Oxidación catalítica selectiva de furfural a anhídrido y/o ácido maleico

Tesis Doctoral inédita cotutelada por en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física de Materiales. Fecha de lectura: 21-07-201

Selective oxidation of furfural to maleic acid with aqueous H2O2 by using catalysts based on Ti silicalites

Trabajo presentado en el 3rd International Symposium on Green chemistry, celebrado en La Rochelle (Francia) del 3 al 7 de mayo de 2015.Peer Reviewe

Procedimiento para la oxidación de furfural a ácido maleico

Procedimiento para la oxidación de furfural a ácido maleico. Constituye el objeto de la presente invención un procedimiento para la obtención de ácido maleico a partir de furfural. El procedimiento está basado en el tratamiento del furfural en fase líquida con un agente oxidante, particularmente peróxido de hidrógeno, en presencia de al menos un catalizador.Peer reviewedConsejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic

Selective oxidation of furfural to maleic acid with H2O2 by using SiO2 anchored TiO2 catalysts

Trabajo presentado en el Workshop on materials and catalysis for clean energy, celebrado en Málaga (España) del 23 al 24 de junio de 2014.Peer Reviewe

Gas phase oxidation of furfural to maleic anhydride on V2O5/g-Al2O3 catalysts: Reaction conditions to slow down the deactivation

An alumina-supported vanadium oxide catalyst (13.9 wt.% vanadium oxide) has been characterized by different techniques and tested in the gas phase oxidation of furfural. These studies have shown that the catalyst unavoidably deactivates by deposition of maleates and resins over the surface. Full regeneration is accomplished by burning off these deposits at 773 K. The studies have also demonstrated that if the primary contact occurs at temperatures at which furfural conversion is low and then the temperature is increased in a low- to high-temperature mode, intense deposition of maleates and resins takes place and the catalyst is rapidly deactivated. The increase of the temperature does not result in removal of deposits but accelerates the deposition. Under this protocol, the yield of maleic anhydride never exceeded 30%, irrespective of the reaction conditions (temperature and O2/furfural mole ratio). In contrast, if the catalyst first contacts the reaction mixture at high oxidizing potential, then the rate of maleate and resin deposition is much slower, and so is the deactivation rate, and the catalyst can display a higher yield of maleic anhydride for a longer period of time. A high oxidizing potential can be attained at a high reaction temperature (close to full conversion). A higher oxidizing potential at a given high temperature can be accomplished by increasing the O2/furfural mole ratio. Thus, for example, first contacting the catalyst at 593 K (full conversion), 1 vol.% of furfural, and O2/furfural mole ratio = 10, obtained an initial maleic anhydride yield of 68%, and the yield was still greater than 50% after 15 h on stream. On contacting at 573 K with 1 vol.% furfural and 20 vol.% O2, the maleic anhydride yield was initially close to 75% and was above 60% after 15 h.Financial support from the Spanish Ministry of Economy and Competitiveness is gratefully acknowledged Project (CTQ2015-64226-C3-1-R).Peer Reviewe

Poly-(styrene sulphonic acid): An acid catalyst from polystyrene waste for reactions of interest in biomass valorization

This article reports on the use of poly-(styrene sulphonic acid) (PSSA) prepared by sulphonation of polystryrene waste as catalyst in reactions demanding acid sites. Two different waste derived catalysts (waste to catalyst, WTC) were studied: soluble PSSA (WTC-PSSA) and solid SiO2-PSSA nanocomposite (WTC-SiO2-PSSA). The catalytic properties of these waste derived acid catalysts have been explored in three different reactions of interest in biomass valorization: biodiesel synthesis, xylose dehydration to furfural and furfural oxidation to maleic and succinic acids. The results show that both soluble and nanocomposite WTC catalysts present promising catalytic properties. The WTC-PSSA requires ultrafiltration for reutilization whereas the WTC-SiO2-PSSA can be separated from the reaction mixtures by more usual techniques (centrifugation or conventional filtration). Further research is required for improving the hydrothermal stability of WTC-SiO2-PSSA in order to substantially reduce the leaching of polymer that takes place during the catalytic runs.This work was funded by the Spanish Ministry of Economy and Competitiveness (Project CTQ2012-38204-C03-01, CARBIOCAT) and the Autonomous Government of Madrid (S2009/ENE-1660, CARDENER-CM partly funded by FSE funds).Peer Reviewe

Aqueous-phase catalytic oxidation of furfural with H2O2: High yield of maleic acid by using titanium silicalite-1

This investigation explores the selective liquid-phase oxidation of furfural to maleic acid (MA) using hydrogen peroxide as an oxidant and titanium silicalite (TS-1) as a catalyst. The effect of temperature and of the concentration of H2O2, furfural and catalyst on the MA yield was studied. The highest yield, 78 mol%, was obtained under the following reaction conditions: 4.6 wt% of furfural, 4.6 wt% of catalyst, a H2O2/furfural mol ratio of 7.5, corresponding to 12.3 wt% of H2O2, 323 K and 24 hours of reaction. To reduce the amount of H2O2 employed, a two-step sequence of reactions was conducted using TS-1 and Amberlyst 70 consecutively as catalysts in the first and second steps, respectively. In this case, a H2O2/furfural mol ratio = 4.4 was required, which is quite close to the stoichiometric ratio (3.0), and a maleic acid yield close to 80% was obtained under 4.6 wt% of furfural, 4.6 wt% of catalyst and 28 h of reaction at 323 K; after 52 h of reaction, the MA yield reached 92%. Fresh and used catalysts were characterised by X-ray diffraction (XRD), Raman spectroscopy, total reflection X-ray fluorescence (TXRF), X-ray photoelectron spectroscopy (XPS), N2 adsorption–desorption isotherms and thermogravimetric analysis. Ti was largely incorporated within the silicalite framework, but the presence of some TiO2 anatase was also confirmed. Ti leaching was observed, especially during the first run but became much less important in successive cycles. Leaching affects both anatase and Ti species within the silicalite framework. Notwithstanding the leaching, when using pure furfural, TS-1 could be reused for six runs without noticeable deactivation, whereas when using furfural directly derived from biomass, weak but visible deactivation occurred upon reutilisation; this deterioration must be related to the presence of some organic products other than furfural.Financial support from Spanish Ministry of Economy and Competitiveness (CTQ2012-38204-C03-01) is gratefully acknowledged.Peer Reviewe

Cynara biomass and valorization of by products to biofuels and chemicals

Trabajo presentado en el Workshop on materials and catalysis for clean energy, celebrado en Málaga (España) del 23 al 24 de junio de 2014.Peer Reviewe