- Hydroisomerization of n-octane on molybdenum based catalyst
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Balanced metal-acid bifunctional MoO2-x(OH)y catalytic system has been prepared. 2-3 monolayers of this phase on the sample surface were obtained following controlled reduction by hydrogen of equivalent 5 monolayers of MoO3/sub
- Al-Kandari,Al-Kharafi,Katrib
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- Preparation method of branched alkane (by machine translation)
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The preparation method of the branched alkane disclosed by the invention comprises, the following steps: under. a protective atmosphere condition, mixing the alkyl alcohol intermediate with an: alkyl metal reagent and an, organic solvent, to obtain the branched alkane, and the method disclosed by, the invention is; simple in synthesis route, high in yield and, high in, purity. (by machine translation)
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- Enhancement of dehydrogenation and hydride transfer by La3+ cations in zeolites during acid catalyzed alkane reactions
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La3+ cations exchanged into ultrastable zeolite Y and zeolite X promote catalytic isomerization, cracking, and alkylation of alkanes. La 3+ cations stabilize the zeolite lattices and, more importantly, polarize alkane C-H bonds to enhance the rates of all three reactions. This unique activity leads to stable cracking and isomerization of reactive alkanes, with polarizable C-H bonds with adjacent tertiary or quaternary carbon atoms below 370 K. The presence of La3+ cations also enhances the zeolite catalyzed hydride transfer rate for isobutane alkylation with 2-butene leading to high catalyst stability. Solid state MAS NMR shows that the strongest positive effects are associated with nonhydroxylated La3+ cations accessible to the reacting molecules in supercages of the zeolite. The high activity is the result of a cooperative polarization of C-H bonds of alkanes by La3+ cations and the presence of stable and strong Bronsted acid sites.
- Schuessler, Florian,Schallmoser, Stefan,Shi, Hui,Haller, Gary L.,Ember, Erika,Lercher, Johannes A.
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p. 1743 - 1752
(2014/06/24)
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- Alkylation of isobutane with 2-butene using ionic liquids as catalyst
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Alkylation of isobutane with 2-butene was performed in a batch reactor using the ionic liquid 1-n-octyl-3-methylimidazolium bromide aluminium chloride ([OMIM]Br-AlCl3) pure, and in a mixture with compounds containing SO3H-groups. The acidity of the ionic liquid (IL) was modified by the addition of acid cation exchange resins (dry or with a small amount of water), or by the addition of a second IL ([(HO3SBu)MIM]HSO4). A high content of the desired trimethylpentanes (up to 64%) and thus a high research octane number (RON up to 96) of the alkylate was obtained. The reusability of the IL systems was studied and compared with a catalyst commercially used at present (H2SO4).
- Bui, Thi Le Thuy,Korth, Wolfgang,Aschauer, Stephan,Jess, Andreas
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scheme or table
p. 1961 - 1967
(2010/06/15)
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- Stages of aging and deactivation of zeolite LaX in isobutane/2-butene alkylation
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The formation of carbonaceous deposits and their effect on aging and deactivation of zeolite LaX during isobutane/2-butene alkylation at 348 K were investigated by stopping the reaction at different times on stream. Four stages of the reaction were identified: (1) stable alkylation, (2) deposit transformation, (3) slow deactivation, and (4) rapid deactivation. Deposits consist mostly of bicyclic compounds and branched carbenium ions, which are formed already at the beginning of the reaction and block Bronsted acid sites. During the deposit transformation, migration of smaller entities toward the pore mouth occurs. These cyclic compounds are further alkylated and lead to pore mouth plugging. In the final stage of rapid deactivation, the catalyst stops producing alkylate, and butene oligomerization is the main reaction leading to olefin desorption and massive deposit formation at the outside of the zeolite particles.
- Sievers, Carsten,Zuazo, Iker,Guzman, Alexander,Olindo, Roberta,Syska, Hitrisia,Lercher, Johannes A.
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p. 315 - 324
(2008/02/13)
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- Alkylation process with recontacting in settler
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A system and/or process for decreasing the level of at least one organic fluoride present in a hydrocarbon phase contained in an alkylation settler by contacting the hydrocarbon phase with an HF containing stream, containing greater than about 80 wt. % and less than about 94 wt. % HF, in the intermediate portion of the settler which contains at least one tray system, with each tray system comprising a perforated tray defining a plurality of perforations and a layer of packing below the perforated tray, are disclosed.
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Page/Page column 3-5
(2008/06/13)
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- Alkene oligomerization process
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A process for oligomerising alkenes having from 3 to 6 carbon atoms which comprises contacting a feedstock comprising a) one or several alkenes having x carbon atoms, and, b) optionally, one or several alkenes having y carbon atoms, x and y being different, with a catalyst containing a zeolite of the MFS structure type, under conditions to obtain selectively oligomeric product containing predominant amounts of certain oligomers. The process is carried out at a temperature comprised between 125 and 175° C. when the feedstock contains only alkenes with 3 carbon atoms and between 140 and 240° C., preferably between 140 and 200° C. when the feedstock contains comprises at least one alkene with 4 or more carbon atoms.
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- Catalyst for acid-catalyzed by hydrocarbon conversions
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A catalyst for acid-catalyzed hydrocarbon conversions, in particular for the alkylation of olefins with isoparaffins, containing a crystalline zeolite with an SiO2—Al2O3 molar ratio of + ions and/or polyvalent cations, the residual concentration of alkali cations amounting to less than around 0.2% by weight, the concentration of the Bronsted centers, determined as a function of the pyridine chemisorbed on the catalyst surface, amounting to around 0.1 to 4 mmol/g of catalyst, and the ratio between the concentration of the acid centers of the Bronsted type (B) and of the Lewis type (L), expressed as the surface ratio of the absorption bands at 1540±5 cm?1 (B) and 1450±5 cm?1 (L) after heating to a temperature of 450° C. amounting to around 1.4 or higher, is described.
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- Formation of trimethylpentanes from isobutane and 1-butene catalyzed by sulfated metal oxides
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The gas-phase alkylation of 1-butene with isobutane was carried out over superacids of sulfated metal oxides, SO4/Fe2O3, SO4/Al2O3, SO4/TiO2, SO4/SnO2, and SO4/ZrO2, at 0 °C; SO4/SnO2 gave the highest yield of trimethylpentane (TMP). It was proved from relationship between the catalyst acidities and the yields of C8 paraffins that the first intermediate species was a t-butyl cation formed on the superacidic Lewis site by abstraction of H- followed by the alkylation with butenes to form TMP.
- Satoh, Kunihiko,Matsuhashi, Hiromi,Arata, Kazushi
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p. 231 - 232
(2007/10/03)
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- MxOy/SO42--/dealuminated zeolite β (M=Ti, Fe) as novel catalysts for alkylation of isobutane with 1-butene
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A new kind of MxOy/SO42--/H-form dealuminated β (DHβ) catalysts prepared here were applied to alkylation of isobutane with 1-butene. The group of MxCy/SO42-/DHβ (M = Ti, Fe) catalysts has a lower rate of deactivation and higher selectivity of this alkylation than other group of Hβ and DHβ. It is proposed that the strong acid sites corresponding to the active sites for this alkylation can be formed by the interaction among DHβ, MxOy, and SO42-.
- Sun, Mingxing,Sun, Jianwei,Li, Quanzhi
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p. 519 - 520
(2007/10/03)
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- Isobutane/2-Butene Alkylation on Ultrastable Y Zeolites: Influence of Zeolite Unite Cell Size
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The alkylation reaction of isobutane with trans-2-butene has been carried out on a series of steam-dealuminated Y zeolites with unit cell sizes ranging from 2.450 to 2.426 nm.A fixed-bed reactor connected to an automatized multiloop sampling system allowed us to make differential product analysis from very short (1 min or less) to longer times on stream.A maximum in the initial 2-butene conversion was found on samples with unit cell sizes between 2.435 and 2.450 nm.However, the TMP/DMH ratio, i.e., the alkylation-to-oligomerization ratio, continuously increased withzeolite unit cell size.The concentration of reactants in the pores, the strength distribution of Broensted acid sites, and the extent of hydrogen transfer reactions, which in turn depend on the framework Si/Al ratio of a given zeolite, were seen to affect activity and product distribution of the catalysts.Finally, the influence of these factors on the aging characteristics of the samples was also discussed.
- Corma, A.,Martinez, A.,Martinez, C.
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p. 185 - 192
(2007/10/02)
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- Isomerisation des radicaux insatures. III. Radicaux α,α,β-, α,β,γ- et α,α,γ-trimethallyles
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α,α,β-, α,β,γ-, and α,α,γ-trimethallyl radicals have been generated in the 147.0-nm gas phase photolysis of 2,3,3-trimethyl-1-butene, 3,4-dimethyl-2-pentene, and 2,4-dimethyl-2-pentene, respectively.Under these conditions, the majority of allyl radicals have an internal energy sufficient for further decomposition: they give rise to the formation of various 1,3-dienes and small amounts of either 1,2- or 2,3-dienes.An internal sigmatropic 1,2-hydrogen atom transfer process is part of the proposed mechanism to explain such products.Moreover, the fragmentation of the trimethyl substituted allyl radicals involves the split of one β(C-C) bond, then one β(C-H), and, to a lesser extent, one central C-CH3 bond.
- Deslauriers, Helene,Collin, Guy J.
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p. 3168 - 3173
(2007/10/02)
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- Two-stage Reduction of Carbon Dioxide by Hydrogen in a Discharge and in the Presence of a Cobalt-Zirconium Catalyst Deposited on Kieselguhr
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The reduction of carbon dioxide by hydrogen has been investigated in a circulation system at a pressure of 1066 GPa, for discharge parameters of 1.9 kV and 150 mA, and at a temperature of 190 to 195 deg C in the catalytic reactor.The overall rate of the reaction was determined by the rate of its catalytic stage; for a contact time between the gas and the catalyst shorter than 3 s, the reaction is displaced towards the formation of paraffinic hydrocarbons.The qualitative and quantitative compositions of the liquid phase depended on its condensation conditions.At positive condensation temperatures, a condensate with relatively heavy components was obtained, up to 60-80percent of which consisted of C9H20-C12 H26 hydrocarbons.Their predominance in the condensate can be explained by secondary reactions on the catalyst involving relatively light saturated hydrocarbons.
- Eremin, E. N.,Rubstsova, E. A.,Ivanter, V. I.,Belova, V. M.
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p. 1722 - 1724
(2007/10/02)
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- The sec-butyl cation; reaction with 2-butene
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The products from the reaction of 2-butene with BF3.CH3OH are olefins in the range C8 to above C20; about 60percent of the product is the normal dimer-trimer-tetramer material but the remaining 40percent is rearranged product.We have identified most of the skeletal structures up to C13 and suggest that the rearrangements are most easily interpreted by postulating that alkyl transfers can occur in the same way as proton transfers.
- Lachance, Pierre,Eastham, Arthur M.
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p. 2621 - 2628
(2007/10/02)
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