBs in a cost-effective way. In prior work, a novel method of degradation of PCBs via hydrodehalogenation with ball milled zero-valent magnesium and activated carbon showed promising results even with water present in the system. In this research, a detailed study of the byproducts formed in the dechlorination process for PCB 151 (used as an example of hexa-chlorinated PCB) and a study of the mechanism involved in this reaction via density functional theory (DFT) computations are presented. It was demonstrated that these reactions are exothermic and involved two transition states, the formation of the ionic transition state being the rate limiting step of the reaction. The torsion angle of the PCB congeners was also shown to be an extremely important factor to be able to use activated carbon as part of the remediation process.

Selective O-benzoylation of hydroxamic acids is achieved by the treatment of BPO and DABCO. Aliphatic alcohols are not reactive under these conditions. Various radical or oxidation sensitive functional groups are compatible with this protocol, and no anhydrous reagents or solvents are required for the high yields of the benzoylations.

The DABCO mediated reaction of hydroxamic acids with benzoyl peroxide provides the corresponding O-benzoylated products.