Examinando por Autor "Aresta, Michele"

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Heterogeneous catalysts for the selective aerobic oxidation of 5-hydroxymethylfurfural to added value products in water
(Elsevier, 2018) Ventura, María; Dibenedetto, Angela; Aresta, Michele
This review presents the state of the art of the aerobic selective oxidation of 5-hydroxymetylfurfural (5-HMF) with heterogeneous catalysts in water, for the preparation of added value products. Aspects such as kind of metals used for making the catalysts and external additives will be examined. The paper is divided into four main parts each dealing with a specific product obtained from 5-HMF: (a) 2,5-diformylfuran (DFF), (b) 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), (c) 5-formyl-2-furancarboxylic acid (FFCA), (d) 2,5-furandicarboxylic acid (FDCA).
Selective Aerobic Oxidation of 5-(Hydroxymethyl)furfural to 5-Formyl-2-furancarboxylic Acid in Water
(Wiley-VCH Verlag, 2016) Ventura, Maria; Aresta, Michele; Dibenedetto, Angela
A simple, cheap, and selective catalyst based on copper/cerium oxides is described for the oxidation of 5-(hydroxymethyl)furfural (5-HMF) in water. An almost quantitative conversion (99 %) with excellent (90 %) selectivity towards the formation of 5-formyl-2-furancarboxylic acid, a platform molecule for other high value chemicals, is observed. The catalyst does not require any pretreatment or additives, such as bases, to obtain high yield and selectivity in water as solvent and using oxygen as oxidant. When a physical mixture of the oxides is used, low conversion and selectivity are observed. Air can be used instead of oxygen, but a lower conversion rate is observed if the same overall pressure is used, and the selectivity remains high. The catalyst can be recovered almost quantitatively and reused. Deactivation of the catalyst, observed in repeated runs, is due to the deposition of humins on its surface. Upon calcination the catalyst almost completely recovers its activity and selectivity, proving that the catalyst is robust
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.