system. New solid oxo-rhenium and oxo-molybdenum catalysts for the deoxydehydration of glycols to olefins. Nelly Ntumba Tshibalonza, Jean-Christophe M. Monbaliu. Oxidative cleavage of diols allows the catalytic reaction to be performed in neat substrate thereby removing the need for solvent. Alkene was obtained in up to 84% yield. Cyclic diols, however, were found to have appreciably lower yields (approx. 6.18 Eliminations to Form Alkenes, Allenes, and Alkynes and Related Reactions. The total conversion of the reaction was found to be 74% with allyl alcohol as the major product. Hydrodeoxygenation of Vicinal OH Groups over Heterogeneous Rhenium Catalyst Promoted by Palladium and Ceria Support. Deoxydehydration of glycerol to allyl alcohol catalyzed by rhenium derivatives. Part III. Information. Notably, when sacrificial reducing alcohols are used as solvents, glycerol still competes with the alcohol as a transfer-hydrogenation agent, forming acrolein or propanal. 4 publications. The proposed mechanism is analogous to that for the previously studied Re systems shown in scheme 3 but incorporates a V(V)/V(III) redox cycle. The authors declare no competing interest. László T. Mika, Edit Cséfalvay, István T. Horváth. Possible DODH reaction mechanisms of RReO3 exploiting reduction by oxo-abstraction. Two higher energy conventional (tight) transition states, along with the pathways to 1,2-OH-migration, as well as direct H-abstraction, are also identified and analyzed. Roaming Reactions and Dynamics in the van der Waals Region. In the present study, we propose a new low-energy, roaming-like mechanism based on a detailed dispersion-corrected DFT and ab initio level analysis of the gas-phase dehydration of DRs obtained from the combination of OH radicals with allyl alcohol (AA, CH2═CHCH2OH)—the simplest relevant model of the unsaturated alcohols. Using Cp*ReO3 and aryl phosphines as reductants, they demonstrated catalytic activity at elevated temperatures and produced alkenes in good yield. Diol radicals (DRs) are important intermediates in biocatalysis, atmospheric chemistry, and biomass combustion. As a result, the development of processes to produce valuable carbon-based commodity chemicals from renewable carbon feedstocks has become an important field of study [3]. tt Perrhenate-Catalyzed Deoxydehydration of a Vicinal Diol: A Comparative Density Functional Theory Study. Two types of roaming-like first-order saddle points (SP) are identified for unimolecular dehydration of 1,2- and 1,3-DR radical adducts involving either both hydroxyl groups of diol radicals to generate an oxygen-centered radical, or β-OH group and a skeletal α-hydrogen atom of the 1,2-DR to form a resonantly stabilized hydroxyallyl radical. Get article recommendations from ACS based on references in your Mendeley library. Peng Liu and Kenneth M. Nicholas . McClain & Nicholas showed zinc, carbon, iron and manganese act as elemental reductants for the DODH of polyols using ammonium perrhenate (APR) affording upwards of 90% yield for a variety of substrates [37]. Part I. MTO and 3-octanol successfully converted glycerol to allyl alcohol in 90% yield. Mo-catalyzed deoxygenation of epoxides to alkenes. Current DODH catalysts.Download figureOpen in new tabDownload powerPoint. Oxo-donors such as DMSO can be used to re-oxidize the reduced Mo centres by oxo transfer, implying that these reactions are reversible [76]. Daniel Lupp, Niels Johan Christensen, Johannes R. Dethlefsen, Peter Fristrup. They are particularly generated from photolysis of halogenated diols and addition of hydroxyl radical to a double bond of unsaturated alcohols, such as lignols. system. Molybdenum-oxo compounds are particularly promising because a large number of complexes can be synthesized readily from easily accessible starting materials.
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