The Experts below are selected from a list of 17538 Experts worldwide ranked by ideXlab platform
E V Chernikova - One of the best experts on this subject based on the ideXlab platform.
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effect of comonomer composition on the controlled free radical copolymerization of styrene and Maleic Anhydride by reversible addition fragmentation chain transfer raft
Polymer, 2003Co-Authors: E V Chernikova, Polina Terpugova, Chuong Bui, Bernadette CharleuxAbstract:Controlled free-radical copolymerization of styrene and Maleic Anhydride was performed in 1,4-dioxane or tetrahydrofurane solution at 60 °C using the RAFT technique. The effect of monomer feed ratio on copolymerization kinetics and on control over molar mass distribution was examined. It was shown that polymerization was faster and quality of control was poorer when the proportion of Maleic Anhydride in the monomer feed was larger. These features were assigned to a decrease in the chain transfer constant of the polymeric RAFT agent, most probably due to an increase in the apparent rate constant of propagation with the proportion of Maleic Anhydride.
Min Shi - One of the best experts on this subject based on the ideXlab platform.
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phosphine catalyzed annulations of 4 4 dicyano 2 methylenebut 3 enoates with maleimides and Maleic Anhydride
ChemInform, 2015Co-Authors: Xiaonan Zhang, Genqiang Chen, Xiangying Tang, Yin Wei, Min ShiAbstract:The novel [4 + 1] annulation reactions of maleimides afford spirocyclic products whereas [3 + 2] annulation reactions of Maleic Anhydride provide functionalized cyclopentenones.
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phosphine catalyzed annulations of 4 4 dicyano 2 methylenebut 3 enoates with maleimides and Maleic Anhydride
Angewandte Chemie, 2014Co-Authors: Xiaonan Zhang, Genqiang Chen, Xiangying Tang, Yin Wei, Min ShiAbstract:A novel phosphine-catalyzed [4+1] annulation of maleimides with 4,4-dicyano-2-methylenebut-3-enoates has been developed to afford spirocyclic products, and the maleimides serves as C-1 synthons. Moreover, a phosphinecatalyzed formal [3+2] annulation between 4,4-dicyano-2-methylenebut-3-enoates and Maleic Anhydride has been also achieved, and Maleic Anhydride behaved as a C-3 synthon in the reaction, thus efficiently affording the functionalized cyclopentenones. A stable phosphinium-containing zwitterionic compound is the key reactive intermediate in both annulations and was successfully isolated. Plausible mechanisms have been proposed on the basis of control experiments and deuterium-labeling experiments.
Jean-claude Volta - One of the best experts on this subject based on the ideXlab platform.
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vanadium phosphorus oxides for n butane oxidation to Maleic Anhydride
Applied Catalysis A-general, 1997Co-Authors: M. Abon, Jean-claude VoltaAbstract:Abstract This publication presents recent developments of the knowledge of the vanadium phosphorus oxides used as catalysts for n -butane oxidation to Maleic Anhydride. We emphasize particularly the nature of the active phase, the active centres and the role of the redox and acido-basic properties contrasting informations between catalysts presenting different degree of disorder. The nature of the active oxygen species and the mechanistic aspects of the reaction are discussed from studies conducted in our laboratory and by comparison with the present knowledge.
Endalkachew Sahledemessie - One of the best experts on this subject based on the ideXlab platform.
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Maleic Anhydride hydrogenation over pd al2o3 catalyst under supercritical co2 medium
Applied Catalysis B-environmental, 2003Co-Authors: Unnikrishnan R Pillai, Endalkachew Sahledemessie, Douglas M YoungAbstract:Abstract Hydrogenation of Maleic Anhydride (MA) to either γ-butyrolactone (GBL) or succinic Anhydride (SAH) over simple Pd/Al2O3 impregnated catalyst in supercritical CO2 medium has been studied at different temperatures and pressures. A comparison of the supercritical CO2 medium reaction with the conventional hydrogenation in the presence of commonly employed organic solvents is also described. The use of various co-solvents for CO2 has also been investigated. Selectivities different from traditional liquid phase reactions are observed under supercritical conditions. A 100% MA conversion with more than 80% selectivity to γ-butyrolactone could be obtained at 473 K and at a pressure of 2.1 MPa H2 and 12 MPa CO2. Temperature is found to be critical in obtaining the desired high γ-butyrolactone selectivity. Catalyst deactivation is observed after extended number of recycle experiments, which resulted in a lower butyrolactone selectivity. The lactone selectivity, however, could be improved by increasing the H2 partial pressure or by increasing the reaction temperature. Hydrogenation of Maleic Anhydride under supercritical CO2 as solvent is found to be promising for the selective hydrogenation of low vapor pressure solid compounds without employing environmentally harmful organic solvents.
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selective hydrogenation of Maleic Anhydride to gamma butyrolactone over pd al2o3 catalyst using supercritical co2 as solvent
Chemical Communications, 2002Co-Authors: Unnikrishnan R Pillai, Endalkachew SahledemessieAbstract:A selective hydrogenation of Maleic Anhydride to either gamma-butyrolactone or succinic Anhydride over simple Pd/Al2O3 catalyst under supercritical CO2 medium is described for the first time which has considerable promise for both lab-scale as well as industrial selective hydrogenations of low vapor pressure compounds without employing environmentally harmful organic solvents.
Bernadette Charleux - One of the best experts on this subject based on the ideXlab platform.
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effect of comonomer composition on the controlled free radical copolymerization of styrene and Maleic Anhydride by reversible addition fragmentation chain transfer raft
Polymer, 2003Co-Authors: E V Chernikova, Polina Terpugova, Chuong Bui, Bernadette CharleuxAbstract:Controlled free-radical copolymerization of styrene and Maleic Anhydride was performed in 1,4-dioxane or tetrahydrofurane solution at 60 °C using the RAFT technique. The effect of monomer feed ratio on copolymerization kinetics and on control over molar mass distribution was examined. It was shown that polymerization was faster and quality of control was poorer when the proportion of Maleic Anhydride in the monomer feed was larger. These features were assigned to a decrease in the chain transfer constant of the polymeric RAFT agent, most probably due to an increase in the apparent rate constant of propagation with the proportion of Maleic Anhydride.