Search results for "furfural"
showing 10 items of 48 documents
Ring transformation of furfural into an unusual bicyclic system: Characterisation and dynamic stereochemistry of 6,7-diethoxycarbonyl-6,7-diaza-8-oxa…
1997
Abstract 2-Formylthiophene and 3-formylindole react with diethyl azodicarboxylate to give simple products derived from reactions on the formyl group whereas 2-formylfuran reacts to give the unexpected bicyclic title compound. 1 H and 13 C NMR studies indicate that this compound undergoes a series of three dynamic conformational changes over the temperature range 50 to −90°C which are ascribed to slow rotation about the exocyclic carbamate bonds and hindered bridge inversion.
Midinfrared FT-IR as a Tool for Monitoring Herbaceous Biomass Composition and Its Conversion to Furfural
2015
A semiquantitative analysis by means of midinfrared FT-IR spectroscopy was tuned for the simultaneous determination of cellulose, hemicellulose, and lignin in industrial crops such as giant reed (Arundo donaxL.) and switchgrass (Panicum virgatumL.). Ternary mixtures of pure cellulose, hemicellulose, and lignin were prepared and a direct correlation area/concentration was achieved for cellulose and lignin, whereas indirect correlations were found for hemicellulose quantification. Good correspondences between the values derived from our model and those reported in the literature or obtained according to the official Van Soest method were ascertained. Average contents of 40–45% of cellulose, 2…
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…
Ossidazione fotocatalitica selettiva di 5-idrossimetil-2-furfurale a 2,5-furandicarbossilaldeide in sospensioni acquose di nitruro di carbonio
2017
Ossidazione fotocatalitica selettiva di 5-idrossimetil-2-furfurale a 2,5-furandicarbossilaldeide in sospensioni acquose di nitruro di carbonio
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…
PURIFICATION OF HARDWOOD-DERIVED AUTOHYDROLYSATES
2012
Carbohydrate-containing hydrolysates (1.1 to 14.9% of wood dry matter) obtained from autohydrolysis (at 130 to 150°C for 30 to 120 minutes) of birch (Betula pendula) chips prior to pulping were purified with respect to non-carbohydrate materials, without carbohydrate losses, either by ethyl acetate extraction or XAD-4 resin treatment. In the former case, about 50% of lignin and practically all the furanoic compounds (2-furaldehyde and 5-(hydroxymethyl)furfural) could be removed, whereas in the latter case, the corresponding amounts were about 30% and 50 to 90%, respectively. A partial recovery of various unsaturated impurities is of importance, because they may act as inhibitors when bioche…
Catalytic treatment of rapeseed straw for enhanced production of furfural and glucose for bioethanol production
2021
Abstract Ethanol produced from renewable biomass, such as lignocellulosic feedstock, is one of the most promising future biofuels. In this paper, rapeseed straw was tested as an abundant and cost-effective renewable resource material for the production of cellulosic glucose. Pre-treatment of this material is an important step to improve the efficiency of subsequent cellulose hydrolysis. In this study, we used two pre-treatment methods – hydrothermochemical and ultrasound. Studies have shown that, in the initial hydrothermal pre-treatment of rapeseed straw, Al2(SO4)3 may be used as an efficient catalyst, at least in procedures for obtaining glucose. An increase in the amount of this catalyst…
A HS-SPME-GC-MS analysis of IR heated wood: Impact of the water content on the depth profile of oak wood aromas extractability
2013
http://www.sciencedirect.com/science/article/pii/S0963996913003736; International audience; Controlled and reproducible IR heat treatments were applied to oak wood surfaces in order to establish a depth-profiled picture of the extractability of volatile compounds, with particular emphasis on the impact of the initial water content. Headspace-solid phase microextraction-gas chromatography coupled to mass spectrometry (HS-SPME-GC-MS) has been used to compare the concentrations of six aroma compounds (vanillin, furfural, eugenol; guaiacol and cis- and trans-whisky lactones) in hydroalcoholic extracts of series of slices representative of the first 8 mm of the wood facing the IR source. Results…
Photocatalytic Partial Oxidation of 5-hydroxymethyl-2-furfural Under UV and Natural Solar Irradiation in Aqueous Suspension of K Containing C3N4
2020
Background: The influence of the potassium metal cation on the graphitic carbon nitride (g-C3N4) photocatalyst has been studied in the partial oxidation of 5-hydroxymethyl-2-furfural (HMF) to 2,5-furandicarboxaldehyde (FDC). Objective: The aim of this study was to understand if the presence of K in C3N4 could increase the oxidative conversion of HMF to high added value species. Methods: Two sets of photocatalysts were prepared by following two different methodologies. In both series of the materials, the precursor of C3N4 was melamine with different types of the K containing species including KCl and KOH in one case and KNO3 alone in the other case. However, for both series of photocatalys…
Multivariate Correlation between Analysis Data on Dissolved Organic Material from Scots Pine (Pinus sylvestris) Chips and their Autohydrolysis Pre-Tr…
2013
Various chemometric techniques were used to establish the relationship between the autohydrolysis conditions prior to pulping and the chemical compositions of the soluble organic materials removed from Scots pine (Pinus sylvestris) wood chips. The aqueous chip pre-treatments (autohydrolysis) were administered at 130 °C and 150 °C for 30, 60, 90, and 120 min, and the hydrolysates obtained were characterized in terms of total carbohydrates (various mono-, oligo-, and polysaccharides together with uronic acid side groups), volatile acids (acetic and formic acids), lignin, and furans (furfural and 5-(hydroxymethyl)furfural). Based on the analytical data gathered, a relatively accurate model for…