The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Masayuki Shirai - One of the best experts on this subject based on the ideXlab platform.
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hydrogenation of benzothiophene free naphthalene over charcoal supported metal catalysts in supercritical carbon dioxide solvent
2007Co-Authors: Norihito Hiyoshi, Chandrashekhar V Rode, Osamu Sato, Mitsumasa Osada, Masayuki ShiraiAbstract:Abstract Hydrogenation of benzothiophene-free naphthalene was examined over various transition metal (rhodium, ruthenium, palladium, and platinum) catalysts supported on charcoal in supercritical carbon dioxide (scCO 2 ) solvent at low temperature (313 K). Among these, a charcoal-supported rhodium catalyst was found to be the most active, while a charcoal-supported ruthenium catalyst was found to give the highest cis -decahydronaphthalene ( cis -decalin) selectivity. A systematic investigation of hydrogenations of naphthalene and tetrahydronaphthanele (tetralin) in scCO 2 revealed that naphthalene hydrogenation is a consecutive and cis - and trans -decalin were formed via tetralin.
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low temperature hydrogenation of tetralin over supported rhodium catalysts in supercritical carbon dioxide solvent
2006Co-Authors: Norihito Hiyoshi, Eiichi Mine, Chandrashekhar V Rode, Osamu Sato, Masayuki ShiraiAbstract:Hydrogenation of tetralin was studied over supported rhodium catalysts in supercritical carbon dioxide solvent at 333 K. The results were compared with those in an organic solvent and under neat conditions. Higher cis-decalin yield was obtained in supercritical carbon dioxide solvent than under non-supercritical conditions. It was observed that higher hydrogen concentration at the surface in supercritical carbon dioxide solvent led to fast direct hydrogenation of tetralin to cis-decalin; the flipping of the intermediate, octalin, to give trans-decalin could be prevented.
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Tuning cis-decalin Selectivity in Naphthalene Hydrogenation Over Carbon-supported Rhodium Catalyst Under Supercritical Carbon dioxide
2006Co-Authors: Norihito Hiyoshi, Chandrashekhar V Rode, Osamu Sato, Tomoya Inoue, Masayuki ShiraiAbstract:Catalytic hydrogenation of naphthalene to decalin was studied over a carbon-supported rhodium catalyst in supercritical carbon dioxide solvent at 333 K, and the results were compared with those in an organic solvent. cis -, trans -Decalin and tetralin were formed from the beginning of the reaction in supercritical carbon dioxide. Higher concentration of hydrogen in carbon dioxide solvent and on the active site, and also the suppression of desorption of partially hydrogenated tetralin molecules from the active site would be responsible for higher selectivity to cis -decalin in supercritical carbon dioxide than that in an organic solvent.
Changha Lee - One of the best experts on this subject based on the ideXlab platform.
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upgrading of petroleum vacuum residue using a hydrogen donor solvent with acid treated carbon
2018Co-Authors: Doo Wook Kim, Pil Rip Jeo, Seunghyu Moo, Changha LeeAbstract:Abstract Hydrocarbon/carbon systems can be used to perform the hydrogen transfer reaction in heavy oil upgrading, as alternatives to metal catalysts and molecular hydrogen. In this study, a system comprising a hydrogen-donor solvent (tetralin) and acid-treated activated carbon was established to evaluate its ability as a hydrogen transfer agent to upgrade a vacuum residue (VR). The use of tetralin substantially decreased coke formation from 32.7 wt% to a negligible amount in VR upgrading at 450 °C because the solvent could act as a hydrogen donor and diluent for the coke precursors. The acid-treated activated carbon accelerated dehydrogenation of tetralin through hydrogen transfer in the upgrading, resulting in a higher residue conversion and moderate coke formation. In view of the phase behavior, the hydrogen transfer reaction could also be promoted by increasing the contact between the hydrogen acceptor and donor in the supercritical medium. In the VR upgrading using the activated carbon in supercritical tetralin, complete residue conversion was achieved with 47 wt% light fractions (gas and light oil) and 6 wt% coke at 450 °C and 5.33 MPa. The results indicate that the streams available in oil refinery processes, which are rich in hydrocarbons with hydrogen-donor abilities, have great potential for use in heavy oil upgrading.
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a parameter study for co processing of petroleum vacuum residue and oil palm empty fruit bunch fiber using supercritical tetralin and decalin
2016Co-Authors: Doo Wook Kim, Anton Koriakin, Changha LeeAbstract:Abstract Co-processing of petroleum vacuum residue (VR) and oil palm empty fruit bunch (EFB) fiber was carried out through the use of supercritical solvents. The effects of solvent (tetralin and decalin), temperature (400 and 450 °C), a catalyst, and hydrogen on the co-processing were evaluated according to residue conversion and product distribution analysis. The results were compared with only the VR upgrading results as well as the co-processing of VR and microcrystalline cellulose. Supercritical tetralin exhibited high reaction performance in both VR upgrading and co-processing of VR/EFB without significant coke formation, compared with the results in decalin. In the presence of H2, the Fe3O4 catalyst contributed toward suppressing coke formation. The co-processing of VR/EFB using tetralin could achieve a residue conversion of 86.4 wt% with only 0.8 wt% of coke formation, showing more favorable conversion than that of VR/microcrystalline cellulose. Therefore, it led to a positive effect which improved the residue conversions and yielded a great quantity of light product.
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thermochemical decomposition of microcrystalline cellulose using sub and supercritical tetralin and decalin with fe3o4
2015Co-Authors: Anton Koriakin, Doo Wook Kim, Hai Van Nguyen, Changha LeeAbstract:Direct thermochemical liquefaction of microcrystalline cellulose was investigated in sub- and supercritical solvents in a batch reactor. The liquefaction efficiency of hydrogen donor solvents (tetralin and decalin) was compared to that of m-xylene. Tetralin was the most effective solvent with respect to the conversion at every tested condition starting from 350 °C. At 400 °C, the total conversion of cellulose in tetralin approached 96.8–98.3% with a negligible amount of char formation. The pressure of hydrogen had little effect on conversion for any solvent, while the addition of iron oxide catalyst (Fe3O4) led to improved conversion and liquid yield from the reaction compared to reactions without the catalyst at temperatures higher than 350 °C. Hydrogen pressure in the presence of iron oxide catalyst significantly suppressed the char formation and improved liquid production. The thermal-treated chars collected after liquefaction reactions showed a fair adsorption capacity of CO2 compared to activated carbon.
Mark Lautens - One of the best experts on this subject based on the ideXlab platform.
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diastereoselective intramolecular friedel crafts alkylation of Tetralins
2011Co-Authors: Clemence Liebert, Marion K Brinks, Andrew G Capacci, Matthew J Fleming, Mark LautensAbstract:A wide range of cis-hexahydrobenzophenanthridine-derived cyclic compounds is prepared in a mild reaction from the corresponding chiral tetralin substrates with retention of optical purity.
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diastereoselective intramolecular friedel crafts alkylation of Tetralins
2011Co-Authors: Clemence Liebert, Marion K Brinks, Andrew G Capacci, Matthew J Fleming, Mark LautensAbstract:An efficient and versatile synthesis of cis-hexahydrobenzophenanthridines starting from readily available Tetralins has been developed using an intramolecular Friedel–Crafts alkylation as a key ste...
Norihito Hiyoshi - One of the best experts on this subject based on the ideXlab platform.
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hydrogenation of benzothiophene free naphthalene over charcoal supported metal catalysts in supercritical carbon dioxide solvent
2007Co-Authors: Norihito Hiyoshi, Chandrashekhar V Rode, Osamu Sato, Mitsumasa Osada, Masayuki ShiraiAbstract:Abstract Hydrogenation of benzothiophene-free naphthalene was examined over various transition metal (rhodium, ruthenium, palladium, and platinum) catalysts supported on charcoal in supercritical carbon dioxide (scCO 2 ) solvent at low temperature (313 K). Among these, a charcoal-supported rhodium catalyst was found to be the most active, while a charcoal-supported ruthenium catalyst was found to give the highest cis -decahydronaphthalene ( cis -decalin) selectivity. A systematic investigation of hydrogenations of naphthalene and tetrahydronaphthanele (tetralin) in scCO 2 revealed that naphthalene hydrogenation is a consecutive and cis - and trans -decalin were formed via tetralin.
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low temperature hydrogenation of tetralin over supported rhodium catalysts in supercritical carbon dioxide solvent
2006Co-Authors: Norihito Hiyoshi, Eiichi Mine, Chandrashekhar V Rode, Osamu Sato, Masayuki ShiraiAbstract:Hydrogenation of tetralin was studied over supported rhodium catalysts in supercritical carbon dioxide solvent at 333 K. The results were compared with those in an organic solvent and under neat conditions. Higher cis-decalin yield was obtained in supercritical carbon dioxide solvent than under non-supercritical conditions. It was observed that higher hydrogen concentration at the surface in supercritical carbon dioxide solvent led to fast direct hydrogenation of tetralin to cis-decalin; the flipping of the intermediate, octalin, to give trans-decalin could be prevented.
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Tuning cis-decalin Selectivity in Naphthalene Hydrogenation Over Carbon-supported Rhodium Catalyst Under Supercritical Carbon dioxide
2006Co-Authors: Norihito Hiyoshi, Chandrashekhar V Rode, Osamu Sato, Tomoya Inoue, Masayuki ShiraiAbstract:Catalytic hydrogenation of naphthalene to decalin was studied over a carbon-supported rhodium catalyst in supercritical carbon dioxide solvent at 333 K, and the results were compared with those in an organic solvent. cis -, trans -Decalin and tetralin were formed from the beginning of the reaction in supercritical carbon dioxide. Higher concentration of hydrogen in carbon dioxide solvent and on the active site, and also the suppression of desorption of partially hydrogenated tetralin molecules from the active site would be responsible for higher selectivity to cis -decalin in supercritical carbon dioxide than that in an organic solvent.
Meike Niggemann - One of the best experts on this subject based on the ideXlab platform.
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Diastereoselective Synthesis of Indanes and Tetralins via Intramolecular Friedel–Crafts Reaction
2016Co-Authors: Jeannemarie Begouin, Francesca Capitta, Meike NiggemannAbstract:An easy access to tetralin and indane skeletons has been developed using a diastereoselective intramolecular Friedel–Crafts alkylation. Treatment of diastereomeric mixtures of benzyl carbinols with a catalytic amount of Ca(NTf2)2/Bu4NPF6 yields the respective tetralin or indane in good yields with high levels of regio- and diastereoselectivity
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diastereoselective synthesis of indanes and Tetralins via intramolecular friedel crafts reaction
2013Co-Authors: Jeannemarie Begouin, Francesca Capitta, Meike NiggemannAbstract:An easy access to tetralin and indane skeletons has been developed using a diastereoselective intramolecular Friedel-Crafts alkylation. Treatment of diastereomeric mixtures of benzyl carbinols with a catalytic amount of Ca(NTf2)2/Bu4NPF6 yields the respective tetralin or indane in good yields with high levels of regio- and diastereoselectivity.