Obtaining protoanemonin through selective oxidation of Dfructose and 5-(hydroxymethyl) furfural in a self-catalysed reaction

Although different ways of converting 5- (hydroxymethyl)furfural (1) to various substrates with high value have been sought, few transformations have obtained building blocks that can be very useful in the area of fine chemistry. Herein, we report the synthesis of protoanemonin (5-methylenefuran-2(5H)- one) from D-fructose via compound (1), a versatile γalkylidenebutenolide, using an efficient self-catalysed process with formic acid, with high reaction performance and selectivity (up to 94% yield and 98% conversion from (1), while 28% yield from Dfructose). This efficient and simple operational process involved a two-phase aqueous-organic system between chlorinated solvents (CHxCly) and hydrogen peroxide as the initial oxidizing agent. The reaction presents a key cleavage in the 5-hydroxymethyl moiety of (1), due to the Baeyer-Villiger oxidation (BVO) process that generates formic acid in situ. Ultimately, DFF and HMF were successfully obtained in 80% and 98% yield, respectively, starting from D-fructose and using Preyssler heteropolyacids as Brønsted acid catalysts under an atmosphere of oxygen in the absence of hydrogen peroxide.Fil: Martínez, José J.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Páez, Luis A.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Gutiérrez, Luisa F.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Pardo Cuervo, Oscar H.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Rojas, Hugo A.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Romanelli, Gustavo Pablo. Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de la Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Portilla, Jaime. Universidad de Los Andes, Colombia; ColombiaFil: Castillo, Juan Carlos. Universidad Pedagógica y Tecnológica de Colombia; Colombia. Universidad de los Andes; ColombiaFil: Gamboa Becerra, Diana Paola. Universidad Pedagógica y Tecnológica de Colombia; Colombi

Efecto de la modificación del almidón de arracacha y la concentración del plastificante sobre las propiedades mecánicas de películas biodegradables

Arracacha (Arracacia xanthorrhiza Bancroft) native starch (NS) was oxidized (OS) or acetylated (AS) to produce biodegradable films, changing the concentration of glycerol in order to determine the effect of modifying the starch type and concentration of the plasticizer on the mechanical properties of the films. It was observed that the type of modification of starch and the amount of plasticizer used in the formulae to obtain the films have significant effect (p<0.01) in tensile strength (TS), percent elongation at break (%E) and elasticity modulus (EM). When using AS for the production of films, a greater value in the average TS was reached and this is greater when using lowest amount of plasticizer. While using NS, higher average %E was achieved and this is greater when using higher amount of plasticizer. Among the two factors that affect the mechanical properties of the films obtained, there was not interaction.El Almidón nativo (AN) de arracacha (Arracacia xanthorrhiza Bancroft) fue oxidado (AO) o acetilado (AA) para elaborar películas biodegradables, modificando la concentración de glicerol con el fin de determinar el efecto del tipo de modificación del almidón y la concentración del plastificante sobre las propiedades mecánicas de las películas. Se observó que el tipo de modificación del almidón y la cantidad de plastificante utilizado en la formulación para la obtención de las películas tienen efecto significativo (p<0.01), en la resistencia a la tensión (RT), porcentaje de elongación (%E), módulo de elasticidad (ME) y módulo de resiliencia (MR). Al usar AA para la obtención de películas se presenta mayor valor en la RT y en promedio esta es mayor cuando se utiliza la formulación con menor cantidad de plastificante. Al usar AN en la obtención de películas se presenta en promedio mayor %E y este es mayor cuando se usa la formulación con mayor cantidad de plastificante. No existe interacción entre los dos factores estudiados que afecten significativamente las propiedades mecánicas de las películas obtenidas

Effect of Arracacha starch modification and plasticizer concentration on the mechanical properties of biodegradable films

El Almidón nativo (AN) de arracacha (Arracacia xanthorrhiza Bancroft) fue oxidado (AO) o acetilado (AA) para elaborar películas biodegradables, modificando la concentración de glicerol con el fin de determinar el efecto del tipo de modificación del almidón y la concentración del plastificante sobre las propiedades mecánicas de las películas. Se observó que el tipo de modificación del almidón y la cantidad de plastificante utilizado en la formulación para la obtención de las películas tienen efecto significativo (p<0.01), en la resistencia a la tensión (RT), porcentaje de elongación (%E), módulo de elasticidad (ME) y módulo de resiliencia (MR). Al usar AA para la obtención de películas se presenta mayor valor en la RT y en promedio esta es mayor cuando se utiliza la formulación con menor cantidad de plastificante. Al usar AN en la obtención de películas se presenta en promedio mayor %E y este es mayor cuando se usa la formulación con mayor cantidad de plastificante. No existe interacción entre los dos factores estudiados que afecten significativamente las propiedades mecánicas de las películas obtenidas.Abstract: Arracacha (Arracacia xanthorrhiza Bancroft) native starch (NS) was oxidized (OS) or acetylated (AS) to produce biodegradable films, changing the concentration of glycerol in order to determine the effect of modifying the starch type and concentration of the plasticizer on the mechanical properties of the films. It was observed that the type of modification of starch and the amount of plasticizer used in the formulae to obtain the films have significant effect (p<0.01) in tensile strength (TS), percent elongation at break (%E) and elasticity modulus (EM). When using AS for the production of films, a greater value in the average TS was reached and this is greater when using lowest amount of plasticizer. While using NS, higher average %E was achieved and this is greater when using higher amount of plasticizer. Among the two factors that affect the mechanical properties of the films obtained, there was not interaction

Evaluación del límite de resistencia a la corrosión fatiga del acero SAE1020 en ambiente ácido

This paper shows the results of the research in terms of the evaluation of corrosion fatigue resistance of SAE1020 steel in acidic conditions, using as corrosive substance: acetate buffer with pH 2, 4 and 6. The fatigue tests were performed according to the model of cantilever rotating bending. The results were compared with the limit of fatigue resistance of the material tested in air. It was observed a significantly reduced limit with increasing acidity of the substance. Likewise, localized corrosion type filiform corrosion was observed on the surface material, caused by the effect of the specimen aerated to be partially submerged in rotation. Limits fatigue strength determined using staircase method recommended by standard ISO1143 and ISO12107, with confidence level of 50 % and a probability of failure of 10 %.Finally, the surfaces were analyzed to find multiple origins of fracture and crack propagation lengths related to the acidity of the medium.En este artículo se muestran los resultados de investigación en cuanto a la determinación del límite de resistencia a la corrosión fatiga para el acero SAE1020 en condiciones ácidas, tomando como sustancia corrosiva buffer acetato con valores de pH 2, 4 y 6. Los ensayos de fatiga se realizaron de acuerdo con el modelo de flexión rotativa en cantiléver. Los resultados se contrastaron con el límite de resistencia a la fatiga del material ensayado al aire.Se encontró una significativa reducción del límite a medida que aumenta la acidez de la sustancia; igualmente, se observó corrosión localizada del tipo filiformesobre la superficie del material, provocada por el efecto aireado de la probeta al estar parcialmente sumergida y en rotación.Los límites de resistencia a la fatiga se determinan utilizando el método escalera, recomendado por las normas ISO1143 e ISO12107, con nivel de confianza del 50 % y una probabilidad de falla del 10 %. Por último, se analizaron las superficies de fractura y se hallaron múltiples orígenes de grieta y longitudes de propagación relacionadas con el nivel de acidez del medio

Selective Catalytic Dehydration of Xylose to Furfural and Fructose and Glucose to 5‐Hydroximethylfurfural (HMF) Using Preyssler Heteropolyacid

Catalytic dehydration of xylose to yield furfural was studied bytesting different heteropolyacid-type catalysts. Preyssler hetero-polyacid (HPA-Preyssler) (H 14 [NaP 5 W 30 O 110 ]) was the mostefficient. Under the optimal reaction conditions, xylose wasdehydrated into furfural with 73% of yield and 95% ofselectivity using DMSO as solvent at 140 ° C for 4 h. The HPA-Preyssler catalyst also exhibited good catalytic activity in thedehydration of fructose and glucose to yield 5-hydroxymeth-ylfurfural (HMF). Thus, from fructose a yield and selectivity toHMF of 97% and 98%, respectively, was obtained in just10 min, while from glucose, 91% of conversion and 23% ofyield were obtained after 9 h. An easy and efficient method-ology for the recovery and reuse of HPA-Preyssler in at least sixreaction cycles without appreciable loss of its initial catalyticactivity is reported.Fil: Pardo Cuervo, Oscar H.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Romanelli, Gustavo Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Cubillos Lobo, Jairo Antonio. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Rojas, Hugo A.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Martínez, José J.. Universidad Pedagógica y Tecnológica de Colombia; Colombi

Etherification of Hydroxymethylfurfural with Preyssler Heteropolyacids Immobilized on Magnetic Composites

A thermodynamic study about the stability of intermediates in the reaction of 5-hydroxymethylfurfural (HMF) over Preyssler heteropolyacids (HPA-Preyssler) was performed to explain the self-etherification or oxidation of HMF. Although the product of etherification forms in higher proportion when a heteropolyacid is used, other oxidation products are also observed. The availability of HPA-Preyssler protons is essential to conduct the self-etherification; however, this is not favored when the heteropolyacid is immobilized on metallic oxides and besides, the reusability of the supported heteropolyacid is low. In this study, magnetic composites were used to incorporate the HPA-Preyssler to prevent the formation of by-products and to facilitate the separation from the reaction medium. The results of catalytic tests and acidity analysis demonstrated a better proton availability, and the recovery of glutaraldehyde of the heteropolyacid decreases the leaching of immobilized HPA-Preyssler when the composite is reused. The reaction was optimized obtaining a maximum yield to OBMF near 70% in 5 h.Fil: Cuervo, Oscar H. Pardo. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Rojas, Hugo A.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Santos, Lucas A.. Universidade Federal de Lavras; BrasilFil: Ramalho, Teodorico C.. Universidade Federal de Lavras; BrasilFil: Romanelli, Gustavo Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Martínez, José J.. Universidad Pedagógica y Tecnológica de Colombia; Colombi

Structural and magnetic properties of the Bi1-xLuxFeO3 (x = 0.00, 0.02 and 0.04) system

This paper reports the synthesis and characterization of Bi1-xLuxFeO3 (x = 0.00, 0.02 and 0.04) produced by solid-state reaction, in order to evaluate the influence of lutetium on the structural and magnetic properties of bismuth ferrite (BiFeO3). The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and magnetic analysis by vibrating sample magnetometer (VSM) in temperature range from 50 to 320 K. The obtained results allowed to confirm the formation of crystalline materials of rhombohedral structure, space-group R3c (161), with defined morphology and particle sizes between 2.25 and 4.5 μm. The Lu3+ insertion in structure generated an increasing in magnetization, purity of BiFeO3 and a decrease in the synthesis temperature compared with the reported in the literatureEste artículo reporta la síntesis y caracterización de Bi1-xLuxFeO3 (x = 0.00, 0.02 and 0.04) producido por reacción de estado sólido, con el fin de evaluar la influencia del catión lutecio sobre las propiedades estructurales y magnéticas de la ferrita de bismuto (BiFeO3). Las muestras fueron caracterizadas por difracción de rayos X (DRX), microscopia electrónica de barrido (MEB), espectroscopia de energía dispersiva de rayos X (EDX) y análisis magnético por medio de magnetometría de muestra vibrante (VSM) en un rango de temperatura de 50 a 320 K. Los resultados obtenidos permitieron confirman la formación de materiales cristalinos de estructura romboédrica, grupo espacial R3c (161), de morfología definida y tamaños de partícula entre 2.25 y 4.50 μm. La inserción de Lu3+ en la estructura provocó un aumento en la magnetización, la pureza de BiFeO3 y una disminución en la temperatura de síntesis en comparación con lo reportado en la literatur

Obtaining protoanemonin through selective oxidation of Dfructose and 5-(hydroxymethyl)furfural in a self-catalysed reaction

Although different ways of converting 5- (hydroxymethyl)furfural (1) to various substrates with high value have been sought, few transformations have obtained building blocks that can be very useful in the area of fine chemistry. Herein, we report the synthesis of protoanemonin (5-methylenefuran-2(5H)- one) from D-fructose via compound (1), a versatile γ- alkylidenebutenolide, using an efficient self-catalysed process with formic acid, with high reaction performance and selectivity (up to 94% yield and 98% conversion from (1), while 28% yield from Dfructose). This efficient and simple operational process involved a two-phase aqueous-organic system between chlorinated solvents (CHxCly) and hydrogen peroxide as the initial oxidizing agent. The reaction presents a key cleavage in the 5-hydroxymethyl moiety of (1), due to the Baeyer-Villiger oxidation (BVO) process that generates formic acid in situ. Ultimately, DFF and HMF were successfully obtained in 80% and 98% yield, respectively, starting from D-fructose and using Preyssler heteropolyacids as Brønsted acid catalysts under an atmosphere of oxygen in the absence of hydrogen peroxide.Universidad Nacional de La Plat

Efficient Continuous Production of the Biofuel Additive 5-(t-Butoxymethyl) Furfural from 5-Hydroxymethylfurfural

The catalytic etherification of 5-hydroxymethylfurfural (HMF) with t-butanol to a biofuel additive 5-(t-butoxymethyl) furfural (t-BMF) is studied by screening 27 heterogeneous protic and/or Lewis acids. Preyssler heteropolyacid H14[NaP5W30O110] and Montmorillonite-based CLOI_CSP catalysts are identified as the most efficient ones, allowing the etherification to reach the t-BMF/HMF equilibrium faster ( 1:1), thus promoting minimum side reactions. Further optimization of the batch experimental conditions, namely catalyst loading, temperature, HMF concentration, time, t-BMF stability, and additives, allows the t-BMF/HMF equilibrium to be reached in less than 3 h with outstanding selectivity >95%. Under optimized conditions, CLOI_CSP is reused for four cycles without significant loss of efficiency. In addition, it exhibits high efficiency under flow conditions, allowing continuous production of t-BMF up to 0.7 g t-BMF g1 catalyst min1 at high concentrations of HMF.Fil: Pardo Cuervo, Oscar H.. Universidade de Lisboa; Portugal. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Simeonov, Svilen P.. Institute of Organic Chemistry with Centre of Phytochemistry Bulgarian Academy of Sciences; Bulgaria. Universidade de Lisboa; PortugalFil: Peixoto, Andreia F.. Universidad de Porto; PortugalFil: Popova, Margarita D.. Institute of Organic Chemistry with Centre of Phytochemistry Bulgarian Academy of Sciences; BulgariaFil: Lazarova, Hristina I.. Institute of Organic Chemistry with Centre of Phytochemistry Bulgarian Academy of Sciences; BulgariaFil: Romanelli, Gustavo Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Martínez, José J.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Freire, Cristina. Universidad de Porto; PortugalFil: Afonso, Carlos A. M.. Universidade de Lisboa; Portuga