Search results for "Quinone"
showing 10 items of 315 documents
Organics in soda-anthraquinone black liquors from hot-water-extracted non-wood feedstocks
2019
The chemical compositions of black liquors (BLs) obtained from the soda-anthraquinone (AQ) pulping of untreated and hot-water-extracted non-wood feedstocks (okra stalk, miscanthus stalk, and wheat straw) were determined. These under-utilized renewable and widely available feedstocks could provide a cheaper source for producing fiber and precursors for manufacturing green chemicals. These BLs were mainly characterized in terms of carbohydrate-derived volatile carboxylic acids (acetic and formic acids) and non-volatile carboxylic acids (hydroxy acids) as well as lignin. Additionally, in each case, the average molar mass and molar mass distribution of the dissolved lignin were measured. Result…
CCDC 1054374: Experimental Crystal Structure Determination
2015
Related Article: Alexandre Abhervé, Samuel Mañas-Valero, Miguel Clemente-León, Eugenio Coronado|2015|Chemical Science|6|4665|doi:10.1039/C5SC00957J
CCDC 2130642: Experimental Crystal Structure Determination
2022
Related Article: Noemi Monni, José J. Baldoví, Víctor García-López, Mariangela Oggianu, Enzo Cadoni, Francesco Quochi, Miguel Clemente-León, Maria Laura Mercuri, Eugenio Coronado|2022|Chemical Science|13|7419|doi:10.1039/D2SC00769J
Cover Picture: Palladium-Catalyzed Arylation of Linear and Cyclic Polyamines (Eur. J. Org. Chem. 2/2005)
2005
The cover picture shows the model structures of four compounds among the hundred of arylated linear and cyclic polyamines prepared by palladium-catalyzed coupling of mono- and dihalogenoarenes with various aliphatic or aromatic polyamines. The reaction is strongly dependent on the nature and the concentration of the catalytic system, as well as the nature of the base. The competitive reaction between primary and secondary amines and the monoamination of dihalobenzenes have also been detailed in the article by R. Guilard et al. on p. 261 ff. In the following article by the same authors on p. 281 ff, the method has been applied to the synthesis of numerous nitrogen- and oxygen-containing macr…
Wirkung der Insektizide Allethrin, Lindan und Jacutin-Fogetten-Sublimat auf den photosynthetischen Elektronentransport
1977
Summary During our studies of Hill-reactions of isolated chloroplasts we observed an inhibition of electron transport after an application of the smoke of «Jacutine-Fogetten» in the plant growth chamber. Therefore we tested the influence of the insecticides Lindane (Gammexan), the sublimate formed by the fumigation of «Jacutin Fogetten», and of Allethrin on the photosynthetic electron transport reactions of PS II and PS I. 39 μ M Lindane inhibits the basal, coupled and uncoupled electron transport to ferricyanide of broken chloroplasts isolated from leaves of Pisum sativum up to 35%. A higher inhibitory effect with higher concentrations is limited by the low water solubility of Lindane. On …
FORMATION OF ALIPHATIC CARBOXYLIC ACIDS DURING ALKALINE PULPING OF MULI BAMBOO
2002
ABSTRACT A study on the formation of aliphatic carboxylic acids, i.e., formic and acetic acids and various hydroxy monocarboxylic and dicarboxylic acids, during soda-AQ, kraft, and kraft-AQ pulping of muli bamboo (Melocanna baccifera) was carried out. Detailed gas chromatographic analyses revealed that the most abundant hydroxy carboxylic acids were 2-hydroxybutanoic, lactic, glucoisosaccharinic, glycolic, xyloisosaccharinic, 3,4-dideoxypentonic, and 3-deoxypentonic acids. The presence of AQ depressed the formation of 2-hydroxybutanoic, xyloisosaccharinic, and glucoisosaccharinic acids, and accelerated the formation of glycolic and 3-deoxypentonic acids as well as 3-deoxytetronic acid but h…
Donor-Acceptor Polythiophene Copolymers with Tunable Acceptor content for Photoelectric Conversion Devices
2004
The synthesis and characterization of a new series of substituted polythiophenes containing an electron acceptor anthraquinone moiety in the side chain are reported. The acceptor molar content was varied by the co-polymerization of both alkylthiophene and thiophene bearing anthraquinone monomers in different ratios. NMR analysis shows a good correlation between the monomer feed composition at the beginning of the polymerization and the actual unit composition of the backbone. The conjugation length and the chemical composition of the copolymers as a function of the molecular weight have been studied by size exclusion chromatography. Small angle X-ray scattering and UV-Vis absorption spectra…
Conjugation reactions of polyaromatic quinones to mono- and bisglutathionyl adducts: Direct analysis by fast atom bombardment mass spectrometry
1988
The conjugation products of several reactive quinones with glutathione have been identified by fast atom bombardment mass spectrometry. Appropriate conditions have been developed which enabled the direct, dynamic mass spectral analysis of spontaneous, as well as glutathione transferase catalysed conjugation reactions. Applications to a series of quinones provided the direct detection and differentiation of the formation of mono- and bisglutathionyl adducts between regioisomeric quinone substrates in that only 1,4-quinones yielded bisglutathionyl adducts, which were not observed for the 1,2-isomers.
A Metal-Free, Nonconjugated Polymer for Solar Photocatalysis
2017
Heterogeneous catalysts that can absorb light over the solar range are ideal for green photocatalysis. Recently, attention has been directed towards the generation of novel solar-light photocatalysts, in particular, metal-free polymers. Herein, it is demonstrated that a metal-free, nonconjugated, anthraquinone-based copolymer (poly[1,4-diamine-9,10-dioxoanthracene-alt-(benzene-1,4-dioic acid)] (COP)) with a strong absorption in the visible region is effective as a sunlight heterogeneous photocatalyst. As a proof of concept, it has been used to mineralize 2,5-dichlorophenol (2,5-DCP) in water under air and sunlight irradiation. The photocatalytic efficiency of COP compares well with that of …
High-Yield Formation of Arbutin from Hydroquinone by Cell-Suspension Cultures ofRauwolfia serpentina
1992
High-density cell-suspension cultures of Rauwolfia serpentina cultivated in a nutrition medium optimized for the production of the glucoalkaloid raucaffricine synthesize hydroquinone glycosides from continuously added hydroquinone with a total yield of 23.87 g/1 (18 g/1 of arbutin and 5.87 g/1 of a hydroquinone diglycoside) in 7 days. This arbutin production is by far the highest formation of a natural product by plant-cell-culture systems reported to date.