Search results for "5-hydroxymethylfurfural"

Catalytic conversion of glucose to 5-hydroxymethylfurfural over biomass-based activated carbon catalyst

2020

Selective and efficient dehydration of glucose to 5-hydroxymethylfurfural (HMF) has been widely explored research problem recently, especially from the perspective of more sustainable heterogeneous catalysts. In this study, activated carbon was first produced from a lignocellulosic waste material, birch sawdust. Novel heterogeneous catalysts were then prepared from activated carbon by adding Lewis or Brønsted acid sites on the carbon surface. Prepared catalysts were used to convert glucose to HMF in biphasic water:THF system at 160 °C. The highest HMF yield and selectivity, 51% and 78%, respectively, were obtained in 8 h with a catalytic mixture containing both Lewis and Brønsted acid sites…

Conversion of carbohydrates into 5-HMF in Deep Eutectic Solvents under mild reaction conditions

Activity of a Heterogeneous Catalyst in Deep Eutectic Solvents: The Case of Carbohydrate Conversion into 5-Hydroxymethylfurfural

2019

Obtaining industrially relevant products from renewable resources and developing processes under the light of sustainable chemistry is a prominent endeavor of present-day chemical research. In this context, herein we investigated the dehydration of fructose and sucrose in deep eutectic solvents promoted by the ion-exchange resin Amberlyst 15 as heterogeneous catalyst. We optimized the reaction conditions in terms of temperature, catalyst loading, and initial amount of substrate. Then, we looked at the effect of structural variations in the solvent components on the reaction outcome. Under the best experimental conditions, we obtained very good yields of 78% at 60 °C and 69% at 80 °C for fru…

Photocatalytic Partial Oxidation of 5‐Hydroxymethylfurfural (HMF) to 2,5‐Diformylfuran (DFF) Over a Covalent Triazine Framework in Water

2020

Selective photocatalytic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxaldehyde by polymeric carbon nitride-hydrogen peroxide adduct

2018

Abstract Polymeric carbon nitride-hydrogen peroxide adduct (PCN-H2O2) has been prepared, thoroughly characterised and its application for selective photocatalytic conversion of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxaldehyde (FDC) in aqueous suspension has been studied. The PCN-H2O2 adduct is stable in aqueous suspension under UV and solar irradiation up to 100 °C. It is also stable up to 200 °C if heated in air, while at temperatures close to 300 °C its decomposition takes place. Based on the obtained characterisation data it has been proposed that H2O2 attaches to the non-polymerised carbon nitride species and to the heptazine nitrogen atoms, thus producing strong hydrogen bond…

Photoelectrochemical and EPR features of polymeric C 3 N 4 and O-modified C 3 N 4 employed for selective photocatalytic oxidation of alcohols to alde…

2019

Four different C 3 N 4 specimens have been prepared, a bulk one (MCN), a thermally etched (MCN-TE), a solid prepared by hydrothermally treating MCN with H 2 O 2 (MCN-H 2 O 2 ) and a polymeric carbon nitride-hydrogen peroxide adduct (MCN-TE-H 2 O 2 ). The principal aim of this work was to correlate the capability of the prepared material to generate reactive oxygen species (ROS), under irradiation, with their photocatalytic activities in terms of conversion and selectivity for partial oxidation reactions. Photoelectrochemical studies revealed that MCN-TE represented the best material in terms of photoconductivity, whereas MCN-H 2 O 2 was defective and evidenced a poor mobility of carriers. E…

Chemical transformations of glucose in solutions for peritoneal dialysis after sterilization and during storage

2018

The objective of this work was to estimate glucose degradation products (GDPs) in solutions for peritoneal dialysis (PD) including glucose and sodium lactate based on the change of pH and absorption of ultraviolet (UV) light. Spectrophotometric and pH-metric methods were used to measure glucose degradation and transformation of GDPs in laboratory-made solutions after heat sterilization and during storage. Mechanism of transformations of GDPs in the sterilized solutions for PD during storage and spectral characteristic of 5-HMF were studied. Common features for all the batches of the tested solutions for PD after heat sterilization were a reduce in pH, increase in the absorbance in the range…

Selective Photocatalytic Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxaldehyde by Polymeric C3N4-H2O2 Adduct

2018

Selective Photocatalytic Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxaldehyde by Polymeric C3N4-H2O2 Adduct

Spectral characteristics of 5-hydroxymethylfurfural as a related substance in medicinal products containing glucose

2019

Objectives: To study 5-hydroxymethylfurfural (5-HMF) spectral characteristics aiming at their future application in analytical procedures and their validation for the determination of 5-HMF in liquid products containing glucose after sterilization.Method: Direct spectrophotometric method for the determination of 5-HMF using the molar absorption coefficient at the absorption maximum (284 nm).Results and discussion: aqueous 5-HMF solutions have strong absorption in the ultraviolet range below 310 nm and give two absorption maxima at wavelengths of 229–230 nm and 284 nm. An excellent linear relationship between absorbance and 5-HMF concentration was observed in the concentration range of 2.0–1…

Complex technological and biological research of solutions for peritoneal dialysis

2018

Objective : The purpose of our work was to conduct technological, analytical, and biological investigations and stability studies of peritoneal dialysis (PD) solutions containing glucose and sodium lactate in single-chamber containers. Methods : Different formulations of PD solutions were prepared and sterilized at a temperature of 121 °C during 15 m. UV-spectrophotometric determination was performed using purified water as a blank. The spectra of the solutions were run in the range of 220 to 400 nm for the identification of an absorption maximum (λ max ) and measuring the absorbance at 228-230 nm and λ max before and after heat sterilization. λ max of the most PD solutions after sterilizat…