The Experts below are selected from a list of 54 Experts worldwide ranked by ideXlab platform
Alexander I. Petrov - One of the best experts on this subject based on the ideXlab platform.
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Aluminum Derivative peroxides in the t buo 3al 2t buooh catalytic system as a source of electron excited dioxygen a quantum chemical study on a model
RSC Advances, 2016Co-Authors: Oleg B. Gadzhiev, Victor A. Dodonov, Alexander I. PetrovAbstract:The quantum chemical study of the MeOOH/(MeO)3Al model system has been carried out in order to predict the mechanism of the catalytic decomposition of t-BuOOH under mild conditions for the t-BuOOH/(t-BuO)3Al system being a powerful synthetic tool for selective oxidation. To elucidate the chemical excitation of O2 eliminated in the catalytic reaction and to predict the electronic state of O2, the topology of the potential energy surface (PES), the structures of intermediates and transition states, the activation and reaction energies were obtained at the B3LYP/cc-pVTZ theory level. It was shown that the peroxide, (MeO)2AlOOMe, corresponding to the experimentally obtained (t-BuO)2AlOOBu-t, is formed in the first step of the reaction. After that, in the main pathway, the Aluminum-containing peroxide reacts with the second MeOOH molecule through the nucleophilic substitution of the second methoxy group forming the MeOAl(OOMe)2 diperoxide. The diperoxide rearranges to Aluminum-containing ozonide MeOAlOOOMe. The ozonide isomerizes in the mononuclear-metal dioxygen intermediate (MeO)3Al·O2. The latter decomposes through the adiabatic ((MeO)3Al + O2(b1Σ+g)) and non-adiabatic ((MeO)3Al + O2(X3Σ−g)) pathways, which corresponds to experimental data about the incomplete conversion of O2 to O2(b1Σ+g). The generation of O2(b1Σ+g) was revealed by the analysis of the energy diagram calculated with the CCSD(T), CCSDT(Q), and CASSCF methods. It was suggested that the η1-(MeO)3Al·O2 and, thus, (t-BuO)3Al·O2 complexes are new sources of O2(b1Σ+g).
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Aluminum Derivative peroxides in the (t-BuO)3Al–2t-BuOOH catalytic system as a source of electron-excited dioxygen: a quantum chemical study on a model
RSC Advances, 2016Co-Authors: Oleg B. Gadzhiev, Victor A. Dodonov, Alexander I. PetrovAbstract:The quantum chemical study of the MeOOH/(MeO)3Al model system has been carried out in order to predict the mechanism of the catalytic decomposition of t-BuOOH under mild conditions for the t-BuOOH/(t-BuO)3Al system being a powerful synthetic tool for selective oxidation. To elucidate the chemical excitation of O2 eliminated in the catalytic reaction and to predict the electronic state of O2, the topology of the potential energy surface (PES), the structures of intermediates and transition states, the activation and reaction energies were obtained at the B3LYP/cc-pVTZ theory level. It was shown that the peroxide, (MeO)2AlOOMe, corresponding to the experimentally obtained (t-BuO)2AlOOBu-t, is formed in the first step of the reaction. After that, in the main pathway, the Aluminum-containing peroxide reacts with the second MeOOH molecule through the nucleophilic substitution of the second methoxy group forming the MeOAl(OOMe)2 diperoxide. The diperoxide rearranges to Aluminum-containing ozonide MeOAlOOOMe. The ozonide isomerizes in the mononuclear-metal dioxygen intermediate (MeO)3Al·O2. The latter decomposes through the adiabatic ((MeO)3Al + O2(b1Σ+g)) and non-adiabatic ((MeO)3Al + O2(X3Σ−g)) pathways, which corresponds to experimental data about the incomplete conversion of O2 to O2(b1Σ+g). The generation of O2(b1Σ+g) was revealed by the analysis of the energy diagram calculated with the CCSD(T), CCSDT(Q), and CASSCF methods. It was suggested that the η1-(MeO)3Al·O2 and, thus, (t-BuO)3Al·O2 complexes are new sources of O2(b1Σ+g).
Georgiy B Shulpin - One of the best experts on this subject based on the ideXlab platform.
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oxidation of olefins with h2o2 catalyzed by gallium iii nitrate and Aluminum iii nitrate in solution
Journal of Molecular Catalysis A-chemical, 2016Co-Authors: Dalmo Mandelli, Yuriy N Kozlov, Cezar A R Da Silva, Wagner Carvalho, Paolo P Pescarmona, Daniele De A Cella, Polyana Tome De Paiva, Georgiy B ShulpinAbstract:Soluble gallium and Aluminum nitrates (simple salts of non-transition metals) are good catalysts for the epoxidation of olefins (cyclooctene, dec-1-ene) including terpenes (carvone, limonene) with hydrogen peroxide in ethyl acetate or tetrahydrofurane (THF). Typically, the gallium salt is more efficient in comparison with the Aluminum Derivative. Products are formed in yields up to 93%, turnover numbers (TONs) attained 40. Addition of trifluoroacetic acid or pyrazine-2-carboxylic acid (PCA) accelerates the reaction and improves the yield. In striking contrast, added 2,2′-bipyridine or phenanthroline dramatically inhibit the oxidation.
Philippe Guégan - One of the best experts on this subject based on the ideXlab platform.
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Anionic ring‐opening polymerization of N‐glycidylphthalimide: Combination of phosphazene base and activated monomer mechanism
Journal of Polymer Science Part A: Polymer Chemistry, 2018Co-Authors: Somasoudrame Rassou, Nicolas Illy, Ozgul Tezgel, Philippe GuéganAbstract:Anionic ring‐opening polymerization of glycidyl phthalimide, initiated with alcohol–phosphazene base systems and based on monomer activation with a Lewis acid (iBu3Al), has been studied. No propagation occurred for initiator: iBu3Al ratios less or equal to 1:3. For larger Lewis acid amounts, the first anionic ring‐opening polymerizations of glycidyl phthalimide were observed. Polymers were carefully characterized by NMR, MALDI‐TOF mass spectrometry, and size exclusion chromatography and particular attention was given to the detection of eventual transfer or side‐reactions. However, polymer precipitation and transfer reaction to Aluminum Derivative were detrimental to monomer conversion, polymerization control, and limited polymer chain molar masses. The influence of reaction temperature and solvent on polymer precipitation and transfer reactions was studied and reaction conditions have been optimized leading to afford end‐capped poly(glycidyl phthalimide) with narrow molar mass distributions.
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Anionic ring-opening polymerization of N -glycidylphthalimide: Combination of phosphazene base and activated monomer mechanism
Journal of Polymer Science Part A: Polymer Chemistry, 2018Co-Authors: Somasoudrame Rassou, Nicolas Illy, Ozgul Tezgel, Philippe GuéganAbstract:Anionic ring‐opening polymerization of glycidyl phthalimide, initiated with alcohol–phosphazene base systems and based on monomer activation with a Lewis acid (iBu3Al), has been studied. No propagation occurred for initiator: iBu3Al ratios less or equal to 1:3. For larger Lewis acid amounts, the first anionic ring‐opening polymerizations of glycidyl phthalimide were observed. Polymers were carefully characterized by NMR, MALDI‐TOF mass spectrometry, and size exclusion chromatography and particular attention was given to the detection of eventual transfer or side‐reactions. However, polymer precipitation and transfer reaction to Aluminum Derivative were detrimental to monomer conversion, polymerization control, and limited polymer chain molar masses. The influence of reaction temperature and solvent on polymer precipitation and transfer reactions was studied and reaction conditions have been optimized leading to afford end‐capped poly(glycidyl phthalimide) with narrow molar mass distributions.
Oleg B. Gadzhiev - One of the best experts on this subject based on the ideXlab platform.
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Aluminum Derivative peroxides in the t buo 3al 2t buooh catalytic system as a source of electron excited dioxygen a quantum chemical study on a model
RSC Advances, 2016Co-Authors: Oleg B. Gadzhiev, Victor A. Dodonov, Alexander I. PetrovAbstract:The quantum chemical study of the MeOOH/(MeO)3Al model system has been carried out in order to predict the mechanism of the catalytic decomposition of t-BuOOH under mild conditions for the t-BuOOH/(t-BuO)3Al system being a powerful synthetic tool for selective oxidation. To elucidate the chemical excitation of O2 eliminated in the catalytic reaction and to predict the electronic state of O2, the topology of the potential energy surface (PES), the structures of intermediates and transition states, the activation and reaction energies were obtained at the B3LYP/cc-pVTZ theory level. It was shown that the peroxide, (MeO)2AlOOMe, corresponding to the experimentally obtained (t-BuO)2AlOOBu-t, is formed in the first step of the reaction. After that, in the main pathway, the Aluminum-containing peroxide reacts with the second MeOOH molecule through the nucleophilic substitution of the second methoxy group forming the MeOAl(OOMe)2 diperoxide. The diperoxide rearranges to Aluminum-containing ozonide MeOAlOOOMe. The ozonide isomerizes in the mononuclear-metal dioxygen intermediate (MeO)3Al·O2. The latter decomposes through the adiabatic ((MeO)3Al + O2(b1Σ+g)) and non-adiabatic ((MeO)3Al + O2(X3Σ−g)) pathways, which corresponds to experimental data about the incomplete conversion of O2 to O2(b1Σ+g). The generation of O2(b1Σ+g) was revealed by the analysis of the energy diagram calculated with the CCSD(T), CCSDT(Q), and CASSCF methods. It was suggested that the η1-(MeO)3Al·O2 and, thus, (t-BuO)3Al·O2 complexes are new sources of O2(b1Σ+g).
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Aluminum Derivative peroxides in the (t-BuO)3Al–2t-BuOOH catalytic system as a source of electron-excited dioxygen: a quantum chemical study on a model
RSC Advances, 2016Co-Authors: Oleg B. Gadzhiev, Victor A. Dodonov, Alexander I. PetrovAbstract:The quantum chemical study of the MeOOH/(MeO)3Al model system has been carried out in order to predict the mechanism of the catalytic decomposition of t-BuOOH under mild conditions for the t-BuOOH/(t-BuO)3Al system being a powerful synthetic tool for selective oxidation. To elucidate the chemical excitation of O2 eliminated in the catalytic reaction and to predict the electronic state of O2, the topology of the potential energy surface (PES), the structures of intermediates and transition states, the activation and reaction energies were obtained at the B3LYP/cc-pVTZ theory level. It was shown that the peroxide, (MeO)2AlOOMe, corresponding to the experimentally obtained (t-BuO)2AlOOBu-t, is formed in the first step of the reaction. After that, in the main pathway, the Aluminum-containing peroxide reacts with the second MeOOH molecule through the nucleophilic substitution of the second methoxy group forming the MeOAl(OOMe)2 diperoxide. The diperoxide rearranges to Aluminum-containing ozonide MeOAlOOOMe. The ozonide isomerizes in the mononuclear-metal dioxygen intermediate (MeO)3Al·O2. The latter decomposes through the adiabatic ((MeO)3Al + O2(b1Σ+g)) and non-adiabatic ((MeO)3Al + O2(X3Σ−g)) pathways, which corresponds to experimental data about the incomplete conversion of O2 to O2(b1Σ+g). The generation of O2(b1Σ+g) was revealed by the analysis of the energy diagram calculated with the CCSD(T), CCSDT(Q), and CASSCF methods. It was suggested that the η1-(MeO)3Al·O2 and, thus, (t-BuO)3Al·O2 complexes are new sources of O2(b1Σ+g).
Alain Deffieux - One of the best experts on this subject based on the ideXlab platform.
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Living/controlled anionic polymerization and copolymerization of epichlorohydrin with tetraoctylammonium bromide-TriisobutylAluminum initiating systems
International Journal of Biological Macromolecules, 2008Co-Authors: Stephane Carlotti, Amelie Labbe, Virginie Rejsek, Stephane Doutaz, Matthieu Gervais, Alain DeffieuxAbstract:A weakly nucleophilic initiating system obtained by the combination of triisobutylAluminum and tetraoctylammonium bromide has been successfully used to achieve the controlled polymerization of epichlorohydrin (ECH) in hydrocarbon at temperatures ranging from -30 degrees C to room temperature. Besides the formation of a 1:1 aluminate complex of low nucleophilicity between the Aluminum Derivative and the tetraalkylammonium salt, the strategy consists of the formation of a strongly activating complex between the Lewis acid and the epoxide monomer. To that aim trialkylAluminum is added in slight excess with respect to the tetraalkylammonium salt ([i-BU3Al]/[NOct(4)Br] > 1). In these conditions the reactivity of ECH toward nucleophiles is strongly enhanced and the ring opening polymerization proceeds in the presence of weak nucleophiles leading to nonreacted chloromethyl function of the epichlorohydrin. This contrasts with conventional anionic polymerization, which requires much stronger nucleophiles for the ring opening. Fast and controlled polymerization of ECH up to high molar masses and the synthesis of random and block copolymers with propylene oxide were readily achieved.
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Living/Controlled Anionic Polymerization and Copolymerization of Epichlorohydrin with Tetraoctylammonium Bromide−TriisobutylAluminum Initiating Systems
Macromolecules, 2008Co-Authors: Stephane Carlotti, Amelie Labbe, Virginie Rejsek, Stephane Doutaz, Matthieu Gervais, Alain DeffieuxAbstract:A weakly nucleophilic initiating system obtained by the combination of triisobutylAluminum and tetraoctylammonium bromide has been successfully used to achieve the controlled polymerization of epichlorohydrin (ECH) in hydrocarbon at temperatures ranging from −30 °C to room temperature. Besides the formation of a 1:1 aluminate complex of low nucleophilicity between the Aluminum Derivative and the tetraalkylammonium salt, the strategy consists of the formation of a strongly activating complex between the Lewis acid and the epoxide monomer. To that aim trialkylAluminum is added in slight excess with respect to the tetraalkylammonium salt ([i-Bu3Al]/[NOct4Br] > 1). In these conditions the reactivity of ECH toward nucleophiles is strongly enhanced and the ring opening polymerization proceeds in the presence of weak nucleophiles leading to nonreacted chloromethyl function of the epichlorohydrin. This contrasts with conventional anionic polymerization, which requires much stronger nucleophiles for the ring openi...
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living controlled anionic polymerization and copolymerization of epichlorohydrin with tetraoctylammonium bromide triisobutylAluminum initiating systems
Macromolecules, 2008Co-Authors: Stephane Carlotti, Amelie Labbe, Virginie Rejsek, Stephane Doutaz, Matthieu Gervais, Alain DeffieuxAbstract:A weakly nucleophilic initiating system obtained by the combination of triisobutylAluminum and tetraoctylammonium bromide has been successfully used to achieve the controlled polymerization of epichlorohydrin (ECH) in hydrocarbon at temperatures ranging from −30 °C to room temperature. Besides the formation of a 1:1 aluminate complex of low nucleophilicity between the Aluminum Derivative and the tetraalkylammonium salt, the strategy consists of the formation of a strongly activating complex between the Lewis acid and the epoxide monomer. To that aim trialkylAluminum is added in slight excess with respect to the tetraalkylammonium salt ([i-Bu3Al]/[NOct4Br] > 1). In these conditions the reactivity of ECH toward nucleophiles is strongly enhanced and the ring opening polymerization proceeds in the presence of weak nucleophiles leading to nonreacted chloromethyl function of the epichlorohydrin. This contrasts with conventional anionic polymerization, which requires much stronger nucleophiles for the ring openi...