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Issam Hanna - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of the Tricyclic Core of Colchicine via a Dienyne Tandem Ring-Closing Metathesis Reaction
Organic Letters, 2007Co-Authors: François-didier Boyer† And, Issam HannaAbstract:The synthesis of the tricyclic framework of colchicine has been achieved using a tandem ring-closing metathesis reaction of dienynes as the key Step. In this process, both seven-membered rings B and C were formed in one Step. Oxidation of tertiary allylic alcohol derived from the tandem metathesis product furnished an intermediate in the total synthesis of colchicine.
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Synthesis of the tricyclic core of colchicine via a dienyne tandem ring-closing metathesis reaction
Organic Letters, 2007Co-Authors: François-didier Boyer, Issam HannaAbstract:The synthesis of the tricyclic framework of colchicine has been achieved using a tandem ring-closing metathesis reaction of dienynes as the key Step. In this process, both seven-membered rings B and C were formed in one Step. Oxidation of tertiary allylic alcohol derived from the tandem metathesis product furnished an intermediate in the total synthesis of colchicine. © 2007 American Chemical Society.
François-didier Boyer† And - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of the Tricyclic Core of Colchicine via a Dienyne Tandem Ring-Closing Metathesis Reaction
Organic Letters, 2007Co-Authors: François-didier Boyer† And, Issam HannaAbstract:The synthesis of the tricyclic framework of colchicine has been achieved using a tandem ring-closing metathesis reaction of dienynes as the key Step. In this process, both seven-membered rings B and C were formed in one Step. Oxidation of tertiary allylic alcohol derived from the tandem metathesis product furnished an intermediate in the total synthesis of colchicine.
François-didier Boyer - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of the tricyclic core of colchicine via a dienyne tandem ring-closing metathesis reaction
Organic Letters, 2007Co-Authors: François-didier Boyer, Issam HannaAbstract:The synthesis of the tricyclic framework of colchicine has been achieved using a tandem ring-closing metathesis reaction of dienynes as the key Step. In this process, both seven-membered rings B and C were formed in one Step. Oxidation of tertiary allylic alcohol derived from the tandem metathesis product furnished an intermediate in the total synthesis of colchicine. © 2007 American Chemical Society.
Akitsugu Okuwaki - One of the best experts on this subject based on the ideXlab platform.
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Formation of aromatic carboxylic acids from coal-tar pitch by two-Step Oxidation with oxygen in water and in alkaline solution
Fuel, 1994Co-Authors: Takatoshi Oshika, Akitsugu OkuwakiAbstract:Abstract The production of benzenecarboxylic acids by Oxidation of coal-tar pitch with oxygen in the aqueous phase was studied. To reduce the amount of unreacted pitch observed in one-Step Oxidation in NaOH solution, two-Step Oxidation was explored: preOxidation with oxygen in water and subsequent Oxidation with oxygen in NaOH solution. Char formed in the Oxidation of pitch in water was easily oxidized in a 5 molal NaOH solution without formation of troublesome residue. By optimum combination of the Oxidation in water and in NaOH solution, the yield of water-soluble aromatic acids (WSAA) was improved from 51 to 79 wt%. The content of benzenecarboxylic acids in the WSAA reached 40–50 wt%.
Covadonga Pevida - One of the best experts on this subject based on the ideXlab platform.
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production of microporous biochars by single Step Oxidation effect of activation conditions on co2 capture
Applied Energy, 2014Co-Authors: Marta G. Plaza, A.s. González, Fernando Rubiera, J J Pis, Covadonga PevidaAbstract:There is an urgent need to develop materials and processes that reduce the energy penalty associated to the CO2 capture Step. Biochars are appealing adsorbents for post-combustion CO2 capture applications due to their low cost, stability in moisture conditions and microporous nature. Series of carbon adsorbents were prepared from almond shells and olive stones by single-Step activation with air at 400–500°C, and with lower O2 concentration in the activating gas, 3–5%, at higher temperatures (500–650°C). This process entails energy savings compared to conventional activation with carbon dioxide or steam. It has been found that the pore size distribution can be tailored by adequately selecting the activating conditions. Carbons obtained under lower oxygen partial pressures and higher temperatures present narrow microporosity, which is essential for the adsorption of CO2 at low partial pressures. These appealing low-cost adsorbents have competitive CO2 working capacities and high CO2/N2 equilibrium selectivity in conditions that can be considered representative for post-combustion CO2 capture, thus showing potential for this application.
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Evaluation of Microporous Biochars Produced by Single-Step Oxidation for Postcombustion CO2 Capture under Humid Conditions
Energy Procedia, 2014Co-Authors: Marta G. Plaza, A.s. González, Fernando Rubiera, Covadonga PevidaAbstract:Abstract Water vapor is the third component of flue gases after N2 and CO 2 . The permanent dipole moment of the water molecule makes it strongly adsorbable on many adsorbents, which can negatively affect the adsorption capacity of carbon dioxide (even causing an irreversible loss in certain cases). Carbon materials have high stability in moist conditions and present a hydrophobic nature that makes these materials appealing adsorbents for post-combustion CO 2 capture. Furthermore, these adsorbents present the added advantage that can be obtained from a globally available, cheap and renewable source of carbon: biomass. In the present work the effect of water vapor on the adsorption performance of CO 2 using a microporous biochar developed from olive stones by single- Step Oxidation is evaluated. The equilibrium of adsorption of water vapor on the selected biochar was studied in a wide temperature range that is considered of interest for the post-combustion case (12.5-85 °C). This biochar presents a moderate water adsorption capacity and type V adsorption isotherms, which will facilitate the desorption of water vapor during cyclic operation. Breakthrough curves were obtained using a gas mixture which composition resembled flue gas in the presence and absence of water vapor. The breakthrough curves of CO 2 obtained under dry and humid conditions overlap each other, which indicates that the presence of water vapor does not hinder CO 2 adsorption in the short time scale. Moreover, the adsorbent recovered its full adsorption capacity after regeneration. These findings point out that this material could be used to separate CO 2 from humid flue gas using cyclic adsorption processes.