- Fabricating nickel phyllosilicate-like nanosheets to prepare a defect-rich catalyst for the one-pot conversion of lignin into hydrocarbons under mild conditions
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The one-pot conversion of lignin biomass into high-grade hydrocarbon biofuels via catalytic hydrodeoxygenation (HDO) holds significant promise for renewable energy. A great challenge for this route involves developing efficient non-noble metal catalysts to obtain a high yield of hydrocarbons under relatively mild conditions. Herein, a high-performance catalyst has been prepared via the in situ reduction of Ni phyllosilicate-like nanosheets (Ni-PS) synthesized by a reduction-oxidation strategy at room temperature. The Ni-PS precursors are partly converted into Ni0 nanoparticles by in situ reduction and the rest remain as supports. The Si-containing supports are found to have strong interactions with the nickel species, hindering the aggregation of Ni0 particles and minimizing the Ni0 particle size. The catalyst contains abundant surface defects, weak Lewis acid sites and highly dispersed Ni0 particles. The catalyst exhibits excellent catalytic activity towards the depolymerization and HDO of the lignin model compound, 2-phenylethyl phenyl ether (PPE), and the enzymatic hydrolysis of lignin under mild conditions, with 98.3% cycloalkane yield for the HDO of PPE under 3 MPa H2 pressure at 160 °C and 40.4% hydrocarbon yield for that of lignin under 3 MPa H2 pressure at 240 °C, and its catalytic activity can compete with reported noble metal catalysts.
- Cao, Meifang,Chen, Bo,He, Chengzhi,Ouyang, Xinping,Qian, Yong,Qiu, Xueqing
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supporting information
p. 846 - 857
(2022/02/09)
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- Hydrogenation of Aromatic Substrates over Dispersed Ni–Mo Sulfide Catalysts in System H2O/CO
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The activity of unsupported Ni–Mo sulfide catalysts formed during the in situ decomposition of oil-soluble precursors (molybdenum hexacarbonyl, nickel naphthenate) in the hydrogenation of aromatic and naphthene-aromatic compounds is studied. The catalysts are characterized by HRTEM and XPS. Catalytic experiments are conducted at temperatures of 340–380°C and an increased pressure of ?? in the presence of water providing the in situ generation of hydrogen via the water-gas shift reaction. The catalysts exhibit a high activity in the hydrogenation of model substrates (methyl- and dimethyl-substituted naphthalenes and anthracene).
- Vutolkina,Makhmutov,Zanina,Maximov,Glotov,Sinikova,Karakhanov
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p. 528 - 534
(2018/07/29)
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- Synthesis of nickel-tungsten sulfide hydrodearomatization catalysts by the decomposition of oil-soluble precursors
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Nickel-tungsten sulfide catalysts for the hydrogenation of aromatic hydrocarbons have been prepared by the in situ decomposition of an oil-soluble tungsten hexacarbonyl precursor in a hydrocarbon feedstock using oil-soluble nickel salt nickel(II) 2-ethylhexanoate as a source of nickel. The in situ synthesized Ni-W-S catalyst has been characterized by X-ray photoelectron spectroscopy. The activity of the resulting catalysts has been studied in the hydrogenation of bicyclic aromatic hydrocarbons and dibenzothiophene conversion in a batch reactor at a temperature of 350°C and a hydrogen pressure of 5.0 MPa. It has been shown that the optimum W: Ni molar ratio is 1: 2. Using the example of the hydrofining of feedstock with high sulfur and aromatics contents, it has been shown that the synthesized catalyst exhibits high activity in the hydrogenation of aromatic hydrocarbons.
- Sizova,Kulikov,Onishchenko,Serdyukov,Maksimov
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- Nickel-tungsten sulfide aromatic hydrocarbon hydrogenation catalysts synthesized in situ in a hydrocarbon medium
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Nickel-tungsten sulfide nanocatalysts for the hydrogenation of aromatic hydrocarbons (HCs) have been prepared by the in situ decomposition of a nickel thiotungstate precursor in a HC feedstock using 1-butyl-1-methylpiperidinium nickel thiotungstate complex [BMPip]2Ni[WS4]2 as the precursor. The in situ synthesized particles have been characterized by X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. It has been shown that the resulting Ni-W-S particles are nanoplates associated in multilayer agglomerates; the average length of the Ni-W-S particles is 6 nm; the average number of layers in the multilayer packaging is three. The catalytic activity of the synthesized catalysts has been studied in the hydrogenation of model mixtures of mono- and bicyclic aromatic HCs and in the conversion of dibenzothiophene in a batch reactor at a temperature of 350°C and a hydrogen pressure of 5.0 MPa. It has been shown that the studied catalysts can be used for the hydrofining of light cycle oil.
- Sizova,Serdyukov,Maksimov
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p. 470 - 480
(2015/11/23)
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- Novel process for preparation of 2,6-dialkyltetralin
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The present invention provides a novel process for highly selective preparation of 2,6-dialkyltetralin, a key precursor for 2,6-dimethylnaphthalene (2,6-DMN), which does not require an extra step for purifying various isomers obtained from the conventional processes for 2,6-DMN. The present invention is advantageous to improve the synthetic yield, to simplify the operation and thus to reduce the production cost, since different starting materials and different pathways are exploited and thus the additional steps are not necessary.
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Page/Page column 10; 11
(2008/06/13)
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- Regioselective synthesis of 2,6-dimethyltetralin: Key precursor to 2,6-dimethylnaphthalene
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A novel regioselective synthesis for 2,6-dimethyltetralin (2,6-DMT), a key precursor to 2,6-dimethylnaphthalene (2,6-DMN), is described. The synthesis comprises the following three steps; the Heck reaction between commercially available 4-bromotoluene and 3-methyl-3-buten-1-ol, the catalytic reduction of the coupling products, and the acid-catalyzed cyclization of the alcohol intermediate. The process has an advantage over the established processes in that 2,6-DMT is obtained as the only isomer, and the isomerization and/or the complicated separation and purification steps are not required to produce pure 2,6-DMT. 2,6-DMN could be also obtained as a major product depending on the cyclization conditions.
- Byung, Hyun Kim,Jong, Gil Lee,Woon, Ki Kim,Young, Gyu Kim
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p. 814 - 817
(2012/12/26)
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- Characterization of New Methyl-Substituted Tetralins and Indans by 13C NMR Spectroscopy
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In order to perform the analysis of the components contained in fossil fuels, carbon assignments of new methylated derivatives of tetralin and indan were obtained.Their chemical shifts were calculated by applying additivity rules. - Keywords: NMR; 13C NMR; tetralins; indans
- Laurens, T.,Schmit-Quiles, F.,Nicole, D.
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p. 523 - 528
(2007/10/02)
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- Protonation of Anion Intermediates in Metal-Ammonia Reduction: 1,2- vs. 1,4-Dihydro Aromatic Products
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The competition between 1,3-cyclohexadienes and 1,4-cyclohexadienes during metal-ammonia reduction has been examined.The former is usually regarded as a thermodynamic product and the latter as a kinetic product although, in actuality, little thermodynamic difference exists between these two isomers. 1,4-Cyclohexadiene was found to undergo proton abstraction with potassium or sodium amide in ammonia at -50 degC but not with lithium amide.Similarly, 1,3-cyclohexadiene reacts only with potassium amide and not with sodium or lithium amide.Consequences relating to the formation of conjugated and nonconjugated products during metal-ammonia reduction are discussed.The reaction of dihydronaphthalenes with various amides is also presented and again there is considerable variation in behavior.This has led to improved synthetic schemes for the selective production of 1,2-dihydro- and 1,4-dihydronaphthalenes as well as tetralins.Finally, protonation sites in pentadienyl type anions are considered.
- Rabideau, Peter W.,Huser, Diane L.
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p. 4266 - 4271
(2007/10/02)
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