17108-52-0Relevant academic research and scientific papers
Poisoning of Ru/C by homogeneous Br?nsted acids in hydrodeoxygenation of 2,5-dimethylfuran via catalytic transfer hydrogenation
Gilkey, Matthew J.,Vlachos, Dionisios G.,Xu, Bingjun
, p. 327 - 335 (2017/06/19)
It has been proposed that the combination of metal and acid sites is critical for effective ring opening of biomass-derived furans to linear molecules, a reaction that holds promise for the production of renewable polymer precursors and alkanes. In this work, we use 2,5-dimethylfuran (DMF) as a model compound to investigate hydrogenolysis and hydrogenation pathways using a combination of H2SO4 and Ru-mediated catalytic transfer hydrogenation in 2-propanol. Acid-catalyzed hydrolytic ring opening of DMF to 2,5-hexanedione (HDN) occurs readily at 80?°C with a selectivity of 89% in 2-propanol. Over Ru/C, HDN is fully converted after only 2?h at 80?°C, forming a mixture of both ring-closed products (～68% total yield), i.e., 2,5-dimethyltetrahydrofuran (DMTHF) and 2,5-dimethyl-2,3-dihydrofuran (DMDHF), as well as ring opened products (～28% total yield), i.e., 2,5-hexanediol (2,5-HDL) and 2-hexanol (HOL). Rather than observing sequential hydrolysis/hydrogenation reactions, we observe severe suppression of metal chemistry when having both Ru/C and H2SO4 in the reaction system. While minor leaching of Ru occurs in the presence of mineral acids, X-ray photoelectron spectroscopy coupled with CO chemisorption studies suggest that the primary cause of the lack of Ru-mediated chemistry is poisoning by strongly adsorbed sulfate species. This hypothesis is supported by the observation of Ru-catalyzed chemistry when replacing H2SO4 with Nafion, a solid Br?nsted acid, as sulfonic acid groups tethered to the polymer backbone cannot adsorb on the metal sites.
Hydrodeoxygenation of Furylmethane Oxygenates to Jet and Diesel Range Fuels: Probing the Reaction Network with Supported Palladium Catalyst and Hafnium Triflate Promoter
Dutta, Saikat,Saha, Basudeb
, p. 5491 - 5499 (2017/08/17)
Catalytic hydrodeoxygenation of furylmethane oxygenates to high carbon branched chain jet and diesel fuel range alkanes under mild reaction conditions is a promising strategy for energy-efficient production of fuels with minimal C-C cracking to undesired products. Here, we report that a strong Lewis acidic promoter can overcome the energy barrier for furylmethane hydrodeoxygenation at lower temperature. Furan rings of furylmethanes are first hydrogenated to fully saturated cyclic ethers by a hydrogenation catalyst, which then undergo facile ring opening and deoxygenation by the promoter. A cyclic intermediate between ethereal O and the Lewis acidic metal center, assisted by the triflate ligand of the promoter, is formed in the ring-opening step. Probing the reaction pathway with symmetric single furan ring surrogate molecules suggests that the promoter is necessary for the ring opening. Deoxygenation of ring-opened oxygenates takes place more quickly for single furan ring surrogates than for the multiple furan ring furylmethanes. A maximum 97% jet fuel range alkanes with 93% selectivity in C15H32 and C14H30 is achieved from C15-furylmethane under optimal conditions. The yield and selectivity of alkanes with desired carbon numbers can be tuned using furylmethanes with tailored carbon chains, furan numbers, and a carbon center that minimizes C-C cracking. (Chemical Equation Presented).
Pd/C-catalyzed reactions of HMF: Decarbonylation, hydrogenation, and hydrogenolysis
Mitra, Joyee,Zhou, Xiaoyuan,Rauchfuss, Thomas
supporting information, p. 307 - 313 (2018/04/16)
The diverse reactivity of 5-hydroxymethylfural (HMF) in Pd/C-catalyzed reactions is described with emphasis on the role of additives that affect selectivity. Three broad reactions are examined: decarbonylation, hydrogenation, and hydrogenolysis. Especially striking are the multiple roles of formic acid in hydrogenolysis/hydrogenation and in suppressing decarbonylation, as illustrated by the conversion of HMF to DMF. Hydrogenation of the furan ring is suppressed by CO2 and carboxylic acids. These results emphasize the utility of Pd/C as a convenient catalyst for upgradation of cellulosic biomass.
The photolysis of tetrahydrofuran and of some of its methyl derivatives at 185 nm
Kizilkilic, Nuray,Schuchmann, Heinz-Peter,Sonntag, Clemens Von
, p. 2819 - 2826 (2007/10/02)
The uv photolysis of tetrahydrofuran, 1, 2-methyltetrahydrofuran, 2, cis-2,5-dimethylterahydrofuran, 3, trans-2,5-dimethyltetrahydrofuran, 4, and 2,2,5,5-tetramethyltetrahydrofuran, 5, has been investigated by product analysis in the liquid phase, and quantum yields have been determined.The photolysis of tetrahydrofuran itself was also studied in the gas phase at pressures ranging from 1 to 120 atm (pressurizing gas N2); and very little difference was found between the photolytic behaviour of the vapour at 120 atm and that of the liquid.The major products are in all cases the cyclopropanes and the corresponding carbonyl compounds, as well as the olefinic alcohols and the carbonyl compounds that are isomeric with the starting material.These products are considered to be formed by the two primary processes and . The cyclopropanes formed in reaction retain some excess energy (apparently more then is needed to realize the trimethylene form), and in the photolysis of tetrahydrofuran vaapour the hot cyclopropane rearranges to a considerable extent into propene.The propene to cyclopropane yield ratio falls strongly with increasing pressure, to a value of 0.065 at 120 atm.A similar value is observed in the liquid phase photolysis.The five-membered oxyl alkyl diradical from reaction is the likely intermediate in the cis-trans photoisomerization that is observable with the 2,5-dimethyltetrahydrofurans (Φ(cis -> trans) ca. Φ(trans -> cis) ca. 0.2).The photolysis of these compounds also demonstrates that steric factors have a strong bearing on the course of the reaction, e. g. the quantum yield of methylcyclopropane from the cis compound is 0.22, vs. 0.08 from the trans compound.Molecular hydrogen is produced if the tetrahydrofurans carry hydrogen in α-position.Its production is enhanced if the α-position is shared with a methyl group (1 gives a hydrogen quantum yield of 0.07, 2 of 0.17, 3 of 0.27, 4 of 0.29, and 5 of zero).
