Search results for "Maleic anhydride"
showing 10 items of 47 documents
Gas phase heterogeneous partial oxidation reactions
2018
Abstract Mixed metal oxides are used as catalysts in the gas phase partial oxidation of hydrocarbons. This paper will present the principles of catalyst choice for selective oxidation reactions as well as the structural features of metal oxide catalysts. The nature of active sites in selective oxidation reactions will also be briefly discussed. We will pay special attention to several representative reactions: (1) ODH of short chain alkanes (from C1 to C4), (2) propene partial oxidation/ammoxidation on bismuth molybdate based catalysts, (3) n-butane direct oxidation to maleic anhydride on VPO type catalysts, and (4) propane direct oxidation/ammoxidation on mixed MoVTe(Sb)Nb–O catalysts. Fin…
Protecting group-free radical decarboxylation of bile acids: Synthesis of novel steroidal substituted maleic anhydrides and maleimides and evaluation…
2017
Abstract We report the first Barton radical decarboxylation of unprotected bile acids via in situ irradiation of their thiohydroxamic esters in the presence of citraconic anhydride and citracoimide, leading to the synthesis a series of steroidal maleic anhydrides and maleimides as novel hybrid bile acids. The cytotoxic activities were evaluated on C6 rat glioma cells.
Design of new sensitive α,β-unsaturated carbonyl 1,8-naphtalimide fluorescent probes for thiol bioimaging
2017
International audience; We report herein an efficient synthesis of news naphtalimide-based fluorescent derivatives functionalized with an a,(3-unsaturated carbonyl group. Probes were synthesized from reaction of an amino-naphtalimide precursor with maleic anhydride. Photophysical study of fluorescent probes and cells labelling were performed, and showed that the reactive derivatives exhibit rich turn on fluorescence properties in presence of different biological thiol (Glutathione and Cysteine) making these systems a very promising way for thiol bioimaging.
Reaction products and pathways in the selective oxidation of C-2-C-4 alkanes on MoVTeNb mixed oxide catalysts
2010
[EN] The catalytic properties of MoVTeNbO catalysts during the selective oxidation of short chain alkanes and olefins (C-2-C-4) have been comparatively studied The main reaction products have been ethylene from ethane acrylic acid from propane maim anhydride from n-butane and methacrolein from isobutane FTIR studies of the adsorption of the main reaction products i e olefins and aldehydes over MoVTeNbO catalyst has been carried out Accordingly the reaction pathway is explained on the basis of the characteristics of the alkane fed the stability and reactivity of both the intermediates and the reaction products and the nature of the catalytic sites involved in each reaction (C) 2010 Elsevier …
Cycloaddition reactions of 3-vinylthiophen
1987
Abstract Cycloaddition reactions between 3-vinylthiophen and the dienophiles maleic anhydride, methyl acrylate, dimethyl acetylene - dicarboxylate, and methyl propiolate give products including methyl benzo[b]thiophen-7-carboxylate (11) and its dihydroderivative (10), the 6,7-dicarboxylic acid (3), its dimethyl ester (7) and dihydroester (6); the naphtho[a,b]dithiophen (14), and the novel ethano bridged benzo[b]thiophen (15).
Hemoglobin loaded polymeric nanoparticles: preparation and characterizations.
2011
In the present work polymeric nanoparticles based on Poly (maleic anhydride-alt-butyl vinyl ether) 5% grafted with m-PEG (2000) and 95% grafted with 2-methoxyethanol (VAM41-PEG) were loaded with human hemoglobin (Hb) and characterized from a physicochemical point of view. The assessment of structural and functional features of the loaded Hb was performed and the effect of the introduction of different reducing agents as aimed at minimizing Hb oxidation during the nanoparticles formulation process, was also investigated. Nanoparticles possessing an average diameter of 138 ± 10 nm and physicochemical features suitable for this kind of application were successfully obtained. Although the oxida…
Cationic and Zwitterionic Polymerizable Surfactants: Quaternary Ammonium Dialkyl Maleates. 1. Synthesis and Characterization
1999
Cationic and zwitterionic reactive dialkyl maleates with different hydrophobic chain lengths (R = C10H21, C12H25, C16H33, and C18H37), and some similar surfactants without double bonds were synthesized with an aim to use them as stabilizers in the batch and seeded emulsion copolymerization of styrene and butyl acrylate (part 2 of this series). Surfactants are obtained in a three-step synthesis, starting from ring opening of maleic anhydride, followed by O alkylation with an aminoalkyl compound, and finishing with quaternization of the amino group in the hydrophilic part of the molecule. The chemical structure of surfactants was confirmed by 1H NMR. Melting points and critical micelle concen…
Novel Phases in the V-P-O Catalytic System from Oxovanadium Hydrogenphosphate Precursors
1994
ABSTRACTSeveral biphasic VOP04/(VO)2P2O7 redox partners seem to be active in the catalytic cycles involved in the mild oxidation of simple hydrocarbons to maleic anhydride. The present X-ray time resolved thermal-diffractometric study reveals the existence of a new anhydrous variety of the oxidized form, ω-VOPO4, which may appear as an intermediate in the formation of the well known β-VOPO4. This new phase only remains well crystallized at relatively high temperatures, and when it is allowed to cool down in wet air VOPO4·2H2O results. In turn, another well defined phase, VOPO4·1.58H2O, can be recognized in the course of the hydration process.
Cycloaddition reactions of 2-vinylthiophen
1985
Abstract Cycloaddition reactions between 2-vinylthiophen and the dienophiles maleic anhydride, dimethyl acetylenedicarboxylate,' methyl propiolate, and methyl acrylate, are reported. Products include simple benzo[b]thiophen carboxylates (6, 13, 17) and reduced derivatives (3, 4, 18). The acetylenic dienophiles also gave a dihydrobenzthienyl-acrylate (16) or -fumarate (11), and the dithienylcyclohexene esters (7) and (14).
Influence of structural factors and enzyme type on the reactivity and enantioselectivity of the enzymatic esterification of bicyclic meso dialcohols
1992
The meso dialcohols 1–7, obtained from the Diels-Alder adducts furan/maleic anhydride, furan/dimethyl acetylenedi-carboxylate, and cyclopentadiene/maleic anhydride, were subjected to enzymatic esterification in organic solvents. A mixture of the corresponding chiral monoacetates and the meso diacetates was obtained. It has been found that reaction rate and enantioselectivity markedly depend on substrate structure, temperature, enzyme type, and nature of the solvent. The presence of an oxygen bridge and an exo configuration are the two structural features which lead to the highest enantioselectivity values.