Chemical decontamination of methamphetamine and ephedrine using Fe-TAML catalysed hydrogen peroxide oxidation

Abstract

Exposure to contamination from former clandestine methamphetamine laboratories has been linked to adverse health effects including respiratory distress, sensory irritation, and behavioural changes. Therefore, it is important to employ effective remediation strategies to protect public health. Hydrogen peroxide (H2O2) cleaning products are effective for chemical decontamination, however their mechanism of oxidative decomposition of methamphetamine and the identity of breakdown products are still largely undetermined. This inhibits our ability to effectively estimate hazards involved with their use in methamphetamine remediation. This study investigated the formation of products from the oxidative decomposition of methamphetamine, and one common precursor, ephedrine, by an H2O2 solution, catalysed by Fe-TAML (a green chemistry catalyst containing iron coordinated by a tetraamido macrocyclic ligand). Oxidation products identified in these reactions included common chemical precursors benzaldehyde and phenylacetone (also known as phenyl-2-propanone, P2P) as well as by-products typically related to methamphetamine manufacturing processes such as phenylacetone N-methylimine, amphetamine, and N-formylamphetamine. The high efficiency of oxidation of methamphetamine (88 ± 2%) and ephedrine (83 ± 2%) within 5 min, and >96% removal after 60 min with a second intermediary dose of H2O2, gives precedent to the future use of catalysed H2O2 solutions for methamphetamine remediation.