Mechanisms of Solid–Gas Reactions: Reduction of Air Pollutants on Carbons

Humeres, Eduardo; Debacher, Nito Ângelo; Moreira, Regina de Fátima Peralta Muniz; Santaballa, J. Arturo; Canle, Moisés

doi:10.1007/s11244-020-01318-8

Cited by 2 publications

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“…27,28 Incorporation of sulfur functionalities in carbon matrices can be achieved by reduction of SO 2 on carbons whose mechanism has been extensively studied. 29 Theoretical calculations on the chemisorption of SO 2 on partially dehydrogenated pyrene as a model of graphite 30 showed that only physical adsorption can occur on the basal plane while the most favorable site was a triplet biradical zigzag edge that is fully occupied at 900 °C. A dioxathiolane is formed by the OO approach and is at equilibrium with a γ-sultine formed by the SO approach.…”

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confidence: 99%

Intramolecular Amino-thiolysis Cyclization of Graphene Oxide Modified with Sulfur Dioxide: XPS and Solid-State NMR Studies

et al. 2022

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Graphite microparticles were oxidized to graphene oxide (MPGO) by Hummers' method followed by thermal exfoliation (C/O ratio 1.53). Graphene oxide was modified with SO 2 (mMPGO) at 600 °C and by subsequent treatment at 200 °C having a sulfur content of 10.9% (C/O ratio 16.94) and manganese content 9.39 μmol•g −1 . The XPS spectrum of MPGO showed the presence of carbonyl and epoxide groups. The reactivity of mMPGO toward alkyl thiol and alkyl amine showed the same selectivity as other carbons and suggested that oxidation did not modify deeply the edging structure of graphite. Therefore, the tetradehydrogenated-benzo[α]anthracene (TBA) reactive site model is valid. From XPS and solid-state NMR, amino-thiolysis occurred via cyclization. On the basis of the joint analysis of solid-state 1 H and 13 C NMR spectra of mMPGOs treated with mono-and difunctionalized alkanes, a preferred conformation of the alicyclic moiety of aminothiol over the graphene matrix occurred via binding to mMPGO at both amine and thiol ends. It was found that paramagnetic manganese ions in mMPGO can lead to cross-polarization inefficiency in the 13 C CPMAS detection of alkyl chains bound to mMPGO, while ring currents from graphene aromatic layers can shift alkyl 1 H NMR signals to lower frequencies by up to 4 ppm.

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