The selective oxidation of organic and inorganic substrates has gained much importance in recent years, for example in the preparation of high value-added organics or in the field of the environmental remediation. Oxygen atom transfer (OAT) reactions are an important class of oxidation reactions that are widely applied and technologically relevant. A reaction of particular importance is the oxidation of harmful carbon monoxide to the more benign carbon dioxide in the presence of heterogeneous catalysts, a process that is relevant for example in the abatement of environmental pollution or in case of the poisoning of fuel cell, where the absorbed CO molecules, generated as reaction intermediates, block active sites of the catalyst hindering further reactions. OAT to carbon monoxide has been mainly accomplished by metal-dioxo, metal peroxo and metal-oxo species, that offer pathways for the selective oxidation of this compound. Gas phase studies have been especially useful in elucidating the intrinsic behaviour of such species, that can be investigated with rigorous exclusion of many complicating parameters such as solvent and aggregation effects, counterions, ligands, etc. In contrast, little is known about the reactivity of non-metal oxides, and it is worth investigating these reactions in the gaseous isolated state to gain a better understanding of the mechanism of oxidation of CO. As a continuation of our interests in the activation of small molecules by metal-free ionic species, here we report on the activation of carbon monoxide by oxyhalogenated anions, (XO-, X = Cl, Br, I). The reaction has been studied in the gas phase at room temperature by mass spectrometry in the high pressure regime characteristic of ion trap experiments (ITMS). The gas-phase XO- anions, prepared by electrospray ionization (ESI) of aqueous saline solutions of either NaXO2, NaXO3, or NaXO4, were reacted with CO under the overall pressure of approximately 3 mTorr, which was maintained using a helium gas buffer. The rate constant and the efficiency of the reactions have been measured.
Oxygen atom transfer reaction from oxyhalogenated anions to carbon monoxide / Troiani, Anna. - STAMPA. - unico:(2015), pp. 267-267. (Intervento presentato al convegno Third EuCheMS Inorganic Chemistry Conference: Chemistry over the horizon tenutosi a Wroklaw, Poland nel 28 june- 1 july 2015).
Oxygen atom transfer reaction from oxyhalogenated anions to carbon monoxide
TROIANI, Anna
2015
Abstract
The selective oxidation of organic and inorganic substrates has gained much importance in recent years, for example in the preparation of high value-added organics or in the field of the environmental remediation. Oxygen atom transfer (OAT) reactions are an important class of oxidation reactions that are widely applied and technologically relevant. A reaction of particular importance is the oxidation of harmful carbon monoxide to the more benign carbon dioxide in the presence of heterogeneous catalysts, a process that is relevant for example in the abatement of environmental pollution or in case of the poisoning of fuel cell, where the absorbed CO molecules, generated as reaction intermediates, block active sites of the catalyst hindering further reactions. OAT to carbon monoxide has been mainly accomplished by metal-dioxo, metal peroxo and metal-oxo species, that offer pathways for the selective oxidation of this compound. Gas phase studies have been especially useful in elucidating the intrinsic behaviour of such species, that can be investigated with rigorous exclusion of many complicating parameters such as solvent and aggregation effects, counterions, ligands, etc. In contrast, little is known about the reactivity of non-metal oxides, and it is worth investigating these reactions in the gaseous isolated state to gain a better understanding of the mechanism of oxidation of CO. As a continuation of our interests in the activation of small molecules by metal-free ionic species, here we report on the activation of carbon monoxide by oxyhalogenated anions, (XO-, X = Cl, Br, I). The reaction has been studied in the gas phase at room temperature by mass spectrometry in the high pressure regime characteristic of ion trap experiments (ITMS). The gas-phase XO- anions, prepared by electrospray ionization (ESI) of aqueous saline solutions of either NaXO2, NaXO3, or NaXO4, were reacted with CO under the overall pressure of approximately 3 mTorr, which was maintained using a helium gas buffer. The rate constant and the efficiency of the reactions have been measured.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
