Examinando por Autor "Nocito, Francesco"

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Selective Aerobic Oxidation of 5-Hydroxymethylfurfural to 2,5-Diformylfuran or 2-Formyl-5-furancarboxylic Acid in Water by using MgOCeO2 Mixed Oxides as Catalysts
(Wiley-VCH Verlag, 2018) Ventura, Maria; Lobefaro, Francesco; de Giglio, Elvira; Distaso, Monica; Nocito, Francesco; Dibenedetto, Angela
Mixed oxides based on MgO⋅CeO2 were used as efficient catalysts in the aerobic oxidation of 5-hydroxymethylfurfural (5-HMF) to afford, with very high selectivity, either 2,5-diformylfuran (DFF, 99 %) or 2-formyl-5-furancarboxylic acid (FFCA, 90 %), depending on the reaction conditions. 5-Hydroxymethyl-2-furancarboxylic acid (HMFCA, 57–90 %) was formed only at low concentration of 5-HMF (<0.03 m) or in presence of external bases. The conversion of 5-HMF ranged from a few percent to 99 %, according to the reaction conditions. The oxidation was performed in water, with O2 as oxidant, without any additives. The surface characterization of the catalysts gave important information about their acid–base properties, which drive the selectivity of the reaction towards DFF. FFCA was formed from DFF at longer reaction times. Catalysts were studied by XPS and XRD before and after catalytic runs to identify the reason why they undergo reversible deactivation. XRD showed that MgO is hydrated to Mg(OH)2, which, even if not leached out, changes the basic properties of the catalyst that becomes less active after some time. Calcination of the recovered catalyst allows recovery of its initial activity. The catalyst is thus recoverable (>99 %) and reusable. The use of mixed oxides allows tuning of the basicity of the catalysts, avoiding the need for external bases for efficient and selective conversion of 5-HMF and waste formation, resulting in an environmentally friendly, sustainable process.
Selective Oxidation of 5-(Hydroxymethyl)furfural to DFF Using Water as Solvent and Oxygen as Oxidant with Earth-Crust-Abundant Mixed Oxides
(American Chemical Society, 2018-12-28) Nocito, Francesco; Ventura, Maria; Dibenedetto, Angela; Aresta, Michele
5-Hydroxymethylfurfural (5-HMF) can be considered a prominent building block: because of the presence of the alcohol and aldehyde moieties, it can be used to generate useful molecules as chemicals of industrial interest with high added value, monomers for polymers, and even fuels. This article shows how building up mixed oxides of different complexities and properties may drive the selectivity toward one of the possible products generated from 5-HMF. In particular, mixed oxides based on cerium and other metals abundant on the earth-crust perform the selective oxidation of 5-HMF to 2,5-diformylfuran (94%), using oxygen as oxidant and water as solvent. The roles of the reaction conditions (temperature, reaction time, oxygen pressure, concentration of the substrate), the chemical composition, the acidic/basic properties, and redox properties of the catalysts are discussed.
Sustainable Synthesis of Oxalic and Succinic Acid through Aerobic Oxidation of C6 Polyols Under Mild Conditions
(Wiley, 2018-08-20) Ventura, Maria; Williamson, David; Lobefaro, Francesco; Jones, Mathew; Mattia, David; Nocito, Francesco; Aresta, Michele; Dibenedetto, Angela
The sustainable chemical industry encompasses a shift from the use of fossil carbon to renewable carbon. The synthesis of chemicals from nonedible biomass (cellulosic or oil) represents one of the key steps for “greening” the chemical industry. In this paper, we report the aerobic oxidative cleavage of C6 polyols (5-HMF, glucose, fructose and sucrose) to oxalic acid (OA) and succinic acid (SA) in water under mild conditions using M@CNT and M@NCNT (M=Fe, V; CNT=carbon nanotubes; NCNT=N-doped CNT), which, under suitable conditions, were recoverable and reusable without any loss of efficiency. The influence of the temperature, O2 pressure (Pmathematical equation ), reaction time and stirring rate are discussed and the best reaction conditions are determined for an almost complete conversion of the starting material and a good OA yield of 48 %. SA and formic acid were the only co-products. The former could be further converted into OA by oxidation in the presence of formic acid, resulting in an overall OA yield of >62 %. This process was clean and did not produce organic waste nor gas emissions.
Tunable mixed oxides based on CeO2 for the selective aerobic oxidation of 5-(hydroxymethyl) furfural to FDCA in water
(Royal Society of Chemistry, 2018-07-31) Ventura, Maria; Nocito, Francesco; de giglio, Elvira; Cometa, Stefania; Altomare, Angela; Dibenedetto, Angela
Chemicals derived from 5-HMF, via selective oxidation of its pending arms are becoming increasingly important due to their applications. This paper discusses the use of Earth crust abundant new mixed oxides based on CeO2 able to perform the selective oxidation of 5-HMF to 2,5-furandicarboxylic acid (99%), in water, using oxygen as the oxidant.