In situ enzymatic generation of H2O2 from O2 for use in oxidative bleaching and catalysis by TAML activators

Abstract

Iron-TAML activators of peroxides are functional mimics of peroxidase and short-circuited cytochrome P450 enzymes that perform numerous transformations that appear by all measures to date to be fully life cycle compatible with the environment. Here we show how to design the same catalytic chemistry without the direct addition of H 2 O 2 , thereby removing the need to transport and store hydrogen peroxide. In this new approach, dioxygen is reduced in situ by D-glucose in the presence of glucose oxidase (GO) from Aspergillus niger. The resulting tandem TAML-GO system exhibits similar catalytic efficiency to the TAML/H 2 O 2 prototype. The tandem system is shown here to efficiently decolorize Orange II and oxidize NADH, both near neutral pH (7.5). Computational simulations of the kinetic data suggest that denaturing of GO by oxidized TAML intermediates does not occur throughout each process. This tandem system brings the advantage of in situ generation of low concentrations of H 2 O 2 during the catalytic cycles. This minimizes both unproductive H 2 O 2 consumption resulting from the catalase-like activity of iron TAMLs and suicidal inactivation. Kinetic data for oxidation of NADH by TAML/H 2 O 2 are also reported.

Enantioselective Hydroxylation of Benzylic C(sp3)–H Bonds by an Artificial Iron Hydroxylase Based on the Biotin–Streptavidin Technology

“…Lastly, we developed an enzymatic cascade with Glucose Oxidase (GO) to enable the in situ production of H 2 O 2 , using O 2 as oxidant and glucose as reductant (Scheme ). To our delight, after combining biot C4 –1 ·Sav S112R and GO the oxidation reactions progressed in a similar way compared to the single batch addition of H 2 O 2 . A TTON of 50 was obtained for PhEt oxidation, with an initial ee of ( R )-PhEtOH of 47%, which eroded to 37% after kinetic resolution.…”

Homogeneous Catalysis Under Ultradilute Conditions: TAML/NaClO Oxidation of Persistent Metaldehyde

“…In one case, a system in which H 2 O 2 is generated enzymatically in situ has been devised. 39 1). The effect of [1a] on the oxidation was examined with the aim of increasing both v and the %Cvn.…”

“…To minimize the performance reducing impacts of the latter in ultradilute catalysis, a low [H 2 O 2 ] is generally employed. In one case, a system in which H 2 O 2 is generated enzymatically in situ has been devised . By using NaClO, we have eliminated the H 2 O 2 -dependent catalyst inactivation pathways altogether.…”

“…In one case, a system in which H 2 O 2 is generated enzymatically in situ has been devised. 39 By using NaClO, we have eliminated the H 2 O 2 -dependent catalyst inactivation pathways altogether. The TON increases by 70% on changing from H 2 O 2 to NaClO.…”

Enhanced Catalytic Hydrogen Peroxide Production from Hydroxylamine Oxidation on Modified Activated Carbon Fibers: The Role of Surface Chemistry

“…Nevertheless, in many practical applications, H 2 O 2 with only a low concentration could satisfy the demand in the reactions, such as selective oxidation, on-site degradation of dye, sewage treatment and disinfection (<30 mM) [4][5][6]. In this context, research on alternative production methods of H 2 O 2 and it's in situ use has been the research focus [5,[7][8][9][10][11][12][13][14][15]. The direct generation of H 2 O 2 by the reaction of molecular hydrogen (H 2 ) and oxygen (O 2 ) is considered the most promising method [16][17][18][19], but the industrial application is obscured by the dangers of the explosive reaction mixture and the insufficiency of catalysts with high selectivity without considering the reaction systems of O 2 and H 2 at high pressure [20][21][22][23][24][25].…”